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HomeMy WebLinkAboutOrdinances - MC-04-860.A - 12/20/2004 - Chapter 17 Storm Water ManagementOrdinance No. MC-04-860.A
An Ordinance Amending Chapter 17 of the City of McHenry
Municipal Code, By Adding Article U Storm Water Management Ordinance
Within the City of McHenry, Illinois
NOW, THEREFORE, BE IT ORDAINED, by the Mayor and City Council of the City of
McHenry, McHenry County, in the State of Illinois, that the McHenry Municipal Code be amended as
follows:
SECTION 1: A new Chapter 17 Planning and Zoning, Article H, is hereby added to the
McHenry Municipal Code and shall read as follows:
Article H. Storm Water Management Ordinance
SECTION 2: This ordinance shall be in effect upon its passage, approval and publication as
provided by law.
PASSED and APPROVED this 20`s day of December, 2004.
Voting Aye: Bolger, Glab, Low, Murgatroyd, Wimmer, Peterson, Condon
Voting Nay: None
Not Voting: None
Abstaining: None
Absent: None
Signed: t"'4L z -
Mayor
Attest: \ k-x- r
City le
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CITY OF McHENRY
RMWATER. MANAGEMENT
ORDINANCE
For
THE CITY OF MCHENRY, ILLINOIS
January 1, 2005
TABLE OF CONTENTS
I. AUTHORITY AND PURPOSE............................................................................ 1
A. AUTHORITY 1
B. PURPOSE 1
II. DEFINITIONS..................................................................................................... 2
III. GENERAL PROVISIONS AND JURISDICTION ................................................. 11
A. REGULATED DEVELOPMENT
11
B. EXEMPTED DEVELOPMENT
11
C. DEVELOPMENT CLASSIFICATION
12
D. APPROVALS PRIOR TO PERMITTING
13
E. FEES AND APPLICATION REVIEW TIME
13
F. PERMIT TERMS, CONDITIONS AND EXTENSIONS
13
IV.
PERFORMANCE STANDARDS.........................................................................
14
A. GENERAL
14
B. WATER QUALITY PROTECTION
14
C. BUFFER AREAS
15
D. STREAMS & CHANNELS
18
E. SOIL EROSION AND SEDIMENTATION CONTROL
19
F. STORMWATER MANAGEMENT
22
G. FLOODPLAIN MANAGEMENT
30
H. WETLAND PROVISIONS
41
V.
APPLICATION REQUIREMENTS......................................................................
48
VI.
VARIANCES AND APPEALS.............................................................................
54
A. VARIANCES
54
B. APPEALS
55
VII.
INSPECTION AND ACCESS..............................................................................
56
VIII.
VIOLATION AND PENALTY............................................................................
56
IX.
DISCLAIMER OF LIABILITY............................................................................
56
X.
SEVERABILITY.................................................................................................
57
XI.
ABROGATION AND GREATER RESTRICTIONS .............................................
57
XII.
EFFECTIVE DATE.............................................................................................
57
APPENDICES
A.-IDNR/OWR LIST OF PUBLIC WATERS 58
B.-MCHENRY COUNTY WATERSHEDS 59
60
C.-HIGH QUALITY AQUATIC RESOURCES
INTRODUCTION
This Ordinance is an effort to adopt a uniform standard for Watershed Development and is required
pursuant to the adopted McHenry County Comprehensive Stormwater Management Plan. It sets forth
the minimum requirements for watershed development within the City of McHenry. The McHenry
County Stormwater Committee (MCSC) is the corporate enforcement authority for the McHenry
County Stormwater Management Ordinance. Illinois Compiled Statutes Chapter 55, Act 5, Section 5-
1062 (55 ILCS 5/5-1062) states, "The purpose of this Section is to allow management and mitigation of
the effects of urbanization on stormwater drainage... by consolidating the existing stormwater
management framework into a united, countywide structure..." The McHenry County Comprehensive
Stormwater Management Plan, adopted by Ordinance by the McHenry County Board on June 16, 1997
states, "To provide a consistent level of protection and to provide equity throughout the county, a
program for consistent countywide regulation and enforcement should be developed with standards
established at the countywide level and, where appropriate, modified at the watershed level to meet
watershed specific needs. A countywide regulatory program would involve development of a
countywide watershed development ordinance that applies to both incorporated and unincorporated
areas.... the watershed development ordinance should be comprehensive (and) specify standards for
stormwater drainage and detention, Flood -plain management, soil erosion and sedimentation control, and
stream and Wetland protection in a single document." The MCSC has detennined that uniform and
consistent enforcement by municipalities that adopt the standards of the Watershed Development
Ordinance will enhance the effectiveness of the program. The MCSC also understands that local
conditions may sometimes require additional or more restrictive standards to meet the purpose of this
Ordinance. In those instances where the requirements of this Ordinance are not stipulated in a
municipal ordinance or are more restrictive than municipal requirements, this Ordinance shall prevail.
The MCSC may develop a Technical Reference Manual which would be a recommended guide for
users of this Watershed Development Ordinance.
ii
ARTICLE I. AUTHORITY AND PURPOSE
A. AUTHORITY
This Ordinance is enacted pursuant to the powers granted to McHenry County by 55 ILCS 5/5-
1041, 1042, 1049, 1062, 1063, 1104, 12003 & 15001 et seq., (County) and by 65 ILCS 5, Sections
1-2-1, 11-12-12, 11-30-8, 11-30-2, 11-31-2 and 615 ILCS 5, Sections 5 et seq. including 18g (1994
State Bar Edition). The administration and enforcement of this Ordinance shall be performed by:
Certified communities, within their respective jurisdictions; and,
2. The Stormwater Committee, its consultants, agents or employees in both incorporated
and unincorporated areas of McHenry County.
B. PURPOSE
The purpose of this Ordinance is to establish reasonable rules and regulations for development of
watershed integrity in order to:
1. Protect and preserve the quality and environmental values of land and water resources
in the City of McHenry;
2. Encourage development in a manner that promotes the orderly, sustainable and cost-
effective utilization of land and water resources;
3. Assure that development does not increase flood and drainage hazards, create unstable
conditions susceptible to erosion or reduce water quality at or downstream of the site;
4. Minimize the need for additional expenditure of public funds for flood control projects,
repairs to flood damaged public facilities and utilities, and flood related emergency
operations;
5. Prevent additional disruption of governmental services and the economy due to flooding
and drainage problems;
6. Maintain eligibility for the National Flood Insurance Program (NFIP) by equaling or
exceeding Federal Floodplain development regulations (NFIP codified as 44 CFR 59-
79, as amended) thereby making federally subsidized flood insurance available to
residences in participating communities;
7. Protect the hydrologic, hydraulic, water quality and other beneficial functions of
streams, lakes, Wetlands, Floodplains and flood prone areas;
8. Meet the requirements of The Rivers, Lakes and Streams Act, 615 ILCS 5/18g (1994
State Bar Edition) effective November 18, 1987;
9. Prevent additional harm due to periodic flooding including loss of life and property and
threats and inconveniences to public health, safety and welfare; and,
10. Protect buildings and improvements to buildings from flood damage.
ARTICLE H. DEFINITIONS
The following definitions are intended to be used with the Watershed Development Ordinance. Some
definitions may be somewhat different than those used in other municipal ordinances. These
definitions are intended to supersede any other definitions; however, they must be used when
applying the standards of this Ordinance.
adequate downstream stormwater capacity: A downstream channel or stormwater management
system with the ability to store and convey the anticipated 100-year Stormwater runoff without
increasing flood height, flow, or damage to an adjacent or downstream building or structure.
ADID: Wetland Maps generated by an Advanced Identification (ADID) Wetland Study conducted
in McHenry County by the U.S. Army Corps of Engineers and the United States Environmental
Protection Agency in 1997.
applicant: Any person, firm, or governmental agency who owns property or its duly appointed
representative and proposes to develop that property and executes the necessary forms to procure
a permit to obtain authorization for such development from the MCSC or a Certified community.
Upropriate use: The only development within the Regulatory Floodwav that is permissible and will
be considered for permit issuance. The appropriate uses are listed in the Floodwav Standards
section of this Ordinance.
base flood: The flood having a one percent statistical probability of being equaled or exceeded in any
given year. The base flood is also known as the 100-year frequency flood event.
Base Flood Elevation (BFE): The water surface elevation that can be expected during the base flood.
Determination of the BFE at any location is as described in the Floodplain management section of
this Ordinance.
basement: Any area of a building having its floor below grade (below grade level) on all sides.
basin plan: A study and evaluation of an individual drainage basin's stormwater management,
Floodplain management and flood control needs and capabilities.
Best Management Practice (BMP): Land planning and engineered practices designed to reduce soil
erosion, sediment deposition, and water quality impacts, and enhance the environmental quality of
the stormwater runoff.
buffer: An area of predominantly vegetated land located adjacent to channels, Wetlands, lakes or
ponds for the purpose of, but not limited to, reducing contaminants in stormwater that flows to
such areas.
building: A structure that is principally above ground and is enclosed by walls and a roof. The term
includes a gas or liquid storage tank, a manufactured home, mobile home or a prefabricated
building. This term also includes Recreational vehicles and travel trailers installed on a site for more
than 180 consecutive days.
certified community: A community which has petitioned the MCSC and has been found by the MCSC
to be capable of enforcing an ordinance (or ordinances) which contain stormwater and regulatory
Floodplain management rules and regulations which are consistent with or at least as stringent as the
regulations of the McHenry County Watershed Development Ordinance.
channel: Any river, stream, creek, brook, branch, depression, ponded area, lakes, flow path, slough,
ditch, conduit, culvert, gully, ravine, swale, wash, or drainageway, in or into which surface or
groundwater flows, either perennially or intermittently.
channel modification: Alteration of a channel by changing the physical dimensions or materials of its
bed or banks. Channel modification includes damming, rip -rapping or other armoring, widening,
deepening, straightening, relocating and lining and significant removal of bottom or woody
vegetation of the channel. Channel modification does not include the clearing of dead or dying
2
vegetation, debris, or trash from the channel.
community: Any municipality (as defined at Ill. Rev. Stat.,1989, Ch. 24, 1-1-2 { 1 }) or the
unincorporated county within McHenry County acting as a unit of local government.
compensatory storage: An excavated, hydraulically equivalent volume of storage used to offset the loss
of existing flood storage volume when fill, materials or structures are placed within a Regulatory
Floodplain and flood prone area.
Conditional Letter of Map Revision (CLOMR): A letter which indicates that the Federal Emergency
Management Agency will revise the BFE flood insurance rate zones, flood boundaries or
Regulatory atory Floodway as shown on an effective Flood Hazard Boundary & Floodway Map or
Flood Insurance Rate Map, once the as -built grading plans are submitted and approved.
control structure: A structure designed to control the rate of flow.
critical duration: The duration of a storm event that results in the greatest peak runoff.
dam: All obstructions, wall embankments or barriers, together with their abutments and appurtenant
works, if any, constructed for the purpose of storing or diverting water or creating a pool.
Underground water storage tanks are not included.
damage: Reduction of value of a structure or a portion of a structure from any cause.
depressional storage area: A non-riverine depression where stonmwater collects; only regulated when
total storage exceeds 0.75 acre-feet.
design storm: A selected duration stone event, described in terms of the statistical probability of
occurring once within a given number of years, for which stormwater or flood control
improvements are designed and built.
designated Floodway See Re ug_ latory Floodway.
detention facility (detention pond): A man made structure for the temporary storage of Stormwater
runoff with a controlled release rate.
development: Any man-made change to real estate by private or public agencies including:
A. Construction, reconstruction, repair, or placement of a building or any addition to a
building;
B. Installation of a manufactured home on a site, preparation of a site for a manufactured
home, or the placement of a Recreational vehicle on a site for more than 180
consecutive days. If the travel trailer or Recreational vehicle is on the site for less than
180 days, it must be fully licensed and ready for highway use;
C. Drilling, mining, installation of utilities, construction of roads, bridges, or similar
projects;
D. Demolition of a structure or redevelopment of a site;
E. Clearing of land as an adjunct of construction;
F. Construction or erection of levees, walls, fences, dams, or culverts; channel
modification; other activities that might change the direction, height, volume or velocity
of flood or surface water, including extensive removal of vegetation;
G. Rehabilitative maintenance and in -kind replacement of bridges, culverts, dams and
levees located in the Regulatory Floodplain.
Development does not include maintenance of existing buildings and facilities such as resurfacing
of roadways that results in no increase in road elevation or gardening, plowing, and similar
agricultural practices that do not involve filling, grading, or the construction of levees.
drainage area: The land area above a given point that contributes runoff from rainfall and/or snowmelt.
dry detention facility: A dry detention facility is a detention facility designed to drain completely after
temporary storage of stormwater and is normally dry over the majority of its bottom area.
elevation certificates: A form published by the Federal Emergency Management Agency that is used
to certify the lowest floor (including the basement) elevation to which a building has been
constructed.
enforcement officer: The MCSC chief engineer or the Certified community's development regulations
officer.
erosion: The process whereby soil is detached.
fee -in -lieu of on -site detention: A fee assessed to contribute to the cost of the capital improvement
component of a basin plan (i.e. regional detention site(s), flood control projects or improvements to
downstream conveyance capacity) instead of constructing on -site detention.
FEMA: Federal Emergency Management Agency and its regulations codified as 44 CFR 59-79
effective as of October 1, 2001. This incorporation does not include any later editions or
amendments.
flood: A general and temporary condition of partial or complete inundation of normally dry land areas
from overflow of inland or tidal waves, or the unusual and rapid accumulation of runoff of surface
waters from any source.
flood damage: Reduction of value of a structure or a portion of a structure due to temporary, total, or
partial inundation of the structure by overland flood water.
flood frequency: A period of years, based on a statistical analysis, during which a flood of a stated
magnitude may be expected to be equaled or exceeded.
flood fringe: That portion of a Regulatory Floodplain located outside of the Regulatory
Floodwav (when a Floodwav is designated).
Flood Insurance Rate Maps (FIRM): A map prepared by the Federal Emergency Management Agency
or HUD that depicts the Mecial flood hazard area (SFHA) within a community. This map includes
insurance rate zones and Regulatory Floodplains and may or may not depict Remulatory Floodways.
Flood Insurance Study (FIS): A report published by FEMA for a community in conjunction with the
community's Flood Insurance Rate Map. The study contains such background data as the base flood
discharges and water surface elevations that were used to prepare the FIRM.
flood prone area: Any area inundated by the base flood that has a Tributary area greater than 20 acres
and depressional storage areas or is shown on the United States Geologic SurveyHydrologic
Investigation Atlases Flood of Record Maps.
Flood Protection Elevation (FPE): The elevation of the BFE plus 2 feet of freeboard.
Floodplain (re atorv): See also Regulatoa Floodplain. Any land area susceptible to being
inundated by flood waters from any source during the base flood.
floodplain management: An overall program of corrective and preventive measures for avoiding or
reducing future flood damage.
floodproofing: Any combination of structural and non-structural additions, changes or adjustments to
structures or property which reduce or eliminate flood damage to real estate or improved real
property, water and sanitary facilities, structures and their contents.
floodproofing certificate: A form published by the Federal Emergency Management Agency that is
used to certify that a building has been designed and constructed to be structurally dry floodproofed
to the FPE.
Floodwav (regulatory): See also Re lgu atory Floodway. That portion of the Re 1Qu atory Floodplain or
flood prone area adjacent to a stream or channel which is needed to store and convey the existing
0
and anticipated fixture critical duration 100 year frequency flood discharge with no more than a 0.1
foot increase in flood stage due to the loss of flood conveyance or storage, and no more than a 10%
increase in velocities.
freeboard: An increment of height added to the BFE to provide a factor of safety for uncertainties in
calculations, unknown local conditions, wave actions and unpredictable effects such as those caused
by ice or debris jams.
functional assessment: An assessment of a Wetlands flood storage, water quality and other
beneficial functions.
HEC-1: Hydrograph producing hydrologic computer model created by the U.S. Army Corps of
Engineers in the Hydrologic Engineering Center.
HEC-2: Hydraulic step backwater computer model created by the U.S. Army Corps of Engineers in
the Hydrologic Engineering Center.
HEC-RAS: WindowsTM based hydraulic step backwater computer model created by the U.S.
Army Corps of Engineers in the Hydrologic Engineering Center.
High Functional Value Wetland (HFVW): Any Waters of the United States or Isolated Waters of
McHenry County identified as such in the USEPA Advanced Identification Study of McHenry
County (ADID) or any Waters of the United States or Isolated Waters of McHenry County that,
through a functional assessment, meets the criteria defined in that study for determining high
functional value, related specifically to hydrological and water quality functions.
High Quality Aquatic Resources (HQARs): Waters of the United States or Isolated Waters of McHenry
County that are determined to be critical due to their uniqueness, scarcity, function and/or value as
defined in Appendix C of this Ordinance; or meets the criteria defined in Appendix C through a
functional assessment.
High Quality Habitat Sites (HQHS): Waters of the United States or Isolated Waters of McHenry
County that are identified as having high quality wildlife habitat, high floristic quality or high quality
aquatic habitat based on the McHenry County ADID study; or meets the criteria defined in that
study through a functional assessment.
highest adjacent grade: the highest natural elevation of the ground surface prior to construction next to
the proposed walls of a structure.
historic structure: A "historic structure" is any structure that is:
A. Listed individually in the National Register of Historic Places or preliminary
determined by the Secretary of the Interior as meeting the requirements for
individual listing on the National Register;
B. Certified or preliminary determined by the Secretary of the Interior as contributing
to the historic district or a district preliminary determined by the Secretary to qualify
as a registered historic district;
C. Individually listed on the State inventory of historic places by the Illinois Historic
Preservation Agency; or
D. Individually listed on a local inventory of historic places that has been certified by the
Illinois Historic Preservation Agency.
hydraulically equivalent compensatory storage: Compensatory storage not located adjacent to the
development but can be shown by hydrologic and hydraulic analysis to be equivalent to
compensatory storage located adjacent to the floodplain fill.
hydrologic and hydraulic calculations: Engineering analysis which determines expected flood flows
and flood elevations based on land characteristics and rainfall events.
hydrologically disturbed: An area where the land surface has been cleared, grubbed, compacted, or
otherwise modified that changes runoff, volumes, rates, or direction.
IDNR: Illinois Department of Natural Resources
IEPA: Illinois Environmental Protection Agency
5
impervious surface, impervious area: Any hard -surfaced, compacted area that does not readily absorb
or retain water, including but not limited to building roofs, parking and driveway areas, graveled
areas, building pads, sidewalks and paved recreation areas.
Index of Biotic Integrity (IBI): Ecologically based water quality score calculated from multiple types of
fish data utilized to classify streams.
in -kind replacement (culvert): An in -kind culvert replacement has an equivalent cross -sectional area,
shape, roughness coefficient, and inlet and outlet elevations; or the replacement may be shown to
have an equivalent hydraulic capacity using appropriate engineering calculations.
Isolated Waters of McHenry County (IWMC): All waters such as lakes, ponds, streams (including
intermittent streams), farmed wetlands, and wetlands that are not under U. S. Army Corps of
Engineers jurisdiction.
A. The limits of the Isolated Waters of McHepa CgLmy extend to the ordinary high
water mark or the delineated wetland boundary.
B. Isolated Waters of McHenry County exclude permitted excavations created for
such purposes as stormwater conveyance, detention/retention areas constructed as
part of a stormwater management system, recreation, mining, stock watering,
irrigation, settling basins or wastewater treatment systems and roadside ditches.
C. Compensatory wetland mitigation created to meet the requirements of this
Ordinance or Section 404 of the Clean Water Act is not excluded.
inspect: To check or to review a site and as -built plans for compliance with this Ordinance, permitted
plans and permit conditions.
lake: A body of water encompassing an area of two or more acres which retains a normal water level
throughout the year.
Letter of Map Amendment (LOMA): An official determination by FEMA that a specific structure or
parcel of land is above the BFE and was inadvertently included in a Special Flood Hazard Area
provided that the topography has not been altered since the effective date of the first NFIP map. A
LOMA amends the effective Floodplain limits on a Flood Hazard Boundary Map (FHBM) or
Flood Insurance Rate Mau (FIRM). A LOMA does not modify a Floodway limit or the BFE.
Letter of Map Revision (LOMR): Letter issued by FEMA or IDNR/OWR that revises base flood
elevations, flood insurance rate zones, flood boundaries or Regulatory Floodways as shown on an
effective FHBM, FIRM, or Flood Boundary & Floodway Map.
low opening elevation: The elevation at which water could enter a structure through any nonwatertight
opening such as a doorway threshold, a window sill, or a basement window well.
lowest floor: Lowest floor of the lowest enclosed area, including basement.
manufactured home (or mobile home): A structure, transportable in one or more sections, which is
built on a permanent chassis and is designed for use with or without a permanent foundation when
connected to the required utilities. The term manufactured homes also include park trailers,
Recreational vehicles and other similar vehicles installed on site for more than 180 consecutive days.
manufactured home park (mobile home park, trailer park) or subdivision: A parcel (or contiguous
parcels) of land that two or more manufactured homes are harbored, either for free of charge, rent or
for sale.
MCCD: McHenry County Conservation District
MCSC: McHenry County Stormwater management Committee. See "Stormwater Committee"
MCSC Chief En 'sneer : A Registered Professional En f� neer representing the McHenry County
Stormwater Committee as the Enforcement officer of the Watershed Development Ordinance.
3
minimum floor elevation: The lowest elevation for the construction, erection or the placement of any
floor including the basement.
mitigation: Measures taken to offset negative impacts from development activities, such as
construction in Wetlands, Regulatory Floodplain or a flood prone area. Wetland mitigation
typically involves Wetland creation or augmentation. Floodplain and flood prone area mitigation
typically involves compensatory storage and created conveyance capacity.
native vegetation: Generally, all warm season, deep rooted (4' to 15'), grass and forb species believed
to have grown naturally in the pre -settlement landscape of northern Illinois and southern
Wisconsin.
new impervious area: Impervious surface area created after the effective date of this Ordinance.
NGVD: National Geodetic Vertical Datum of 1929. Reference surface set by the National Geodetic
Survey deduced from a Continental adjustment of all existing sea level adjustments in 1929. Mean
Sea Level for 1929 (MSL adj.1929), is an equivalent.
no feasible alternative: A development activity resulting in a direct or indirect site impact that cannot be
avoided by site planning, engineering, or construction alternatives; or development activity that
could not occur at another on -site or off -site location not resulting in site impacts.
non-riverine: Areas not associated with a stream or river such as isolated depressional storage areas,
ponds and lakes.
NRCS: United States Department of Agriculture — Natural Resource Conservation Service
online detention: Any detention facility that has runoff from off -site Tributary area draining through
it.
on -stream detention: Any detention facility that restricts the flow of a stream.
ordinary high water mark: The point on the bank or shore at which the presence and movement of
surface waters are continuous so as to leave a distinctive mark, such as by erosion, destruction or
prevention of terrestrial vegetation, predominance of aquatic vegetation, or other such recognized
characteristics.
overland flow path: The route that stormwater will travel based on the topography of the land.
Overland flow routes are typically viewed without consideration of infiltration, evaporation or
underground drainage structures.
Parcel Identification Number (PIN): Permanent index number used to identify properties.
perennial water resource: a water course which intersects the groundwater table continuously and
flows throughout the year.
permanent erosion control: Permanent features of a development site designed to control soil erosion
and sedimentation.
pond: A body of water of less than two acres which retains a normal water level year round.
public bodies of water: All open public rivers, streams, and lakes specifically designated by
IDNR/OWR. A list of the IDNR/OWR public waters is in the Appendix of this Ordinance.
Generally, public bodies of water are capable of being navigated by watercraft, in whole or in part,
for commercial uses and purposes, or which in their natural condition were capable of being
improved and made navigable, or are connected with or discharge their waters into navigable lakes
or rivers within, or upon, the borders of the State of Illinois, together with all bayous, sloughs,
backwaters, submerged lands and lakes that are open to the main channel or body of water and
directly accessible thereto.
public flood control project: A flood control project which will reduce flood damage to an existing
building or structure and constructed by a governmental entity.
recreational vehicle(RV): Unit primarily designed as temporary living quarters for recreational,
7
camping, or travel use, which either has its own mode of power or is mounted on or drawn by
another vehicle. The "Recreational vehicle" shall include the following types (1) travel trailer, (2)
motor home, (3) pick up coach/truck camper, (4) camping trailer, (5) park trailer.
redevelopment: The process of developing land previous) damped.
Registered Land Surveyor: A surveyor registered in the State of Illinois, under the Illinois Professional
Land Surveyor Act of 1989 225 ILCS 330/1, et seq.(1994 State Bar Edition).
Registered Professional Engineer: An engineer registered in the State of Illinois, under the
Professional Engineering Practice Act of 1989 225 ILCS 325/1, et seq. (1994 State Bar
Edition).
Regulatory Floodplain: A flood prone area is a Re u�ry Floodplain if the area is indicated as a
Si)ecial Flood Hazard Area on the FEMA Flood Insurance Rate Man, and is located with the best
available topography to be inundated by the base flood. A flood prone area that is not shown as a
Special Flood Hazard Area is a ReQul�ry Floodplain if the tributary drainage area is one square
mile or greater.
Regulatory Floodway_ Those portions of the floodplain depicted as floodway on maps
recognized by IDNR-OWR for regulatory purposes.
_rehabilitative maintenance (roadway): Rehabilitative maintenance is repair or maintenance that does
not increase the impervious area and may involve changes to the roadway elevation. Rehabilitative
maintenance does not include changes to roadway elevations within a Regulatory Floodplain or a
flood prone area.
repair, remodeling or maintenance: Development activities which do not result in any changes in the
outside dimensions of a building, any changes to the dimensions of a structure or increase in
impervious area.
retention facility (retention pond): A facility designed to completely retain a specified amount of
stormwater runoff without release except by means of evaporation or infiltration.
riverine: Relating to, formed by, or resembling a stream (including creeks and rivers).
sediment trap: A structure or area that allows for the temporary deposition of sediment materials from
Stormwater runoff.
sedimentation: The processes that deposit soils, sediment, debris, and other materials.
sedimentation or sediment basin: A structure that temporarily detains stormwater to allow most of the
sediment load to settle out into an excavated area at the base of the structure.
silt fence: A temporary barrier of entrenched geotextile fabric (filter fabric) stretched across and
attached to supporting posts used to intercept sediment laden runoff from small drainage areas of
disturbed soil.
Special Flood Hazard Area (SFHA): Any area subject to inundation by the base flood from a river,
creek, stream, or any other identified channel or ponding and shown on the Regilato Floodplain
map as listed in Appendices A or B.
Stormwater Committee (MCSC): The McHenry County Stormwater Committee established and
existing under 55 ILCS 5/51062 (1994 State Bar Edition) for the purposes of developing, revising and
implementing a countywide stormwater management plan and ordinance.
stormwater facility maintenance: Activities required to restore facilities to their original design or
permitted condition.
stormwater management: A set of actions taken to control Stormwater runoff with the objectives of
providing controlled surface drainage, flood control and pollutant reduction in runoff.
stormwater management system: The collection of facilities which define the stormwater
management for a development.
0
stormwater runoff: Precipitation that flows off of permeable and impermeable surfaces.
stream: A course of running water flowing in a channel (includes creeks and rivers).
structure: The results of a man-made change to the land constructed on or below the ground, including
the construction, reconstruction or placement of a building or any addition to a building; installing a
manufactured home on a site; preparing a site for a manufactured home or installing a Recreational
vehicle or travel trailer on a site for more than 180 consecutive days.
substantial improvement: Any repair, reconstruction or improvement of a structure, the cost of which
equals or exceeds 50 percent of the market value of the structure either,
A. Before the improvements or repair is started, or
B. If the structure has been damaged, and is being restored, before the damage
occurred.
For the purposes of this definition, "substantial improvement" is considered to begin when the first
alteration of any wall, ceiling, floor or other structural part of the building commences, whether or
not that alteration affects the external dimensions of the structure. The term does not, however,
include:
A. Any project for improvement of a structure to comply with existing state or local
health, sanitary, or safety code specifications which are solely necessary to assure
safe living conditions or
B. Any alteration of a structure listed on the National Register of Historic Places or a
State Inventory of Historic Places.
sub -watershed: A sub -section of a larger watershed. For the purpose of the ordinance, subwatersheds
would include the drainage areas of named streams within a given watershed, such as Rush,
Lawrence, and Mokeler Creeks within the Piscasaw Watershed.
temporary erosion control: erosion control measures used to control soil erosion and
sedimentation during the construction phase of a development.
TR-20: Technical Release 20 is a hydrograph producing hydrology computer model created by the
Natural Resources Conservation Service (NRCS, formerly SCS).
TR-55: Technical Release 55 (NRCS, June 1986) is a document that presents simplified procedures for
estimating runoff and peak discharges in small watersheds.
transition section: Reaches of the stream where water flows from a narrow cross-section to a wide
cross-section and vice -versa.
tributary area: All of the land surface that contributes runoff to a given point.
tributary stream: A stream that discharges to a larger stream at a point. A stream will typically have
more than one tributary stream.
USACE: United States Army Corps of Engineers
variance: A grant of relief by a community from the terms of this Ordinance.
violation: The failure of a structure or other development subject to the provisions of this Ordinance
to be fully compliant with this Ordinance.
water deyendent facilities: Structures or facilities relating or requiring access to the water or shoreline.
Examples include shoreline protection, pumping and boating facilities and improvements.
watershed: A geographic area within a drainage basin that collects, concentrates and contributes
surface runoff from precipitation to a given point on a waterway. For the purpose of the ordinance,
and as listed in Appendix D, the watersheds found in McHenry County include:
G1
Piscasaw Creek
2. Nippersink Creek
3. Kishwaukee River
4. Upper Fox River
5. Lower Fox River
6. Coon Creek
watershed benefit: A decrease in flood damages to a structure upstream or downstream of the
development site created by installation of the stormwater management system. The benefit
must be beyond the benefit provided by meeting the minimum requirement of the Watershed
Development Ordinance.
watershed development permit: A pen -nit established by this ordinance shall be issued by the MCSC or
certified communities prior to the approval of a building permit. Issuance of a Watershed
Development Permit signifies conformance with provisions of this ordinance.
Waters of the United States (WOTUS): For the purpose of this Ordinance, the term Waters of the
United States refers to those areas that are under the U. S. Army Corps of Engineers (USACE)
regulatory jurisdiction.
wet detention facility (detention pond): A wet detention facility designed to maintain a permanent
pool of water after the temporary storage of Stormwater runoff.
Wetland: A wetland is considered a subset of the definition of the Waters of the United States.
Wetlands are land that is inundated or saturated by surface or ground water at a frequency and
duration sufficient to support, under normal conditions, a prevalence of vegetation adapted for life
in saturated soil conditions (known as hydrophytic vegetation). A wetland is identified based upon
the three attributes: 1) hydrology, 2) soils and 3) vegetation as mandated by the current Federal
wetland determination methodology.
Wetland creation: The introduction of wetlands to an area where none existed historically.
Wetland enhancement: The improvement in wetland functional value of an area currently meeting the
technical definition of a wetland.
Wetland Impact: Isolated Waters of McHenry County or Waters of the U. S. that are hydrologically
disturbed or otherwise adversely affected by flooding, filling, excavation, or drainage which results
from implementation of a development activity, or any development activity within the boundary of
a delineated wetland. For those areas regulated by the U.S. Environmental Protection Agency and
the U.S. Army Corps of Engineers impacts are defined based on 33 CFR Part 230 — Section
404(b)(1) and 33 CFR Parts 320 through 330 as amended.
Wetland Mitigation: Compensation for impacts to wetlands through the restoration, creation,
enhancement, or preservation of wetlands.
Wetland mitigation banking: The process of purchasing "credits" from a financial institution
established by a third party to compensate for permitted losses.
Wetland preservation: The permanent preservation of an area currently meeting the technical
definition of a wetland.
Wetland restoration: The re -introduction of wetlands to an area where wetlands existed historically,
but not prior to the mitigation activity.
Wetland restoration activities: Those restoration activities in Isolated Waters of McHenry County
(IWMC) or adjacent buffer areas determined to be necessary and beneficial to the preservation,
maintenance, or restoration of wetland plant communities, wildlife habitat and ecosystems native to
McHenry County. All excavation and grading quantities under this category are limited to less than
500 square feet of disturbance or 40 cubic yards of material.
[to]
ARTICLE III: GENERAL PROVISIONS AND JURISDICTION
A. Regulated Development
No person, firm, corporation or governmental agency, unless specifically exempted, shall
commence any regulated development on any lot or parcel of land without first obtaining
a Watershed Development Permit from the MCSC or, if applicable, the certified
community. A Watershed Development Permit is required for regulated development,
including finalization of a plat, replat, Planned Development (PD), Planned Unit
Development (PUD) or Manufactured home park site plan. Development that meets any
of the following criteria is considered regulated development:
1. Any development that is located partially or completely in a Re ug_ latorX
Floodway; or,
2. Any development that is located partially or completely in a Regulatory
Floodplain; or
3. Any development that is located partially or completely in a flood prone area; or,
4. Any development that results in an additional 5,000 square feet of impervious
area from the original effective date of this Ordinance; or,
5. Any development which hydrologically disturbs 5,000 square feet or more; or,
6. Any development that results in change in the direction of stormwater runoff
from a site; or,
7. Any land disturbing activity that will affect an area in excess of 500 square feet if
the activity is within 25 feet of a lake, pond, stream, or Wetland; or,
8. Excavation, fill, or any combination thereof that will exceed 100 cubic yards.
9. Any activity resulting in a wetland impact.
B. Exempted Development
1. Development that is part of a court decree or court order is not subject to the
provisions of this ordinance, provided that the court decree or court order
specifically exempts the development from the requirements of this ordinance.
2. Development that is undertaken by a statutorily created entity that possesses the
statutory authority to engage in such activities shall be subject to the provisions
of this ordinance only to the extent of those activities that are outside the limits
of their statutory authority.
3. Landscape or stormwater facility maintenance.
4. Exempted development must meet and obtain the required permits for all
minimum state, federal and local watershed development regulations,
stormwater regulations and Floodplain regulations.
5. A development is not subject to the provisions of this Ordinance if the following
approvals were issued prior to June 1, 2004 provided that the development is
completed within 5 years of the approval:
a. An approved building permit;
b. Any of the following approvals that result in no increase in the
impervious surface area or the development includes an approved
drainage study that is consistent with stormwater and Floodplain
ordinances in effect at the time of the approval by the appropriate
municipality: An approved preliminary or tentative plat; or, An
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annexation agreement; or, Replat of an industrial or commercial
subdivision;
c. In the case of a public road development project:
(1) An awarded construction contract; or,
(2) An approved preliminary engineering plan, including a drainage
component, which is consistent with the regulations in effect at the time of
the approval by the appropriate jurisdictional authority.
d. Existing earth extraction and mining operations shall be exempt beyond
the 5 year period from wetland jurisdiction provided a reclamation plan
is submitted and approved.
6. A Public Road Development that is located in a Re aulatory Floodway and
obtained a permit from the Illinois Department of Transportation / Division of
Highways is exempt from the Floodwav Requirements of this Ordinance.
C. Development Classification
All activities requiring a Watershed Development Permit shall be classified as a minor,
intermediate, major, or public road development. Major development may also be
classified as Floodplain and floodprone development. The definition for each
classification follows:
Minor Development
A minor development is defined as regulated development that:
a. Is not partially or completely located in a depressional storage area, flood
prone area, a Regulatory Flood -plain, or a Regulatory atory Floodwav; or is not
adjacent to a perennial water resource; and,
b. Consists of hydrologic disturbance of less than 20,000 square feet; and,
c. Is not a Public Road Development.
2. Intermediate Development
Intermediate development is defined as regulated development that:
a. Is not partially or completely located in a depressional storage area, flood
prone area, a Regulatory Floodplain; or a ReQulatory Floodwav; and,
b. Consists of hydrologic disturbance between 20,000 square feet and 5
(five) acres; and,
c. Is not a Public Road Development.
Public Road Development
Public Road Development is defined as regulated development that: a. Takes
place in a public right-of-way or part thereof; and,
b. Does not include the construction of a building; and,
c. Consists of culverts, bridges, roadways, sidewalks, bike paths and related
construction.
4. Major Development
A major development is defined as all other development that is not defined by
the above criteria and is not partially or completely located in a depressional
storage area, flood prone area, a Regulatory Flood -plain; or a Regulatory
atory
Floodway.
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Special Flood Hazard Area Development
Special Flood Hazard Area development is defined as regulated development
that:
a. Is partially or completely located in a depressional storage area, flood
prone area, a Regulatory Floodplain, or a Re latory Floodwav: and,
b. Can otherwise be classified as minor, intermediate, or major if area of
development was not in the SFHA.
D. Approval Prior to Permitting
Prior to the issuance of a watershed development permit, the applicant may request a
Conditional Approval. Conditional approval of the Regulatory Floodplain, flood prone
area Regulatory Floodwav delineation, overland flow path, Wetland delineation and the
detention and bypass computations for a development may be granted by the
Enforcement officer. The conditional approval will be based on conformance with the
performance standards, and the submittal of the appropriate application requirements as
listed in this Ordinance. A letter will be sent to the applicant stating the results of the
review and the conditions placed on any approvals.
E. Fees and Application Review Times
1. A review, permit, variance, appeals and site inspection fee schedule in
accordance with the provisions of this ordinance shall be found in section 3.4
Fees and Deposits, in the City of McHenry Subdivision Control and
Development Ordinance.
2. A fee schedule may be developed and implemented by the City of McHenry.
3. Permit applications shall be reviewed within 15 business days of receipt to
determine if the application package is complete. A completed application
package shall be approved or denied within 45 business days of the latest item
submitted.
F. Permit Terms, Conditions and Extensions
1. The term of a Watershed Development Permit shall be from the issue date to the
expiration date which is two years after the issue date.
2. Special Conditions may be added to a permit by the Enforcement officer to
clarify the purpose or authorization granted by the permit. Special conditions
may also specify other restrictions and constraints of the authorized work.
3. If the permitted work is not completed within the term of the permit, the
permittee may request, in writing, an extension of time on the permit. The
Enforcement officer may extend the permit for an additional six months. The
Enforcement officer may amend or add special conditions to the permit at the
time of the extension. Permit Extension requests may not be made prior to 90
days of the permit expiration date.
4. A permit may be terminated during its term or a permit extension may be denied
for, but not limited to, any of the following reasons:
a. Noncompliance with any condition of the permit;
b. The permittee's failure to disclose fully all relevant facts in the
application process or the permittee's misrepresentation of any relevant
facts at any time, or
c. If the authorized work is suspended or abandoned for a period of six
months after the time of commencing the work.
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ARTICLE IV. PERFORMANCE STANDARDS
A. GENERAL
The following performance standards and provisions apply to all regulated
development.
1. The performance standards for all development shall be utilized in site planning and
addressed in the drainage plan component of subdivisions, plats, re -plats,
manufactured home parks, Planned Unit Developments (PUDs) and Planned
Developments (PDs).
2. Subdivisions, plats, replats, manufactured home parks, PUDs and PDs shall:
a. Show the BFE, Regulatory Floodplain or flood prone area limits,
Re lalatory Floodway limits, and perennial water sources or wetlands
within one hundred (100) feet.
b. The plats, replats, manufactured home parks, PUDs, PDs or engineering
plans and studies shall include a signed statement by a Re 'sg� tered
Professional Engineer that accounts for changes in the drainage of surface
waters in accordance with the Plat Act (765 ILCS 205/2).
3. All plats and subdivisions which border on or include public bodies of water as
defined by IDNR/OWR shall be submitted by the applicant to IDNR/OWR for
review and approval.
4. A community will not approve of any PUD, PD, Plat of Subdivision located
outside its corporate limits but within its extraterritorial jurisdiction if such PUD,
PD, or Plat fails to meet the minimum performance standards of this Ordinance.
5. Stormwater management systems for erosion control, sedimentation control and
Stormwater runoff control shall be installed prior to or concurrently with each
phased portion of the development or hydrologically disturbed area. Permits for
buildings within a phase of a development will not be issued until the
appropriate stormwater management systems are fully operational within that
phase.
B. Water Quality Protection.
The standards of this section shall apply to all regulated development.
1. Public Road developments that result in less than 1.5 acres of new impervious
area or less than the rate of 1.5 acres of new impervious area per linear mile shall
meet the water quality and buffer standards to the extent that is practicable due to
limited site conditions as indicated in the countywide permit developed by the
MCSC.
2. Water Quality
The development shall provide water quality treatment for runoff from increased
impervious areas to minimize impacts of post -construction stormwater runoff on
water quality. The site development plan shall include a description of the water
quality protection measures incorporated into the site design. The following
treatment methods shall be evaluated
and incorporated wherever feasible to reduce pollution and stormwater volumes
to the maximum extent practicable:
a. Wet detention facilities (including stormwater wetlands).
b. Sedimentation facilities, (basins and traps),
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c. Infiltration basins.
d. Infilitration strips.
e. Filter strips.
f. Vegetated swales.
Alternative treatment methods may also be used with approval of the
Enforcement officer, and shall be as effective as the above methods.
C. Buffer Areas
Buffer areas shall be required for all areas defined as Waters of the United States
(WOTUS) and Isolated Waters of McHenry County (IWMC). The buffer area for all
WOTUS and IWMC shall extend landward from the ordinary high water mark. The
buffer area for jurisdictional or mitigated wetlands shall extend from the edge of the
delineated wetland. A property may contain a buffer area that originates from WOTUS
or IWMC on another property. Buffer areas are divided into two types, linear buffers
and water body buffers.
l . Linear buffers shall be designated along both sides of all channels meeting the
definition of WOTUS or IWMC.
a. When the channel has a watershed greater than twenty (20) acres, the
minimum buffer shall be thirty (30) feet on each side of the channel.
b. Channels with an Index of Biotic Integrity (IBI) greater than thirty five
(35) shall have a minimum buffer width of one hundred (100) feet on
each side of the channel. (Initial IBI based on MCCD, IDNR, IEPA
data, or site specific assessment, whichever is most current.)
2. Water body buffers shall encompass all non -linear bodies of water meeting the
definition of WOTUS and IWMC including wetlands, lakes, and on nds.
a. For all water bodies with a total surface area greater than onequarter
(0.25) acre but less than one (1) acre, a minimum buffer width of thirty
(30) feet shall be established.
b. For all water bodies with a total surface area greater than one (1) acre
but less than two and one-half (2.5) acres, a minimum buffer width of
forty (40) feet shall be established.
c. For all water bodies with a total surface area greater than two and one-
half (2.5) acres, a minimum buffer width of fifty (50) feet shall
be established.
d. Non -linear water bodies that have been designated as HFVW, HQAR,
or HQHS by the McHenry County ADID procedure shall have a
minimum buffer width of one hundred (100) feet.
3. Additional Buffer Requirements
a. Areas having state or federal threatened and endangered species present
or for Illinois Natural Area Inventory Sites, buffer widths shall be
modified upon approval of the Enforcement Officer, to meet the terms
and conditions specified during consultation with the Illinois
Department of Natural Resources or United States Fish and Wildlife
Service pursuant to state and federal laws and regulations.
b. Buffer Averaging: The buffer width for a development site may be
varied to a minimum of one-half ('/z) of the buffer width required, upon
15
approval of the Enforcement Officer, provided that the total buffer area
required is achieved adjacent to WOTUS or IWMC being buffered.
Buffer averaging may not be utilized where stormwater flows leaving
stormwater management facilities will enter WOTUS or IWMC. The
consultation process of the USACE, IDNR, or U.S. Fish & Wildlife
Service may also override the ability to average buffer areas.
c. All roadside drainage ditches, existing excavated detention facilities (as
of the amended date of this Ordinance), borrow pits, quarries and
improvements to existing public road developments or alignments are
exempt from buffer requirements.
d. Filling WOTUS or IWMC to meet buffer requirements of this
Ordinance or any other applicable regulatory program shall not be
allowed.
4. Buffer areas shall be located within special easements or covenants with
adjacent stormwater facilities, ponds, lakes, or channels that are under the
control of a local unit of government, homeowners association, not for profit
land trust, or other entity acceptable to the Enforcement Officer. Any site
development activity that requires the use of buffers shall:
a. Depict the surveyed location extent of any required buffers on the site
plan.
b. Provide a written characterization of the current condition of the buffer
area(s), including the existing plant community(s) present; a species list of
plant species present characterized individually as native or non-native;
any plant community management requirements to control non-native or
invasive plants species; Soil Erosion and Sediment Control practices
required to control any existing or potential channel, streambank or
shoreline stabilization problems; and provide representative
photographs of the buffer area(s).
c. Include a copy of the recorded conservation easement / covenant language
to be enacted for the buffer area(s). This document shall include the
identification of the entity that will regulate the conservation easement /
covenant.
d. Shall identify the source of any funding mechanism used to implement
future land management activities proposed for the buffer area(s).
5. Buffer areas not occupied by trails, water dependent structures, or other
permissible use, shall be vegetated to 100 percent cover using the following
criteria:
a. Existing communities of desirable, native plant species within proposed
buffer areas shall be protected from any development impacts. Buffer
areas hydrologically disturbed shall be revegetated using the Native
Plant Guide for Streams and Stormwater Facilities in Northeastern Illinois,
(MRCS, et al., as amended) as a minimum standard. Overseeding the
buffer areas required to achieve a permanent 100 percent vegetative cover
can only use non-native species in the one-third (1/3) of the buffer area
furthest away from the ordinary high water mark.
b. Buffer areas shall be designed to withstand erosive forces due to wave
action, streamflow, and changes in water level. Deep-rooted vegetation
and gradual slopes are preferred for shoreline stabilization. Abrupt
structural measures such as seawalls, gabion baskets, concrete blocks,
16
retaining walls, or rip -rap armoring shall only be allowed if no feasible
alternative exists.
c. Mowing of buffer areas will only be allowed if timed to control the seed
production of undesirable species, the growth of invasive, woody species,
or to replicate the benefits of controlled burn management. The cut
surface of any vegetation located within a buffer area can be no less than
eight (8) inches in height above the ground surface, unless a site specific
buffer management plan is approved by the Enforcement Officer.
d. Any maintenance requiring the selective application of herbicides shall
utilize registered herbicides approved for use in or near aquatic
environments in accordance with the manufacturer's guidelines, and shall
only be applied by an herbicide applicator registered with the Illinois
Department of Agriculture.
6. All buffer areas shall be maintained free from development including
disturbance of the soil, dumping or filling, erection of structures and placement of
impervious surfaces except as follows:
a. Passive recreation (e.g., birdwatching„ picnicking).
b. Pedestrian, bicycle, or equestrian trails running parallel to the axis of the
buffer. The trail shall be no wider than twelve (12) feet and the runoff
from such facilities is diverted away from the WOTUS or IWMC or
enters the buffer area as sheet flow. Permeable surfaces are required,
unless site runoff characteristics at specific locations warrant a non -
erodible surface.
c. Pedestrian, bicycle, or equestrian trails running perpendicular to the axis
of the buffer. The trail shall be no wider than six (6) feet. Only one such
access path is allowed every one hundred (100) lineal feet of WOTUS
or IWMC shoreline. Permeable surfaces are required, unless site runoff
characteristics at specific locations warrant a non -erodible surface.
d. Minor structures relating to parks and recreation and accessory
structures that are less than 300 square feet. Except for the case of water
dependent facilities, a minimum buffer width of ten (10) feet shall be
maintained between the proposed structure and the buffered water
body.
e. Utility structures and maintenance of utilities including drainage
facilities.
f. Anchoring and placement of boat docks, ramps and piers.
g. A single sand beach or canoe launch area less than 300 square feet.
h. Unimproved access through buffer areas for maintenance purposes.
i. Water quality management systems designed to: restore wetland
hydrology to adjacent buffer areas, provide water quality filtering,
contribute to aquatic habitat restoration, or other environmental
benefits. A buffer of native vegetation shall be established between
designed normal and high water levels around constructed water quality
treatment basins.
7. The provision of additional buffer width extending outward from the edge of
the stormwater detention area located within a water body buffer may be
required by the Enforcement Officer. Proposed stormwater management
17
features that require a buffer may not be located in such a way that the newly
created buffer area boundaries extend into an adjoining property unless a
written agreement and recorded buffer easement is platted on the adjoining
property prior to construction.
8. In the event the implementation of the buffer requirements of this Ordinance
preclude an otherwise legally buildable parcel from being developed, the
Enforcement Officer may allow the minimal amount of variance from the
buffer requirements in order to restore the parcel to a buildable condition. The
Enforcement Officer may require a "fee-in-lieuof 'payment or other
arrangement to mitigate the environmental impacts of the loss of buffer area.
D. Streams and Channels
If the proposed activity involves a channel modification, it shall be demonstrated
that:
1. There are no practicable alternatives to the activity that would accomplish its
purpose with less impact to the natural conditions of the body of water affected.
Possible alternatives include levees, bank stabilization, flood proofing of existing
structures, removal of structures from the Floodplain, clearing the channel, high
flow channel, or the establishment of a stream side buffer strip or green belt.
Channel modification is acceptable if the purpose is to restore natural
conditions and improve water quality and fish and wildlife habitat;
2. Water quality, habitat, and other natural functions would be improved by the
modification and no significant habitat area may be destroyed, or the impacts are
offset by the replacement of an equivalent degree of natural resource values;
3. Migration of fish and other aquatic organisms will not be adversely impacted,
sediment bedload transport (a critical component of stream geomorphology and
function) will not be impaired, temporary or permanent accumulation of
sediment will not result, and that increases in stream water temperatures will not
occur;
4. The activity has been planned and designed and will be constructed in a way
which will minimize its adverse impacts on the natural conditions of the body of
water affected, consistent with the following criteria:
a. The physical characteristics of the modified channel shall match as
closely as possible those of the existing channel in length, crosssection,
slope and sinuosity. If the existing channel has been previously modified,
restoration of more natural physical conditions should be incorporated
into channel modification design, where practical.
b. Hydraulically effective transitions shall be provided at both the upstream
and downstream ends of the project, designed such that they will prevent
erosion.
c. One-sided construction of a channel shall be used when feasible. For
example, removal of streamside (riparian) vegetation should be limited to
one side of the channel, where possible, to preserve the shading and
stabilization effects of the vegetation.
d. Clearing of stabilization vegetation shall be limited to that which is
essential for construction of the channel.
e. Channel banks shall be constructed with a side slope no steeper than 3:1
horizontal to vertical, wherever practicable.
In
f. All disturbed areas associated with the modifications shall be seeded or
otherwise stabilized as soon as possible upon completion of construction to
control erosion during normal and flood flows. Erosion blanket or an
equivalent material shall be required to stabilize disturbed channel banks
prior to establishment of the vegetative cover. Permanent stabilization
shall be installed as soon as practical but not later than 10 days after the
channel construction is complete.
g. Temporary erosion control shall be installed prior to excavation
associated with a channel modification and must be maintained
throughout the construction period.
h. If the existing channel contains considerable bottom diversity such as
deep pools, riffles, and other similar features, such features shall be
provided in the new channel. Spawning and nesting areas and flow
characteristics compatible with fish habitat shall also be established,
where appropriate.
i. New or relocated channels should be built in the dry and all items of
construction, including vegetation, should be completed prior to diversion
of water into the new channel.
j. There shall be no increases in stage or velocity as the channel enters or
leaves the project or unless necessitated by a public flood conntrol project
or unless such an increase is justified as part of a habitat improvement or
erosion control project.
k. Unless the modification is for a public flood control project, there shall be
no reduction in the volume of floodwater storage outside the Floodwav as
a result of the modification.
1. A channel maintenance easement is required along all channels draining
100 acres or more. The minimum width of the maintenance easement shall
be 25 feet centered on the channel or the distance between the tops of
banks plus 20 feet, whichever is greater.
E. Soil Erosion and Sedimentation Control
Soil erosion and sediment control related measures are required for all regulated
development.
1. Sedimentation and Erosion Control Standards
The following standards must be met by all regulated development:
a. Temporary and permanent soil stabilization measures shall be appropriate
for the site conditions including the time of year, slope and soil type.
b. All areas located downstream from disturbed areas of a development site
shall be protected from potential increase of erosion and sedimentation
resulting from upstream activities.
c. Temporary crossings of waterways shall be constructed of nonerosive
materials and shall be able to withstand the force from the 100-year flood
prior to the commencement of land disturbance.
d. Soil erosion and sediment control features shall be constructed and
functional prior to or concurrently with the start of disturbance.
e. Temporary and permanent stabilization measures shall be initiated as
soon as practicable in portions of the site where construction activities
19
have temporarily or permanently ceased. But, in no case shall these
measures be installed more than 14 days after the construction in the area
temporarily or permanently ceases.
2. Sedimentation and Erosion Control Methods
The following Sedimentation and Erosion Control methods are based on the
anticipated area tributary to the control device. The following does not preclude
the use of other methods of sedimentation and erosion control. However, the use
of other control methods must be approved by the Enforcement officer.
a. Disturbed areas with drainage areas less than 25 feet long parallel to the
flow direction may be protected by a vegetated filter strip.
b. Disturbed areas with drainage areas less than 300 feet long perpendicular
to the flow direction shall at least be protected by a filter barrier
(including reinforced filter fences, vegetated filter strips or equivalent
control measures) to control the sediment load from the disturbed area.
Vegetated filter strips shall have a minimum width of 25 feet and consist
of no less than 75% vegetative cover. This method may only be used if the
runoff from the drainage area is expected to be sheet flow.
c. Disturbed areas, with drainage areas that drain less than 2 acres to a single
point and cannot or are not protected with a filter barrier, shall utilize at
least a sediment trap or equivalent control measure to minimize the
sediment load in the runoff. The sediment trap shall be maintained at a
volume of no less than 134 cubic yards per tributary acre.
d. Disturbed areas with drainage areas more than 2 acres shall drain to a
control measure to remove sediment.
(1) Sediment storage may be incorporated into a proposed wet detention
facility. In this case the sediment storage volume shall equal or exceed
the anticipated sediment load for the duration of the construction.
(2) Sediment basins and sediment traps shall include both detention storage
and sediment storage. The detention storage shall be composed of equal
volumes of "wet" detention storage and "dry' detention storage and each
shall be sized for the 2 year, 24 hour runoff from the site under
maximum runoff conditions during construction. The release rate of the
basin shall be that rate required to achieve minimum average detention
times of at least 10 hours. The elevation of the outlet structure shall be
placed such that it only drains the dry detention storage.
(3) The sediment storage shall be sized to store the estimated sediment load
generated from the site over the duration of the construction period with
a minimum storage equivalent to the volume of sediment generated in
one year. For construction periods exceeding 1 year, the 1-year
sediment load and sediment removal schedule may be substituted. The
anticipated sediment load shall be based on the Revised Universal Soil
Loss Equation.
e. All storm sewer structures that receive runoff during construction shall
include inlet protection to prevent debris and excessive sediment from
entering the storm sewer piping system. These protective measures shall
be properly installed, maintained, and removed in their entirety after the
area tributary to the storm structure is stabilized.
20
f. Discharges from dewatering operations shall enter or be routed to a
sediment and erosion control system or device.
g. All temporary erosion and sediment control measures shall be removed
within 30 days after final site stabilization is achieved or after the
temporary measures are no longer needed. Trapped sediment shall be
properly stabilized or disposed.
h. For major developments, a stabilized construction entrance shall be
located at any point where traffic will be entering or leaving a
construction site, consistent with the current standards set forth in the
Illinois Urban Manual. The stabilized construction entrance shall be
periodically maintained to remove mud and debris and shall consist
of Asphalt or concrete with the quality and subgrade materials to
withstand the construction traffic; An acceptable non -erosive durable
surfacing material; or An appropriate geotextile fabric covered with at
least six inches of clean stone that is at least two inches in diameter.
i. Temporary earthen embankments, grade transitions and berms shall be
constructed with side slopes no steeper than 3H:1 V, unless permanent
structural measures are incorporated into the design. Side slopes below
normal water level shall be no steeper than 2H:1V. More gradual slopes
may be required for soils that easily erode.
3. Maintenance
All temporary measures and permanent erosion and sediment control must be
maintained in an effective working condition as identified by required
inspections. This includes, but is not limited to, the following:
a. Repair, replace or maintain erosion and sediment control structures after a
singular or cumulative rainfall event(s) of 0.5 inches or more over a 24-
hour period.
b. Make adjustments to the sedimentation and erosion control plan and
methods, as needed, to accomplish the intended purpose.
4. Inspections
Plans for upgrading, stripping, excavating, and filling work bearing the stamp
of approval of the Enforcement officer shall be maintained at the site during the
progress of the work. The permitee shall make inspections and maintain on -site
records of such inspections at the intervals specified below.
a. Upon completion of installation of sediment and runoff control measures
(including perimeter controls and diversions), prior to proceeding with any
other earth disturbance or grading.
b. After rough grading.
c. After final grading, and
d. Weekly and after each rainfall event of 0.5 inches or more over a 24-hour
period.
Any necessary repairs to soil erosion and sediment control measures shall be
made and reported in the on -site inspection records. Copies of the inspection
records shall be submitted to the Enforcement officer in a monthly inspection
report.
Notifications
21
To facilitate inspections by the Enforcement officer and to ensure compliance
with the approved erosion and sediment control plan, the grading or building
permit, and this Ordinance, the permitee shall notify the Enforcement officer
within two (2) working days of the completion of the construction stages
specified below:
For Intermediate and Major Developments:
a. Upon completion of installation of sediment and runoff control (controls
and diversions), prior to proceeding with any other earth disturbance or
grading,
b. After stripping and clearing,
c. After rough grading,
d. After final grading,
e. After seeding and landscaping deadlines, and
f. After final stabilization and landscaping, prior to removal of sediment
controls.
If stripping, clearing, grading and/or landscaping are to be done in phases or
areas, the pernutee shall give notice at the completion of each of the above work
stages in each phase or area. For Minor Developments only a, c, and f of the
above requirements shall apply.
6. Special Precautions
a. If at any stage of the grading of any development site the Enforcement
officer determines by inspection that the nature of the site is such that
further work authorized by an existing permit is likely to imperil any
property, public way, stream, lake, Wetland, or drainage structure, the
Enforcement officer may require, as a condition of allowing the work to
be done, that such reasonable special precautions be taken as is considered
advisable to avoid the likelihood of such peril. "Special Precautions" may
include, but shall not be limited to, a more level exposed slope,
construction of additional drainage facilities, berms, terracing,
compaction, or cribbing, installation of plant materials for erosion
control, and
b. Recommendations of a registered soils engineer and/or engineering
geologist which may outline requirements for further work.
c. Where it appears that storm damage may occur due to incomplete
grading at site, work may be stopped and the pemutee required to install
temporary structures or take such other measures as may be required to
protect adjoining property or the public safety. On large developments or
where unusual site conditions prevail, the Enforcement officer may
specify the start and end dates for grading operations or may require that
the operations be conducted in specific stages so as to insure completion of
protective measures or devices prior to the advent of seasonal rains.
F. STORMWATER MANAGEMENT
The provisions of this section apply to intermediate and major developments and the
storm sewers and swales and overland flow paths subsections apply to all regulated
developments. Public Road developments that result in less than 1.5 acres of new
imperviousness or less than the rate of 1.5 acres of new imperviousness per linear mile
22
shall meet the stormwater management standards to the extent that is practicable due to
limited site conditions as indicated in the Countywide permit developed by the MCSC.
The detention facility for the adjacent development shall include the public roadway
improvements that are required as part of the development.
1. An applicant shall choose a strategy to meet the release rate requirements that
minin- zes the increase in runoff volumes and rates from the development and
addresses the water quality treatment requirements in Article V.B., of this
Ordinance. The applicant shall use appropriate best management practices as
presented in the Technical Reference Manual and the following hierarchy in
preparing a drainage plan suitable for the development site:
a. Preservation of natural resource features of the development site (e.g.
floodplains, wetlands, Isolated Waters of McHenry County, prairies and
woodlands);
b. Preservation of the existing natural streams, channels and drainageways;
c. Minimizing impervious surfaces created at the site (e.g. narrowing road
width, minimizing driveway length and width, clustering homes and
shared driveways);
d. The use of natural landscaping as an alternative to turf grass;
e. The use of open vegetated channels, filter strips, and infiltration to
convey, filter, and infiltrate stormwater runoff;
f. Preservation of the natural infiltration and storage characteristics of the
site (e.g. disconnection of impervious cover and on -lot bioretention
facilities);
g. Structural measures that provide water quality and quantity control;
h. Structural measures that provide only quantity control and conveyance.
2. Runoff Calculations
These runoff calculation standards may be superseded by the runoff calculation
standards in the Floodplain Management section of this Ordinance.
a. TR-20, HEC-1, HEC-HMS, or an MCSC approved hydrograph
producing hydrologic model shall be used for the following:
(1) To determine peak runoff rates for area with a drainage area of 100
acres or greater; or,(2) To confirm the stormwater storage requirements
for stormwater facilities that have a drainage area of 10 acres or more.
b. TR-55 may be used to calculate discharges for areas that drain less than
100 acres. TR-55 with a pond routing program such as TR-20 or HEC-1
may be used to confirm stormwater storage requirements.
c. The Rational Method may be used to calculate discharges for drainage
areas of less than 20 acres and storm sewer design. The Rational Method or
the Modified Rational Formula shall not be used to determine detention
storage requirements.
d. Sectional rainfall data as presented in the Illinois State Water Survey
Bulletin 70 shall be used for all hydrologic analysis.
e. Rainfall should be distributed using the appropriate Huff rainfall
distribution except that SCS Type II distribution is acceptable with TR-55.
23
f. Runoff calculations for all offsite tributary land shall be based on either
the anticipated future land use conditions or existing land use conditions.
Anticipated future land use conditions will be based on future land use
and existing offsite storage facilities. Existing land use conditions will be
based on existing land use and existing offsite storage facilities.
g. Peak runoff rates shall be based on critical storms for drainage areas of
100 acres or more. For drainage areas less than 100 acres, peak run off rates
shall be based on either the critical duration storm, or the 24 hour NRCS
(SCS) Type II distribution.
3. Release Rates and Discharges
a. Release rates shall not exceed 0.04 cubic feet per second per acre for the 2-
year, 24-hour storm event nor 0.15 cubic feet per second per acre for the
100-year, 24-hour storm event. The release rate requirement shall apply
to the hydrologically disturbed area of the ownership parcel.
b. If the MCSC adopts a Basin plan that includes more restrictive release
rates than the rates indicated above, those release rates in the adopted
Basin plan shall prevail.
c. Release rates shall not exceed the existing conditions peak discharge from
the 2 year or 100 year storm if the existing release rates are less than the
rates as indicated in Section V.F.3.a and there is inadequate downstream
stormwater capacity for the release rates specified in Section V.F.3.a.
d. Where a single pipe outlet or orifice plate is to be used to control
discharge, it shall have a minimum diameter of four (4) inches. If this
minimum size permits release rates greater than those specified in this
Section, alternative outlet designs shall be utilized which incorporate self-
cleaning flow restrictors.
e. All concentrated stormwater discharges leaving a site must be conveyed
into an existing channel, storm sewer, or overland flow path with
adequate downstream stormwater capacity and will not result in increased
erosion, flood damage or other drainage hazard.
f. The design of stormwater management systems shall not result in any
inter -basin transfer of water unless no reasonable alternative exists as
determined by the Enforcement officer.
g. Compensatory storage, that is required due to the proposed filling of a
depressional storage area, shall be maintained on -site or added to the
required on -site detention volume. This combined volume shall be
released at a rate no greater than the release rates specified in Article
V.F.3.a.
h. Concentrated stormwater discharge shall not be connected to an existing
field tile or any other drainage tile system unless the applicant submits a
maintenance agreement, recorded easement and a report that indicates the
existing system from the connections to the discharge point in an open
channel has adequate hydraulic capacity and structural integrity. The
recorded easement and maintenance agreement must extend from the
connection to the discharge point in an open channel. The recorded
easement and maintenance agreement must be approved by the MCSC
Chief Engineer prior to issuance of a Watershed Development Permit.
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4. Detention Facilities
a. Detention will only be required for projects that involve the creation of
20,000 square feet of new impervious area.
b. All stormwater infiltration, retention and detention facilities shall be
provided with an emergency overflow structure or path capable of
passing the inflow from a critical duration 100 year storm without
damages to any structures on adjacent property. The emergency overflow
structure shall have an invert elevation at or above the design high water
elevation.
c. Single pipe outlets shall have a minimum inside diameter of 12 inches.
Control devices such as perforated risers, weirs and orifices may be used
to meet restricted release rates. The outlet pipe and control devices shall be
designed to minimize maintenance requirements and prevent tampering.
d. In no case shall the restricted release rate exceed that described in the
Release Rates and Discharge section for the entire Tribu area of the
facility.
e. Online detention facilities shall meet the following requirements:
(1) Online detention shall not be permissible on perennial streams. This
shall include all streams exhibiting year round flow and depicted as a
solid blue line on the USGS 7.5 minute quadrangle maps.
(2) Online detention shall not be permissible with an off -site to on -site
drainage area ratio greater than 10:1 except for development providing
a Watershed benefit.
(3) Online detention shall not be permissible if the drainage area is greater
than 640 acres except for development that provides a Watershed benefit.
(4) The release rate shall be 0.04 cfs per acre of the total Tributary area (on -
site and off -site) at the elevation created by impoundment of the on -site 2
year storm volume and 0.15 cfs per acre at the elevation created by
impoundment of the on -site 100 year storm volume. This release rate
calculation shall be used unless other on -site or off -site conditions
warrant further analysis and modifications from this standard. The on -
site storm volumes (2 year and 100 year) shall be calculated using the
critical duration storm and the on -site drainage area, assuming no
offsite flow.
(5) A stable overflow structure capable of passing the 100year, critical
duration offsite flow rate shall be provided. The offsite flow rates shall
be calculated assuming existing conditions or future conditions with
detention required per this ordinance, whichever is greater.
(6) Modifications to the intermittent stream to accommodate on-line
detention shall meet the standards of Article V.D.
(7) The water quality protection standards in Article V.B.I shall be met
prior to discharge to on-line detention facilities.
(8) All permitting requirements of USACE and IDNR / OWR.
(9) On-line detention volume shall be in addition to the existing floodplain
storage
25
f. Inlet and Outlet Orientation: To the extent feasible, the distance between
detention inlets and outlets should be maximized. If possible, they should
be at opposite ends of the basin. There shall be no low flow bypass
between the inlet and outlet and paved low flow channels shall not be
used.
g. Side slopes: The side slopes at the shoreline of wet and Wetland detention
basins (from at least six inches below to at least six inches above normal
water level) shall be no steeper than 10:1 to prevent shoreline erosion due
to wave action and fluctuating water levels. Above shoreline areas, or in
dry bottom portions, the maximum side slope shall be 4:1.
h. Safety shelf: A safety shelf with a minimum eight foot width shall be
constructed no more than one foot below normal water level.
i. Bank Erosion Protection: The shoreline of wet detention basins shall be
protected from erosion. The preferred method of shoreline stabilization is
native Wetland and wet prairie vegetation with deep root system to
stabilize the soils.
j. Off -site flow may be diverted around a proposed detention facility
provided that the other applicable standards regarding Re lgu atory
Floodplain or flood prone areas are met.
k. Any development involving the construction, modification or removal of a
dam as defined in 92 Ill. Adm. Code 702 (Rules for Construction of Dams
shall obtain an IDNR/OWR Dam Safety permit or a letter stating no
permit is required prior to the start of such activity.
1. Berms for stormwater infiltration, retention and detention facilities shall
not be constructed in a Re ug latory Floodplain or a flood prone area
unless approved by the MCSC chief engineer in a non -certified
community or the Enforcement officer in a certified community. If a
berm is constructed in a Regulatory Floodplain or a flood prone area, the
development must meet the requirements of the Floodplain management
section of this Ordinance. The volume inside the stormwater facility shall
not be considered available for compensatory storage unless the volume is
in addition to the required detention volume and is available at the
appropriate storage interval.
m. If the depressional storage volume is filled or drained, the volume must
either be replaced as a depression or the volume can be added to the 2-year
detention storage volume. Existing depressional storage volume shall be
no more than the volume at an elevation 0.5 feet above the overflow
elevation or the volume during the critical duration storm event. For the
purpose of establishing the existing depressional storage volume the
critical duration shall not exceed the 240-hour duration.
n. Stormwater detention volume verification shall be required for detention
facilities that either have a Tributary area of 10 acres or more or the
required release rate is different than that on the MCSC approved
Detention Volume vs. Percent Impervious Chart.
o. The MCSC approved Detention Volume vs. Percent Impervious Chart
may be used for stormwater detention facilities that have a Tributar,area
less than 10 acres provided that required release rates are the same as those
shown on the chart.
26
p. Detention facilities may connect to existing drain tiles or storm sewers
only if the applicant submits a maintenance agreement, recorded easement
and a report that indicates the existing system from the connection to the
discharge point in an open channel has adequate hydraulic capacity and
structural integrity. The recorded easement and maintenance agreement
must extend from the connection to the discharge point in an open
channel. The recorded easement and maintenance agreement must be
approved by the MCSC Engineer prior to issuance of a Watershed
Development Permit.
q. Infiltration basins may be used as detention facilities subject to the
following:
(1) The basin must be designed to dewater within 72 hours
following the end of the critical duration storm.
(2) The underlying soils must have an infiltration rate of at least 0.5 inches
per hour as determined by a geotechnical engineer.
(3) Pretreatment facilities must be provided to prevent obstruction.
(4) The basin must be at least 100 feet away from any water supply wells.
(5) Runoff from the areas that have water quality concerns or subject to
frequent winter deicing must not be routed to the infiltration facility.
(6) The bottom of the infiltration basin must be at least four (4) feet above
the seasonal high groundwater elevation.
5. Drainage/Detention into Wetlands
Drainage into, or detention within, Wetlands classified as Waters of the United
States (WOTUS) may be allowed, subject to obtaining regulatory permitting or
written clearance from U.S. Army Corps of Engineers.
Drainage into Isolated Wetlands of McHenry County (IWMC) is allowed,
provided no wetland impacts result from complying with other stormwater
conveyance, retention/detention, or water quality requirements of this Ordinance
and the IWMC is not designated as HQAR, HQHS, or HFVW.
The provision of stormwater detention capacity within Isolated Wetlands of
McHenry County is allowed, but is considered a wetland impact, subject to the
wetland mitigation requirements of this Ordinance.
In addition to the other requirements of this ordinance, the following
requirements shall be met for all developments whose drainage flows into Waters
of the United States (WOTUS) or Isolated Wetlands of McHenry Coun
(IWMC).
a. The water quality standards of Article V.B.
b. The 2 year discharge rate to the WOTUS or IWMC shall not exceed 0.04
cfs/acre (the 2-year detention volume must be provided upstream of the
WOTUS or IWMC .
c. The existing depressional storage of the WOTUS or IWMC shall be
maintained and the volume of detention storage provided to meet the
discharge rate requirements shall be in addition to the existing
depressional storage.
27
d. The site drainage patterns shall not be altered to substantially decrease or
increase the area tributary to the WOTUS or IWMC.
6. Non -detention Impact Fee in Lieu of On -Site Detention
a. The MCSC may require, or the applicant may request, the payment of a
non -detention impact fee in lieu of on -site detention to fulfill all or part of
on -site detention requirements for a development. The MCSC will request
a non -detention impact fee in lieu of onsite detention or will reject its use
within 21 days of receipt of a complete request including engineering
studies and an estimated fee.
b. Non -detention impact fees in lieu of on -site detention shall be based on
the approved MCSC rates. The MCSC shall establish a fee rate for both
impervious and pervious areas based on the following:
(1) A fee that is computed for each acre-foot of storage that is not being
provided on site, or,
(2) The estimated cost, as approved by the MCSC, of the applicant's
proposed and approved on -site detention, including land costs, if the
MCSC would require or allow its construction.
c. A fund will be maintained by the MCSC for each major watershed for
the purpose of identifying and controlling all revenues derived from
nondetention impact fees in lieu of on -site detention. All nondetention
impact fees received from each watershed shall be deposited in the
respective major watershed fund. Disbursements for costs to mitigate
stormwater and Floodplain impacts shall be made from the appropriate
major watershed fund.
d. Criteria
The following requirements must be met before a nondetention impact
fee in lieu of on -site detention will be utilized for a development that
results in 20,000 square feet or greater of hydrologically disturbed area:
(a) The downstream stormwater management system has adequate
downstream stormwater capacity; and
(b) The elimination of on -site detention facilities is consistent with an.
approved MCSC Master Plan or an adopted Basin plan or the
applicant's engineer and the MCSC chief engine determine that such
an exemption will not result in an increased erosion, flood or drainage
hazard.
7. Storm Sewers and Swales
a. The 10-year critical duration storm shall be used as a minimum for the
design of storm sewers, minor swales, and appurtenances. Storm sewer
design shall be based on full flow conditions; otherwise, hydraulic grade
line calculations shall be performed that demonstrate that rims are not
inundated at the design storm.
b. Storm sewers and swales shall not connect to sanitary sewers.
c. Storm sewers and swales may connect to existing drain tiles or storm
sewers only if the applicant submits a maintenance agreement, recorded
easements and a report that indicates the existing system from the
W.
connection to the discharge point in an open channel has adequate
hydraulic capacity and structural integrity. The recorded easement and
maintenance agreement must extend from the connection to the discharge
point in an open channel. The recorded easement and maintenance
agreement must be approved by the MCSC chief engine prior to
issuance of a Watershed Development Permit.
d. Field tile systems disturbed during development must be reconnected by
those responsible for their disturbance unless the approved drainage plan
includes provisions for the system. All abandoned field tiles shall be
removed in their entirety.
e. All storm sewers and minor swales shall be located in a public road right-
of-way, a maintenance easement or a covenant running with the land of
sufficient size to maintain and re -construct the conveyance system.
f. Design practices intended to minimize erosion shall be provided at
the inlets and outlets for all pipes, transitions and channels.
g. The minimum storm sewer size shall be 12 inches for the first pipe reach
and 12 inches for subsequent reaches unless approved by the
Enforcement officer.
h. The minimum design velocity for a storm sewer shall be 2.5 feet per
second. The maximum design velocity for a storm sewer shall be 8.0 feet
per second.
8. Overland flow paths
a. All areas of development must provide an overland flow path that will
pass the 100-year flood flow (including offsite tributary flow) without
damage to structures or property. If the drainage area is less than 20 acres,
the storm sewer pipe and inlet may be sized for the 100-year flow instead
of providing an overland flow path.
b. The overland flow path shall be protected from any development, such as
fencing, landscaping, storage sheds, or other obstructions which could
impair its function by impeding flow. This protection shall be established
through a properly recorded covenant running with the land restricting the
use of the overland flow path area.
c. Structures adjacent to an overland flow path shall have the following
lowest opening elevation for the following tributary areas:
(1) 0.5 (one-half) foot above the overflow elevation for Tributary areas of
20 acres or less.
(2) 1 (one) foot above the overflow elevation for Tributary areas between
20 acres and 100 acres.
(3) At or above the FPE for Tributary areas of 100 acres or greater.
9. For all Intermediate and Major Developments, a plan for the ongoing
maintenance of all stormwater management system components including
Wetlands and buffer areas is required prior to plan approval. The plan shall
include:
a. Maintenance tasks.
b. The party responsible for performing the maintenance tasks.
29
c. A description of all permanent public or private access maintenance
easements and overland flow paths, and compensatory storage areas.
d. A description of dedicated sources of funding for the required
maintenance.
G. FLOODPLAIN MANAGEMENT
This Section applies to all development located in a flood prone area, depressional
storage area, Regulatory Floodplain and Regulatory Floodway.
Regulatory Floodplain, Base Flood Elevation (BFE) and Regulato Floodwav
Locations
a. The Regulatory Floodplain or a flood prone area is the land area with the
ground elevation at or below the BFE. The BFE should be delineated
onto the site topography to establish the Re lgu atory Floodplain or the
flood prone area limits.
b. The BFE shall be as noted below;
(1) The elevation as indicated in the flood profiles in the FEMA Flood
Insurance Studies listed in Appendix A, or
(2) In the case of FEMA delineated "AH Zones" the elevation noted on the
map shall be the BFE. In the case of FEMA delineated "AO Zones" the
BFE shall be the depth number shown on the map added to the highest
adjacent grade, or at least two feet above the highest adjacent grade if no
depth number is provided, or
(3) When no BFE information exists, the BFE shall be determined by a
Registered Professional Engineer using appropriate hydrologic and
hydraulic models as follows:
Hydroloyic models:
Drainage area less than 20 acres: HEC-HMS, TR-20, HEC-1, TR-55, rational
formula. Drainage area 20 acres or more and less than 100 acres: HEC-
HMS, TR-20, HEC-1, TR-55. Drainage area 100 acres or more: HEC-HMS,
TR-20, HEC-1.
Hv&aulic models: HEC-2, HEC-RAS
Or a technique approved by the MCSC and the IDNR/OWR.
(a) The BFE determination shall be submitted to MCSC and approved
prior to issuance of a Watershed Development Permit.
(b) For non-riverine, depressional floodplain with less than 20 acres of
tributary drainage area, the above analysis shall be submitted to the
Enforcement Officer in certified communities to review and approve.
(c.) Where a channel has a tributary drainage area of 640 acres or more, the
above analyses shall be submitted to MCSC for approval and
forwarded to the IDNR/OWR for concurrent approval.
(d) For a non-riverine Reg—ulatga Floodplain or a flood prone area, the
historic flood of record plus three feet may be used for the BFE instead
of performing a detailed hydrologic and hydraulic study.
c. The location of the Regulatory Floodwav boundary shall be scaled onto
C
the site plan using references common to both the map and the plan
(typically the centerlines of adjacent roadways). Where an interpretation
is needed to determine the exact location of the Regulatory Floodway
boundary, IDNR/OWR should be contacted. Note: If an area is located
in the Re ug_ latory FloodwaX that is higher than the BFE, that area is
subject to the Floodwav Standards, including the appropriate use criteria,
of this section until such time as a Letter of Map Amendment (LOMA) is
received from the IDNR/OWR and FEMA.
d. Nothing contained herein shall prohibit the application of these
regulations to land that can be demonstrated by a topographic survey to
lie within any Regulatory Floodplain or a flood prone area. Conversely,
any lands (except for those located in a Re ulatory Floodwav) that can
be demonstrated by a topographic survey certified by a Re 'sgi tered
Professional Engineer or Registered Land Surveyor to lie beyond the
Regulatory Floodplain or a flood prone area, and show to the satisfaction
of the Enforcement officer, to have been higher than the BFE as of the
effective date of the first Floodplain mapping denoting the site to be in a
Special Flood Hazard Area, shall not be subject to the Floodplain
management regulations except for the flood protection standards in
V.G.4.
2. The general performance standards of this section applicable to all development
in a Regulatory Floodplain, and flood prone areas shall apply except when
superseded by more stringent requirements in the subsequent sections.
a. No development shall be allowed in the RegulatoW Floodplain or
floodprone areas that singularly or cumulatively creates a damaging or
potentially damaging increase in flood heights or velocity or threat to
public health, safety and welfare.
b. For all projects involving a channel modification, fill, stream
maintenance, or a levee, the flood conveyance of the Floodwav and
storage capacity of the Regulatory Floodplain and flood prone areas shall
not be reduced except for public flood control projects.
c. If the proposed development would result in a change in the Regulatga
Floodplain or BFE as indicated in Appendix A, the applicant shall obtain
a Letter of Map Revision (LOMR) from FEMA. No buildings may be
built in the existing or proposed Regulatory Floodplain until the LOMR
is obtained from FEMA unless the building meets all the Building
Protection Standards. Proposed changes to the Regulatory Floodplaim
Re ugulatory Floodwav delineation and the BFE must be submitted to
MCSC. IDNR/OWR concurrence is required for changes to the published
BFE, Regulatory Floodway delineation and LOMR requests for channels
that drain more than one square mile.
d. If the development is located in a public body of water, as defined by
IDNR/OWR (Appendix C), a permit must also be received from
IDNR/OWR.
e. Any work involving construction, modification or removal of a dam shall
obtain an IDNR/OWR Dam Safety Permit or letter indicating a permit is
not required prior to the start of development activity.
f. For public flood control projects, the Floodplain mana eg ment standards
will be considered met if the applicant can demonstrate to IDNR/OWR
31
and MCSC that each of the following conditions are met:
(1) Demonstrate by hydraulic and hydrologic modeling that the proposed
project will not singularly or cumulatively result in increased flood
heights outside the project right-of-way or any increases will be
contained in easements for all flood events up to and including the base
flood event.
(2) Demonstrate that the project will be operated and maintained by a
public agency.
(3) Demonstrate that the project will reduce flood damage to an existing
building or structure. These standards do not preclude the design,
engineering, construction or financing, in whole or in part of a public
flood control project by persons or parties who are not public agencies.
3. Public Health Protection Standards
a. New and replacement water supply systems, wells and sanitary sewer lines
may be permitted if all manholes or other aboveground openings located
below the FPE are watertight.
b. New on -site waste disposal systems, such as septic systems, shall not be
constructed within the Regulatory Floodplain.
c. New, substantially improved or replacement wastewater treatment plants
shall have watertight openings for those openings located below the FPE.
Such facilities should be located to avoid impairment to the facility or
contamination of floodwaters during the base flood.
d. No development in the SFHA shall include locating or storing
chemicals, explosives, fertilizers, flammable liquids, pollutants, or
other hazardous or toxic materials below the FPE
4. Building Protection Standards
The Building Protection Standards apply to all buildings located in a flood prone
area that has at least 100 acres Tributary area or the Regulatory Floodplain.
however, it should be noted that most new and replacement buildings are not
appropriate uses of the Regulatory Floodway.
a. The lowest floor including basements of all new residential structures,
substantially improved structures, and additions shall be elevated up to at
least the FPE. An attached garage must be elevated up to at least'h of one
foot above the BFE.
(1) If placed on fill, the top of the fill for the residential structure shall be
above the FPE and shall not adversely affect the flow. The top of fill
for an attached garage shall be at least '/z of one foot above the BFE.
The fill shall be placed at that elevation for a distance of ten feet out from
the building unless the building design is certified by a registered
structural engineer to be protected from damages due to hydrostatic
pressures. Additionally, the fill shall not settle below the FPE for the
residential structure and not below '/Z of one foot above the BFE for an
attached garage, and shall be adequately protected against erosion, scour
and differential settlement.
(2) If elevated by means of walls, pilings, or other foundation, the building's
32
supporting structure must be permanently open to flood waters and not
subject to damage by hydrostatic pressures of the base flood. The
permanent openings shall be no more than one foot above existing
grade, and consist of a minimum of two openings. The openings must
have a total net area of not less than one square inch for every one square
foot of enclosed area subject to flooding below the BFE. The lowest
inside grade must not be below the lowest existing and proposed outside
grade adjacent to the structure. The foundation and supporting members
shall be anchored and aligned in relation to flood flows and adjoining
structures so as to minimize exposure to hydrodynamic forces such as
current, waves, ice and floating debris. All areas below the FPE shall
be constructed of materials resistant to flood damage. The lowest floor
(including basement) for the residential structure and all electrical,
mechanical, heating, ventilating, plumbing, and air conditioning
equipment and utility meters shall be located at or above the FPE.
Water and sewer pipes, electrical and telephone lines, submersible
pumps and other waterproofed service facilities may be located below
the FPE. No area less than'`/2 foot above the BFE shall be used for
storage of items or materials.
b. A non-residential building may be structurally dry floodproofed (in lieu
of elevation) provided that a Registered Professional Engineer or
structural engineer shall certify that the building has been structurally dry
floodproofed below the FPE and the structure and the attendant utility
facilities are watertight and capable of resisting the effects of the base
flood. The building shall not be used for human habitation. All areas
below the base FPE shall be constructed with waterproof material.
Structures located in a Regulatory Flood wav shall meet the Floodwav
Standards. The structure shall be anchored to prevent flotation and
movement. The building design shall take into account flood velocities,
duration, rate of rise, hydrostatic and hydrodynamic forces, the effects of
buoyancy and impacts from debris or ice. Floodproofing measures shall
be operable without human intervention and without an outside source of
electricity. (Levees, berms, floodwalls and similar works are not
considered floodproofing for the purpose of this subsection.)
c. Manufactured homes and Recreational vehicles to be installed on a site
for more than 180 days, shall be elevated to or above the FPE and shall
be anchored to resist flotation, collapse, or lateral movement by being tied
down in accordance with the Rules and Regulations for the Illinois
Mobile home Tie -Down Act issued pursuant to 77 Ill. Adm. Code 870.
d. Accessory structures, which are not substantial improvements on an
existing single-family platted lot, may be constructed with the lowest floor
below the FPE in accordance with the following criteria:
(1) The building shall not be used for human habitation
(2) All areas below the base FPE shall be constructed with waterproof
materials. Structures located in the Regulatory Floodwav shall meet
floodway standards
(3) The structure shall be anchored to prevent floatation and movement
(4) Service facilities such as electrical and heating equipment shall be
33
elevated or floodproofed to the FPE.
(5) The building shall be used only for the storage of vehicles or tools and
may not contain other rooms, workshops, greenhouses or similar uses.
(6) The structure shall be designed to allow automatic entry and exit of
floodwaters.
Accessory structures that do not meet all of the above criteria may be
constructed if they are dry floodproofed or elevated at least'/Z of one foot
above the BFE.
e. A non -conforming structure damaged may be restored unless the damage
meets or exceeds fifty percent (50%) of its market value before it was
damaged, in which case it shall conform to the Floodplain Manage
ment
standards of this Ordinance.
Compensatory Storage Volume Standards
a. Hydraulically equivalent compensatory storage volume requirements for
development in a riverine Regulatory Flood -DI ain or a flood prone area
shall be at least 1.5 times the Regulatory Floodplain or a flood.prone area
storage total volume displaced. Hydraulically equivalent storage will only
be required for areas draining greater than 100 acres. The storage volume
displaced below the existing 10-year frequency flood elevation must be
replaced below the proposed 10-year frequency flood elevation. The
storage volume displaced above the 10-year existing frequency flood
elevation must be replaced above the proposed 10-year frequency flood
elevation. The additional storage volume (0.5 times the total volume
displaced) may be provided at any elevation between normal water level
and the BFE.
b. Compensatory storage volume requirements for development in a non-
riverine Regulatory Flood -plain or a flood prone area that is also adjacent
to a lake shall be at least 1.5 times the storage volume displaced.
c. Compensatory storage volume requirements for development in a non-
riverine Regulatory Floodplain or a flood prone area that is not adjacent
to a lake shall be at least equal to the storage volume displaced. This
standard also applies to depressional storage areas.
d. Compensatory storage areas shall be designed to drain freely and openly
to the channel and shall be located adjacent to the development. This
standard does not apply to depressional storage areas. (See Release Rates
and Discharge in the Stormwater management Section of the Ordinance.)
e. A recorded covenant running with the land is required to maintain the
compensatory storage volume in areas modified to provide compensatory
storage volume.
f. Fee -in -lieu of compensatory floodplain, flood prone area and
depressional storage.
(1) The MCSC or certified community may require, or the applicant may
request, the payment of a fee -in -lieu of providing excavated
compensatory storage to fulfill all or part of the required compensatory
34
storage volume resulting from a development. The MCSC will request
a fee -in -lieu of compensatory storage or will reject its use within 21
days of a complete request including engineering studies and an
estimated fee.
(2) Fee -in -lieu of compensatory storage shall be the greater of:
(a) A fee, as approved by the MCSC, that is computed for each cubic
yard of compensatory storage that is not being provided by the
development. This fee shall be established in accordance with the
MCSC approved procedures and schedules; or,
(b) The estimated cost, as verified by MCSC, of the applicant's
proposed and approved on -site excavated compensatory storage
volume, including land costs, had the MCSC or certified
community required or allowed its construction.
(3) A fund will be maintained by the MCSC for each major watershed for
the purpose of identifying and controlling all revenues derived from fee -
in -lieu of compensatory storage. All fees received from each watershed
shall be deposited inthe respective major watershed fund.
Disbursements for costs to mitigate stormwater and Floodplain impacts
shall be made from the appropriate major watershed fund.
(4) Criteria
(a) Fee -in -lieu of compensatory storage volume shall not be allowed
within the Regulatory Floodway:
(b) Fee -in -lieu of compensatory storage shall not be allowed if the fill
would reduce the proposed riverine Floodplain or a flood prone
area storage volume to less than 95% of the existing riverine
Floodplain or a flood prone area storage volume in the project
reach.
(c) Fee -in -lieu of compensatory Floodplain or a flood prone area
storage shall not singularly or cumulatively allow more than 20
(twenty) cubic yards of lost storage volume for a development site.
(d) Fee -in -lieu of compensatory storage shall not be allowed for fill
proposed in a regulatory Floodway.
6. Floodway Standards
The only development in a Re ug latory Floodway which will be allowed are
appropriate uses which will not cause an increase in flood heights for all flood
events up to and including the base flood. Only those appropriate uses listed
below will be allowed in the Regulatory Floodway. Appropriate uses do not
include the construction or placement of any new structures, fill, building
additions, buildings on stilts, fencing (including landscaping or planting designed
to act as a fence) and storage of materials except as specifically defined below as
an appropriate use. If the development is proposed for the Regulatory Floodway
portion of the Regulatory Floodplain, the following standards apply in addition
to the standards for the Re i� latory Floodplain:
a. Only the construction, modification, repair or replacement of the
following appropriate uses will be allowed in the Re ato Floodway:
OR
(1) Public flood control structures and private improvements relating to the
control of drainage and flooding of existing buildings, erosion, water
quality or habitat for fish and wildlife;
(2) Structures or facilities relating to functionally water dependent uses such
as additions, modifications, and improvements to existing wastewater
treatment plants and facilities and improvements relating to recreational
boating (this does not include new wastewater treatment plants);
(3) Storm and sanitary sewer outfalls;
(4) Underground and overhead utilities if sufficiently floodproofed;
(5) Recreational facilities such as playing fields, open pavilions, gazebos
and trail systems including any related fencing (at least 50% open when
viewed from any one direction) built parallel to the direction of flood
flows;
(6) Bridges, culverts and associated roadways, sidewalks and railways,
necessary for crossing over the ReaatM Floodway or for providing
access to other appropriate uses in the Regglatoly Floodway and any
modification thereto;
(7) Parking lots built at or below existing grade provided that either:
(a) The BFE is less than 1 foot above the proposed parking lot; or
(b) The parking lot will be used for short-term outdoor recreational use
facilities and the owner agrees to restrict access during periods of
inundation and agrees to accept liability for all dama a caused by
vehicular access during flooding events;
(8) Regulatory Floodway grading, without fill, to create a positive non -
erosive slope toward a channel;
(9) Flood proofing activities to protect previously existing lawful structures
including the construction of water -tight window wells, elevating
structures, or the construction of flood walls or berms around residential,
commercial or industrial principal structures where the outside toe of the
floodwall or berm shall be no more than ten (10) feet away from the
exterior wall of the existing structure, and, which are not considered to
be substantial improvements to the structure;
(10) The repair of a damaged building, provided that none of the outside
dimensions of the building are increased and provided that the building
repair cost is less than 50% of the building's market value before it was
damaged. When damage is 50% or more (a substantial improvement),
the activity shall conform to the Floodplain management Section of this
Ordinance;
(11) Modifications to an existing building that would not increase the
enclosed floor area of the building below the BFE and which will not
block flood flows. These modifications include fireplaces, bay
windows, decks, patios and second story additions. No enclosed floor
areas may be built on stilts. The modifications may not singularly or
cumulatively reach or exceed 50% of the building's market value.
b. Additions or changes to the above list of appropriate uses must be
36
approved by MCSC and IDNR/OWR.
c. All development in the Regulatory Floodway shall require a Permit from
the MCSC or Certified community and IDNR/OWR (if notdelegated)
and must be in accordance with all provisions of this Ordinance.
d. Construction of an appropriate use will be considered permissible provided
that the proposed project meets the following engineering and mitigation
criteria and is so stated in writing with supporting plans, calculations and
data prepared by a Registered Professional Engineer.
(1) All effective Regulatga Floodway conveyance lost due to the
development of Appropriate uses, other than bridge or culvert crossings
or on -stream structures or dams, shall be replaced for all flood events up
to and including the base flood. In calculating effective Regulato
Floodway conveyance, the following factors shall be taken into
consideration:
(a) Regulatory Floodway conveyance (K),
"K"= (1.48/n)AR2/3
where:
"n" is The Manning roughness coefficient,
"A" is the effective area of the cross-section in square feet, and "R" is the
ratio of the area to the wetted perimeter in feet.
(b) The same The Manning roughness coefficient shall be used for both
existing and proposed conditions unless a recorded maintenance
agreement with a federal, state, or local unit of government can
ensure the proposed conditions will be maintained or the land cover
is changing from a vegetative to a non -vegetative land cover.
(2) The following expansion and contraction ratios shall be used to determine
transition sections in calculations of effective Regulatory Floodway
conveyance:
(a) Water will expand no faster than at a rate of one foot horizontal for
every four feet of the flooded stream's length.
(b) Water will contract no faster than at a rate of one foot horizontal for
every one foot of the flooded stream's length.
(c) Water will not expand or contract faster than one foot vertical for
every ten feet of flooded stream length.
(d) All cross -sections used in the calculations shall be located
perpendicular to flood flows.
(e) Transition sections may be used to determine the effective
conveyance areas on adjacent properties.
(3) The development of all appropriate uses shall not result in an increase in
the average channel or Regulatory Floodway velocities or stage, for all
flood events up to and including the base flood event. However, in the
case of bridges or culverts or on stream structures built for the purpose
of backing up water in the stream during normal or flood flows,
velocities may be increased at the structure site if scour, erosion and
sedimentation will be avoided by the use of rip -rap or other design
37
measures.
(4) On -Stream Structures for the purpose of backing up water.
(a) Any increase in upstream flood stages when compared to the
existing conditions, for all flood events up to and including the 100-
year frequency event, shall be contained within the channel banks
(or with existing vertical extensions of the channel banks) such as
within the design protection grade of existing levees or flood walls or
within recorded flood easements.
(b) A permit or letter indicating a permit is not required must be
obtained from IDNR/OWR for any structure built for the purpose
of backing up water in the stream during normal or flood flow.
(c) All dams and impoundment structures as defined in Article 11 shall
meet the permitting requirements of 17 IL. Adm. Code Part 3702
(Construction and Maintenance of Dams).
(d) If the proposed activity involves a modification of the channel or
Floodway to accommodate an impoundment, it shall be
demonstrated that:
(i) The impoundment is determined to be in the public interest by
providing flood control, public recreation, or regional
stonnwater detention;
(ii) The impoundment will not prevent the migration of indigenous
fish species, which require access to upstream areas as part of
their life cycle, such as spawning;
(iii) The impoundment will not cause or contribute to degraded
water quality or habitat conditions. Impoundment design should
include gradual bank slopes, appropriate bank stabilization
measures, and a pre -sedimentation basin;
(iv) A nonpoint source plan has been implemented in the
upstream watershed to control the effects of sediment runoff
as well as minimize the input of nutrients, oil and grease,
metals, and other pollutants. If there is more than one
municipality in the upstream watershed, the municipality in
which the impoundment is constructed should coordinate
with upstream municipalities to ensure comprehensive
watershed control.
(5) If flood proofing construction is required beyond the outside
dimensions of an existing habitable, residential or commercial building,
the outside perimeter of the flood proofing construction shall be placed
no further than 10 feet from the outside of the building. Compensation
of lost storage and conveyance will not be required for flood proofing
activities within the 10 foot perimeter provided flood damage to other
buildings is not increased.
(6) General criteria for analysis of flood elevations:
(a) The flood profiles, flows and data in the study, referenced in the
Floodplain management section, must be used for analysis of the
base conditions. If the study data appears to be in error or conditions
have changed, IDNR/OWR and MCSC shall be contacted for
approval and concurrence on the appropriate base conditions data
to use.
(b) If the BFE at the site of the proposed development is affected by
backwater from a downstream receiving stream with a larger
drainage area, the proposed development shall be shown to meet the
requirements of this section with the receiving stream at both the
normal water and BFEs.
(c) If the applicant is informed by IDNR/OWR, local governments, or
a private owner that a downstream or upstream restrictive bridge or
culvert is scheduled to be removed, reconstructed, modified, or a
regional flood control project is scheduled to be built, removed,
constructed or modified within the next five years, the proposed
development shall be analyzed and shown to meet the requirements
of this section for both the existing conditions and the expected flood
profile conditions when the bridge, culvert or flood control project
is built.
(d) If the appropriate use will result in a change in the Regulatory
Floodwav location or a change in the BFE, the applicant shall
submit to MCSC the information required to be issued a
Conditional Letter of Map Revision CL( OMR) from FEMA. A
public notice inviting public comment on the proposed change in
the BFE or location of the Regulatory Floodwav will be issued
by IDNR/OWR or its designee before a CLOMR is issued.
Filling, grading, dredging or excavating may take place upon
issuance of a conditional approval from FEMA or its designee
and the local jurisdiction. No further development activities shall
take place in the existing or proposed Floodplain until a Letter of
Map Revision LOMR is issued by and FEMA and such
development meets all the requirements of the Floodplain
Management Section of this Ordinance.
e. For those circumstances listed below and located in a RegWatory
Floodwav, the following information shall be submitted to MCSC and
IDNR/OWR (unless solely delegated to MCSC through agreement with
IDNR/OWR):
(1) Analysis of the flood profile due to a proposed bridge, culvert crossings
and roadway approaches.
(2) An engineer's determination that an existing bridge or culvert crossing or
approach road is not a source of flood damage and the analysis
indicating the proposed flood profile.
(3) Alternative transition sections and hydraulically equivalent
compensatory storage.
(4) Watershed Development Permits to local units of government for
Regulatory Floodwav and Floodplain development.
39
f. IDNR will retain permit authority for all jurisdictional dams, projects in
public bodies of water and all state, federal or MCSC projects.
7. Riverine Floodplain and Floodprone area Standards
a. These standards apply to Riverine Regulatory Floodplains and
floodprone areas without Regulatory Floodwa ss.
b. The Applicant, through MCSC, shall obtain approval from IDNR/OWR
for all development located partially or completely within either the
Regulatory Floodplain (without a delineated Regulatory Floodwav) or a
flood prone area with a tributary drainage area of 640 acres or more.
c. The development shall not singularly or cumulatively result in an
obstruction of flood flows or potential flood damages outside the
development right-of-way due to an increase in flood heights, velocities,
or loss of Floodplain or flood prone area storage.
d. A Registered Professional Engineer shall submit a study that
demonstrates one of the following;
(1) Determine a Floodwav which meets the definition of a Regulatory
Floodwav and demonstrate that the proposed development meets the
Floodwav Standards, or
(2) Determine a BFE and demonstrate that the proposed development will
maintain the existing conditions conveyance, will not increase flood
velocities, will not increase flood profiles, and will compensate for any
lost Floodplain or flood prone area storage at a 1.5 to 1 ratio, or
(3) That for a range of flood elevations and flows, as approved by the
MCSC, that the proposed development will maintain the existing
conditions conveyance, will not increase flood velocities, will not
increase flood profiles, and will compensate for all lost Floodplain or
flood prone area storage at a 1.5 to 1 ratio.
e. Show that the proposed development will meet the Floodplain
Management requirements of this Ordinance.
8. Bridge and Culvert Standards
a. These standards are for the Reconstruction, Modification or New
Construction of Bridges, Culvert Crossings and Roadway Approaches
located in the Regulatory Floodplain or flood prone areas.
b. A proposed new structure shall not result in an increase of upstream flood
stages greater than 0.1 foot when compared to the existing conditions for
all flood events up to and including the base flood event unless contained
within the channel banks or recorded easements. The evaluation must be
submitted to the MCSC for review and concurrence before a permit is
issued.
c. If the proposed new structure will increase upstream flood stages greater
than 0.1 foot, the applicant must contact IDNR/OWR for a permit or
waiver.
d. Lost Re ugulatory Floodplain or flood prone area storage must be replaced
as required in compensatory storage Section of this Ordinance except that
40
artificially created storage lost due to a reduction in head loss behind an
existing bridge or culvert crossing shall not be required to be replaced,
provided no flood damage will be incurred downstream.
e. Velocity increases must be mitigated by use of appropriate measures to
avoid scour, erosion and sedimentation at the structure.
f. For modification or replacement of existing structures, the existing
structure must first be evaluated in accordance with IDNR/OWR Rules
17 IL. Adm. Code Part 3708 to determine if the existing structure is a
source of flood damage. If the structure is a source of flood damage,
the applicant's engineer shall submit justification to allow the damage
to continue and evaluate the feasibility of relieving the structure's
impact. Modifications or replacement structures shall not increase flood
stages (0.0 feet) compared to the existing condition for all flood events up
to and including the base flood event. The evaluation must be
submitted to IDNR/OWR or its designee for review and concurrence
before a permit is issued.
g. If any work is proposed in, near or over a public body of water, a permit or
letter indicating a permit is not required must be obtained from
IDNR/OWR.
h. The hydraulic analysis for the backwater caused by the bridge showing
the existing condition and proposed regulatory profile must be submitted
to IDNR/OWR for concurrence that a CLOMR is not required.
i. Construction vehicles shall cross streams by the means of existing bridges or
culverts. Where an existing crossing is not available, a temporary crossing
shall be constructed in which:
(1) The approach roads will be 0.5 feet or less above existing grade.
(2) The crossing will allow stream flow to pass without backing up the
water above the stream bank vegetation line or above any drainage tile
or outfall.
(3) The top of the roadway fill in the channel will be at least 2 feet below
the top of the lowest bank. Any fill in the channel shall be non -erosive
material, such as rip -rap or gravel.
(4) The access road and temporary crossings will be removed within one
year after installation, unless an extension of time is granted by the
Enforcement officer.
(5) All applicable state and federal permits are received prior to
construction.
H. Wetland Provisions
In order to protect the wetland, lake, and stream resources of McHenry County,
wetland impacts to WOTUS and IWMC are prohibited by the McHenry County
Watershed Development Ordinance (MCWDO), unless no feasible alternatives exist
and all applicable regulatory approvals or clearances are granted prior to the onset of
the development activity.
Jurisdictional areas include:
41
a. Waters of the United States (WOTUS). Wetland impacts to WOTUS on
or adjacent to a development site will require regulatory approval or
clearance from the USACE, the IDNR/OWR and the IEPA.
b. Isolated Waters of McHenry Countyy (IWMC). Wetland impacts to
IWMC on or adjacent to a development will require issuance of a
McHenry County Watershed Development Permit.
c. Buffer Areas (as defined in Article V.C) to WOTUS and IWMC
required by the USACE and/or the MCWDO.
2. Non jurisdictional areas are appropriate wetland restoration activities
requiring minor earthmoving or grading in Isolated Waters of McHenry
Coll= or adjacent buffer areas. These activities are exempt upon receiving
written approval from the MCWDO Enforcement Officer prior to the onset of
the activity.
United States Geologic Survey (USGS) quadrangle map;
NRCS Wetland Inventory map;
FEMA floodplain map; McHenry County soil survey;
Hydrologic Atlas, and
McHenry County Advanced Identification (ADID) Wetland map
3. Applicability: A McHenry County Watershed Development Permit is required
for any development:
a. that proposes wetland impact(s) within an area(s) defined as Waters of
the United States, or
b. within buffer area(s) adjacent to Waters of the United States required by
the regulatory authority of the USACE; or
c. that proposes wetland impacts) with a total and cumulative impact area
of one -quarter (0.25) acre in size or greater to an area(s) defined as
Isolated Waters of McHenry County.
d. within buffer area(s) required by the MCWDO adjacent to Isolated
Waters of McHenry County.
4. Wetland submittal requirements depend upon whether the development is
located within WOTUS or IWMC as provided below. For development that
impacts both WOTUS and IWMC, submittal requirements follow provisions
under Isolated Waters of McHeruCojjnty. Projects involving both WOTUS
and IWMC will require coordination between the USACE and the MCWDO
Enforcement Officer for permitting process. The submittal requirement details
are listed in Section VI.F.
5. Requirements for Wetland Delineation
a. Applicant shall identify the boundaries, extent, function, and quality of
all potential wetland areas on the development site and prepare a
Wetland Determination Report. The presence and extent of
jurisdictional wetland areas shall be determined using an on -site wetland
procedure in accordance with the current Federal wetland delineation
methodology. Farmed Wetlands will be determined using the National
Food Security Act Manual or by contacting the Natural Resource
42
Conservation Service (MRCS).
b. Wetland Determination Report: The following are minimum
requirements for the Wetland Determination Report:
(1) A plan showing the exact location and extent of all wetlands within
the development boundaries. The boundary of the wetland(s) shall be
flagged in the field and surveyed;
(2) An aerial photograph delineating the identified wetland(s) and the
development boundary, as well as the estimated location and extent of
any off -site wetland(s) contiguous to, or extending off --site from, the
development parcel;
(3) The most recent copy of the following maps, delineating the
development boundary:Upon receipt of an approved MCWDO permit
authorizing a wetland impact that is not designated as HQAR, HQHS,
or HFVW, up to one quarter (0.25) acre of approved fill material can
be placed without providing mitigation. All other regulatory aspects
of the MCWDO (such as drainage, compensatory storage, etc.) will
be complied with before the exemption is granted.
(4) USACE wetland delineation data sheets with representative color
photographs provided for each wetland;
(5) A written description of the wetland(s) that includes a Floristic
Quality Assessment, as determined by methodology contained in the
publication Plants of theChicago Region (Swink & Wilhelm 4t'
Edition, The Indiana Academy of Science, Lisle, Illinois 1994). Floristic
quality assessments shall be conducted during the local growing
season between May 15 and October 1. Nongrowing season
assessments may be considered for sites with apparent plant
community monocultures or low floristic diversity potential, however,
the Enforcement Officer reserves the right to require additional
sampling during the growing season prior to issuing a permit.
(6) A functional assessment for each wetland using the Modified
Michigan Department of Natural Resources Method or the Ludwig
wildlife habitat evaluation methodology. Other functional assessment
methods are allowed but shall be approved prior to submittal.
(7) The approximate location, extent, and relative quality of offsite
wetlands adjoining the development shall be identified by using the
first of the following documents or procedures pertaining at the time of
development:
(a) Site specific delineation according to the Federal wetland
delineation methodology. If such delineation is not available, use
Paragraph (b) below.
(b) Wetlands identified on McHenry County Wetland Inventory maps
(most current MCWI map) and on McHenry County ADID study.
6. Wetland Mitigation Requirements
In order to further the goal of "no net -loss" of the County's wetland resources,
all permitted wetland impacts shall be mitigated at the ratio specified by this
31
Ordinance. The objective shall be to replace the impacted wetland functions
where they can be most successfully protected and maintained in perpetuity.
a. Mitigation for impacts to IWMC, shall provide for the replacement of the
wetland environment lost to development at the following proportional
rates (i.e., creation acreage to impact acreage):
(2) The one quarter (0.25) acre mitigation exemption may only be
exercised one time per approved MCWDO permit, regardless of the
number of IWMC present on the development site. The Enforcement
Officer can require that the remaining on -site portion of the IWMC
for which the exemption is granted be protected by buffers or other
protective measures as defined by the MCWDO.
(3) The Enforcement Officer may deny the mitigation exemption if' it is
determined that:
(a) any IWMC will be eliminated or adversely impacted as a result of
more than one application filling the same IWMC, resulting in a
cumulative fill greater than 0.25 acre.
(b) any IWMC already subject to the one quarter acre mitigation
exemption.
(c) an intermediate or major development project subdivided into
phases in order to submit multiple MCWDO applications.
(4) A minimum one and one half to one (1.5:1) replacement ratio is
required for approved wetland impacts to IWMC under Categories II
and III that are not designated as HQAR, HQHS, or HFVW.
(5) A minimum three to one (3:1) ratio is required for wetland impacts to
IWMC that are designated as HFVW.
(6) A minimum five to one (5:1) ratio is required for wetland impacts to
IWMC that are designated as HQHS or HQAR.
(7) Wetland impacts within or affecting an IWMC prior to issuance of a
MCWDO Permit, or other unauthorized impact to a wetland, shall
presume the IWMC disturbed was a HOAR wetland requiring
mitigation at a minimum mitigation replacement rate of five to one
(5:1), if it is determined that mitigation is acceptable in lieu of
restoration.
b. On -site wetland mitigation is preferred, but only if the applicant can
document that it can expand the extent or improve the quality of other
existing, undisturbed on -site or adjacent wetlands.
c. The mitigated wetland(s) shall be designed to duplicate or improve the;
hydrologic, biologic, botanic, and wildlife features of the original
wetland(s) impacted.
d. Creation of wetlands for the mitigation of wetland impacts shall take
place only within areas not currently comprised of jurisdictional
WOTUS or IWMC. The Enforcement Officer may allow partial
mitigation credit for appropriate wetland restoration practices in
otherwise undisturbed, degraded IWMC. The mitigation credit shall be
up to one -quarter (0.25) acre of wetland mitigation acreage credited for
each one (1) acre of degraded IWMC restored.
e. If the required wetland mitigation acreage is less than one and onehalf
(1.5) acres, credit for mitigation acreage can be achieved by payment
into an MCSC approved wetland mitigation bank, or into a MCSC /
MCWDO Certified Community approved Wetland Restoration Fund.
f. If the required wetland mitigation acreage is one and one-half (1.5)
acres in size or greater, the potential for on -site mitigation must be
evaluated. Credit for mitigation acreage by payment into an MCSC
approved wetland mitigation bank, or into a MCSC / MCWDO
Certified Community approved Wetland Restoration Fund is allowed if
the applicant can demonstrate that the long term preservation of
existing or created on -site wetlands is unlikely as a result of existing or
proposed land use practices in adjacent upland areas.
g. Any funds paid into an MCSC / MCWDO Certified Community
approved Wetland Restoration Fund for mitigation of wetland impacts
shall only be used to fund wetland restoration activities located fully
within McHenry County, or within the MCSC designated sub -
watershed (even outside McHenry County) in which the permitted
wetland impact occurred.
h. Preference for the ownership of wetland mitigation sites is as follows:
(1) Land owned and managed by a governmental entity, notfor-profit
land trust, or other appropriate non -governmental organization for
conservation purposes.
(2) Wetland mitigation bank approved by the USACE and/or the MCSC.
(3) Privately owned sites with appropriate deed restrictions, covenants, or
easements with a dedicated funding source in place to fund and protect
the mitigation site in perpetuity.
i. To the extent practicable, all wetland mitigation shall be provided at a
suitable location as close to the wetland impact site as possible. Other
locations may be proposed, with respect to the following hierarchy:
(1) Within the same MCSC designated sub -watershed within McHenry
County.
(2) Within the same MCSC designated sub -watershed, located outside
McHenry County.
(3) Within an adjacent McHenry County, MCSC designated sub -
watershed.
(4) Within an adjacent MCSC designated sub -watershed located outside
McHenry County.
(5) Within the same McHenry County, MCSC designated watershed.
(6) Within an adjacent McHenry County, MCSC designated watershed.
(7) Within the same MCSC designated watershed outside of McHenry
County.
As geographic distance increases between wetland impact site and
mitigation site, the Enforcement Officer may impose a mitigation
45
multiplier on the mitigation ratio specified in Section V.H.6.a of this
Ordinance.
k. Development in or affecting a wetland environment shall be initiated
only after a mitigation plan has been approved and adequate securities,
such as a performance bond or letter of credit, are provided as specified
in this Ordinance.
1. A project mitigation document (PMD) shall be submitted for all
mitigation projects in conformance with the current USACE Chicago
District Mitigation Guidelines and Requirements.
m. A plan for the perpetual management, operation, and maintenance of the
mitigation areas, including the designation of the person(s) or organization
legally responsible for long-term operation and maintenance, and
dedicated funding sources shall be submitted.
n. All wetland impacts mitigated on private property shall be protected by
a conservation easement, deed restriction, or other legal mechanism
recorded on the plat of survey for the parcel on which the mitigation is
located.
o. The applicant shall provide annual monitoring reports on the status of the
constructed mitigation measures. The applicant shall undertake all
necessary remedial action to bring the area into compliance with the
mitigation plan in conformance with the Chicago District Mitigation
Guidelines.
p. If the Enforcement Officer believes adequate mechanisms can be
established to protect and fund the mitigated wetlands, a mitigation
multiplier may be established on the mitigation ratio specified in
Article V.H.6.a of this Ordinance.
7. Wetland Banking
a. Where development affecting Isolated Waters of McHenry County
meets the requirements of this Ordinance and the long term
preservation of existing wetland functions or characteristics is unlikely
as a result of existing or proposed land use practices in adjacent upland
areas, then the Applicant may provide mitigation wholly or in part
through investment in a USACE certified wetland banking project, [or
payment into the Wetland Restoration Fund in lieu of constructing new
wetlands.]
b. Such wetland banking shall be allowed only if no long-term net loss of
wetlands results within McHenry County and if the adverse impacts of
development in isolated wetlands are fully mitigated.
c. Wetland Banks must be certified by the USACE and comply with the
Interagency Coordination Agreement On Wetland Mitigation Banking
Within The Regulatory Boundaries Of Chicago District, dated January,
1997, or current agreement.
d. A Watershed Development Permit will not be issued until a copy of the
receipt of payment is provided.
e. Payment into the Wetland Restoration Fund is only allowable if no
wetland banks are within the watershed that the development is proposed.
8. Wetland Hydrology
a. The following hydrology threshold requirements shall be met by the
development activity. If the development activity exceeds the
hydrology threshold limits, a wetland impact to Isolated Waters of
McHenry Co un shall be assumed, and the mitigation requirements of
this section of the ordinance shall apply.
b. The design shall maintain between 80% and 150% of the exiting condition
storm event runoff volume to the wetland up through the 2 year-24 hour
storm event. The design shall meet the total off site release rate
requirements of the McHenry County ordinance, or the minimum orifice
size requirements.
ib
ARTICLE V. APPLICATION REQUIREMENTS
All the following application requirements shall be submitted when applicable to the
development, to the Enforcement officer. The Enforcement officer shall provide a permit
application form.
A. Application Requirements for Minor Developments
1. A completed permit application that includes the name and legal address of the
applicant, legal description of the property and/or parcel identification number,
and common address and a site location map of the development, a brief
description of the proposed development and the mailing address of the property
owner and the signature of the applicant or the applicant's agent.
2. A general description of the existing and proposed stormwater management
s sy tern.
A grading plan showing proposed and existing contours.
4. A site drainage plan locating overland flow paths, Floodway, Floodplain,
floodprone area and Wetland limits.
5. An area drainage plan.
6. A description and depiction of measures to be taken to control erosion. This may
include, but is not limited to, the standard soil erosion and sedimentation control
notes as established by the MCSC.
7. Copies of ADID (Advanced Identification), NWI (National Wetland Inventory),
NRCS (Natural Resources Conservation Service), HA (Hydrologic Atlas)
Wetland Maps, and current version of the NRCS Soil Survey for McHenry
County, extended 100 feet from property boundaries.
a. If these maps and a site inspection do not indicate the potential presence of
unmapped IWMC, the Enforcement Officer may determine no farther
wetland submittals are required.
b. If these maps do indicate the potential presence of unmapped IWMC, the
Enforcement Officer may require additional wetland investigations to
determine the presence, location, functional value, or quality of on -site or
adjacent wetlands.
c. In the case of the potential presence of unmapped WOTUS, the
Enforcement Officer may require documentation that the proposed
activity is in conformance with the USACE regulatory program, or other
current federal, state, or local wetland regulations.
B. Application Requirements for Intermediate Developments
In addition to the requirements for minor developments, intermediate
development applications require the following information:
1. A topographic map of the existing conditions of the development site
showing the location of all roads, all drainage paths, the boundaries of
predominate soil types, the boundaries of predominate vegetation, and the
location of any drainage easements, detention or retention basins, including
their inflow and outflow structures, if any. The map shall also include the
location, size, and the utilized flow capacity of all existingstorm or combined
sewers and other utility lines within the site. The map shall be prepared using a
minimum 2-foot contour interval and shall be prepared at an appropriate scale
for the type of project and shall include specifications and dimensions of any
proposed channel modifications, location and orientation of cross -sections, if any,
north arrow, and a graphic or numerical scale. All elevations shall be referenced
to National Geodetic Vertical Datum NGVD (1929 adjusted).
2. Include cross-section views for the stormwater managements stem showing
existing and proposed conditions including principal dimensions of the work, and
existing and proposed elevations, normal water and calculated BFEs, and
overland flow depth and path.
3. A vicinity map shall be included along with the Parcel Identification Numbers
of all parcels comprising the proposed development.
4. A watershed development report with supporting analyses and documentation to
describe the hydrologic and hydraulic methods used to design the proposed
project shall be included with the application. The report shall include the name
of affected stream or body of water, a statement of purpose of proposed activity,
and a detailed description of the runoff for the project site under existing and
developed conditions. This includes documentation of the design volumes and
rates of the proposed runoff for each portion of the watershed tributary to the
stormwater management system and the effects the development will have upon
the receiving channel and high water elevations. Runoff calculations shall
include all discharges entering the site from upstream areas. The watershed
development report shall describe how the proposed project meets all the
standards of this ordinance.
5. For detention facilities, a section in the watershed development report that
includes a plot or tabulation of storage volumes and water surface areas with
corresponding water surface elevations, stage -discharge or outlet rating curves,
and design hydrographs of inflow and outflow for the 2year, 24-hour and the
100-year, 24-hour storm events under existing and developed conditions.
6. A soil erosion and sedimentation control plan for all disturbed areas, which
includes:
a. A site map prepared at the same scale as the drainage plan that identifies
both temporary and permanent vegetative and structural erosion and
sediment control measures to be implemented.
b. A narrative description of the sequencing of grading and soil disturbance
and construction activities, the temporary and permanent sediment and
erosion control measures to be implemented to mitigate any negative
effects of grading including: supporting calculations; estimated schedule
for installing, maintaining and removing both temporary and permanent
structures; and the final stabilization and vegetation measures.
7. A maintenance plan for the ongoing maintenance of all stormwater management
system components including Wetlands and buffer areas is required prior to
plan approval. The plan shall include:
49
a. Maintenance tasks.
b. The party responsible for performing the maintenance tasks.
c. A description of all permanent public or private access maintenance
easements and overland flow paths, and compensatory storage areas.
d. A description of dedicated sources of funding for the required
maintenance.
The development shall meet the requirements of this Ordinance and shall be
certified and sealed by a Registered Professional Engineer.
9. A description of the anticipated dates of initiation and completion of activity.
10. The applicant shall obtain and provide a copy of an IDNR/OWR Dam Safety
Permit or a letter stating that a Dam Safety Permit is not required if the
development includes a dam before the applicant obtains a watershed
development permit
11. A listing of all local, state and federal permits or approval letters that may be
required for this type of development including the application date. The
applicant shall obtain and provide copies of any and all required federal, state and
local permits for development in the Regulatory Floodplain or flood prone area
before the applicant obtains a watershed development permit.
12. The applicant shall submit the data required to MCSC, IDNR/OWR, and
FEMA for proposed revisions to the BFE of a Regulatory Floodplain study or
relocation of a Regulatory Floodwav or Floodplain boundary L( OMR request).
13. For a Letter of Map Amendment L( OMA) request for a correction in a
delineated Floodplain boundary the applicant shall submit the following data to
the MCSC and FEMA:
a. Certification that a land parcel is located above the BFE based on the
current effective flood profile, and;
b. An affidavit or documentation to demonstrate that the existing ground
elevation existed prior to the effective date of the first Floodplain map
14. For any development located in, near or adjacent to a Wetland as shown on the
ADID, NWI, or the NRCS Wetland maps, the applicant shall provide a copy of
the Chicago District, U.S. Army Corps of Engineers' permit or a letter from the
Corps indicating that a permit is not required from their agency for the proposed
development.
15. Subsurface Drainage (Tiles) Submittal Requirements
a. Intermediate, Major and Public Road Development applicants shall
submit a subsurface drainage survey unless evidence can be provided that
the site has no drain tiles present.
b. The inventory shall locate existing farm and storm drainage tiles by means
of slit trenching and other appropriate methods performed by an
experienced subsurface drainage consultant.
go]
c. All existing drain tile damaged during the investigation should be
repaired and functional.
d. The applicant shall provide a topographical boundary map locating these
lines showing:
(1) Location of each slit trench and identified to correspond with the file
investigation report and field staked at no less than 50 foot intervals;
(2) Location of each drain tile with a flow direction arrow, tile size and any
connection to adjoining properties.
(3) A summary of the tile investigation report showing trench identification
number, file size, material and quality, percentage of the tile filled with
water, percentage of restrictions caused by sediment; depth of ground
cover and file system classification.
(4) Name, address and phone number of the person or FIRM conducting
the tile location investigation.
e. Information collected during the drainage investigation shall be used to
design and develop a long term subsurface drainage system appropriate for
the soils under the development and properly connect all upstream and/or
downstream properties.
C. Application Requirements for Major Developments
The application requirements for major development are the same as those for an
intermediate development.
D. Special Flood Hazard Area Application Requirements
If the development is located in a Regulatory Floodplain or flood prone area, the
applicant shall provide the following additional information:
1. Site location of the property, drawn to scale on the Re ug_latory Floodwav map,
indicating whether it is proposed to be in an incorporated or unincorporated area;
2. A plan view of the project showing:
a. The existing and proposed Regulatory_ Floodwav limit(as scaled from the
Regulatory Map), Regulatory Floodplain or flood prone area limit (as
determined by the BFE) and the existing water line for public bodies of
water as defined by IDNR/OWR.
b. Cross-section views of the project for the impacted reach showing
existing and proposed conditions including principal dimensions of the
work as shown in plan view, existing and proposed elevations, normal
water elevation, 1 0-year frequency flood elevation, 100year frequency
flood elevation, and graphic or numerical scales (horizontal and vertical).
c. A copy of the Regulatory Floodwav map with the project site delineated
and marked to reflect any proposed change in the Regulatory Floodwav
location.
3. A written report that describes the hydrologic and hydraulic methodology
including the engineering calculations and supporting data that show the proposed
work meets the performance standards of this Ordinance.
51
4. All changes in grade resulting from any proposed excavation or filling; and
existing and proposed Regulatory Floodplain, flood prone area and Regulato
Floodwav limits; the location and dimension of all buildings and additions to
buildings; and the elevation of the lowest floor (including basement) and lowest
opening elevation of all proposed buildings.
5. Structural Elevation and Flood proofing Certifications
a. Elevation certificates of the lowest floor elevation (including basements
and attached garages)must be submitted for all residential structures
located in a Regulatory Floodplain or a flood prone area.
b. Flood proofing Certificates must be submitted that show the elevation to
which all non-residential buildings are flood proofed in the Regulatory
Floodplain or a flood prone area.
c. Certificates are also required to show that all structures (located outside
the Regulatory Floodplain or a flood prone area) have a lowest opening
above the FPE.
E. Public Road Development Application Requirements
A completed and signed watershed development permit application.
2. The applicant shall obtain and provide copies of any and all required federal, state
and local permits for development in the Regulatory Floodplain or a flood prone
area before the applicant obtains a watershed development permit.
3. A report, supporting analyses, documentation and plans of the proposed
Stormwater management system, including the location and size of all existing
and proposed drainage improvements including plan, section, and profile views
of storm sewers, field tiles, culverts, channels, and detention areas.
4. A report, supporting hydrologic and hydraulic analyses, documentation and
plans of any proposed Floodwav, Floodplain or flood prone area modifications,
including the construction or reconstruction of any existing and proposed
development that may include bridges, culverts, approach roads, resurfacing,
road construction, road widening or alterations of any existing stormwater
facilities.
5. A Soil Erosion and Sediment Control Plan.
F. Wetland Submittal Requirements
Wetland submittal requirements depend upon whether the development is located within
WOTUS or IWMC as provided below. For development that impacts both WOTUS
and IWMC, submittal requirements follow provisions under Isolated Waters of
McHenry County. Projects involving both WOTUS and IWMC will require
coordination between the USACE and the MCWDO Enforcement Officer for
permitting process.
1. Wetland impacts to only WOTUS or their adjoining buffer areas shall follow
application requirements of the USACE.
2. For wetland impacts to IWMC or their adjoining buffer areas, the following
information is required:
52
(a) A cover letter that provides a clear project purpose and need statement,
a description of the proposed activity, composition of fill material, area
(in acres) of wetland impact, and a statement on the permit category,
designated by the Enforcement Officer, to be used as follows:
Category -I: Wetland impacts with a cumulative impact area of one quarter
(0.25) acre or less and do not impact HOAR, HFVW, and/or HQHS;
Category -II: Wetland impacts with a cumulative impact area between one
quarter (0.25) and two (2) acres in size and do not impact HOAR, HFVW,
and/or H HS•
Category -III: Wetland impacts with a cumulative impact area of two (2) acres
or greater in size, or that impact HQAR, HQHS, and/or HFVW;
Category -IV: Wetland impacts for the restoration, creation and enhancement
of wetlands provided that there are net gains in aquatic resource function,
including streambank and shoreline stabilization projects that utilize
appropriate bioengineered practices.
(b) A delineation of the wetlands consistent with the requirements provided
in "Requirements for Wetland Delineation"
(c) A statement on the occurrence of any High Quality Aquatic Resource
or High Quality Habitat Site on or adjacent to the development;
(d) Documentation that the development is in compliance with the Illinois
Department of Natural Resources Endangered Species Consultation
Program and the Illinois Natural Areas Preservation Act [520 ILCS
10/11 and 525 ILCS 30/17];
(e) Documentation that the development is in compliance with the U. S.
Fish and Wildlife Service's consultation program under the Endangered
Species Act;
(f) A mitigation plan meeting the requirements of this Ordinance;
(g) A copy of the Natural Resources Information Report (NRI) performed by
the McHenry County Soil and Water Conservation District pursuant to
state statute 70 ILCS 405/22.02a;
(h) Alternative measures taken to avoid, minimize, or mitigate for impacts
to Isolated Waters of McHenry County (Category -II requirement only);
(i) Measures taken to avoid and minimize impacts to Isolated Waters of
McHenry County (Category -III requirement only); and,
(j) Benefits to the aquatic environment of the proposed development
(Category -IV requirement only).
(k) For any proposed impact to a IWMC designated as HQAR, HQHS, or
HFVW, an alternative analysis for wetland avoidance. This shall be similar
to the 404(b)(1) requirements of the Clean Water Act.
53
ARTICLE VI. VARIANCES AND APPEALS
A. VARIANCES
The Enforcement officer upon application, after public hearing, and subject to the process
and standards that follow, may grant variances to the provisions of this Ordinance as will not
cause detriment to the public good, safety or welfare nor be contrary to the spirit, purpose
and intent of this Ordinance where, by reason of unique and exceptional physical
circumstances or condition of a particular property, the literal enforcement of the provisions
of this Ordinance would result in an unreasonable hardship.
In Certified Communities, the Certified community's. Enforcement officer shall
administer the variance provisions.
2. In non -Certified Communities and for Public Road Developments, the
MCSC chief en i- neer shall administer the variance provisions.
3. A public notice will be issued to adjacent property owners via posted sign on
parcel or local newspaper inviting public comment on all proposed variances to
any performance standard. In a Certified community a copy of the variance
request and the public notice will be sent to MCSC.
4. Variances may be granted in the following instances:
a. Showing of good and sufficient cause, and
b. A determination that the variance is the minimum necessary to afford
relief, considering the flood hazard and water quality, and
c. A finding that failure to grant the variance would result in exceptional
hardship to the applicant, and
d. A finding that the granting of a variance would not result in increased
flood heights or damages, additional threats to public safety,
extraordinary public expense, a created nuisance, fraud or victimization
of the public, nor conflict with existing local laws or stated purpose of
any ordinances, and
e. A finding that all buildings will be protected by methods that will
minimize flood damag up to the BFE, and
f. A finding that the development activity cannot be located outside the
Re ug_latory Floodplain or flood prone area, and
g. The applicant's circumstances are unique and do not represent a general
problem.
5. Upon consideration of the factors noted above and the intent of the Ordinance,
the Enforcement officer may attach such conditions to the granting of a variance
deemed necessary to further the purposes and objectives herein.
6. Variances requested in connection with restoration of a historic site or building
listed on the National Register of Historical Places or documented as worthy of
preservation by the Illinois Historic Preservation Agency or Certified Local
Agency, may be granted using criteria more permissive than the requirements
contained in this Ordinance.
7. The Enforcement officer shall notify an applicant in writing that a variance from
54
the requirements of the Building Protection Standards in the Floodplain
management Section that lessen the degree of protection to a building may
result in increased premium rates for flood insurance and may increase the risk
of loss of life and property. The Enforcement officer shall require that the
applicant acknowledge, in a signed exception to title, the assumption of the risks
and liability. If the variance is approved the applicant will pay the fee for
recording the exception.
In a flood prone area or a Regulatory Floodplain (without a mapped Re ug latory
Floodwa where the tributary drainage area is 640 acres or more, a variance may
not be granted that will reduce the Re ugulatory Floodplain or flood prone area
storage volume by greater than 5% of the existing Regvlatga Floodplain or
flood prone area storage volume on the site. In addition, hydrologic and
hydraulic analysis must demonstrate that issuance of a variance will not result in
singular or cumulative increases in flood heights.
9. Variances requested for the development of previously developed sites, that are
intended to meet the goal of downtown redevelopment or neighborhood
revitalization, may be granted using criteria that is less restrictive than the
Stormwater management requirements provided the issuance of the variance will
not result in an increase in the runoff rate or volume and the site has adequate
downstream stormwater capacity,
10. Variances requested for Public Road Developments that will continue the public
policy of minimizing the condemnation of private property may be granted using
criteria less restrictive than the Stormwater management requirements to the
extent necessary to reduce the amount of condemnation provided the variance
will not result in a downstream drainage hazard, and
11. Variances requested for any work within the Regulatory Floodway must obtain
written concurrence from the IDNR/OWR that the proposed work conforms
with the IDNR/OWR Rules entitled: Floodwav Construction in Northeastern
Illinois.
12. Written findings shall be made public for all Variances and shall be on file with
the MCSC.
B. APPEALS:
1. Any person aggrieved by a decision of a Certified community's Enforcement
officer may request review thereof by the Community's board of elected
officials or the appropriate body.
2. Any person aggrieved by a decision, requirement, ruling or interpretation of this
Ordinance by the MCSC chief engineer may appeal it to the MCSC by written
notice filed with the MCSC chief engineer within 10 days of the determination.
55
ARTICLE VII. INSPECTIONS AND ACCESS
Representatives of the MCSC and of any federal, state and local unit of government are authorized
to enter upon any land or water to inspect development activity that is relevant or appears to be
relevant to this Ordinance.
Representatives of the MCSC may, after 10 days written notice to the owner or occupant, enter upon
any lands or waters within the county for the purpose of inspecting stormwater or Floodplain
facilities, structures or areas. The MCSC representatives may cause the removal of obstructions to an
affected watercourse.
ARTICLE VIII. VIOLATION AND PENALTY
A. Whenever an Enforcement officer finds a violation of this Ordinance, or of any permit
or order issued pursuant thereto, within their respective jurisdiction, the Enforcement
officer may issue a stop work order on all development activity on the subject property or
on the portion of the activity in direct violation of the Ordinance. In every case, the
Enforcement officer shall issue an order that:
Describes the violation;
2. Describes corrective action including;
a. Meeting the Ordinance Standards and Application Requirements and
obtaining a Watershed Development permit; or,
b. Remove the violation and stabilize the site from erosion.
3. Specifies the time period for corrective action;
4. Inform the owner that failure to correct or mitigate the violation is considered a
willful act to increase flood damage or sedimentation problems; and,
5. Inform the owner that failure to correct or mitigate the violation may cause
coverage by a Standard Flood Insurance Policy to be suspended.
B. Failure to comply with any of the requirements of this Ordinance shall constitute a
violation, and any person convicted thereof shall be fined not more than seven hundred
fifty ($750.00) dollars for each offense. Each day the violation continues shall be
considered a separate offense.
C. The MCSC or Certified community may also take any other legal action, including a
temporary restraining order, necessary to prevent or remedy any violation including
appropriate equitable or injunctive relief and, if applicable, an assessment to the violator
for the removal, correction, or termination of any adverse effects upon any property
resulting from any unauthorized activity for which legal action under this section may
have been brought.
D. After notice is sent to the owner(s) of the parcel(s) upon which the violation is located,
the MCSC or the Certified community may record the notice of violation or the order
with the title to the property at the McHenry County Recorder of Deeds Office.
ARTICLE IX DISCLAIMER OF LIABILITY
It is recognized that the degree of flood protection required by this Ordinance is considered
reasonable for regulatory purposes and is based on scientific and engineering considerations.
However, on occasion, greater floods than the base flood will occur and will result in greater flood
heights and flood damage. Furthermore, flood heights may be increased by other man
made or natural causes. These provisions do not imply that land outside the Floodplain or flood prone
area areas or that uses permitted within such areas will be free from flooding or flood damages. These
56
provisions shall not create liability on the part of the Stormwater Committee nor any Certified
community nor any officer or employee thereof for any flood damages that result from reliance on this
Ordinance or any administrative decision lawfully made there under.
ARTICLE X. SEVERABILITY
If any section, provision, or portion of this Ordinance is adjudged unconstitutional or invalid by a court
of competent jurisdiction, the remainder of this ordinance shall not be affected thereby. From time to
time the lists in the appendix of this Ordinance need to be updated to reflect new or revised Floodwav
maps, Floodplain maps or flood studies. Routine revisions to update these lists are required by FEMA
and IDNR/OWR. Public notice and review of new or revised Floodwav maps, Floodplain maps or
flood studies is required by FEMA and IDNR/OWR prior to final adoption. The public notice and
review process applies to both the impacted community and individual property owners. For this
reason, the Appendix lists that relate to Floodwav maps, Floodplain maps and flood studies may be
updated without additional public notice.
ARTICLE M. ABROGATION AND GREATER RESTRICTIONS
This Ordinance is not intended to repeal, abrogate or impair any existing easements, covenants, or
deed restrictions. Where this Ordinance and other ordinance, easements, covenants, or deed
restrictions conflict or overlap, whichever imposes the more stringent restrictions shall prevail. This
Ordinance is intended to repeal the original ordinance or resolution which was adopted to meet the
National Flood Insurance Program regulations, but is not intended to repeal the resolution which the
community passed in order to establish initial eligibility for the program.
ARTICLE MI EFFECTIVE DATE
The effective date of this Ordinance shall be JANUARY 1, 2005.
57
APPENDIX A
PUBLIC BODIES OF WATER IN MCHENRY COUNTY
The following public bodies of water were navigable in their natural condition or were improved for
navigation and opened to public use. The entire length and surface area in Illinois, including all
backwater lakes and sloughs open to the main channel or body of water at normal flows or stages, that are
open to the public.
1) Fox River (Illinois River Basin)
2) Fox Chain-O-Lakes (Lake and McHenry Counties): Bluff Lake, Lake Catherine,
Channel Lake, Fox Lake, Grass Lake, Lake Marie, Nippersink Lake, Dunns Lake,
Pistakee Lake, Lake Jerilyn, Lac Louette, Redhead Lake;
3) Griswold Lake including the connecting channel to the Fox River.
The following public bodies of water are navigable waters that were dedicated to public use. This list
is incomplete. It is believed there are numerous channels and slips in subdivisions on the margins of
public bodies of water which have been dedicated by plat. Additional channels and slips have been
dedicated by common law.
1)No list for McHenry County.
NOTE: The above lists are provided by the Illinois Department of Natural Resources / Office of Water
Resources (IDNR/OWR). An IDNR/OWR permit is required for development within the listed
waterways and adjacent Wetlands.
58
APPENDIX B
MCHENRY COUNTY WATERSHEDS
In McHenry County the six major watersheds are officially defined as:
The Piscasaw Creek Watershed
The Nippersink Creek Watershed The
Kishwaukee River Watershed The
Upper Fox River Watershed
The Lower Fox River Watershed, and The
Coon Creek Watershed
59
APPENDIX C
HIGH QUALITY AQUATIC RESOURCES
The following are descriptions of high -quality aquatic resources:
1. Advanced Identification (ADID) sites: Wetland and aquatic sites that have been
identified by the Chicago District of the U. S. Army Corps of Engineers and U.S.
Environmental Protection Agency. (U.. S. Environmental Protection Agency. 1997.
Advanced Identification (ADID) Study. McHenry County, Illinois. Chicago. Illinois) or
latest ADID study.
a. Bog: A low nutrient peatland, usually in a glacial depression, that is acidic in the
surface stratum and dominated by the genus Sphagnum.
b. Ephemeral pool: A seasonally inundated depression within forested or open
areas, usually located on a moraine, glacial outwash plain, or in an area shallow
to bedrock; also known locally as a "vernal pool." These areas may or may not
be permanently vegetated.
C. Fen: An herbaceous or wooded peatland created and maintained by the constant
surface water flow of cold mineralized (calcareous) groundwater flow.
d. Forested wetland: A wetland, including wooded seeps, shrub swamps, and
floodplain forests, dominated by shrubs or trees growing on soils that are
inundated or saturated much of the year, but that do dry out at the surface.
e. Sedge meadow: Saturated, sometimes flooded open wetlands dominated by
grasses and sedges, including hummock forming Tussock Sedge (Carex stricta).
f. Seep: A wetland, herbaceous or wooded, with saturated soil or inundation
resulting from the diffuse flow of groundwater to the surface stratum.
g. Streams shown on the most recent USGS quadrangle map as a perennial (solid
blue line) or intermittent (dashed blue line) that are not determined to be a Waters
of the U. S. If a site specific Index of Biological Integrity (1BI) assessment is
greater than 35, this stream reach shall be considered a HQAR.
h. Streamside marsh: A wetland that is within a 100-year riverine floodplain and
dominated by herbaceous species.
i. Wet prairie: A wetland dominated by native graminoid species with a diverse
indigenous forb component that is seasonally saturated and/or temporarily
inundated.
2. Wetlands supporting Federal or Illinois endangered or threatened species: For current
state -listed species, reference Illinois Endangered Species Protection Board's
"Checklist of Endangered and Threatened Animals and Plants of Illinois" and/or contact
the Illinois Department of Natural Resources. For Federally -listed species, reference
the U.S. Fish and Wildlife Service's "Endangered and Threatened Wildlife and
Plants" list (latest edition) and/or contact the U.S. Fish and Wildlife Service.
3. Wetlands with a Floristic Quality Index of 20 or greater or a mean C-value of 3.5 or
greater: Reference Plants of the Chicago Region (F. Swink and G. Wilhelm, 4`" edition.
Indianapolis: Indiana Academy of Science, 1994).
4. Wetlands that have an initial wildlife quality value of 5.0 or higher using the Modified
Michigan Department of Natural Resources Method or have a mean rated wildlife
quality (MRWQ) value of 8.0 or higher, as calculated by the Ludwig wildlife habitat
60
evaluation methodology. If both wildlife quality methods are performed, the Ludwig
Value shall prevail as the determining value.
5. Wetlands that are within a designated Illinois Natural Areas Inventory Site (INAI).
61
CITY OF McHENRY
WATERSHED DEVELOPMENT PERMIT APPLICATION
Section 1
Applicant Information:
Name:
Address:
Phone:
333 S. Green Street
McHenry, I inois 60085
Phone: (815) 363-2100
Fax: (815) 363-2173
Owner Information:
Name:
Address:
Phone:
Developer Information:
Name:
Address:
Phone:
Check the appropriate box that indicate which submittals apply to application:
(See attached Development Descriptions)
Minor Development
Q Intermediate development
El Major Development
0' Public Road Development
0; Special Flood Hazard Area Development
Wetlands
The attached Development Checklist can be used as a guideline to determine if the appropriate
application requirements have been met for a complete Watershed Development Permit application.
All applicable requirements will be submitted with this application to the City of McHenry.
Common Address of Development:
Property Identification Number (P
I hereby certify that all information presented in this application is true and accurate to the best of my
knowledge. I have read and understand the City of McHenry Subdivision Control Ordinance and
McHenry County Stormwater Management Ordinance, and fully intend to comply with those
provisions.
Signature of Developer Date
Office Use Only
Date Application Received: Date Permit Issued:
REGULATED DEVELOPMENT
Regulated Development
No person, firm, corporation or governmental agency, unless specifically exempted, shall
commence any regulated development on any lot or parcel of land without first obtaining a
Watershed Development Permit from the MCSC or, if applicable, the certified community. A
Watershed Development Permit is required for regulated development, including finalization
of a plat, replat, Planned Development (PD), Planned Unit Development (PUD) or
Manufactured home park site plan. Development that meets any of the following criteria is
considered regulated development:
1. Any development that is located partially or completely in a Re ug latory Floodway; or,
2. Any development that is located partially or completely in a Regulatory Floodplain; or
3. Any development that is located partially or completely in a flood prone area; or,
4. Any development that results in an additional 5,000 square feet of impervious area
from the original effective date of this Ordinance; or,
5. Any development which hydrologically disturbs 5,000 square feet or more; or,
6. Any development that results in change in the direction of stormwater runoff from a
site; or,
7. Any land disturbing activity that will affect an area in excess of 500 square feet if the
activity is within 25 feet of a lake, pond, stream, or Wetland; or,
8. Excavation, fill, or any combination thereof that will exceed 100 cubic yards.
9. Any activity resulting in a wetland impact.
Exempted Development
1. Development that is part of a court decree or court order is not subject to the provisions
of this ordinance, provided that the court decree or court order specifically exempts the
development from the requirements of this ordinance.
2. Development that is undertaken by a statutorily created entity that possesses the
statutory authority to engage in such activities shall be subject to the provisions of this
ordinance only to the extent of those activities that are outside the limits of their
statutory authority.
3. Landscape or stormwater facility maintenance.
4. Exempted development must meet and obtain the required permits for all minimum.
state, federal and local watershed development regulations, stormwater regulations
and Floodplain regulations.
5. A development is not subject to the provisions of this Ordinance if the following
approvals were issued prior to June 1, 2004 provided that the development is
completed within 5 years of the approval:
a. An approved building permit;
b. Any of the following approvals that result in no increase in the
impervious surface area or the development includes an approved drainage
study that is consistent with stomiwater and Floodplain ordinances in
effect at the time of the approval by the appropriate municipality: An
approved preliminary or tentative plat; or, An annexation agreement; or,
Replat of an industrial or commercial subdivision;
C. In the case of a public road development project:
(1) An awarded construction contract; or,
(2) An approved preliminary engineering plan, including a drainage
component, which is consistent with the regulations in effect at the
time of the approval by the appropriate jurisdictional authority.
d. Existing earth extraction and mining operations shall be exempt beyond the
5 year period from wetland jurisdiction provided a reclamation plan is
submitted and approved.
6. A Public Road Development that is located in a Regulatory Floodway and obtained a
permit from the Illinois Department of Transportation / Division of Highways is
exempt from the Floodway Requirements of this Ordinance.
2
DEVELOPMENT DESCRIPTIONS
Minor Development
A minor development is defined as regulated development that:
1. Is not partially or completely located in a depressional storage area, flood prone
area, a regulatory floodplain, a regulatory floodway or is not adjacent to a
perennial water resource;
2. Consists of hydrologic disturbance of less than 20,000 square feet; and
3. Is not a Public Road Development.
Intermediate Development
An intermediate development is defined as a regulated development that:
1. Is not partially or completely located in a depressional storage area, flood prone
area, a regulatory floodplain or a regulatory floodway
2. Consists of hydrologic disturbance of between 20,000 square feet and 5 (five)
acres; and
3. Is not a Public Road Development.
Public Road Development
Public Road Development is defined as a regulated development that:
1. Takes place in a public right-of-way or part thereof;
2. Does not include the construction of a building; and
3. Consists of culverts, bridges, roadways, sidewalks, bike paths and related
construction.
Maior Development
A major development is defined as all other development that is not defined by the above
criteria.
Special Flood Hazard Area Development
A development that is partially or completely located in a depressional storage area,
floodplain or flood prone area.
Wetland Submittal
A wetland submittal is required for any development located in, near, or adjacent to a
wetland. Any of the following items can trigger the requirement for a wetland submittal:
1. The presence or proximity of a hydric soil -mapping unit as documented in the
current Soil Survey for McHenry County, produced by the Natural Resource
Conservation Service, or by any on -site soil investigation by a soil scientist.
2. The presence or proximity of any regulatory floodway or floodplain areas, as
documented on current Flood Insurance Rate Maps, produced by the Federal
Emergency Management Agency, or as the result of any other engineering
studies.
3. The presence or proximity of any "flood of record" areas, as documented on
Hydrologic Atlas Maps, produced by the Northeastern Illinois Planning
Commission.
4. The presence or proximity of any potential wetland areas as documented on
maps or aerial photographs maintained by the Natural Resource Conservation
Service for use in determining compliance with United States Department of
Agriculture programs.
5. The presence or proximity of any wetland areas, as documented on National
Wetland Inventory Maps, produced by the U.S. Fish and Wildlife Service.
6. The presence or proximity of any wetland areas, as documented on McHenry
County Advanced Identification (ADID) Wetland Maps, produced by the U.S.
Fish and Wildlife Service, U.S. Army Corps of Engineers and the U.S.
Environmental Protection Agency.
7. Any other mapping, anecdotal, or resource information that indicates the
potential presence of wetlands.
2
DEVELOPMENT CHECK LIST
Minor Development Submittal Checklist
The following items should be submitted for a Minor Development:
0 Watershed Development Permit Application including:
Site location map of development
Brief description of the proposed development
Signature of applicant or applicant's agent
0. General Description of the existing and proposed stormwater management
system
A grading plan showing proposed and existing contours (recommended
minimum (contour interval of 2 feet, elevations referenced to NGVD)
A site drainage plan (same scale as grading plan) showing the following
existing and proposed drainage features:
Wetlands, lakes and ponds
Overland flow paths
Floodway and floodplain boundaries
Flood prone areas
Discharge points
Storage facilities
Easements and buffers
Drainage divides
Q' An area drainage plan
An erosion and sediment control plan including description and depiction of
measures to be taken
Intermediate and Major Development Submittal Checklist
The following items should be submitted for an Intermediate and Major Development:
Q' Watershed Development Permit Application including:
Site location map of development
Brief description of the proposed development
Signature of applicant or applicant's agent
El A vicinity map with the Parcel Identification Numbers (PIN) of all parcels
comprising the proposed development
El Anticipated dates of initiation and completion of activities
0 Existing and proposed plans (grading, drainage, etc.) of the development
including:
Topography (minimum 2-foot contour interval, elevations referenced to
NGVD)
Location of all roads
Overland Flow Paths
Boundaries of predominate soil types
Boundaries of predominate vegetation
Drainage easements
Location of detention and/or retention basins (including their inflow and
outflow structures)
Location, size and utilized flow capacities of all storm or combined sewers
Location of all utilities and easements
Specifications and dimensions of any proposed channel modifications, location
and orientation of cross -sections
Wetlands, lakes and ponds
Floodplain and floodway boundaries
Flood prone areas
Easements and buffers
Cross-section views for the stormwater management system including:
Existing and proposed conditions
Existing and proposed elevations
Normal and base flood elevations
Overland flow depths and paths
0 Hydrologic and hydraulic report including:
Names of the streams or bodies of water affected
A statement of purpose of the proposed activity
An analysis of the existing drainage system including the methodology
and support calculations in computing runoff rates, runoff
volumes, velocities, water surface elevations, and floodplain and
2
depressional storage. This analysis will also include methodology
and supporting calculations used to determine the effects from the
upstream drainage areas
An analysis of the proposed drainage system including runoff rates, runoff
volumes, velocities, water surface elevations, and floodplain and
depressional storage. This analysis will also include the
methodology and supporting calculations used to determine the
effects from the upstream drainage areas
An analysis of the effects that the improvements will have on the receiving
stream or body of water
All supporting design calculations and computer models
How the proposed project meets all standards of the McHenry County
Stormwater Management Ordinance
El A section in the hydrologic and hydraulic report for detention facilities (if
required) including:
Plots or tabulations of storage volumes and water surface areas with
corresponding water surface elevations
Stage -discharge or outlet rating curves
Design hydrographs of inflow for the 2- and 100-year, critical duration
(for storage) storm event under existing and proposed conditions
Design hydrographs of outflow for the 2- and 100-year, critical duration
(for storage) storm event under existing and proposed conditions
All supporting design calculations
© A soil erosion and sedimentation control plan including:
Name and telephone number of parties responsible for maintenance of
erosion and sediment control practices
The types of control to be used
Site map (same scale as drainage plans) indicating the location of the
control measures
Detail drawings and specifications of the control measures
All supporting design calculations
Sequence of grading and soil disturbances
Estimated installation schedule
Regular maintenance schedule
0 A maintenance plan including:
Name, legal address and telephone numbers of parties responsible for
performing maintenance tasks
Description of annual maintenance tasks
Description of all permanent public or private easements, overland flow
paths and compensatory storage areas
Description of dedicated sources of funding for maintenance
El
Subsurface Drainage (Tiles)
Subsurface drainage survey
Topographical boundary map locating each of the following: each slit
trench; each drain tile with flow direction arrow, tile size and
connection to adjoining properties; summary of tile investigation
report showing trench identification number, tile size, material and
quality, percentage of tile filled with water, percentage of
restrictions caused by sediment, depth of ground cover, tile system
classification; name, address and phone number of person/firm
conducting investigation
0. A listing of all local, state and federal permits or approval letters that may be
required including the application date
El Submitting data required to MCSC, IDNR/OWR and FEMA for a LOMR (if
applicable)
EI Submitting data required to MCSC, IDNR/OWR and FEMA for a LOMA (if
applicable)
0. A copy of the Chicago District, U.S. Army Corps of Engineer's permit or a
letter indicating that a permit is not required (For developments located in, near
or adjacent to a wetland as shown on either the ARID, NWI or the NRCS)
0, IDNR/OWR Dam Safety permit or letter stating that it is not required if the
development includes a dam prior to obtaining a Watershed Development
Permit.
Sealed statement from a registered professional engineer that the application
meets the requirements of the McHenry County Stormwater Management
Ordinance
0
Special Flood Hazard Area Submittal Checklist
These additional items should be submitted for development in a regulatory Floodplain
or flood prone area:
El Location map of the property, drawn to scale on the regulatory floodplain and
floodway maps, and indicating what community it is in
EI Plans (grading, drainage, etc.) of the development including:
Existing and proposed regulatory floodway limit, regulatory floodplain or
flood prone area limit
Existing water line for public bodies of water as defined by IDNR/OWR
Cross-section views of the impacted reach showing existing and proposed
conditions including principal dimensions with existing and
proposed water surface elevations
Normal elevations and 10- and 100-year frequency flood elevations
Copy of the regulatory floodway map with project site delineated and
marked to reflect any proposed changes in the regulatory floodway
QA written hydrologic and hydraulic report including engineering calculation and
supporting data showing that the proposed work will meet the performance
standards of the Ordinance
El Changes in grade resulting from any proposed excavation/filling
Location and dimension of all building and additions to buildings including the
elevations for the lowest floor and lowest opening of all proposed buildings
® For all buildings in the floodplain, elevation certificates of the lowest floor
(including basements) or the elevation to which a non-residential building has
been flood proofed
0 Structural and flood proofing certificates
Elevation certificates of the lowest floor elevation for all residential
structures
Flood proofing certificates that show the elevation to which all non-
residential buildings are flood proofed
Certificates that show that all structures outside the Regulatory Floodplain
or flood prone area have a lowest opening above the flood
protection elevation (FPE)
Public Road Development Submittal Checklist
The following items should be submitted for a Public Road Development:
Watershed Development Permit Application including:
Name, legal address and telephone number of applicant
Name, legal address and telephone number of the owner if different from
the applicant
Name, legal address and telephone number of applicant's agent (if used)
Common address of development
Site location map of development
Brief description of the proposed development
Signature of applicant or applicant's agent
© A listing of all local, state and federal permits or approval letters that may be
required including the application date
El' Report, supporting analyses, documentation and plans of the proposed drainage
system including:
Location and size of all existing and proposed drainage structures and
improvements
Plan, section and profile views of all existing and proposed drainage
structures and improvements
Hydrologic and hydraulic report including:
Names of the streams or bodies of water affected
A statement of purpose of the proposed activity
Anticipated dates of initiation and completion
Documentation and plans of any proposed floodway, floodplain or flood
prone area modifications including construction or reconstruction
of any existing and proposed development
An analysis of the effects that the improvements will have on the receiving
stream or body of water.
All supporting design calculations and computer models
How the proposed project meets all standards of the McHenry County
Stormwater Management Ordinance
A soil erosion and sedimentation control plan including:
Name and telephone number of parties responsible for maintenance of
erosion and sediment control practices
The types of control to be used
Site map (same scale as drainage plans) indicating the location of the
control measures Detail drawings and specifications of the control
measures
0
All supporting design calculations
Sequence of grading and soil disturbances
Estimated installation schedule
Regular maintenance schedule
Wetlands Submittal Checklist
For any development located in or adjacent to a wetland, it is necessary to determine the
location, extent, and jurisdictional status of all potential wetland areas. A wetland
determination report shall be prepared and submitted with any development permit
application. If the area involves farmed wetlands subject to USDA-NRCS authority, a
copy of that determination shall be submitted. If the applicant has requested a received a
"Jurisdictional Determination" from the USACE for the subject area, that should also be
submitted.
Any of the preceding wetland information submitted with a development permit
application must be no more than two years old, to ensure that the information is still
current.
The following items in the first grouping are typically contained in a wetland
determination. The second, third and fourth groupings must be submitted if the proposed
wetland impact proposes compensatory wetland mitigation.
0 Wetland Determination Report
Aerial photograph showing wetlands and project boundaries
Hydric soil map and verification
Watershed boundaries
Detailed wetland plant lists and representative color photographs
A written description of the wetland(s) including a functional assessment
of at least the hydrologic functions, water quality functions and
special considerations
0' Wetland Mitigation Plan
Names, addresses and telephone numbers of principals associated with
implementation of the mitigation plan
Statement of the concept, goals and objectives of the mitigation plan.
Mapping of the development sites proposed conditions including wetland
alterations, topography (recommended 1 "= 200' and 2' minimum
contours), erosion and sediment control practices and construction
storage and staging areas
Documentation of hydrologic analysis that include normal and 100-year
surface elevations and estimated seasonal water surface elevations
A plan identifying how a site will be prepared for planting
A planting plan which will notate the wetland community location, plant
species, propagule type, commercial source of planting stock,
planting density, planting method and planting schedule
Statement of performance criteria for evaluating the success of the
mitigation plan
Wetland Monitoring Plan
Names, addresses and telephone numbers of principals responsible for
management and monitoring
Statement of expected management techniques and schedule
Monitoring schedule, methods and reporting schedule
El' Long -Term Maintenance Plan
Names, addresses and telephone numbers of principals responsible for
long-term maintenance
Documentation of all deed restrictions, covenants or conservation
easements
Documentation of a funding mechanism for the long-term maintenance of
the wetlands
0