(A) Title, statutory authority.
(1) This chapter shall be known and may be cited as the “Village of Forreston Stormwater Management Ordinance”.
(2) The Village Board adopts this chapter pursuant to its authority to regulate stormwater management and govern the location, width, course and release rate of all stormwater runoff channels, conduits, streams and basins in the village. This chapter is enacted pursuant to the police powers granted to the village by 65 ILCS 5/11-110-1 et seq.
(B) Purpose.
(1) The principal purpose of this chapter is to promote effective, equitable, acceptable and legal stormwater management measures by establishing reasonable rules and regulations for development.
(2) Other purposes of this chapter include:
(a) Managing and mitigating the effects of urbanization on stormwater drainage throughout the village through planning, appropriate engineering practices and proper maintenance;
(b) Protecting the public health safety and reducing the potential for loss of human life and property from flood damage;
(c) Protecting the public from degradation of water quality;
(d) Controlling sediment and erosion in and from stormwater facilities, development and construction sites and reducing and repairing stream bank erosion;
(e) Requiring planning for new development to provide for water resource management, taking into account natural features such as vegetation, wildlife, waterways, wetlands and topography in order to reduce the probability that new development will create unstable conditions susceptible to erosion or degrade the quality of groundwater and surface waters;
(f) Reducing flood damage by requiring appropriate and adequate provisions for site runoff control, especially when the land is developed with a large amount of impervious surface;
(g) Encouraging the use of stormwater storage and infiltration of stormwater in preference to stormwater conveyance;
(h) Lessening the taxpayer’s burden for flood-related disasters, repairs to flood-damaged public facilities and utilities, and flood rescue and relief operations caused by increased stormwater runoff quantities from new development and redevelopment;
(i) Protecting and improving surface water quality and promoting beneficial uses of
ponds, lakes, wetlands and streams by reducing point source and nonpoint source discharges of pollutants;
(j) Requiring regular, planned maintenance of stormwater management facilities;
(k) Requiring control of stormwater quality at the most site-specific level and preventing unauthorized or unmitigated discharge of flow off site; and
(l) Requiring strict compliance with and enforcement of this chapter.
(C) Definitions. For the purpose of this chapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
AGRICULTURAL LAND. Land predominantly used for agricultural purposes.
ALLOWABLE PEAK DISCHARGE. The rate of flow allowed to escape beyond the confines of the property.
APPLICABLE ENGINEERING PRACTICE. Procedures, methods or materials recommended in standard engineering textbooks or references as suitable for the intended purpose.
APPLICANT. Any person who submits an application under this chapter.
BASE FLOOD. The flood having a 1% probability of being equaled or exceeded in a given year (100-year event).
BFE and BASE FLOOD ELEVATION. The highest water surface elevation that can be expected during the base flood.
BMP and BEST MANAGEMENT PRACTICES. A measure used to control the adverse stormwater-related effects of development, and includes structural devices (for example, swales, filter strips, infiltration trenches and site runoff storage basins), designed to remove pollutants, reduce runoff rates and volumes, and protect aquatic habitats, and nonstructural approaches, such as public education efforts to prevent the dumping of household chemicals into storm drains.
BUFFER. An area of predominantly deeply rooted native vegetative land adjacent to channels, wetlands, lakes, ponds, rivers or streams for the purpose of stabilizing banks, reducing contaminants, including sediments in stormwater that flow to such areas.
BUILDING. A structure that is principally above ground and is enclosed by walls and a roof; a building includes a gas or liquid storage tank, a manufactured home or prefabricated building.
BULLETIN 71. The Rainfall Frequency Atlas of the Midwest, by Floyd A. Huff and James R. Angel of the Illinois State Water Survey (1992). Furthermore, rainfall distributions shall be in accordance with the minimums as set forth in Table 1: Sectional Mean Frequency Distributions for Storm Periods of 5 Minutes to 10 Days and Recurrence Intervals of 2 Months to 100 Years in Illinois. Durations shall be based upon the 24-hour storm event rainfall intervals for Sectional Code 01 (Northwest).
CHANNEL. Any river, stream, creek, brook, branch, natural or artificial depression, ponded area, flowage, slough, ditch, conduit, culvert, gully, ravine, wash or natural or human-made drainageway which has a definite bed and bank or shoreline, in or onto which surface water, groundwater, effluent or industrial discharges flow.
CHANNEL MODIFICATION. Alteration of a channel by changing the physical dimensions or materials of its beds or banks, and includes damming, rip-rapping (or other armoring), widening, deepening, straightening, relocating, lining and significant removal of bottom or woody rooted vegetation, but does not include clearing of debris or removal of trash or dredging to previously documented elevations and side slopes.
COMPENSATORY STORAGE. An excavated, hydrologically and hydraulically equivalent volume of storage created to offset the loss of existing flood storage.
CONTROL STRUCTURE. A structure designed to control the rate of flow that passes through the structure given a specific upstream and downstream water surface elevation.
CRITICAL DURATION. The duration of a storm event that results in the greatest peak runoff.
DAM. Any obstruction, wall embankment or barrier, together with any abutments and appurtenant works, constructed to store or divert water or to create a pool (not including underground water storage tanks).
DEPRESSIONAL STORAGE. The volume contained below a closed contour on a one-foot contour interval topographical map, the upper elevation of which is determined by the invert of a surface gravity outlet.
DETENTION FACILITY. A facility which stores stormwater runoff with a normally dry basin and a gravity release.
DEVELOPER. A person who creates or causes a development.
DEVELOPMENT.
(a) The term DEVELOPMENT means any human-made change to the land and includes:
1. Preparation of a plat of subdivision for three or more parcels;
2. The construction, reconstruction, repair or replacement of a building or an
addition to a building;
3. Redevelopment of a site for commercial and/or industrial purposes;
4. The installation of utilities, construction of roads, bridges or similar projects;
5. Drilling and mining;
6. The construction of levees, walls, fences, dams or culverts;
7. Channel modifications, filling, dredging, grading, excavating, paving or other nonagricultural alterations of the ground surface;
8. The storage of materials and the deposit of solid or liquid waste;
9. Any wetland impact; and
10. Any other activity of humans that might change the direction, height or velocity of flood or surface waters, including the extensive removal of vegetation.
(b) The term DEVELOPMENT, however, does not include:
1. Maintenance of existing buildings and facilities, such as re-roofing or resurfacing of roads, driveways or parking areas where there is no increase in elevation;
2. For agricultural uses, maintenance of existing drainage systems for the limited purpose of maintaining cultivated areas and crop production;
3. For agricultural uses, improvements undertaken pursuant to a written NRCS conservation plan; or
4. Maintenance, construction or rehabilitation of certain village capital improvements infrastructure projects which may include, but are not limited to, street and/or roadway pavement removal and replacement, resurfacing, overlays, widening, curb and gutter installation, storm sewers, drainage systems and the removal/replacement or addition of sidewalks or other pedestrian paths.
DRAINAGE AREA. The land area above a given point that may contribute runoff flow at the point from rainfall.
EROSION. The process whereby soil is detached by the action of water or wind.
FEMA. The Federal Emergency Management Agency, Department of Homeland Security, or its duly authorized designee.
FLOOD. A general and temporary condition of partial or complete inundation of normally dry land areas from overflow of inland or tidal waters or the unusual and rapid accumulation of runoff or surface waters from any source. Refer to additional requirements in Chapter 151 of this code of ordinances (Flood Control Regulations).
FLOOD FREQUENCY. A frequency normally expressed as a period of years, based upon a percent chance of occurrence in any given year from statistical analysis, during which a flood of a stated magnitude may be expected to be equaled or exceeded, as in the two-year flood frequency has a 50% chance of occurrence in any given year and the 100-year flood frequency has a 1% chance of occurrence in any given year. Refer to additional requirements in Chapter 151 of this code of ordinances (Flood Control Regulations).
FLOOD FRINGE. That portion of the floodplain outside of the designated floodway. Refer to additional requirements in Chapter 151 of this code of ordinances (Flood Control Regulations).
FLOODPLAIN. That land typically adjacent to a body of water with ground surface elevations at or below the base flood or the 100-year frequency flood elevation. Refer to additional requirements in Chapter 151 of this code of ordinances (Flood Control Regulations).
FLOODWAY and DESIGNATED FLOODWAY. The channel, on-stream lakes and that portion of the floodplain adjacent to a stream or channel which is needed to store and convey the 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. Refer to additional requirements in Chapter 151 of this code of ordinances (Flood Control Regulations).
FLOODWAY CONVEYANCE. The measure of the flow carrying capacity of the floodway section. Refer to additional requirements in Chapter 151 of this code of ordinances (Flood Control Regulations).
FREEBOARD. The increment of height added to the 100-year design water surface elevation to provide a factor of safety for uncertainties in calculations, unknown local conditions, wave action and unpredictable effects such as those caused by ice or debris jams. Refer to additional requirements in Chapter 151 of this code of ordinances (Flood Control Regulations).
HYDROGRAPH. The graph produced by a table of ordinates showing the flow rate, or discharge, with respect to time for a given location in a drainage area.
HYDROLOGY. The science of the behavior of water, including its dynamics, composition and distribution in the atmosphere, on the surface of the earth, and underground.
IDNR-OWR. The Illinois Department of Natural Resources, Office of Water Resources, or its duly authorized designee.
IEPA. The Illinois Environmental Protection Agency, or its duly authorized designee.
IMPERVIOUS AREA. Those areas which contain concrete or asphalt ground cover, pavements, structures, rooftops, compacted aggregate surfaces, compacted soils, curbs or other areas of significant impermeability as may be determined by the Village Engineer.
INFILTRATION. The passage or movement of water into the soil surfaces.
MAJOR STORMWATER FACILITY. That portion of a stormwater facility needed to store and convey flows beyond the capacity of the minor stormwater system.
MASS GRADING. Development in which the primary activity is a change in topography affected by the movement of earth materials.
MINOR STORMWATER FACILITY. All infrastructure including curb, gutter, culverts, conduits, roadside ditches and swales, storm sewers, and subsurface drainage systems intended to convey stormwater runoff at less than a ten-year frequency.
MITIGATION. Measures taken to offset negative impacts from development and includes those measures necessary to minimize the negative effects that stormwater drainage, as a result of development activities, has on the public health, safety and welfare.
ON-STREAM STORAGE FACILITIES. Site runoff storage facilities located within the floodway.
OVERLAND FLOW PATH. A design feature of the major stormwater system which carries flows in excess of the minor stormwater system design capacity in an open channel or swale, or as sheet flow or weir flow over a feature designed to withstand the particular erosive forces involved.
PEAK FLOW. The maximum rate of flow of water at a given point in a channel or conduit.
POSITIVE DRAINAGE. Provision for overland paths for all areas of a property including depressional areas that may also be drained by storm sewer.
PROFESSIONAL ENGINEER. An engineer registered in the state under the Illinois Professional Engineering Practice Act of 1989, 225 ILCS 325/1 et seq.
PROFESSIONAL LAND SURVEYOR. A land surveyor registered in the state under the Illinois Professional Land Surveyor Act of 1989, 225 ILCS 330/1 et seq.
RECORD DRAWINGS. Drawings prepared, signed and sealed by a professional engineer or professional land surveyor representing the final record of the actual in-place elevations, locations of structures and topography of proposed improvements.
REGIONAL STORAGE FACILITY. A site runoff storage facility that stores stormwater from multiple parcels of land.
REGULATORY FLOODPLAIN. The floodplain depicted on maps recognized by IDNR-OWR for regulatory purposes.
REGULATORY FLOODWAY. The floodway depicted on maps recognized by IDNR-OWR for regulatory purposes.
RETENTION FACILITY. A facility which stores stormwater runoff with a normally wet basin and with or without a gravity release.
RUNOFF. The waters derived from melting snow or rain falling within a tributary drainage basin that exceeds the infiltration capacity of the soils of that basin.
SEDIMENTATION. The process that deposits hydraulically moved soils, debris and other materials on other ground surfaces or in bodies of water or stormwater drainage systems.
SITE. All of the land contemplated to be part of a coordinated development of one or more parcels.
SITE RUNOFF STORAGE FACILITY and STORAGE FACILITY. A human-made structure or area for the temporary storage of stormwater runoff with a controlled release rate.
SPECIAL FLOOD HAZARD AREA or SPECIAL MANAGEMENT AREA. A floodplain, regulatory floodplain or floodway, wetland, wetlands mitigation area, stream, river or other water body.
STORMWATER FACILITY. All ditches, channels, conduits, bridges, culverts, levees, ponds, natural and human-made impoundments, wetlands, riparian environments, tiles, swales, sewers or other natural or artificial structures or measures which serve as a means of draining surface water and groundwater from land.
TIME OF CONCENTRATION. The elapsed time for stormwater to flow from the most hydraulically remote point in a drainage basin to a particular point of interest in that watershed.
TRIBUTARY WATERSHED. All of the land surface area that contributes runoff to a given point.
USACE. The United States Army Corps of Engineers.
VILLAGE. The Village of Forreston, Illinois, or its representatives.
WATERSHED. All land drained by, or contributing to, the same stream, lake, stormwater facility or draining to a point.
WETLAND RETENTION AREA. That area of the retention facility that contains permanent shallow waters that commonly support aquatic beds and emergent plants (erect, rooted, non woody plants that are mostly above water). These areas shall be generally free from non-native and noxious seed and plant growth. The Village Engineer, upon review of a landscape plan, shall make final determination as to the appropriateness of the proposed plantings.
(Prior Code, § 4-4-1) (Ord. 2015-17, passed 8-3-2015)