For the purpose of this chapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
ADVERSE IMPACTS. Any negative impact on plant, soil, air or water resources affecting their beneficial uses including recreation, aesthetics, aquatic habitat, quality, and quantity.
APPLICANT. Any person, firm, or governmental agency who executes the necessary forms to procure official approval of a development or permit to carry out construction of a new development or re-development from the Village of Maryville.
BASE FLOOD ELEVATION. The elevation at all locations delineating the level of flooding resulting from the 100-year frequency flood event, which has a 1% chance of occurring in any given year.
BUILDING PERMIT. A permit issued by the Village of Maryville for the construction, erection or alteration of a structure or building and the related ground and surface preparation prior to and after completion of construction, erection or alteration of a structure or building.
BYPASS FLOWS. Stormwater runoff from upstream properties tributary to a property’s drainage system but not under its control.
CERTIFY OR CERTIFICATION. Formally attesting that the specific inspections and tests were performed, and that such inspections and tests comply with the applicable requirements of this chapter.
CHANNEL. Any defined river, stream, creek, brook, branch, natural or artificial depression, ponded area, on-stream lake or impoundment, Karst area (sinkhole), flowage, slough, ditch, conduit, culvert, gully, ravine, wash, or natural or manmade drainage way, which has a definite bed and bank or shoreline, 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, riprapping (or other armoring), filling, widening, deepening, straightening, relocating, lining, and significant removal of bottom or woody rooted vegetation. Channel modification does not include the manmade clearing of debris or removal of trash.
CLEARING. Any activity which removes the natural vegetative ground cover.
COMPENSATORY STORAGE. An artificially excavated, hydraulically equivalent volume of storage within the floodplain used to balance the loss of natural flood storage capacity when fill or structure are placed within the floodplain.
CONDUIT. Any channel, pipe, sewer or culvert used for the conveyance or movement of water, whether open or closed.
CUBIC YARD. A one yard by one yard by one yard amount of material in excavation and/or fill.
DETENTION BASIN. A facility constructed or modified to provide for the temporary storage of stormwater runoff and the controlled release by gravity of this runoff at a prescribed rate during and after a flood or storm.
DETENTION TIME. The amount of time stormwater is held within a detention basin.
DEVELOPMENT. Any manmade change to real estate or property, including:
(1) The division or subdivision of any duly recorded parcel of property;
(2) Construction, reconstruction or placement of a building or any addition to a building;
(3) Installation of a manufactured home on a site, preparing a site for a manufactured home, or installing a travel trailer on a site for more than 180 days per year;
(4) Construction of roads, bridges, or similar projects;
(5) Redevelopment of a site;
(6) Filling, dredging, grading, clearing, excavating, paving or other non-agricultural alterations of a ground surface;
(7) Storage of materials or deposit of solid or liquid waste;
(8) Any other activity that might alter the magnitude, frequency, direction, or velocity of stormwater flows from a property.
DRAINAGE PLAN. A plan, including engineering drawings and supporting calculations, which describes the existing stormwater drainage system and environmental features, including grading, as well as proposed alterations or changes to the drainage system and environment of a property.
DRY BASIN. A detention basin designed to drain after temporary storage of stormwater flows and to normally be dry over much of its bottom area.
EROSION. The general process whereby soil or earth is moved by rainfall, flowing water, wind or wave action.
EXCAVATION. Any act by which organic matter, earth, sand, gravel, rock or any other similar material, is cut into, dug, quarried, uncovered, removed, displaced, re-located or bulldozed and shall include the conditions resulting from such actions.
EXCESS STORMWATER RUNOFF. The volume and rate of flow of stormwater discharged from a new development or re-development which is or will be in excess of that volume and rate which existed before development or re-development.
EXISTING GRADE. The vertical location of the existing ground surface prior to excavation or filling.
FILL. Any act by which earth, sand, gravel, rock, or any other material, is deposited, placed, replaced, pushed, dumped, pulled, transported or moved by man to a new location and shall include the conditions resulting therefrom.
FINAL GRADE. The vertical location of the ground surface after grading work is completed in accordance with the engineering plans.
FLOOD FRINGE. That area as designated by the Federal Emergency Management Agency (FEMA) on either side of the floodway. This area is subject to inundation from the base flood but conveys little or no flow.
FLOOD HAZARD BOUNDARY MAP (FHBM). A very generalized map prepared by the Federal Emergency Management Agency (FEMA) which shows only where floodplains are located based on very basic data. FHBM’s do not include base flood elevations.
FLOOD INSURANCE RATE MAP (FIRM). A map prepared by the Federal Emergency Management Agency (FEMA) that depicts the special flood hazard area (SFHA) within a community. This map includes insurance rate zones and regulatory floodplains and may or may not depict regulatory floodways.
FLOODPLAIN. That land adjacent to a body of water with ground surface elevations at or below the base flood or the 100-year frequency flood elevation which is subject to inundation. The floodplain as designated by the Federal Emergency Management Agency (FEMA) is also known as the Special Flood Hazard Area (SFHA). These areas can be found on the (FIRM), Flood Boundary and Floodway Map, or the Flood Hazard Boundary Map (FHBM) of the community. This area is the collective combination of the regulatory floodway and the flood fringe.
FLOODWAY. The channel and that portion of the floodplain, including on-stream lakes, adjacent to a stream or watercourse which is needed to store and convey the anticipated existing and future 100-year frequency flood discharge with no more than a 0.1 foot increase in stage due to any loss of flood conveyance or storage and no more than a 10% increase in velocities. Floodways are designated by FEMA on some Flood Insurance Rate Maps and Flood Boundary and Floodway Maps. However, there are floodways on all streams whether mapped by FEMA or not.
GRADING. The excavation or fill or any combination thereof and shall include the conditions resulting from any excavation or fill.
HYDROGRAPH. A graph showing for a given location on a stream or conduit, the flow rate with respect to time.
HYDROGRAPH METHOD. This method estimates runoff volume and runoff hydrographs for the point of interest by generating hydrographs for individual sub areas, combining them, and routing them through stream lengths and reservoir structures. Factors such as rainfall amount and distribution, runoff curve number, time of concentration, and travel time are included.
IMPERVIOUS SURFACE. That area of property that is covered by materials other than soil and vegetation and that has no intended capacity to absorb water, such as parking lots, driveways, sidewalks, patios, tennis courts, roofs and other structures.
INFILTRATION. The passage or movement of water into the soil surfaces.
LOESSAL SOIL. A sediment, commonly non-stratified and un-consolidated, composed predominately of silt sized particles with accessory clay and sand.
LOT. An individual platted parcel in an approved subdivision.
MAJOR DRAINAGE SYSTEM. That portion of a drainage system needed to store and convey flows beyond the capacity of the minor drainage system.
MINOR DRAINAGE SYSTEM. That portion of a drainage system designed for the convenience of the public. It consists of street gutters, storm sewers, small open channels, and swales and, where manmade, is to be designed to handle the ten-year runoff event.
MITIGATION. Mitigation is when the prescribed controls are not sufficient and additional measures are required to offset the development, including those measures necessary to minimize the negative effects which stormwater drainage and development activities might have on the public health, safety and welfare. Examples of mitigation include, but are not limited to compensatory storage, soil erosion and sedimentation control, and channel restoration.
MODIFIED RATIONAL METHOD. As described in the Illinois Department of Transportation “Drainage Manual” is based on the principal that the maximum rate of runoff from a given drainage area occurs at that point in time when all parts of the watershed are contributing to the flow. The rainfall generating the peak flow is assumed to be of uniform intensity for the entire watershed with a rainfall duration equal to the time of concentration.
NATURAL. Conditions resulting from physical, chemical, and biological processes without intervention by man.
NATURAL DRAINAGE. Channels formed in the existing surface topography of the earth prior to changes made by unnatural causes.
ONE HUNDRED-YEAR EVENT. A rainfall, runoff, or flood event having a 1% chance of occurring in any given year. A 24-hour storm duration is assumed unless otherwise noted.
PARCEL. All contiguous land in one ownership.
PEAK FLOW. The maximum rate of flow of water at a given point in a channel or conduit.
PERMITTEE. Any person to whom a building permit is issued.
PERSON. Any individual, firm or corporation, public or private, the State of Illinois and its agencies or political subdivisions, the United States of America, and its agencies or political subdivisions, and any agent, servant, officer or employee of any of the foregoing.
POSITIVE DRAINAGE. Provision for overland paths for all areas of a property including depressional areas that may also be drained by storm sewer.
PRIME FARMLAND. Land that is best suited to food, feed, forage, fiber and oilseed crops. It may be cropland, pasture, woodland, or other land, but it is not urban and built up land or water areas. It is either used for food or fiber or is available for those uses. The soil qualities, growing season and moisture supply are those needed for a well managed soil to economically produce a sustained high yield of crops. Prime farmland produces the highest yields with minimum inputs of energy and economic resources, and farming it results in the least damage to the environment.
PROPERTY. A parcel of real estate.
RETENTION BASIN. A facility designed to completely retain a specified amount of stormwater runoff without release except by means of evaporation, infiltration, emergency bypass or pumping.
SEDIMENTATION. The process that deposits soils, debris, and other materials either on other ground surfaces or in bodies of water or stormwater drainage systems.
SINKHOLE, (KARST AREAS). A Sinkhole or Karst topography is a land surface depression or blind valley which may or may not have surface openings to cavernous underground areas and are the result of water movement through silts and jointed limestone. These conditions make such areas unstable and susceptible to subsidence and surface collapse. Fractures in the limestone may channel runoff water to public or private water supplies, making those sources especially susceptible to groundwater contamination.
SITE. A parcel of land, or a contiguous combination thereof, where grading work is performed as a single unified operation.
SLOPE DISTURBANCE LINE. The line which delineates relatively level building areas from areas where slopes exceed 8% and where special precautions must be taken.
STORM SEWER. A closed conduit for conveying collected stormwater.
STORMWATER DRAINAGE SYSTEM. All means, natural and manmade, used for conducting stormwater to, through or from a drainage area to the point of final outlet from a property. The stormwater drainage system includes but is not limited to any of the following: conduits and appurtenance features, canals, channels, ditches, streams, culverts, streets, storm sewers, detention basins, swales and pumping stations.
STORMWATER RUNOFF. The waters derived from melting snow or rain falling within a tributary drainage basin which are in excess of the infiltration capacity of the soils of that basin, which flow over the surface of the ground or are collected in channels or conduits.
STREAM. Any river, creek, brook, branch, flowage, ravine, or natural or manmade drainage way which has a definite bed and banks or shoreline, in or into which surface or groundwater flows, either perennially or intermittently.
STRIPPING. Any activity which removes the vegetative surface cover including tree removal, by spraying or clearing, and storage or removal of top soil.
TEN-YEAR EVENT. A runoff, rainfall, or flood event having a 10% chance of occurring in any given year. A 24-hour storm duration is assumed unless otherwise note.
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.
TWO-YEAR EVENT. A runoff, rainfall, or flood event having a 50% chance of occurring in any given year. A 24-hour storm duration is assumed unless otherwise noted.
VACANT. Land on which there are no structures or only structures which are secondary to the use or maintenance of the land itself.
WATERSHED. All land area drained by, or contributing water to, the same stream, creek, ditch, lake, marsh, stormwater facility, groundwater or depressional area.
WET BASIN. A detention basin designed to maintain a permanent pool of water after the temporary storage of stormwater runoff.
WETLANDS. Wetlands are defined by regulation as “those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions.” For general, but not inclusive locations of designated wetlands refer to mapping prepared jointly by the U.S. Department of Interior, Fish and Wildlife Service and the Illinois Department of Natural Resources, Office of Resource Conservation; National Wetlands Inventory Mapping, 1987. The applicant may be required to provide a field investigation by a qualified wetland delineator.
(Ord. passed 12-9-02)