§ 55.005  DEFINITIONS.
   For the purposes of this chapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
   ADMINISTRATIVE VIOLATION.  Occurs when rules and procedures regarding permit applications and stormwater management permits are not followed.
   ADMINISTRATOR.  The person designated by the permitting authority to administer and enforce this chapter.
   AGRICULTURAL REVIEW ADVISORY COMMITTEE.  Shall be composed of at least three county residents who live and own and operate or tenant operate at least 60 contiguous acres of farmland in the county and representatives appointed by the following agencies: Will and South Cook Soil and Water Conservation District U.S.D.A., Natural Resource Conservation Service and the County Farm Bureau. The Stormwater Management Committee will appoint these individuals in accordance with Article 3, § 1D of the bylaws. The Stormwater Committee will consider Committee member nomination recommendations from any active county agricultural not for profit organization.
   AGRICULTURAL SUBSURFACE DRAINAGE.  A water management technique driven by economic and safety concerns, where the rate at which surplus ground water should be removed is determined primarily by the moisture/air requirements of the vegetation (commonly called “tiles”, “field tiles” and the like).
   APPLICABLE ENGINEERING PRACTICE.  Procedures, methods or materials recommended in standard engineering textbooks or references as suitable for the intended purpose.
   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 development from the county or appropriate certified local governmental unit.
   APPROPRIATE USE.  Only uses of the designated floodway that are permissible and will be considered for permit issuance. The list of permissible uses is contained in §§ 55.060 through 55.066.
   BASE FLOOD.  The flood having a 1% probability of being equaled or exceeded in a given year.
   BASE FLOOD ELEVATION (BFE).  The highest water surface elevation that can be expected during the base flood.
   BEST MANAGEMENT PRACTICES (BMP).  A measure used to control the adverse stormwater-related effects of development. BMPs include structural devices (e.g., swales, filter strips, infiltration trenches and detention basins) designed to remove pollutants, reduce runoff rates and volumes and protect aquatic habitats. BMPs also include nonstructural approaches, such as public education efforts to prevent the dumping of household chemicals into storm drains.
   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 to be installed on a site for more than 180 days, unless fully licensed and ready for highway use.
   BUFFER.  An area of predominantly vegetated land located adjacent to channels, wetlands, lakes or ponds for the purpose of reducing contaminants in stormwater that flows to those areas.
   BULLETIN 70.Frequency Distributions of Heavy Precipitation in Illinois: Updated Bulletin 70 by James Angel and Momcilo Marcus of the Illinois State Water Survey, Prairie Research Institute (March 2019).
   BYPASS FLOWS.  Stormwater runoff or ground water from upstream properties tributary to a property’s drainage system but not under its control.
   CERTIFIED COMMUNITY.  A community which has met the requirements to be delegated the responsibility for ordinance enforcement as determined by the Stormwater Committee.
   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 drainage way, which has a definite bed and bank or shoreline, in or into which surface, ground water, effluent or industrial discharges flow 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), widening, deepening, straightening, relocating, lining and significant removal of bottom or woody rooted vegetation but does not include the clearing of debris or removal of trash or dredging to previously documented thalwag elevations and side slopes.
   COMMERCIAL.  Sale of goods to the public at large where the traffic generated warrants construction of site improvements.
   COMMERCIAL REDEVELOPMENT.  Development on a parcel upon which the existing condition is buildings, parking lots and infrastructure associated with commercial activities. Additions to existing buildings and new impervious surfaces added after the effective date of the chapter are specifically excluded from this definition.
   COMMITTEE. The County Stormwater Management Committee.
   COMMUNITY.  The county or any city or village within the county.
   COMPENSATORY STORAGE.  An excavated, hydrologically and hydraulically equivalent volume of storage created to offset the loss of existing flood storage.
   CONDITIONAL LETTER OF MAP AMENDMENT (CLOMA). A FEMA comment letter on a development proposed to be located in, and affecting only that portion of, the area of floodplain outside the regulatory floodway and having no impact on the existing regulatory floodway or base flood elevations.
   CONDITIONAL LETTER OF MAP REVISION (CLOMR). A letter that indicates that FEMA will revise base flood elevations, flood insurance rate zones, flood boundaries or floodways as shown on an effective FIRM or FBFM after the record drawings are submitted and approved.
   COE.  The United States Army Corps of Engineers.
   CONSERVATION PLANNING.  The practices and procedures associated with the management of soil, water, plants, plant nutrients and other elements of agricultural production. Documentation of the management system shall only be as required by the NRCS or in cases of a complaint, as requested by the Administrator in response to a notification of a complaint.
   CONTROL STRUCTURE.  A structure designed to limit the rate of flow that passes through the structure to a specific rate, given a specific upstream and downstream water surface elevation.
   COUNTY.  Will County, Illinois.
   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).
   DEPARTMENT.  The County Land Use Department.
   DEPRESSIONAL STORAGE.  The volume contained below a closed contour on a one-foot contour interval topographic map, the upper elevation which is determined by the invert of a surface gravity outlet.
   DETENTION BASIN (SITE RUNOFF STORAGE FACILITY).  A constructed structure for the temporary storage of stormwater runoff with a controlled release rate.
   DEVELOPER.  A person who creates or causes a development.
      (1)   Any constructed change to real estate including:
         (a)   Construction, reconstruction, repair or replacement of a building or an addition to a building;
         (b)   Installing a manufactured home on a site, preparing a site for a manufactured home, or installing a travel trailer or recreational vehicle on a site for more than 180 days. If the travel trailer or recreational vehicle is on-site for less than 180 days, it must be fully licensed and ready for highway use;
         (c)   Drilling, mining, installing utilities, construction of roads, bridges or similar projects;
         (d)   Construction or erection of levees, walls, fences, dams or culverts, channel modifications, filling, dredging, grading, excavating, paving or other nonagricultural alterations of the ground surface, storage materials, deposit of solids or liquid waste;
         (e)   Any other activity of humans that might change the direction, height or velocity of flood or surface water, including extensive vegetation removal; and/or
         (f)   Plowing and cultivation and other similar agricultural practices that do not involve filling, grading or construction of levees as regulated in § 55.024.
      (2)   The following are not considered development: maintenance of existing buildings and facilities such as reroofing or resurfacing of roads with an impervious surface when there is no increase in elevation.
   DIRECT DISCHARGE SITE.  Parcels of land, or portions thereof, which are immediately adjacent and naturally drain directly to the banks of the Des Plaines River, Chicago Sanitary and Ship Canal, DuPage River and Kankakee River without crossing over other private or public property.
   DIRECTOR.  The County Executive or his or her designee charged with performing the duties specified in this chapter.
   DRAINAGE AREA. The land area above a given point that may contribute runoff flow at that point from rainfall.
   EFFECTIVE DATE.  The date to be determined by the County Board.
   ELEVATION CERTIFICATES. A form published by FEMA, or its equivalent, that is used to certify the base flood elevation and the lowest elevation of usable space to which a building has been constructed.
   EPHEMERAL STREAM.  A stream whose bed elevation does not intersect the ground water table, it carries flow only during and immediately after a runoff producing rainfall event.
   EROSION.  The process whereby soil is detached by the action of water or wind.
   EXISTING MANUFACTURED HOME PARK OR SUBDIVISION. A manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including at a minimum the installation of utilities, the construction of streets and either final site grading or the pouring of concrete pads) has been completed before April 1, 1990.
   EXPANSION TO AN EXISTING MANUFACTURED HOME PARK OR SUBDIVISION.  The preparation of additional sites by the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including the installation of utilities, the construction of streets and either final site grading or the pouring of concrete pads).
   EXTENDED DETENTION.  A volume of runoff temporarily detained and released over a long period of time as specified in § 55.023.
   FEE-IN-LIEU OF DETENTION. A fee paid by a developer to the permitting authority, commensurate with the costs and fee schedules adopted by the county and/or the certified community based on the detention volume required for the development to meet the ordinance release rates. Rules and procedures for fee in lieu of detention are contained in § 55.215 of this chapter.
   FEDERAL EMERGENCY MANAGEMENT AGENCY (FEMA).  The federal agency and its regulations, at 44 C.F.R. §§ 59 through 79, effective as of September 29, 1989 or as amended.
   FLOOD.  A general and temporary condition of partial or complete inundation of normally dry land areas from overflow of inland or tidal ways or the unusual and rapid accumulation of runoff of surface waters from any source.
   FLOOD BOUNDARY AND FLOODWAY MAP (FBFM).  A floodplain management map issued by FEMA that depicts, based on detailed analysis, the boundaries of the base flood, the 0.2% probability flood and the floodway.
   FLOOD FREQUENCY.  Normally expressed as a period of years, based on 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. For example, the two-year flood frequency has a 50% chance of occurrence in any given year. Similarly, the 100-year flood frequency has a 1% chance of occurrence in any given year.
   FLOOD FRINGE.  The portion of the floodplain outside of the designated floodway.
   FLOOD HAZARD BOUNDARY MAP (FHBM). A map issued by FEMA that is an official community map, which depicts generalized areas of floodplains, replaced by a detailed flood insurance study.
   FLOOD INSURANCE RATE MAP (FIRM).  A map issued by FEMA that is an official community map, on which map FEMA has delineated both the special flood hazard areas and the risk premium zones applicable to the community. This map may or may not depict floodways.
   FLOOD INSURANCE STUDY (FIS).  A study of flood discharges and flood profiles for a community, adopted and published by FEMA.
   FLOODPLAIN.  The 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 including detached special flood hazard areas, ponding areas and the like. The floodplain is also known as the SPECIAL FLOOD HAZARD AREAS (SFHA).
   FLOOD PROTECTION ELEVATION (FPE).  The elevation of the BFE plus one foot of freeboard for structures within the plan limits of the base flood elevation. Outside the plan limits, the water table or 100-year design water surface elevation of any adjacent stormwater facility, whichever is higher, plus one foot of freeboard.
   FLOODPROOF. Any combination of structural and nonstructural 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 FEMA that is used to certify that a building has been designed and constructed to be structurally dry floodproofed to the FPE.
   FLOODWAY or DESIGNATED FLOODWAY. Includes 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 one-tenth-foot increase in flood stage due to the loss of flood conveyance or storage, and no more than a 10% increase in velocities.
   FLOODWAY CONVEYANCE.  The measure of the flow carrying capacity of the floodway section and is defined using Manning’s equation as:
   K = 1.4863 AR 23 /n
where “n” is Manning’s roughness factor, “A” is the effective area of the cross-section, and “R” is ratio of the wetted area to the wetted perimeter.
   FREEBOARD.  An increment of height added to the BFE or 100-year design water surface elevation 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.  Refers to stormwater facilities, which serve their primary purpose of meeting developed release rate requirements but do not meet all of the final design conditions. For example, a detention basin, which has been excavated but has not, had the side slopes graded, nor the final landscaping placed, may be considered FUNCTIONAL as a site runoff storage facility.
   GOOD HUSBANDRY.  Generally accepted agricultural practices found in good farm management.
   GROUND WATER.  Water that is located within soil or rock below the surface of the earth. Same as SUBSURFACE WATER.
   GROUND WATER CONTROL SYSTEM.  A designed system which may consist of tiles, under drains, French drains or other appropriate stormwater facilities whose purpose is to lower the ground water table to a predictable elevation throughout the year.
   HISTORIC STRUCTURE.  Any structure that is:
      (1)   Listed individually in the National Register of Historic Places, or preliminarily determined by the Secretary of the Interior as meeting the requirements for individual listing on the National Register;
      (2)   Certified or preliminarily 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;
      (3)    Individually listed on the State Inventory of Historic Places by the State Historic Preservation Agency; and
      (4)   Individually listed on a local inventory of historic places that has been certified by the State Historic Preservation Agency.
   HYDRAULICS. The science and study of the mechanical behavior of water in physical systems and processes.
   HYDRAULICALLY CONNECTED IMPERVIOUS AREA. Consists of those areas of concrete, asphalt and gravel surfaces along with roof tops which convey flows directly to an improved drainage system consisting of storm sewers or paved channels. Rooftops whose downspouts discharge to unpaved surfaces which are designed for the absorption and filtration of stormwater runoff shall not be considered as HYDRAULICALLY CONNECTED IMPERVIOUS SURFACES. Roadways whose primary conveyance is through open ditches and swales shall not be considered as HYDRAULICALLY CONNECTED IMPERVIOUS SURFACE. Roadways drained by curb and gutter and storm sewer, and driveways hydraulically connected to those roadways shall be considered as directly connected impervious surface.
   HYDRAULICALLY EQUIVALENT COMPENSATORY STORAGE. Compensatory storage either adjacent to the floodplain fill or 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 development.
   HYDROLOGICALLY DISTURBED.  An area where the land surface has been cleared, grubbed, compacted or otherwise modified that changes runoff, volumes, rates or direction.
   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 State Department of Natural Resources, Office of Water Resources.
   IMPERVIOUS.  Surfaces that cause the majority of rainfall to be converted to direct runoff. Asphalt, concrete and roofing systems will be considered IMPERVIOUS.
   INDUSTRIAL REDEVELOPMENT.  Development on a parcel upon which the existing condition is buildings, parking lots and infrastructure associated with industrial activities. Additions to existing buildings and new impervious surfaces added after the effective date of the chapter are specifically excluded from consideration as INDUSTRIAL REDEVELOPMENT.
   INTERIM WATERSHED PLAN.  A regional study of a watershed which does not address the entire range of purposes, goals and objectives outlined in the Countywide Stormwater Management Plan approved by the Committee and adopted by the county.
   INTERMITTENT STREAM. A stream whose bed intersects the ground water table for only a portion of the year on the average or any stream which flows continuously for at least one month out of the year but not the entire year.
   LAKE. A natural or artificial body of water encompassing an area of two or more acres, which retains water throughout the year.
   LETTER OF MAP AMENDMENT (LOMA).  The official determination by FEMA that a specific structure is not in a regulatory floodplain. A LOMA amends the effective FHBM, FBFM or FIRM.
   LETTER OF MAP REVISION (LOMR).  A letter from FEMA that revises base flood elevations, flood insurance rate zones, flood boundaries or floodway as shown on an effective FHBM, FBFM or FIRM.
   MAJOR STORMWATER SYSTEM. The portion of a stormwater facility needed to store and convey flows beyond the capacity of the minor stormwater system.
   MANUFACTURED HOME.  A structure transportable in one or more sections, which is built on a permanent chassis and is designated for use with or without a permanent foundation when attached to the required utilities. The term MANUFACTURED HOME also includes park trailers, travel trailers and other similar vehicles placed on site for more than 180 consecutive days. The term MANUFACTURED HOME does not include a recreational vehicle.
   MANUFACTURED HOME PARK OR SUBDIVISION. A parcel (or contiguous parcels) of land divided into two or more manufactured home lots for rent or sale.
   MASS GRADING. Development in which the primary activity is a change in topography affected by the movement of earth materials.
   MINOR STORMWATER SYSTEM.  Consists of all infrastructure including curb, gutter, culverts, roadside ditches and swales, storm sewers and subsurface drainage systems intended to convey stormwater runoff at less than a 100-year flood frequency. The design frequency for MINOR STORMWATER SYSTEMS shall be in accordance with the applicable ordinances of the local Community or Highway Department jurisdiction.
   MITIGATION.  Measures taken to offset negative impacts from development in wetlands or the floodplain.
   NATIONAL FLOOD INSURANCE PROGRAM (NFIP).  A federal program whose requirements are codified in C.F.R. Title 44.
   NET BENEFIT IN WATER QUALITY.  The institution of best management practices as part of a development that when compared to the pre-development condition can be judged to reduce downstream sediment loading or pollutant loadings.
      (1)   A finding that, when compared to the existing condition, the developed project will do one of the following:
         (a)   Substantially reduce (more than 10%) downstream peak discharges;
         (b)   Reduce downstream flood stages (more than one-tenth foot); or
         (c)   Reduce downstream damages to structures occurring in the pre-development condition.
      (2)   The demonstration of one of these conditions must be through detailed hydrologic and hydraulic analysis of watersheds on a regional scale as approved by the Administrator.
   NEW MANUFACTURED HOME PARK OR SUBDIVISION. Manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including at a minimum the installation of utilities, the construction of streets and either final site grading or the pouring of concrete pads) has been completed on or after April 1, 1990.
   NON-RIVERINE.  Areas not associated with a stream or river such as isolated depressional storage areas, ponds and lakes.
   NRCS. The United States Department of Agriculture, Natural Resources Conservation Service.
   OBSERVATION STRUCTURES.  Structures built on a field tile where the pipe inflow and outflow is visible upon removal of a lid.
   OPEN CHANNEL. A conveyance system with a definable bed and banks carrying the discharge from field tiles and surface drainage. OPEN CHANNELS do not include grassed swales within farm fields under agricultural production, which are ephemeral in nature.
   ORDINARY HIGH WATER MARK (OHWM).  The point on the bank or shore up to which the presence and action of surface water is so continuous so as to leave a distinctive mark, such as by erosion, destruction or prevention of terrestrial vegetation, predominance of aquatic vegetation or other easily recognized characteristic.
   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.
   OVERSIGHT COMMITTEE.  A certified community’s body of officials charged by the certified community with overseeing variance of the Stormwater Management Ordinance within the certified community. The Oversight Committee may be a body of elected or appointed officials. See § 55.164.
   PERENNIAL STREAMS.  Riverine watercourses whose thalwag generally intersects the ground water table elevation and flows throughout the year.
   PERMITTING AUTHORITY.  The county or a certified community.
   PLAN.  The  County Comprehensive Countywide Stormwater Management Plan, adopted by the  County Board on October 13, 1998, as amended from time to time.
   POND.  A body of water of less than two acres, which retains a normal water level year round.
   PRIMARY GRAVITY OUTLET. The outlet structure designed to meet the release rate requirements of this chapter.
   PROFESSIONAL ENGINEER.  An engineer registered in the state, under the State Professional Engineering Practice Act. (ILCS Ch. 225, Act 325, §§ 1 et seq.), as amended.
   PROFESSIONAL LAND SURVEYOR. A land surveyor registered in the state, under the State Land Surveyors Act. (ILCS Ch. 225, Act 330, §§ 1 et seq.), as amended.
   PROPERTY. Contiguous land under single ownership or control.
   PUBLIC BODIES OF WATER.  All open public streams and lakes capable of being navigated by watercraft in whole or in part for commercial uses and purposes and all lakes, rivers and streams, which in their natural conditions were capable of being improved and made navigable, or that are connected with or discharge their waters into navigable lakes or rivers within, or upon the borders of the state, together with all bayous, sloughs, backwaters and submerged lands that are open to the main channel or body of water directly accessible thereto.
   PUBLIC FLOOD CONTROL PROJECT.  A flood control project, which will be operated and maintained by a public agency to reduce flood damages to existing buildings and structures, which includes a hydrologic and hydraulic study of the existing and proposed conditions of the watershed. Nothing in this definition shall preclude the design, engineering, construction or financing in whole or in part of a flood control project by persons or parties who are not public agencies.
   PUBLIC FLOOD EASEMENT.  An easement acceptable to the appropriate jurisdictional body that meets the regulations of the OWR, the Department and the community, and that provides legal assurances that all areas subject to flooding in the created backwater of the development will remain open to allow flooding.
   RECORD DRAWINGS.  Drawings prepared, signed and sealed by a registered professional engineer or registered land surveyor representing the final “as-built” record of the actual in-place elevations, location of structures and topography.
      (1)   Built on a single chassis;
      (2)   Four hundred square feet or less when measured at the largest horizontal projection;
      (3)   Designed to be self propelled or permanently towable by a light duty truck; and
      (4)   Designed primarily not for use as a permanent dwelling, but as a temporary living quarters for recreational camping travel or seasonal use.
   REGISTERED STRUCTURAL ENGINEER.  A person licensed under the laws of the state as a structural engineer.
   REGULATORY FLOODPLAIN. The floodplain as depicted on maps recognized by FEMA as defining the limits of the SFHA.
   REGULATORY FLOODWAY.  Those portions of the floodplain depicted on maps as floodway and recognized by the IDNR-OWR for regulatory purposes.
   RETENTION FACILITY.  Stores stormwater runoff without a gravity release.
   RIVER FRONTAGE.  The property that is immediately adjacent to and naturally drains directly to the Des Plaines River, Chicago Sanitary and Ship Canal, DuPage River or Kankakee River without crossing over other private or public property.
   RIVERINE.  Related to, formed by, or resembling a channel (including creeks and rivers).
   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.
   SEASONAL HIGH GROUND WATER TABLE.  The upper limits of the soil temporarily saturated with water, being usually associated with spring wetness conditions. This may be indicated by soil mottles with a Munsell color of two chroma or less.
   SEDIMENTATION. The process that deposits hydraulically moved soils, debris and other materials either on other ground surfaces or in bodies of water or stormwater drainage systems.
   SEDIMENT TRAP.  A structure or area that allows for the temporary deposit and removal or disposal of sediment materials from stormwater runoff.
   SEEPAGE. The movement of drainable water through soil and rock.
   SPECIAL FLOOD HAZARD AREA (SFHA).  An area having special flood, mudslide or mudflow, or flood-related erosion hazards and which area is shown on an FHBM or FIRM as Zone A, AO, A1-30, AE, A99, AH, VO, V1-30, VE, V, M or E.
   STORMWATER FACILITY. All ditches, channels, conduits, bridges, culverts, levees, ponds, natural and human-made impoundments, wetlands, riparian environment, tile, swales, sewers or other natural or artificial structures or measures which serve as a means of draining surface and subsurface water from land.
   STORMWATER MANAGEMENT PERMIT.  The permit issued under §§ 55.080 through 55.085.
   STRUCTURE.  The results of a built 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 travel trailer on a site for more than 180 days unless they are fully licensed and ready for highway use.
      (1)   The following three occasions, when work is performed on an existing building taking place during a ten-year period, cumulatively, is classified as a SUBSTANTIAL IMPROVEMENT:
         (a)   An improvement made to a building whose cost is equal to or exceeds 50% of the buildings’ market value before the improvement;
         (b)   Reconstruction or repair of a building, the cost of which equals or exceeds 50% of the market value of the building before reconstruction or repair; or
         (c)   Additions to an existing building whose cost equals or exceeds 50% of the market value of a structure, or increases the floor area by more than 20%.
      (2)   Note that if a building is substantially improved, then the entire building must comply with the building protection standards.
   SUBSURFACE DRAINAGE.  The removal of excess soil water to control water table levels at predetermined elevations for structural, environmental or other reasons in areas already developed or being developed for agricultural, residential, industrial, commercial or recreational uses.
   SUBSURFACE WATER.  Water beneath the ground or pavement surface. Sometimes referred to as GROUND WATER or SOIL WATER.
   T FACTOR.  The soil loss tolerance. It is defined as the maximum amount of erosion at which the quality of a soil as a medium for plant growth can be maintained. Erosion losses are estimated by Universal Soil Loss Equation (USLE) and Revised Universal Soil Loss Equation (RUSLE).
   TECHNICAL MANUAL. The manual adopted by the County Board, which refers to this chapter and provides additional explanations and examples.
   THALWAG. A line along the lowest point in a channel.
   TRANSITION SECTION.  Reaches of the stream or floodway where water flows from a narrow cross-section to a wide cross-section, or vice versa.
   USABLE SPACE.  Space used for dwelling, storage, utilities or other beneficial purposes, including without limitation basements.
   WATER TABLE. The upper limit of a free water surface in a saturated soil or underlying material.
   WATERS OF THE UNITED STATES.  As defined by the United States Army Corps of Engineers in their Federal Methodology for the Regulation of Wetlands. For purposes of this chapter, WATERS OF THE UNITED STATES include wetlands, lakes, rivers, streams, creeks, bogs, fens and ponds. WATERS OF THE UNITED STATES do not include maintained stormwater facilities.
   WATERSHED.  All land area drained by, or contributing water to, the same stream, lake, stormwater facility or draining to a point.
   WATERSHED CHARACTERISTICS.  Include land use, physiology, habitat, climate, drainage system and community profile.
   WATERSHED PLAN.  A study and evaluation of an individual drainage basin’s stormwater management, floodplain management, water quality and flood control needs and capabilities.
   WETLAND. As defined in current federal methodology recognized by the United States Army Corps of Engineers for regulatory purposes.
(Res. 02-441, passed 10-17-2002; Res. 02-495, passed 11-21-2002; Res. 04-87, passed 3-17-2004; Res. 10-72, passed 3-18-2010; Ord. 19-239, passed 9-19-2019)