§ 34-908. Definitions.

For the purpose of this division, the following terms shall be defined by meaning given each, as follows:

Affiant: The person, as that term is defined herein, which assumes financial and legal responsibility for the maintenance, operation, and effectiveness of structural controls, and the performance of required monitoring of surface water, related to a development for which an affidavit is, filed pursuant to section 34-911 of this division.

Best management practices (BMP): An effective integration of stormwater management systems, with appropriate combinations of landscape conservation, enhancement, structural controls, impervious cover, schedules of activities, prohibitions of practices, maintenance procedures and other management practices which provide an optimum way to convey, store and release runoff, so as to reduce peak discharge, remove pollutants, and enhance the environment.

Center line: The center line of the waterway refers to existing topographically defined channels. If not readily discernible, the center line shall be determined by, the "low flow line" whenever possible; otherwise by the center line of the two-year floodplain.

Commercial development: Any lot, parcel, or tract, not to be used as single or multi-family residential, recreational, open space or agricultural.

Degradation: Pollution of a representative sample of water which unreasonably reduces the quality of such water. The quality of a representative sample of water is unreasonably reduced when such water is rendered harmful, detrimental, or injurious to humans, animal life, vegetation, or property or the public health, safety, or welfare, or impairs the usefulness or the public enjoyment of the water for any lawful or reasonable purpose.

Detention: The temporary storage of storm runoff, which is used to control the peak discharge rates, and which provides gravity settling of pollutants.

Detention time: The amount of time a parcel of water actually is present in a stormwater basin. Theoretical detention time for a runoff event is the average time a parcel of water resides in the basin over the period of release from the BMP.

Development: Buildings, roads and other structures; construction; and excavation, dredging, grading, filling and clearing or removing vegetation associated with residential, recreational, commercial, industrial or institutional construction.

Edwards Aquifer Recharge Zone (EARZ): Generally, that area where the stratigraphic units constituting the Edwards Aquifer crop out, and including the outcrops of other formations in proximity to the Edwards Aquifer, where caves, sinkholes, faults, fractures, or other permeable features would create a potential for recharge of surface waters into the Edwards Aquifer. The recharge zone is identified as that area designated as such on official maps located in the offices of the Texas Natural Resource Conservation Commission (TNRCC).

Filtration basin: Filtration basins are secondary treatment structures that follow sedimentation basins and release storm water runoff through a filter media to remove additional pollutants.

First flush: At least the first one-half inch of runoff from a storm event which flushes off and contains a disproportionately large loading of the accumulated pollutants from impervious and non-impervious surfaces.

Floodplain buffer zone: Lands and waters as defined in section 34-913.

Floodplain preservation area: Lands and waters as established in section 34-912(a).

Ground water: Any water percolating below the surface of the ground.

Impervious cover: Roads, parking areas, buildings, pools, patios, sheds, driveways, private sidewalks, and other impermeable construction covering the natural land surface; this shall include, but not [be] limited to, all streets and pavement within the subdivision. "Percent impervious cover" is calculated as the area of impervious cover within a lot, tract, or parcel or within the total site being developed, divided by the total area within the perimeter of such lot, tract, parcel or development. Vegetated water quality basins, vegetated swales, other vegetated conveyances for overland drainage, and public sidewalks shall not be calculated as impervious cover.

Intermediate floodplain: Any channel, creek, stream, branch, or watercourse for surface water drainage that drains an area greater than three hundred twenty (320) acres but less than six hundred forty (640) acres.

Major floodplain: Any channel, creek, stream, branch, or watercourse for surface water drainage that drains six hundred forty (640) acres or more.

Minor floodplain: Any channel, creek, stream, branch, or watercourse for surface water drainage that drains an area greater than one hundred (100) acres but less than three hundred twenty (320) acres.

Non-degradation. The proper use of BMP's and pollution prevention criteria in activity so as to prevent degradation as defined herein.

Overland flow: Stormwater runoff that is not confined by any natural or manmade channel such as a creek, drainage ditch, storm sewer, or the like.

Peak-shaving: Controlling post-development peak discharge rates to pre-development levels by providing temporary detention in a BMP.

Person: Any natural person, corporation, partnership, joint venture, association (including home owner's or neighborhood associations), trust, or any other entity recognized by law.

Pollutants: Any element, chemical, compound, organism or material which alters the chemical, physical, biological, and or radiological integrity of water.

Pollution: The alteration of the physical, thermal, chemical or biological quality of, or the contamination of, any water.

Project: Project shall have the meaning contained in chapter 35 of this Code.

Resource protection and compliance department: The department within the San Antonio Water System (SAWS) designated to apply the provisions of this section.

Sedimentation basins: Sedimentation basins remove pollutants by creating conditions under which suspended solids can settle out of the water column.

Streamflow: Water flowing in a natural channel, above ground.

Structural controls: A range of pollution prevention best management practices ranging from vegetated buffers to on-site runoff detention and treatment facilities.

Swale: A natural depression or wide shallow ditch used to temporarily store, route, or filter runoff.

(Ord. No. 81491, § 1(App. I), 1-12-95; Ord. No. 2006-02-16-0241, § 2, 2-16-06; Ord. No. 2014-08-14-0581, §§ 3, 9, 8-14-14)

Cross reference

Definitions and rules of construction generally, § 1-2.