§ 56-109. Definitions.

For the purposes of this division, the following words and terms shall be defined as follows, unless the context in which they are used clearly indicates otherwise. The definitions of words and terms set forth in division 3 of this article shall also apply herein to the extent that they are not inconsistent herewith:

(.5)

Controlled release means the rate of peak outflow from detention storage controlled by physical or mechanical means.

(1)

Design year storm means the selected or established frequency or return period of rainfall time-duration for which drainage facilities are to be designed.

(1.5)

Detention means short term storage of stormwater runoff, designed to reduce the peak flow from a drainage basin by reducing the peak outflow to less than the peak inflow.

(2)

Developer (and land developer) means a person whose intent or function is to change the scope, type or amount of man-made use of real property.

(3)

Drainage basin (and watershed) means the catchment area from which stormwater is carried off by a watercourse or storm drainage system. The area served by a drainage system receiving storm and other surface-borne water. The definition of drainage basin boundaries is a product of natural topography and drainage system configuration.

(4)

Existing (and presently existing) means those conditions which obtain, are in place, or are taking place, as of the date of enactment of the ordinance from which this division was derived.

(5)

Facilities (and drainage facilities) means all man-made structures or natural watercourses for the conveyance of storm runoff. Drainage facility examples are storm sewers, detention and water quality ponds, channels, bridges, gulches, pipes, ditches, siphons, catch basins, streets, alleys, curbs, gutters, and crosspans.

(6)

Function means a group of related activities which are designed to accomplish a major service or regulatory program for which a governmental agency is responsible.

(7)

Impervious surface means surfaces on or in a lot or parcel of real property where the infiltration of stormwater into the earth has been reduced by the works of man.

(8)

Land developer. See "developer."

(9)

Master drainage plan means a plan defining gravity drainage basin boundaries containing criteria to be used in preliminary design, presenting the location and characteristics of all drainage facilities (including those presently existing and those expected to be needed under ultimate development as shown in the city's comprehensive plan), providing preliminary designs of required improvements, and including recommended staging of facilities construction, together with cost estimates.

(10)

Peak flow means the maximum rate of runoff from precipitation or snow melt during a given storm event.

(11)

Person means a natural individual person, a firm, a partnership, a co-partnership, a joint venture, a corporation, an estate or trust, a governmental entity other than the city, or any other group or combination acting as a unit, or other legal entity, and includes the plural as well as the singular number.

(12)

Pervious surface means land surface where the rate of absorption of stormwater is equal to or higher than the rate which existed in the natural and undeveloped state of the land surfaces.

(13)

Ratio group means a specified range of ratios of impervious surface to total surface area of lots or parcels of real property to which a particular lot or parcel of real property is assigned for the purposes of fixing the charge per one hundred (100) square feet of impervious surface on or in the aforesaid lot or parcel.

(14)

Ratio of impervious surface means that ratio obtained by dividing total square footage of surface area of a lot or parcel of real property into the total square footage of impervious surface area. That ratio shall not exceed one (1) for the purpose of determining the ratio group or the service charge.

(15)

Runoff means that part of rainfall which is not absorbed, transpirated, evaporated or left in surface depressions; and which then flows controlled or uncontrolled into a stream channel or body of water.

(15.5)

Statement of system continuity means stormwater drainage infrastructure, surface and/or subsurface, that will collect and convey stormwater runoff from a watershed to a watercourse or body of water.

(16)

Storm drain means an improved storm drain is a closed conduit or paved open ditch for conducting collected stormwater. An unimproved storm drain is an unpaved open ditch, natural or specifically constructed for conveying collected stormwater.

(17)

Storm drainage system means all facilities used in whole or in part for collecting and conveying stormwater to, through and from drainage areas to the points of final outlet including, but not limited to, any and all of the following: conduits and appurtenant features, channels, ditches, streams, gulches, gullies, flumes, culverts, streets, alleys, curbs, gutters, crosspans, and pumping stations.

(18)

Total square footage of the surface area of the lot or parcel of real property means that square footage of a lot or parcel using the outside boundary dimensions in feet to obtain the total enclosed square footage, without regard for topographic features of the enclosed surface. The boundary dimensions in feet of the enclosed surface area may be established by any of the following methods:

a.

On-site measurements, or measurements estimated, calculated or computed using aerial photography, photogrammetry or equivalent technology, of the apparent outside boundary dimensions of the lot or parcel of real property made by the city or in its behalf; or

b.

Computation of the area using dimensions of the lot or parcel of real property which are set forth and contained in the records of the office of the assessor of the city; or

c.

Computation of the area using dimensions of the lot or parcel of real property which are set forth and contained in the records of the clerk and recorder of the city.

(19)

Urban Storm Drainage Criteria Manual means the current version of the manual published by the Urban Drainage and Flood Control District.

(20)

Watercourse means a stream, usually flowing in a particular direction (though it need not flow continuously in a definite channel), having a bed or banks and usually discharging into some other stream or body of water.

(21)

Watershed: See "drainage basin."

(Ord. No. 160-80, § 1(167A.2), 4-14-80; Ord. No. 78-87, §§ 37—40, 2-9-87; Ord. No. 1101-01, § 1, 12-17-01; Ord. No. 200-02, §§ 5—7, 3-11-02; Ord. No. 267-11, § 9, 5-16-11)

Cross reference

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