1) Abbreviations: Acceptable abbreviations for showing types of new and existing pipe materials and facilities on the plans are as follows:

2) Building Storm Drain: That part of the piping of a stormwater drainage system which begins at the connection to the building drain and conveys stormwater to an approved point of disposal.

3) Catch Basin: An approved receptacle designed to receive surface drainage and direct it to a stormwater collection system.

4) Creek: Any and all surface water generally consisting of a channel having a bed, banks, and/or sides in which surface waters flow to drain higher land to lower land, both perennial and intermittent, excluding flows which do not persist for more than 24-hours after the cessation of ½-inch of rainfall in a 24- hour period from October through March.

5) Detention: The holding of runoff for a short period of time while releasing it to the downstream drainage system at a controlled rate.

6) Drainage Basin: Any area of land where precipitation collects and drains off into a common outlet, such as into a creek, pond, or other body of water

7) Drainage Facilities/System: Pipes, ditches, detention basins, creeks, culverts, etc. used singularly or in combination with each other for the purpose of conveying or storing stormwater runoff.

8) Impervious Areas/Surfaces: Those hard surface areas located upon real property which either prevent percolation of water into the land surface or reduce the percolation rate which existed under natural conditions prior to development. Also surfaces which cause water to run off the land surface in greater quantities or at increased flow rates than under natural conditions which existed prior to development. Common impervious surfaces include but are not limited to rooftops, driveways, parking lots or storage areas, sidewalks, patios, etc.

9) Natural Historical Drainage: The location of those channels, swales, and other non-man­ made drainage conveyance systems as defined by the first documented topographic contours existing for the subject property either from maps, drawings, or photographs.

10) On-site Detention: The storage of excess runoff on the development site and gradual release of the stored runoff into a public storm drain system after the peak of the runoff has passed.

11) Peak Discharge: The maximum water runoff rate determined for the design storm, or remaining available downstream conveyance, whichever is left.

12) Private Storm Drain: A storm drain located on private property serving parking lot catch basins or more than one structure on the same premises, and is not operated or maintained by the City.

13) Public Storm Drain: Any stormdrain in a public right-of-way or easement operated or maintained by the City.

14) Receiving Body of Water: Creeks, streams, lakes, and other bodies of water into which runoff is naturally or artificially directed.

15) Release Rate: The controlled rate of release of drainage and runoff water from property, storage ponds, detention basins, or other facility during and following a storm event.

16) Retention Facility: Facilities which hold water for a considerable length of time and then consume it by evaporation, plant transpiration, or infiltration into the soil.

17) Sedimentation: Deposition of erosional debris and soil sediment displace by erosion and transported by water from a higher elevation to an area of lower gradient where sediments are deposited as a result of slack water.

18) Terrace: A relatively level step constructed in the face of a slope for drainage, erosion control and maintenance purposes.

19) Trunk Drainage System: That portion of the drainage system consisting of 18” or larger pipe which receives waters from upstream land areas. The drainage system may consist of watercourses or manmade facilities such as pipes, ditches, and culverts.

20) Wetlands: As defined by the Division of State Lands and the US Army Corps of Engineers.