Victorville Municipal Code Ch. 17.60 Drainage

Definitions of minimum drainage requirements are as follows:

(1) "Flood hazard" means overflow of water having sufficient velocity to transport or deposit debris, to scour the surface soil, or to dislodge or damage buildings, or to cause erosion of the banks of channels;

(2) "Inundation" is used to indicate ponded water or water in motion of sufficient depth to damage property due to the mere presence of the water or deposition of silt;

(3) "Minor drainage channels" or "conduits" means those channels or conduits drainage to which originates from within the subdivision within which the minor drainage channels or conduits are located;

(4) "Ponding of local stormwater" means the standing of water in local depressions. As distinguished from "sheet overflow", this water originates on or in the vicinity of the property and due to the condition of a ground surface is unable to reach a drainage channel or conduit;

(5) "Possible flood hazard" means possible extension of areas denoted as subject to "flood hazard" and shall reflect the uncertainty of degree or extent of bank erosion;

(6) "Primary drainage channels" or "conduits" means those channels or conduits, all or any part of the drainage to which, originates from outside of the boundaries of the subdivision in which the drainage channel or conduit is located.

(7) "Sheet flow" means water or minor depth either quiescent or flowing at velocities less than those necessary to produce serious scour.

(8) "Special flood hazard area" means those areas designated by the appropriate Federal agency having jurisdiction as being areas of special flood hazard. Boundaries of the areas so designated are shown upon maps entitled, "Federal Insurance Administration Flood Hazard Boundary Map", copies of which are on file in the office of the city clerk and by this reference made a part of this chapter. Reference is made to Title 16 for building and use restrictions applying in special flood hazard areas.

(9) "Designated floodways" means the portion of the area of a natural drainage course which has been established by the appropriate federal agency having jurisdiction as a designated floodway; the boundaries of the areas so designated are delineated on maps contained in a study entitled "Flood Insurance Study—Victorville, California," prepared for the Federal Insurance Administration and based on the one hundred-year frequency of occurrence of flood flow. Copies of the study are on file in the office of the city clerk and by this reference made a part of this chapter.

(Ord. 999 § 1 (part), 1985)

(Ord. No. 2266, 1-18-2011)

Calculation of design flood flows shall be based on the frequency of occurrence hereinafter stipulated in this title using the rational method of analysis and assuming full development of all the property within the drainage area based upon the general plan of the city for future development and Title 18, Zoning of this code and the general plan and zoning code of the county where applicable. Any outlet channel required to carry the stormwater from the proposed subdivision to a defined drainage channel or conduit shall be designed in accordance with the standards set forth in this chapter, for the ultimate stage of development of the subdivision and any additional tributary areas and the one hundred-year frequency of occurrence flood.

(Ord. 999 § 1 (part), 1985)

Drainage channels and conduits shall have the following minimum capacities:

(1) Primary drainage channels and conduits shall have sufficient capacity to contain the one hundred-year frequency of occurrence runoff when designed in accordance with the Standard Specifications for Public Improvements.

(2) Minor drainage channels or conduits shall have sufficient capacity to contain a ten-year frequency of occurrence runoff when designed in accordance with the Standard Specifications for Public Improvements.

(Ord. 999 § 1 (part), 1985)

Proposed subdivisions shall not cause inundation or flood hazard to existing inhabited areas or downstream properties. Measures shall be taken in design to minimize sedimentation and concentration of flood flows on downstream properties.

(Ord. 999 § 1 (part), 1985)

Drainage shall be accomplished by gravity surcharge into catch basins or manholes, except by design in accordance with standards set forth in this chapter and the Standard Specifications for Public Improvements of the city.

(Ord. 999 § 1 (part), 1985)

Catchbasins shall have inlets of varying length so designed that the water is diverted into the catchbasin without bypassing. Catchbasin inlets shall be designed in accordance with the Standard Specifications for Public Improvements.

(Ord. 999 § 1 (part), 1985)

(a) Cross-gutters shall be used to carry water across minor streets at intersections only. Where a street must cross a major wash, the standard wash crossing as set forth in the Standard Specifications for Public Improvements shall be utilized. The street shall be designed to pass the full flood flow of the wash without damage to the street or the adjacent properties.

(b) Where it is necessary to carry local drainage across the street in the middle of the block, it shall be carried in pipe designed in accordance with the Standard Specifications for Public Improvements.

(Ord. 999 § 1 (part), 1985)