A Preliminary WQMP is required to ensure compliance with all jurisdictional requirements applicable to the development project. A Preliminary WQMP is required when a project falls within the jurisdictional boundaries of the MS4 Phase I & proposed MS4 Phase II boundaries AND falls under any of the below categories within their respective boundaries.
Within the MS4 Phase 1 Permit Area/Santa Ana Watershed boundary the project categories that require a Preliminary WQMP are as follows:
- All significant re-development1 projects – defined as the addition or replacement of 5,000 or more square feet (sq. ft) of impervious surface on an already developed site subject to discretionary approval of the permitting jurisdiction.
- New development projects that create 10,000 sq. ft. or more of impervious surface (collectively over the entire project site) including commercial, industrial, residential housing subdivisions (i.e., detached single family home subdivisions, multi-family attached subdivisions or townhomes, condominiums, apartments, etc.), mixed-use, and public projects. This category includes development projects on public and private land, which fall under the planning and building authority of the permitting jurisdiction.
- New development or significant re-development1 of automotive repair shops (with SIC Codes 5013, 5014, 5541, 7532-7534, 7536-7539) where the project creates, adds and/or replaces 5,000 square feet or more of impervious surface.
- New development or significant re-development1 of restaurants (with SIC Code 5812) where the land area of development is 5,000 sq. ft. or more.
- All hillside developments of 5,000 sq. ft. or more which are located on areas with known erosive soil conditions or where the natural slope is 25% or more.
- Developments of 2,500 sq. ft. of impervious surface or more adjacent to (within 200 feet) or discharging directly into environmentally sensitive areas or waterbodies listed on the CWA Section 303(d) list of impaired waters(3).
- Parking lots of 5,000 sq. ft. or more exposed to storm water. A parking lot is defined as land area or facility for the temporary parking or storage of motor vehicles.
- New development or significant re-development1 of Retail Gasoline Outlets that are either 5,000 sq. ft. or more, or have a projected average daily traffic of 100 or more vehicles per day.
Within the MS4 Phase 2 Permit Area/Mojave Watershed boundary the project categories that require a Preliminary WQMP are as follows:
- New development involving the creation of 5,000 ft2 or more of impervious surface collectively over the entire site.
- Significant re-development involving the addition or replacement of 5,000 ft2 or more of impervious surface on an already developed site.
- Road Project – any road, sidewalk, or bicycle lane project that creates greater than 5,000 square feet of contiguous impervious surface.
- LUPs – linear underground/overhead projects that has a discrete location with 5,000 sq. ft. or more new constructed impervious surface.