Division VI. Standard Urban Stormwater Mitigation Plan

Chapter 16.100


16.100.010    Title.

16.100.020    Statutory authority.

16.100.030    Purpose.

16.100.040    Applicability of division.

16.100.050    Limited exclusion.

16.100.010 Title.

The ordinance codified in this chapter shall be known as the “Standard Urban Stormwater Mitigation Plan (SUSMP) Ordinance of the City of Poway.” (Ord. 569 § 2, 2002)

16.100.020 Statutory authority.

A. The municipal stormwater National Pollutant Discharge Elimination System (NPDES) Permit (Order No. R9-2007-0001, NPDES No. CAS0108758, hereinafter referred to as “Municipal Permit”) issued to San Diego County, the Port of San Diego, San Diego County Regional Airport Authority and 18 cities (Copermittees) by the San Diego Regional Water Quality Control Board (Regional Board) on January 24, 2007, requires the development and implementation of a program addressing urban runoff pollution issues in development planning for public and private projects.

B. The requirement to implement a program for development planning is based on Federal and State statutes including: Section 402(p) of the Clean Water Act, Section 6217 of the Coastal Zone Act Reauthorization Amendments of 1990 (“CZARA”), and the California Water Code. The Clean Water Act amendments of 1987 established a framework for regulating urban runoff discharges from municipal, industrial, and construction activities under the NPDES program. The Municipal Permit requires the implementation of a Jurisdictional Urban Runoff Management Program (JURMP). (Ord. 671 § 28, 2008; Ord. 569 § 2, 2002)

16.100.030 Purpose.

A. The primary objectives of this division are to:

1. Ensure that discharges from municipal urban runoff conveyance systems do not cause or contribute to a violation of water quality standards;

2. Effectively prohibit nonstormwater discharges in urban runoff; and

3. Reduce the discharge of pollutants from urban runoff conveyance systems to the maximum extent practicable (MEP statutory standard).

B. The regulations of this division were developed to address postconstruction urban runoff pollution from new development and redevelopment applications that fall under “priority project” categories.

C. The goal of this division is to develop and implement practicable policies to ensure, to the maximum extent practicable, that development does not increase pollutant loads from a project site. This includes mitigation of urban runoff based on the flow rates and velocities of historical rainfall events. This goal may be achieved through site-specific controls and/or drainage area-based or shared structural treatment controls. This division identifies appropriate best management practices (BMPs) for certain designated project types to achieve this goal. (Ord. 671 § 29, 2008; Ord. 569 § 2, 2002)

16.100.040 Applicability of division.

A. The regulations set forth in this chapter shall apply to the development plan approval process for discretionary development applications, and prior to issuing development permits for ministerial projects.

B. To allow flexibility in meeting the design standards set forth in this division, structural treatment control best management practices (BMPs) may be located on- or off-site, used singly or in combination, or shared by multiple developments, provided certain conditions are met.

C. All new development and significant redevelopment projects that fall into one of the following priority project categories are subject to the requirements of this division, subject to the lawful prior-approval provisions of the Municipal Permit. In the instance where a project feature, such as a parking lot, falls into a priority project category, the entire project footprint is subject to the requirements of this division. These categories are:

1. Residential development of 10 units or more;

2. Commercial development greater than one acre;

3. Industrial development greater than one acre;

4. Automotive repair shops;

5. Restaurants;

6. Hillside development greater than 5,000 square feet;

7. Projects discharging to receiving waters within environmentally sensitive areas;

8. Parking lots with 5,000 square feet or more of impervious surface, or with greater than 15 parking spaces, that are potentially exposed to urban runoff;

9. Streets, roads, driveways, highways, and freeways which would create a new paved impervious surface that is 5,000 square feet or greater;

10. Retail gasoline outlets 5,000 square feet or more or with a projected average daily traffic (ADT) of 100 or more vehicles per day; and

11. Pollutant generating development project that is one acre or more of disturbance. Pollutant generating development projects are those projects that generate pollutants at levels greater than background levels.

Where redevelopment results in an increase of less than 50 percent of the impervious surfaces of a previously existing development, and the existing development was not subject to SUSMP requirements, the numeric sizing criteria apply only to the addition and not the entire development. When redevelopment results in an increase of more than 50 percent of the impervious surfaces of a previously existing development, the numeric sizing criteria apply to the entire development. (Ord. 702 § 2, 2010; Ord. 671 § 30, 2008; Ord. 569 § 2, 2002)

16.100.050 Limited exclusion.

The following activities are not considered priority projects: trenching and resurfacing work associated with utility projects, resurfacing and reconfiguring surface parking lots and existing roadways, construction of new sidewalk, pedestrian ramps, or bike lane on existing roads, and routine replacement of damaged pavement such as pothole repair. Parking lots, buildings and other structures associated with utility projects are subject to the requirements of this division if one or more of the criteria for the above categories are met. (Ord. 671 § 31, 2008; Ord. 569 § 2, 2002)