Malibu Municipal Code § 17.4 Development Standards

A. All development shall be evaluated for potential adverse impacts to water quality and the applicant shall consider Site Design, Source Control and Treatment Control BMPs in order to minimize or prevent polluted runoff and water quality impacts resulting from the development. A SWMP requires the implementation of Site Design and Source Control BMPs, as specified in 17.3.2 of the Malibu LIP, and a WQMP requires the implementation of Site Design, Source Control and Treatment Control BMPs, as specified in 17.3.3 of the Malibu LIP. In order to maximize the reduction of water quality impacts, BMPs should be incorporated into the project design in the following progression: (1) Site Design BMPs, (2) Source Control BMPs, and (3) Treatment Control BMPs. Examples of these BMPs can be found in Section 17.5 and Appendix A of the Malibu LIP.

B. BMP Selection Process.

1. In selecting BMPs to incorporate into the project design, the applicant should first identify the pollutants of concern that are anticipated to be generated as a result of the development. Table 1 in Appendix B should be used as a guide in identifying these pollutants of concern. These pollutants of concern should then be prioritized, identifying primary pollutants of concern using the following process:

a. For each of the proposed project's discharge points, identify the receiving water(s) that each discharge point proposes to discharge to, including hydrologic unit basin number(s), as identified in the most recent version of the Water Quality Control Plan for the Los Angeles Basin, prepared by the Los Angeles Regional Water Quality Control Board.

b. Identify any receiving waters, into which the developed area would discharge to, listed on the most recent list of Clean Water Act Section 303(d) impaired water bodies. List any and all pollutants for which the receiving waters are impaired.

c. Compare the list of pollutants for which the receiving waters are impaired with the pollutants anticipated to be generated by the project (as identified in Table 1). Any pollutants identified by Table 1 for the project that are also causing impairment of receiving waters shall be considered primary pollutants of concern.

d. Pollutants generated by the development that exhibit one or more of the following characteristics shall also be considered primary pollutants of concern:

i. Current loadings or historical deposits of the pollutant are impairing the beneficial uses of a receiving water

ii. Elevated levels of the pollutant are found in water or sediments of a receiving water and/or have the potential to be toxic to or bioaccumulate in organisms therein

iii. Inputs of the pollutant are at a level high enough to be considered potentially toxic

2. Site Design and Source Control BMPs are required based on pollutants commonly associated with the project type, as identified in Table 1. Table 2 in Appendix B should be used as guidance to determine the specific areas for each project where Site Design and Source Control BMPs are required to be implemented. BMPs that minimize the identified pollutants of concern may be selected from the examples in Appendix A and Section 17.5 of the Malibu LIP, targeting primary pollutants of concern first. In the event that the implementation of a BMP listed in Appendix A or Section 17.5 of the Malibu LIP is determined to be infeasible at any site, the implementation of other BMPs that will achieve the equivalent reduction of pollutants shall be required.

3. Treatment Control BMPs should be selected using the matrix in Table 3 in Appendix B as guidance to determine the removal efficiency of the BMP for the pollutants of concern for that project. Treatment Control BMPs that maximize pollutant removal for the identified primary pollutants of concern should receive priority for BMP selection, followed by BMPs that maximize pollutant removal for all other pollutants of concern identified for the project. The most effective combination of BMPs for polluted runoff control that results in the most efficient reduction of pollutants shall be implemented. The applicant may select from the list of BMPs in Appendix A. In the event that the implementation of a BMP listed in Appendix A is determined to be infeasible at any site, the implementation of other BMPs that will achieve the equivalent reduction of pollutants shall be required.

A. Soils shall be stabilized and infiltration practices incorporated during the development of roads, bridges, culverts and outfalls to prevent stream bank or hillside erosion. Project plans must include the following BMPs to decrease the potential of slopes and/or channels from eroding and impacting storm water runoff:

B. Additional measures to prevent downstream erosion, such as contour drainage outlets that disperse water back to sheet flow, shall be implemented for projects discharging onto slopes greater than 10 percent.

C. New development on steep slopes, on sites with low permeability soil conditions, or areas where saturated soils can lead to geologic instability should incorporate BMPs that do not rely on or increase infiltration.