Wat. Code, § 10562

(a) One or more public agencies may develop a stormwater resource plan pursuant to this part.

(b) A stormwater resource plan shall:

(1) Be developed on a watershed basis.

(2) Identify and prioritize stormwater and dry weather runoff capture projects for implementation in a quantitative manner, using a metrics-based and integrated evaluation and analysis of multiple benefits to maximize water supply, water quality, flood management, environmental, and other community benefits within the watershed.

(3) Provide for multiple benefit project design to maximize water supply, water quality, and environmental and other community benefits.

(4) Provide for community participation in plan development and implementation.

(5) Be consistent with, and assist in, compliance with total maximum daily load (TMDL) implementation plans and applicable national pollutant discharge elimination system (NPDES) permits.

(6) Be consistent with all applicable waste discharge permits.

(7) Upon development, be submitted to any applicable integrated regional water management group. Upon receipt, the integrated regional water management group shall incorporate the stormwater resource plan into its integrated regional water management plan.

(8) Prioritize the use of lands or easements in public ownership for stormwater and dry weather runoff projects.

(c) The proposed or adopted plan shall meet the standards outlined in this section. The plan need not be referred to as a “stormwater resource plan.” Existing planning documents may be utilized as a functionally equivalent plan, including, but not limited to, watershed management plans, integrated resource plans, urban water management plans, or similar plans. If a planning document does not meet the standards of this section, a collection of local and regional plans may constitute a functional equivalent, if the plans collectively meet all of the requirements of this part.

(d) An entity developing a stormwater resource plan shall identify in the plan all of the following:

(1) Opportunities to augment local water supply through groundwater recharge or storage for beneficial use of stormwater and dry weather runoff.

(2) Opportunities for source control for both pollution and stormwater and dry weather runoff volume, onsite and local infiltration, and use of stormwater and dry weather runoff.

(3) Projects to reestablish natural water drainage treatment and infiltration systems, or mimic natural system functions to the maximum extent feasible.

(4) Opportunities to develop, restore, or enhance habitat and open space through stormwater and dry weather runoff management, including wetlands, riverside habitats, parkways, and parks.

(5) Opportunities to use existing publicly owned lands and easements, including, but not limited to, parks, public open space, community gardens, farm and agricultural preserves, schoolsites, and government office buildings and complexes, to capture, clean, store, and use stormwater and dry weather runoff either onsite or offsite.

(6) Design criteria and best management practices to prevent stormwater and dry weather runoff pollution and increase effective stormwater and dry weather runoff management for new and upgraded infrastructure and residential, commercial, industrial, and public development. These design criteria and best management practices shall accomplish all of the following:

(A) Reduce effective impermeability within a watershed by creating permeable surfaces and directing stormwater and dry weather runoff to permeable surfaces, retention basins, cisterns, and other storage for beneficial use.

(B) Increase water storage for beneficial use through a variety of onsite storage techniques.

(C) Increase groundwater supplies through infiltration, where appropriate and feasible.

(D) Support low-impact development for new and upgraded infrastructure and development using low-impact techniques.

(7) Activities that generate or contribute to the pollution of stormwater or dry weather runoff, or that impair the effective beneficial use of stormwater or dry weather runoff.

(8) Projects and programs to ensure the effective implementation of the stormwater resource plan pursuant to this part and achieve multiple benefits. These projects and programs shall include the development of appropriate decision support tools and the data necessary to use the decision support tools.

(9) Ordinances or other mechanisms necessary to ensure the effective implementation of the stormwater resource plan pursuant to this part.

(e) A stormwater resource plan shall use measurable factors to identify, quantify, and prioritize potential stormwater and dry weather runoff capture projects.