(a) Permanent stormwater pollution prevention measures shall be incorporated into the following projects (collectively referred to sometimes in this chapter as “regulated projects”):
(1) All development projects;
(2) All significant redevelopment projects;
(3) All road projects;
(4) Effective December 1, 2011, all high impact projects;
(5) Effective December 1, 2011, all trail projects;
(6) Effective December 1, 2011, all street widening projects.
(b) Any permanent stormwater pollution prevention measure required by this section must be in effect during the entire life of the project.
(c) Effective December 1, 2011, unless the project is exempt as a special project pursuant to administrative guidelines adopted by the city engineer and approved by the Water Board, all permanent stormwater pollution prevention measures shall include the following low impact development (LID) measures or other alternative measures to be approved by the city engineer:
(1) Source Control Requirements.
(A) Minimization of stormwater pollutants of concern in urban runoff through measures that may include plumbing of the following discharges to the sanitary sewer, subject to the city's authority and standards as contained in Chapter 16.09:
(i) Discharges from indoor floor mat/ equipment/hood filter wash racks or covered outdoor wash racks for restaurants;
(ii) Dumpster drips from covered trash, food waste and compactor enclosures;
(iii) Discharges from covered outdoor wash areas for vehicles, equipment, and accessories;
(iv) Swimming pool water, if discharge to onsite vegetated areas is not a feasible option; and
(v) Fire sprinkler test water, if discharge to onsite vegetated areas is not a feasible option;
(B) Properly designed covers, drains, and storage precautions for outdoor material storage areas, loading docks, repair/maintenance bays, and fueling areas;
(C) Properly designed trash storage areas;
(D) Landscaping that minimizes irrigation and runoff, promotes surface infiltration, minimizes the use of pesticides and fertilizers, and incorporates other appropriate sustainable landscaping practices and programs such as bay-friendly landscaping;
(E) Efficient irrigation systems; and
(F) Storm drain system stenciling or signage.
(2) Site Design and Stormwater Treatment Requirements.
(A) Minimization of disturbances of natural water bodies and drainage systems; minimization of compaction of highly permeable soils; protection of slopes and channels; and minimization of impacts from stormwater and urban runoff on the biological integrity of natural drainage systems and water bodies;
(B) Conservation of natural areas, including existing trees, other vegetation, and soils;
(C) Minimization of impervious surfaces;
(D) Minimization of disturbances to natural drainages;
(E) Minimization of stormwater runoff by implementation of one or more of the following site design measures:
(i) Direct roof runoff into cisterns or rain barrels for reuse.
(ii) Direct roof runoff onto vegetated areas.
(iii) Direct runoff from sidewalks, walkways, and/or patios onto vegetated areas.
(iv) Direct runoff from driveways and/or uncovered parking lots onto vegetated areas.
(v) Construct sidewalks, walkways, and/or patios with permeable surfaces.
(vi) Construct driveways, bike lanes, and/or uncovered parking lots with permeable surfaces.
(F) Treatment of 100% of the amount of runoff identified in subsection (d) below for the regulated project's drainage area with LID treatment measures onsite or with LID treatment measures at a joint stormwater treatment facility.
(i) LID treatment measures are harvesting and re-use, infiltration, evapotranspiration, or biotreatment.
(ii) A properly engineered and maintained biotreatment system may be considered only if it is infeasible to implement harvesting and re-use, infiltration, or evapotranspiration at a project site.
(iii) Infeasibility to implement harvesting and re-use, infiltration, or evapotranspiration at a project site shall be determined in accordance with criteria approved by the Water Board and the city engineer.
(iv) Biotreatment systems shall be designed to have a surface area no smaller than what is required to accommodate a 5 inches/hour stormwater runoff surface loading rate. The planting and soil, media for biotreatment systems shall be designed to sustain plant growth and maximize stormwater runoff retention and pollutant removal and shall conform to material specifications approved by the Water Board and the city engineer.
(v) Green roofs may be considered biotreatment systems for treatment of roof runoff only if they conform to specifications approved by the Water Board and the city engineer.
(d) Stormwater treatment measures proposed as part of a project's permanent stormwater pollution prevention measures shall be designed in accordance with the following hydraulic sizing criteria to treat stormwater runoff.
(1) Volume Hydraulic Design Basis. Stormwater treatment measures whose primary mode of action depends on volume capacity, such as detention/retention units or infiltration structures, shall be designed to treat stormwater runoff equal to:
(A) The maximized storm water quality capture volume for the area, based on historical rainfall records, determined using the formula and volume capture coefficients set forth in Urban Runoff Quality Management, WEF Manual of Practice No. 23/ASCE Manual of Practice No. 87 (1998), pages 175 - 178 (e.g. approximately the 85th percentile 24-hour storm runoff event); or
(B) The volume of annual runoff required to achieve 80% or more capture, determined in accordance with the methodology set forth in the California Stormwater Best Management Practices Handbook for New Development and Redevelopment (2003), using local rainfall data.
(2) Flow Hydraulic Design Basis. Stormwater treatment measures whose primary mode of action depends on flow capacity, such as swales, sand filters, or wetlands, shall be sized to treat:
(A) Ten percent of the 50-year peak flow rate; or
(B) The flow of runoff produced by a rain event equal to at least two times the 85th percentile hourly rainfall intensity for the applicable area, based on historical records of hourly rainfall depths; or
(C) The flow of runoff resulting from a rain event equal to at least 0.2 inches per hour intensity.
(3) Combination Flow and Volume Design Basis. Treatment systems that use a combination of flow and volume capacity shall be sized to treat at least 80% of the total runoff over the life of the project, using local rainfall data.
(e) All plans and construction are subject to inspection and approval by the city engineer.
(f) Compliance with chapter. Prior to the issuance of a building permit or other discretionary permit for a regulated project, the project applicant shall submit a certification by a qualified third party reviewer acceptable to the city that the design of the project complies with the requirements of this chapter. In addition, no final occupancy permit shall be issued without the written certification by a qualified third party reviewer acceptable to the city that a regulated project was constructed or installed in accordance with the approved plans. The third party reviewer must be a civil engineer, licensed architect or landscape architect registered in the State of California, or staff of another permittee subject to the requirements of the current NPDES permit issued to the city and must have current training on stormwater treatment system design for water quality. Any consultant or contractor hired to design and/or construct a stormwater treatment system for a regulated project shall not perform the third party review for said project. Such certifications shall be in the form prescribed by the city engineer and shall not be issued without payment of all applicable fees which may be imposed for administration of this chapter. At the city's sole election, the city engineer may provide any of the certifications required by this section.
(Ord. 5112 § 2, 2010: Ord. 5108 § 3, 2010: Ord. 4799 § 2 (part), 2003)