The following words and phrases, whenever used in this chapter, have the meanings as set forth below:
(a) “Development project” means any private or public project under the planning and building authority of the city that creates 10,000 square feet or more of impervious surface collectively over the entire project site, including but not limited to roof area, parking lots, and other hardscape associated with commercial, industrial, residential subdivision, mixed-use, and public land development projects. A “development project” shall include the issuance of a permit for building, construction, reconstruction, subdivisions, parcel maps or occupancy, but not a permit to operate. The following development shall not constitute a development project:
(1) An individual detached single-family home, which is not part of a larger common plan of development, that is designed with appropriate source control and site design measures.
(b) “High impact project” means a project that falls into one of the categories listed below and that creates and/or replaces 5,000 square feet or more of impervious surface collectively over the entire project site.
(1) High impact categories. This category includes development projects of the following four types on public or private land that fall under the planning and building authority of the city:
(A) Auto service facilities, described by the following Standard Industrial Classification (SIC) Codes: 5013, 5014, 5541, 7532-7534, and 7536-7539;
(B) Retail gasoline outlets;
(C) Restaurants (SIC Code 5812); or
(D) Uncovered parking lots that are stand-alone or part of any other development project. This category includes the top uncovered portion of parking structures unless drainage from the uncovered portion is connected to the sanitary sewer along with the covered portions of the parking structure.
(2) Exceptions. The following development types shall not constitute a high impact project:
(A) Interior remodels;
(B) Routine maintenance or repair, such as roof or exterior wall surface replacement and pavement resurfacing within the existing footprint.
(3) Partial development. High impact projects that result in an increase of, or replacement of, more than 50% of the impervious surface of a previously existing development that was not subject to this chapter shall include permanent stormwater pollution prevention measures sufficient to reduce water quality impacts of stormwater runoff from the entire site for the life of the project.
High impact projects that result in an increase of, or replacement of, 50% or less of the impervious surface of a previously existing development that was not subject to this chapter shall include permanent stormwater pollution prevention measures sufficient to reduce water quality impacts of stormwater runoff from the increased or replaced portion of the site for the life of the project.
(c) “Hydromodification management measures” means an approved combination of on-site, off-site, and in-stream control measures incorporated into specified development projects and significant redevelopment projects in order to reduce stormwater runoff so as to not cause an increase in the erosion potential of the receiving stream over the pre-project condition, in accordance with and as required by Order No. R2-2009-0074 under NPDES Permit No. CAS612008 issued by the California Regional Water Quality Control Board, San Francisco Bay Region (the “Water Board”), as it may be amended from time to time.
(d) “Impervious surface” means land that has been modified by the action of persons to reduce the land's natural ability to absorb and hold rainfall. This includes any hard surface area which either prevents or retards the entry of water into the soil mantle as it entered under natural conditions pre-existent to development, and/or a hard surface area which causes water to run off the surface in greater quantities or at an increased rate of flow from the flow present under natural conditions pre-existent to development. Impervious surfaces include, but are not limited to, rooftops, pavement, sidewalks, walkways, patios, driveways, and parking lots where such surfaces are not constructed with pervious materials and/or are not designed to have zero stormwater discharge.
(e) “Infiltration device” means any structure that is deeper than wide and designed to infiltrate stormwater into the subsurface and, as designed, bypass the natural groundwater protection afforded by surface soil. Infiltration devices include dry wells, injection wells, and infiltration trenches (includes trench drains).
(f) “Low impact development (LID) measures” means an approved combination of source control measures, site design measures, and/or stormwater treatment measures that reduce runoff and mimic a site's predevelopment hydrology by minimizing disturbed areas and impervious cover and then infiltrating, storing, detaining, evapotranspiring, and/or biotreating stormwater runoff close to its source. LID measures embody principles such as preservation and recreation of natural landscape features and minimization of imperviousness to create functional and appealing site drainage that treats stormwater as a resource, rather than a waste product. LID measures include rain barrels and cisterns, green roofs, permeable pavement, preservation of undeveloped open space, and biotreatment through rain gardens, bioretention units, bioswales, and planter/tree boxes. The design and implementation of the LID measures must be in accordance with the guidelines and technical specifications provided by the city or other city-approved authority and the requirements of Order No. R2-2009-0074 and any subsequent orders.
(g) “Permanent stormwater pollution prevention measures” or “PSPPM” means an approved combination of source control measures, site design measures, and/or stormwater treatment measures that reduce stormwater pollution to the maximum extent practicable as required by Order No. R2-2009-0074 under NPDES Permit No. CAS612008 issued by the Water Board, as it may be amended from time to time. The design and implementation of the PSPPM must be in accordance with the guidelines and technical specifications provided by the city or other city-approved authority and the requirements of Order No. R2-2009-0074 and any subsequent orders.
(h) “Significant redevelopment project” means any private or public project under the planning and building authority of the city that creates 10,000 square feet or more of additional or replacement impervious surface collectively over the entire project site, including roof area, parking lots, and other hardscape associated with commercial, industrial, residential subdivision, mixed-use, and public land development projects. Redevelopment is any land-disturbing activity that results in the creation, addition, or replacement of exterior impervious surface area on a site on which some past development has occurred.
(1) Exceptions. The following redevelopment shall not constitute a significant redevelopment project:
(A) Interior remodels;
(B) Routine maintenance or repair including, but not limited to, roof or exterior surface replacement, or pavement resurfacing within the existing pavement footprint; or
(C) An individual detached single-family home, which is not part of a larger common plan of redevelopment, that is designed with appropriate source control and site design measures.
(2) Partial redevelopment. Significant redevelopment projects that result in an increase of, or replacement of, more than 50% of the impervious surface of a previously existing development that was not subject to this chapter shall include permanent stormwater pollution prevention measures sufficient to reduce water quality impacts of stormwater runoff from the entire site for the life of the project.
Significant redevelopment projects that result in an increase of, or replacement of, 50% or less of the impervious surface of a previously existing development that was not subject to this chapter shall include permanent stormwater pollution prevention measures sufficient to reduce water quality impacts of stormwater runoff from the increased or replaced portion of the site for the life of the project.
(i) “Road project” means a project to construct new streets or roads, including sidewalks and bicycle lanes built as part of the new streets or roads, that creates 10,000 square feet or more of newly constructed contiguous impervious surface and that falls under the building and planning authority of the city.
The following projects are not considered road projects for the purposes of this chapter:
(1) Sidewalks built as part of new streets or roads and built to direct stormwater runoff to adjacent vegetated areas.
(2) Bicycle lanes that are built as part of new streets or roads but are not hydraulically connected to the new streets or roads and that direct stormwater runoff to adjacent vegetated areas.
(3) Sidewalks, bicycle lanes, or trails constructed with permeable surfaces (includes pervious concrete, porous asphalt, permeable concrete unit pavers, and granular materials).
(4) Caltrans highway projects and associated facilities.
(j) “Site design measures” means any project design features that reduce stormwater pollution by decreasing or slowing stormwater runoff or intercepting the flow of runoff across a series of contiguous impervious surfaces.
(k) “Source control measures” means any project design features that aim to prevent stormwater pollution by eliminating or reducing the potential for contamination at the source of pollution.
(l) “Stormwater treatment measures” means any engineered system designed to remove pollutants from stormwater by simple gravity settling of particulate pollutants, filtration, biological uptake, media adsorption or any other physical, biological, or chemical process.
(m) “Street widening” means widening of existing streets or roads with additional traffic lanes.
(1) Where the addition of traffic lanes results in an alteration of more than 50% of the impervious surface of an existing street or road that was not subject to this chapter, the entire project, consisting of all existing, new, and/or replaced impervious surfaces, must be included in the treatment system design.
(2) Where the addition of traffic lanes results in an alteration of less than 50% of the impervious surface of an existing street or road that was not subject to this chapter, only the new and/or replaced impervious surface of the project must be included in the treatment system design. However, if the stormwater runoff from the existing traffic lanes and the added traffic lanes cannot be separated, any onsite treatment system must be designed and sized to treat stormwater runoff from the entire street or road.
(n) “Trail project” means a project to construct new impervious trails greater than 10-feet wide or creekside trails (within 50 feet of the top of bank) that creates 10,000 square feet or more of newly constructed contiguous impervious surface and that falls under the building and planning authority of the city.
The following projects are not considered trail projects for the purposes of this chapter:
(1) Impervious trails built to direct stormwater runoff to adjacent vegetated areas, or other non-erodible permeable areas, preferably away from creeks or towards the outboard side of levees.
(2) Sidewalks, bicycle lanes, or trails constructed with permeable surfaces (includes pervious concrete, porous asphalt, unit pavers, and granular materials).
(Ord. 5112 § 1, 2010: Ord. 4909 § 1, 2006: Ord. 4878 § 2, 2005: Ord. 4799 § 2 (part), 2003)