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HomeMy WebLinkAboutStaff Report 353-05requires projects that create or replace one acre or more of impervious surface to incorporate treatment measures and other appropriate source control and site design measures into projects to reduce pollutant discharges to the maximum extent practicable (CMR:255 :03). In accordance with subsequent provisions of the permit, the attached ordinance extends the applicability of the storm water regulations to smaller-sized projects and creates new requirements that address the potential impacts of development on the health oflocal creeks. DISCUSSION The attached ordinance modifies the City's existing storm water pollution prevention regulations (Palo Alto Municipal Code [P AMC] Chapter 16.11). These regulations require specified projects to incorporate treatment measures and other appropriate source control and site design measures into projects to reduce pollutant discharges to the maximum extent practicable. Examples of these storm water control measures are described below. Treatment Measures are features that treat storm water runoff, using settlement, infiltration, bioremediation, or filtration to remove pollutants that have accumulated as the runoff flows across a developed site. Examples include: • Vegetated swales • Detention basins • Catch basin filter inserts Source Control Measures are features that prevent pollutants that may be present on a developed site from entering storm water runoff. Examples include: • Covered loading docks, dumpster areas, and fueling areas • Indoor mat/equipment wash racks for food service facilities • Prohibition of storm drain connections for swimming pool, air conditioner, and fire sprinkler system drains Site Design Measures are features that reduce storm water pollution by decreasing or slowing storm water runoff or interrupting the flow of runoff across a series of contiguous impervious surfaces. Examples include: • Clustering of structures in order to minimize land disturbance • Roof downspouts that drain to landscaped areas • Pervious pavement materials • Minimization of directly connected impervious areas The attached ordinance implements new requirements issued by the Regional Board by modifying the existing regulations in three primary ways. First, the ordinance lowers the impervious surface threshold for compliance with the regulations. The ordinance also creates an exemption for several specific land development activities. Lastly, the ordinance establishes new requirements for hydromodification management in order to control the potential for increased erosion in local creeks caused by land development activity. Change to Criteria for Compliance with Storm Water Pollution Prevention Regulations Under the existing regulations, land development projects that create or replace one acre (43,560 square feet) or more of impervious surface must comply with the storm water pollution prevention provisions of P AMC Chapter 16.11 . The attached ordimince would lower the compliance threshold to 10,000 square feet for certain specified land use categories that have a CMR:353 :05 Page 2 of7 higher potential for storm water pollution, such as gas stations, wrecking yards, loading docks and surface parking lots. This compliance threshold represents a compromise reached between Regional Board staff and Program representatives that has been approved by the Regional Board. The compromise solution was crafted in an effort to minimize the impacts to economic development in the Santa Clara Valley. The Program's 2001 NPDES permit originally required that the one-acre impervious surface threshold for regulation of development activity be lowered to 5,000 square feet, beginning in October 2004. This requirement was relaxed by the Regional Board, however, in recognition of the inequity that exists between the NPDES permits issued to the various storm water programs throughout the Bay Area. The communities of the Santa Clara Valley were the first in the Bay Area to be regulated under an NPDES storm water permit, starting in 1990. Other countywide storm water permits were issued in subsequent years to entities in adjacent counties. The Regional Board's 5-year permit reissuance cycle follows the sequence used to issue the original permits. As a result, new requirements are always imposed upon the Santa Clara Valley Program before they impact the other Bay Area storm water programs. This situation creates an unfair financial burden on Santa Clara Valley communities due to the increased cost of permit compliance and the loss of economic development opportunities caused by the higher level of regulation. Program staff has been diligent in its efforts to remedy the inequity resulting from the differing requirements amongst storm water programs. In 2003, the Regional Board Executive Officer issued a letter modifying the secondary threshold to 10,000 square feet, excluding individual lot single-family residential development from the requirements, and extending the secondary implementation date to April 2005. Program staff and representatives from member agencies continued to push for "a level playing field" with other storm water programs. A further compromise was reached, and an amendment to the Program's NPDES permit was approved by the Regional Board at its July 20,2005 meeting (see Attachment B). The permit amendment lowers the compliance threshold to 10,000 square fe,et . for certain specified land use categories that have a higher potential for storm water pollution, such as gas stations, wrecking yards, loading docks and surface parking lots. The language in the attached ordinance is consistent with the provisions of the permit amendment. In order to permanently resolve the differences between the storm water permits throughout the Bay Area, Regional Board staff has been working cooperatively with storm water program managers towards the issuance of a single regional permit for all Bay Area storm water programs in 2006. The regional permit is expected to lower the compliance threshold to 10,000 square feet for all land uses (except for the exempt categories listed below). Exemption for Specific Land Development Activities In an effort to eliminate other discrepancies between the various storm water permits throughout the Bay Area, the permit amendment approved by the Regional Board provides categorical exemptions from the storm water pollution prevention measures for specified land development activities. These exemptions were already allowed under other Bay Area storm water permits. In the attached ordinance, the following land development activities are exempted from compliance with P AMC 16.11 : • An individual single-family home which is not part of a larger common plan of development, and which is designed with appropriate source control and site design measures • Sidewalks and trails in the public right-of-way CMR.:353 :05 Page 3 of7 • Bicycle lanes on public streets • Interior remodels • Roof or exterior surface replacement • Pavement resurfacing • Road pavement structural section rehabilitation within the existing roadway footprint Hydromodification Management Measures The attached ordinance also establishes requirements for hydromodification management measures to be incorporated into specified land development projects. This new set of requirements is being established in accordance with a provision in the Program's 2001 NPDES storm water permit. Hydromodification is defined as "the change in the natural watershed hydrologic processes and runoff characteristics caused by urbanization or other land use changes that result in increased stream flows and sediment transport." Hydromodification is caused primarily by the process of urbanization under which natural, pervious areas are covered over with impervious surfaces such as buildings, parking lots, streets, etc. The increased hardscape increases storm water runoff, which in turn leads to erosion and bank instability in the streams that receive the runoff. Hydromodification management measures are control measures, typically large holding basins, incorporated into development projects in order to reduce storm water runoff so as to not cause increased erosion in the receiving stream as compared to the pre- project condition. In accordance with the 2001 NPDES storm water permit, the Program retained an engineering consultant to develop a Hydromodification Management Plan (HMP) for the Santa Clara Valley. The consultant has worked cooperatively with Program staff, member agency staff, and Regional Board staff over the past three years to produce a scientifically-based, cost-effective plan. The HMP was approved by the Regional Board at its July 20, 2005 meeting. The ordinance references the HMP, which contains a management standard and a set of performance criteria that define the measures to be taken to effectively control hydromodification. The f.IMP describes a procedure to be followed by designers to identify the potential impacts of a land development project and defines the criteria to be used to design the holding basin required to detain the increased storm runoff resulting from the project. The basin is designed to release the runoff to the receiving storm drain or creek in a pattern similar to the pre-project condition, thus avoiding any erosive impacts to the creek. The HMP also contains provisions that allow a land development permit applicant to contribute to the funding of an off-site hydromodification control measure where construction of an on-site measure is deemed impractical (i.e. where the cost of the on-site flow control measure would exceed 2% of the project construction cost). The NPDES permit only requires hydromodification controls for large development projects that discharge storm runoff to creeks susceptible to erosion. As a result, the HMP contains an extensive set of conditions under which projects are exempt from the controls. Based on the nature of the allowable exemptions, the HMP requirements are expected to have a minimal impact on projects in Palo Alto due to the prevalence of creeks with non-erodible, hardened banks and the scarcity of large-scale development in Palo Alto's built-out community. The attached ordinance contains provisions excluding the following types of development projects from the HMP requirements: 1. Projects that do not create an increase in impervious surface over pre-project conditions. Cl\1R.:353 :05 Page 4 of7 2. Transit-oriented development located within a one-half mile radius of transit stations and/or intermodal transit facilities . 3. Projects located within areas that drain to stream channels within the tidally-influenced area. 4. Projects located within areas that drain to non-earthen stream channels that are hardened on three sides and extend continuously upstream from the tidally-influenced area. S. Projects draining to an underground storm drain that discharges directly to San Francisco Bay. 6. Projects that are located in subwatershed areas that are 90% or more built-out and have more than 6S% impervious surface. 7. Projects that are less than SO acres in total project size that are located in subwatershed areas that are 90% or more built-out and have less than 6S% impervious surface. 8. Projects that demonstrate, upon completion of stream-specific modeling studies that are consistent with the Hydromodification Management Plan approved by the Regional Board, that there will be no increase in potential for erosion or other adverse impact to beneficial uses to any waters of the State. The attached map (Attachment C) depicts the applicability of the HMP to sites in Palo Alto. Even in the non-exempt areas (green areas on the attached map) reduced HMP requirements are applicable to land development projects less than 20 acres in size. Staff Analysis of Proposed Ordinance The control measures required by the proposed ordinance will have direct benefits on the performance of the City's existing storm drain system. By their nature, many storm water quality control measures also reduce storm water runoff volume and peak flow rates by promoting storm water infiltration into the ground and interrupting the continuous flow of runoff over impervious areas. While these measures will not eliminate the need for storm drain capacity upgrades, they will reduce the magnitude of existing drainage system deficiencies as areas are redeveloped. ' Staff has performed outreach to those impacted by these new storm water regulations at both the local and regional level. Regionally, the Program has prepared guidance documents and conducted regional training workshops for agency staff as well as members of the development community. At the local level, staff prepared an informational fact sheet on the new regulations (Attachment D) that has been placed at the Development Center and posted on the web . Staff also sent out a direct mailing to local developers and designers. Due to the Council vacation, the second reading of the ordinance will be postponed until September 12. As a result, the ordinance will not take effect until October 13, thus providing additional time for permit applicants to become familiar with its provisions. The new storm water requirements may increase design and construction costs by up to two percent for developers whose projects must comply with the ordinance. Adoption of the ordinance is not, however, expected to have a significant impact on land development activity in Palo Alto, since there will likely be relatively few developments that will be subject to the ordinance. CMR:353:05 Page 5 of7 RESOURCE IMPACT Enforcement of the proposed ordinance will require additional effort by Public Works and Planning staff both during permit review and periodic follow-up inspections to verify proper maintenance of storm water control measures. Because of the relatively small number of development projects expected to trigger the ordinance's threshold levels, the need for additional staff is not anticipated at this time. Additional costs incurred by the City for plan review and site inspections are recovered through existing permit fees. Staff will reassess workload impacts if the threshold compliance trigger is lowered to 10,000 square feet for all land uses, as expected In August 2006. POLICY IMPLICATIONS The storm water pollution prevention measures contained in the proposed ordinance are consistent with a number of policies and programs contained in the Comprehensive Plan: Program N-29: Actively participate in programs such as the Santa Clara Valley Urban Runoff Pollution Prevention Program to improve the quality of stormwater runoff. Policy N-21: Reduce non-point source pollution in urban runoff from residential, commercial, industrial, municipal, and transportation land uses. Program N-27: Work with regulatory agencies, environmental groups, affected businesses, and other stakeholders to identify economically viable Best Management Practices (RMP) for reducing pollution. Policy N-22: Limit the amount of impervious surface in new development or public improvement projects to reduce urban runoff into storm drains, creeks, and San Francisco Bay. Program N-75: Establish a standardized process for evaluating the impacts of development on the storm drainage system. TIMELINE The attached ordinance will take effect on October 13 (the 31 st day following the scheduled second reading of the ordinance). The provisions of the ordinance will be applicable to permit applications deemed complete by the City on or after the effective date of the ordinance for projects that equal or exceed the threshold size criteria. This implementation schedule is consistent with the revised NPDES permit, which requires the co-permittees to begin enforcing the new development-related storm water pollution prevention requirements no later than October 20,2005. ENVIRONMENTAL REVIEW Adoption of the attached ordinance is exempt from the proVISIOns of the California Environmental Quality Act (CEQA) as a measure taken to implement an action to assure the maintenance, restoration, enhancement, or protection of the environment. CMR.:353:05 Page 6 of7 NOT YET APPROVED SECTION 2. Section 16.11.020 (Definitions) of . Chapter 16 .11 (Stormwater Pollution Prevention), Title 16 [Building Regulations] of the Palo Alto Municipal Code is hereby amended to read in its entirety as follows: 16.11.020 Definitions. The following words and phrases, whenever used in this chapter, shall be as set forth below: (a) "Dev elopment project" shall mean any private or public project under the planning and building authority of the city that creates impervious surface and is in one of the categories described in subsections (a)(l), (a)(2), or (a)(3) below (1) A project shall be considered a development project if it results in the creation of an amount of impervious surface collectively over the entire project si tel including but not limited to parking lots, roof area, streets, and private walkways equal to or more than one of the following thresholds: 1. One acre (43,560 square feet); or ii. 10,000 square feet if the project is in one of the following land use categories: a. Auto service stations; b. Auto wrecking or salvage yards . (2) A project shall be considered a development projedt if it results in the creation of 10,000 square feet or more of impervious surface area used for one of the following functions: 1. Loading dock; or 11. Surface parking lot. (3) A project shall be considered a development project if it results in the creation of 10,000 square feet or more of impervious surface area used for one of the functions described below and the project developer fails to demonstrate to the city engineer that potential pollutant loading will be satisfactorily mitigated through post-construction source control and site design practices: i . Outdoor vehicle or equipment maintenance (including washing and repair) ; 11. Outdoor handling or storage of waste or hazardous materials; 050803 sm 0100383 2 NOT YET APPROVED under natural conditions pre-ex istent to development. Impervious surfaces include, but are not limi ted 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. (d) "Permanent stormwater pollution prevention measures" or "PSPPM" shall mean any combination of source c ontrol measures, si te design measures, and/or stormwater treatment measures that reduce stormwater pollution to the maximum extent practicable as required by Order No. 01-119 under NPDES Permit No . CAS02971 8 issued by the Regional Board, as it may be amended from time to time. The design and implementation of the PSPPM must be in accordance wi th the guidelines and technical specifications provided by the ci ty or other city- approved authority and the requirements of Order No . 01-119 . (e) "Significant redevelopment project" shall mean any private or public proj ect under the planning and building jurisdiction of the city on a previously developed site that creates additional or replacement impervious surface and is in one of the categories described in subsections (e) (1), (e) (2), or (e) (3) below . (1) A proj ect shall be considered a significant redevelopment project if it results in the addition or replacement of an amount of impervious surface collectively over the entire project site, including but not limited to parking lots, roof area, streets, and private walkways equal to or more than one of the following thresholds: l. One acre (43,560 square feet); or ll. 10,000 square feet if the project is in one of the following land use categories: a. Auto service stations; b . Auto wrecking or salvage yards . (2) A proj ect shall be considered a significant redevelopment project if it results in the addition or replacement of 10,000 square feet or more of impervious surface area used for one of the following functions: i . Loading dock; or ii . Surface parking lot. (3) A project redevelopment project 050803 sm 0 I 00383 shall if it 4 be considered a resul ts in the significant addition or NOT YET APPROVED by simple gravity settling of particulate filtration, biological uptake, media adsorption physical, biological, or chemical process. pollutants, or any other SECTION 3. Section 16.11.031 (Hydromodification Management Measures Required) is hereby added to Chapter 16.11 (Stormwater Pollution Prevention), Title 16 [Building Regula tions] of the Palo Alto Municipal Code to read ln its entirety as follows: 16.11.031 Hydromodification Management Measures Required (a) All development projects that result in the creation of one acre (43,560 square feet) or more of impervious surface and all significant redevelopment projects that result in the addition or replacement of one acre (43,560 square feet) or more of impervious surface shall implement hydromodification management measures, except for the following projects: 1. Projects that do not create an increase in impervious surface over pre-project conditions. 2. Transi t-oriented developments half mile radius of existing or planned intermodal transi t facili ties, including terminals or major transfer points. located wi thin a one- transit stations and/or rail and bus stations, 3. Projects located within areas that drain to stream channels within the tidally-influenced area. 4. Projects located within areas that drain to non- earthen stream channels that are hardened on three sides and extend continuously upstream from the tidally-influenced area. 5. Projects draining to an underground storm drain that discharges directly to San Francisco Bay. are 90% surface. 6. Projects that are located in subwatershed areas that or more built-out and have more than 65% impervious 7. Projects that are less than 50 acres in total project size that are located in subwatershed areas that are 90% or more built-out and have less than 65% impervious surface. 8. Projects that demonstrate, upon completion of stream- specific modeling studies that are consistent with the Hydromodification Management Plan approved by the Regional Board, that there will be no increase in potential for erosion or other adverse impact to beneficial uses to any waters of the State. The exceptions described above shall be applied in accordance with the provisions of the requirements of Order No. 050803 sm 0100383 6 ATTACHMENTB CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD SAN FRANCISCO BAY REGION ORDER No. R2-2005-0035 NPDES PERMIT NO. CAS029718 AMENDMENT REVISING ORDER NO. 01-119 FOR: SANTA CLARA VALLEY WATER DISTRICT, COUNTY OF SANTA CLARA, CITY OF CAMPBELL, CITY OF CUPERTINO, CITY OF LOS ALTOS, TOWN OF LOS ALTOS HILLS, TOWN OF LOS GATOS, CITY OF MILPITAS, CITY OF MONTE SERENO, CITY OF MOUNTAIN VIEW, CITY OF PALO ALTO, CITY OF SAN JOSE, CITY OF SANTA CLARA, CITY OF SARATOGA, AND CITY OF SUNNYVALE, which have joined together to form the SANTA CLARA VALLEY URBAN RUNOFF POLLUTION PREVENTION PROGRAM The California Regional Water Quality Control Board, San Francisco Bay Region, hereinafter referred to as the Board, finds that: Findings 1. Incorporation of related documents: The Fact Sheet for this Order includes cited references and additional explanatory information in support of the requirements of this amendment. This information, including any supplements thereto, and any future response to comments on the Tentative Order, is hereby incorporated by reference. ' Existing Orders 2. The Board adopted Order No. 01-024 on February 21,2001, reissuing waste discharge requirements under the National Pollutant Discharge Elimination System (NPDES) permit for the Santa Clara Valley Urban Runoff Pollution Prevention Program (Program) for the discharge of storrnwater to South San Francisco Bay and its tributaries. The Program's NPDES permit is jointly issued to the thirteen cities of Santa Clara County named above, Santa Clara County and the Santa Clara Valley Water District, all of which are Co-permittees. These Co-permittees are referred to as the Dischargers. 3. Order No. 01-024 recognizes the Santa Clara Valley Urban Runoff Management Plan (Management Plan) as the Dischargers' Comprehensive Control Program and requires implementation of the Management Plan, which describes a framework for management of stormwater discharges. The Management Plan describes the Program's goals and objectives and contains Performance Standards, which represent the baseline level of effort required of each of the Dischargers. The Management Plan contains Performance Standards for seven different stormwater management activities. 4. The Board adopted Order No. 01-119 on October 17, 2001, which amended Provision C.3. of Order No. 01 -024 to enhance the Dischargers' existing Performance Standard for new development and significant redevelopment. Order No. 01-024 and Order No. 01-119 are --Order R2-2005-0035 -- Page 1 hereinafter collectively referred to as the Pennit. Order No. 01-119 specifically requires a level of implementati<;m of best management practices (BMPs), including source control, site design, and structural stonnwater treatment measures in new development and significant redevelopment, that removes pollutants from the discharge to the maximum extent practicable (MEP). This is done through additional requirements to incorporate source control measures, site design principles, and structural stonnwater treatment controls in new development and redevelopment projects in order to reduce water quality impacts of stonnwater runoff for the life of these projects. The consistent application of such measures is intended to greatly reduce the adverse impacts of new development and redevelopment on water quality and beneficial uses by reducing stonnwater pollutant impacts, and impacts of increases in peak runoff rate. 5. In September 2003, as allowed by the Pennit, the Program proposed an alternate Group 2 definition under Provision C.3.c. so as to provide consistency between the Pennit and the pennits for other Bay Area Phase I municipal stonnwater pennit holders (hereinafter referred to as "other Bay Area Pennittees"). The other Bay Area Pennittees include the Alameda Countywide Clean Water Program, the Contra Costa Clean Water Program, Fairfield-Suisun Sanitary District, and the San Mateo Stonnwater Pollution Prevention Program. Specifically, the proposed revisions excluded specific projects from the Group 1 and 2 Project categories, increased the threshold for implementation of C.3 . requirements to 10,000 square feet for Group 2 projects, allowed projects with water quality benefits (such as stream restoration) under an alternative compliance program, provided exemptions for certain redevelopment projects, and requested additional time for the implementation ofC.3. requirements for Group 2 Projects by extending the date from October 15, 2004, to April 15, 2005. 6. The Board approved the alternate Group 2 definition at its October 15, 2003 meeting and directed the Executive Officer to sign and send a Letter of Approval to the Dischargers. This Order confonns the Group 1 and 2 Project definitions in the Pennit pursuant to the Board's prior Letter of Approval. Amendments of this Order Group 2 Projects 7. This Order also establishes definitions for Group 2A and 2B Projects to allow implementation to be completed in phases by the Dischargers. The Order extends the implementation date for Group 2A projects from April 15, 2005, to within three months of adoption of this Order. This Order also amends Provision C.3.c.ii. of Order No. 01-119 to extend the implementation date for Group 2B Projects so as to provide consistency with pennits for other Bay Area Pennittees. Hydromodification Management Plan (HMP) Report 8. This Order also amends the Pennit to approve key provisions of the Hydromodification Management Plan (HMP) Final Report! required under this Pennit (hereinafter referred to as the HMP Report), as set forth in Attachment A of this Order, and which are hereby incorporated into I Hydromodification Management Plan Report, Final Draft, Santa Clara Valley Urban Runoff Pollution Prevention Program, April 21, 2005. ' --Order R2-2005-0035 -- Page2 this Permit. The intent of the HMP Report is to reduce the hydromodification impacts from stormwater discharges from certain development projects within the Dischargers' jurisdictions. Provision C.3.f.viii of the Permit required submittal of the HMP Report by October 15, 2003. However, the Dischargers were provided an additional three months to complete the HMP Report in order to provide the Dischargers and other Bay Area Permittees the same net amount of time to complete an HMP Report. Subsequently, the Dischargers submitted components of their HMP and were allowed additional time, approximately 15 more months, to resolve technical and administrative implementation issues and complete their HMP Report. 9. The other Bay Area Permittees submitted their own HMP reports on or about May 15,2005. The next steps include Board staff review of all the HMP reports; comments on the technical merits of each report; collaborative meetings to encourage consistency; revision of the HMP reports as necessary; public notice o·f intent to approve and require the implementation of the HMPs; and a hearing(s) by the Board. Thus, it is expected that the other Bay Area Permittees will be required to implement their HMPs by late 2005 or early 2006. It is the Board's intention to make all the permit requirements and implementation dates essentially uniform for all Bay Area Permittees in the near future. 10. The Board intends to consider making revisions of the Dischargers' HMP provisions if needed to make the Dischargers' HMP consistent with the HMPs of other Bay area Permittees. The Board may do this through approval of a region-wide permit, though a blanket permit amendment for all Bay Area Permittees, or through reissuance of the Dischargers' permit accomplished in a consistent fashion with the other Bay Area Permittees. 11 . The Board intends that the Executive Officer may request that all Bay Area Permittees investigate potential incremental costs, and benefits to waterways, from controlling a range of flows up to the 50-year peak flow versus controlling up to the 10-year peak flow, as required by this Order. Any future revisions ofthe Dischargers' HMP provisions may reflect improved understanding of this . ' Issue. 12. The Board strongly encourages land use planning agencies and developers to carefully consider, early in the development planning process, the potential impacts on water quality and beneficial uses of new development projects. The Board strongly discourages modifying watercourses to adapt to increased flows and durations of runoff, except in limited circumstances where avoidance or other natural alternatives are not feasible. In these limited circumstances, project proponents first demonstrate that hydromodification has been minimized to the extent practicable by minimizing increases in flows and durations of runoff discharge from the site. Second,the project proponents should demonstrate that off site mitigation measures have been employed to the rriaximum extent practicable to avoid hydromodification impacts. Project proponents also should document that there will be no adverse effects to water quality or beneficial uses. 13. For the purposes of this Order, the term "Redevelopment" is defined as a project on a previously developed site that results in the addition or replacement of impervious surface, and the term "Brownfield site" means real property, the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant. --Order R2-2005-0035 -- Page 3 14. Transit village type developments within 'l::I to within Y:z mile of transit stations andlor intermodal facilities, and projects within "Redevelopment Project Areas" (as defined by Health and Safety Code Section 33000, et seq.) that redevelop an existing Brownfield site or create housing units affordable to persons of low or moderate income as defined by Health and Safety Code Section 50093, are excepted from the requirements of Provision C.3.f. and the HMP, and after impracticability of including onsite treatment measures is established, from the requirement for alternate, equivalent offsite treatment. Significant change in impervious surface or significant change in stormwater runoff volume or timing is unlikely in these redevelopment circumstances, because these developments would be within a largely already paved catchment, and on a site that is largely already paved or otherwise impervious. 15. Certain control measures implemented or required by Dischargers for urban runoff management may create a habitat for vectors (e.g., mosquitoes and rodents) if not properly designed or maintained. Close collaboration and cooperative effort among Dischargers, local vector control agencies, Board staff, and the State Department of Health Services is necessary to minimize potential nuisances and public health impacts resulting from vector breeding. 16. The Board recognized in its "Policy on the Use of Constructed Wetlands for Urban Runoff Pollution Control" (Resolution No. 94-102) that urban runoff treatment wetlands that are constructed and operated pursuant to th/lt Resolution and are constructed outside of a creek or other receiving water, are stormwater treatment systems and, as such, are not waters ofthe United States subject to regulation pursuant to Sections 401 or 404 of the federal Clean Water Act. Board staff is working with the California Department ofFish and Game (CDFG) and U.S. Fish and Wildlife Service (USFWS) to identify how maintenance for stormwater controls required under orders such as this Order can be appropriately streamlined, given CDFG and USFWS requirements, and particularly those that address special status species. The Dischargers are expected to work diligently and in good faith with the appropnate agencies to obtain any , approvals necessary to complete maintenance activities for treatment controls. If the Dischargers have done so, when necessary and where maintenance approvals are not granted by the agencies, the Dischargers shall be considered by the Board to be in compliance with Provision C.3 .e of the Permit. Applicable Federal, State, and Regional Regulations 17. Pursuant to 40 CFR Sections 124.5.c.2 and 122.62, only those conditions to be modified by this amendment shall be reopened with this amendment. All other aspects of the existing Permit shall remain in effect and are not subject to modification by this amendment. 18. Provision C.11. of the existing Permit anticipated that amendments, revisions and modifications to the Management Plan and existing Permit would be necessary from time to time, and provided direction that changes requiring major revision of the Management Plan shall be brought before the Board as permit amendments. This Order is consistent with Provision C.ll. of the existing Permit. --Order R2-2005-0035 -- Page 4 19. This action to modify an NPDES permit is exempt from the provisions of the California Environmental Quality Act (Division 13 of the Public Resources Code, Chapter 3, Section 21100, et.seq.) in accordance with Section 13389 of the California Water Code. Notification to Dischargers and Interested Parties 20. The Dischargers and interested agencies and persons have been notified of the Board's intent to modify waste discharge requirements for the existing discharge and have been provided opportunities for public meetings and to submit their written views and recommendations. IT IS HEREBY ORDERED that the Dischargers, in order to meet the provisions contained in Division 7 of the California Water Code and regulations adopted hereunder and the provisions of the Clean Water Act as amended and regulations and guidelines adopted hereunder, shall comply with the following revisions: Provisions C.3 .c. of Order 01-119 are hereby modified and amended as follows: additions to the Provisions are displayed as underlined Bold type, and deletions of text are displayed as strikeout format: C. Provisions 3.c.i. Group 1 Projects: Dischargers shall require Group 1 Projects to design and implement stonnwater treatment BMPs appropriate source control and site design measures and to design and implementstormwater treatment measures, to reduce the discharge of stormwater pollution pollutants to the maximum extent practicable. Implementation of this requirement shall begin on July 15,2003, subject to a workplan, submitted March 1, 2002, acceptable to the Executive Officer, identifying incremental progress already made and to be made toward implementation ofC.3.c.i. by July 15,2003. Ifno acceptable . workplan is received, implementation ofC.3.c.i. requirements shall begin on October 15, 2002. Group 1 Projects consist of all public and private projects in the following categories: 1. Commercial, industrial, or residential developments that create one acre (43,560 square feet) or more of impervious surface, including roof area, streets, and sidewalks. This category includes any development of any type on public or private land, which falls under the planning and building authority of the Dischargers, where one acre or more of new impervious surface, collectively over the entire project site, will be created. Construction of one single-family home, which is not part of a larger common plan of development, with the incorporation of appropriate pollutant source control and design measures, and using landscaping to appropriately treat runoff from roof and house-associated impervious surfaces (e.g., runoff from roofs, patios, driveways, sidewalks, and similar surfaces), would be in substantial compliance with Provision C.3. 2. Streets, road, highways, and freeways that ,are under the Dischargers' jurisdiction and that create one acre (43,560 square feet) or more of new impervious surface. This --Order R2-2005-0035 -- Page5 category includes any newly constructed paved surface used primarily for the transportation of automobiles, trucks, motorcycles, and other motorized vehicles. Excluded from this category are sidewalks, bicycle lanes, trails, bridge accessories, guardrails, and landscape features. 3. Significant Redevelopment projects. This category is defined as a project on a previously developed site that results in addition or replacement, which combined total 43,560 fe or more of impervious surface on such an already developed site ("Significant Redevelopment"). Where a Significant Redevelopment project results in an increase of, or replacement of, more than fifty percent of the impervious surface of a previously existing development, and the existing development was not subject to stormwater treatment measures, the entire project must be included in the treatment measure design. Conversely, where a Significant Redevelopment project results in an increase of, or replacement of, less than fifty percent of the impervious surface of a previously existing development, and the existing development was not subject to stormwater treatment measures, only that affected portion must be included in treatment measure design. Excluded from this category are interior remodels and routine maintenance or repair, including roof or exterior surface replacement and repaving. Excluded routine maintenance and repair includes roof or exterior surface replacement, pavement resurfacing, repaving and road pavement structural section rehabilitation within the existing footprint, and any other reconstruction work within a public street or road right-of-way where both sides of that right-of-way are developed. 3.c.ii. Group 2 Projects: Group 2 Projects will be divided into two subgroups: Group 2A and 2B. Group 2A Implementation The Group 2A Project definition is in all ways the same as the Group 1 Project definition above, except that the size threshold of impervious area for new and Significant Redevelopment projects is reduced from one acre (43,560 ft2) to.woo 10,000 square feet and the project is one of the following land use categories: Dischargers shall require Group 2 Projects to design and implement stormwater treatment BMPs to reduce stormwater pollution to the maximum extent practicable. Implementation of this requirement shall begin on October 15, 2004, at ",,,hich time the definition of Group 1 Project is changed to include all Group 2 Projects. • Gas stations; • Auto wrecking yards; • Loading docks and surface parking lots containing 10,000 square feet or more of impervious surface area; and Vehicle or eguipment maintenance areas (including washing and repair), outdoor handling or storage of waste or hazardous materials, outdoor manufacturing area(s), outdoor food handling or processing, outdoor animal care, outdoor horticultural activities, and various other industrial and commercial uses where potential pollutant loading cannot be satisfactorily --Order R2-2005-0035 -- Page 6 mitigated through other post-construction source control and site design practices. Dischargers shall implement Provision C.3.d. with respect to Group 2A projects as soon as the Dischargers can adopt implementing ordinances, policies and/or guidance and, in any event, by no later than 3 months from the date of adoption of this Order. Group 2B Implementation Unless the Board otherwise approves an alternative Group 2 Project defmition pursuant to the items listed below, the Group 2B Project defmition will in all ways become the same as the Group 1 Project definition above (except with respect to implementation of Provision C.3.f.), but the size threshold of impervious area for new and Significant Redevelopment projects will be reduced from one acre (43,450 ft2) to 10,000 square feet. 1. The Board intends to require in the next reissuance of the Dischargers' permit that the Dischargers shall implement Provision C.3.d. with respect to Group 2B projects by August 15, 2006. 2. In the event that this permit is administratively extended until August 15, 2006 or later, then the Dischargers shall implement Provision C.3.d. with respect to Group 2B projects by August 15, 2006. 3. If the Board adopts a regional municipal stormwater permit that includes a different deadline for implementation of Group 2B projects or a different definition of Group 2 Projects, then that deadline and/or defmition shall supersede those implementation dates and/or defmitions set forth above. C.3.iii. Alternative Project Proposal: The Program and/or any Discharger may propose, for approval by the Regional Board, an Alternative Group 2 Project definition, with the goal that any such alternative defmition aim to ensure that the maximum created impervious surface area is treated for the minimum number of projects subject to Discharger review. Any such proposal shall contain supporting information about the Dischargers' development patterns, and pollutant source infonnation, sizes and numbers of proposed projects for several years, that demonstrates that the proposed definition is comparable in effectiveness to would be substantially as effective as the Group 2 Project definition (i.e., that a comparable development area and/or pollutant loading would be addressed under the proposed alternate definition). in Provision C.3.c.ii. Proposals may include differentiating projects subject to the Alternative Group 2 Project definition by land use, by focusing solely on the techniques recommended by "Start at the Source" for documented low pollutant loading land uses, and/or by optimum use of landscape areas required by Dischargers under existing codes as treatment measures. Proposals must be submitted by April 15 , 2004, in order to be considered by the --Order R2-2005-0035 -- Page 7 Regional Board before the Group 2 Project implementation date in C.3.c.ii. Proposals may be submitted anytime, with the understanding that the Group 2 Project definition, as described in Provision C.3.c.li, will be upheld as the default in the absence of an approved Alternative Group 2 Project definition. Provisions C.3.f. of Order 01-119 are hereby modified and amended as follows:. additions to the Provisions are displayed as underlined Bold type, and deletions of text are displayed as strikeout fonnat. C.3.f. i. No later than 3 months after the date of adoption of this Order, t+he Dischargers shall manage increases in peak runoff flow and increased runoff volume, for all Group 1 Projects, where such increased flow and/or volume is likely to cause increased erosion of creek beds and banks, silt pollutant generation, or other impacts to beneficial uses. Such management shall be through implementation of the key provisions of the a Hydromodification Management Plan (HMP) Final Report2 as set forth in Attachment A of this Order and which are hereby incorporated into this Permit. The HMP, once approved by the Regional Board, willshall be implemented so that post-project runoff shall not exceed estimated pre-project rates and/or durations, where the increased stonnwater discharge rates and/or durations will result in increased potential for erosion or other significant adverse impacts to beneficial uses, attributable to changes in the amount and timing of runoff. The tenn duration in this section Provision is defined as the period that flows are above a threshold that causes significant sediment transport and may cause excessive erosion damage to creeks and streams. I, Bruce H. Wolfe, Executive Officer, do hereby certify that the foregoing is a full, true, and correct copy of an order adopted by the California Regional Water Quality Control Board, San Francisco Bay Region, on July 20, 2005. Bruce H. Wolfe Executive Officer Attachment A: Key Provisions of the HMP Report Attachment B: Figure 1. Key Provisions of the HMP Report, Areas of Applicability 2 Hydromodification Management Plan Report, Final Report, Santa Clara Valley Urban Runoff Pollution Prevention Program, Apri121, 2005. --Order R2-2005-0035 -- Page8 Attachment A: Key Provisions of the HMP Report --Order R2-2005-0035 -- Paf{e 9 hydromodification management standard threshold ofEp < 1.0 from the point of discharge to the stream as far downstream as potential impacts will occur. Operation & Maintenance The operation and maintenance requirements of Provision C.3.e shall apply to stormwater controls implemented under the requirements of Provision C.3.f.8 Conditions of Applicability All Group 1 New and Redevelopment Projects that create or replace one acre or more of impervious surface shall implement hydromodification controls that meet the performance criteria above, except for the following projects: 1. Projects that do not create an increase in impervious surface over pre-project conditions. 2. Projects located within areas that drain to stream channels within the tidally influenced area. Such areas are shown in purple on Figure 1, Attachment B. 3. Projects located within areas that drain to non-earthen stream channels that are hardened on three sides and extend continuously upstream from the tidally influenced area. Such areas are shown in purple on Figure 1, Attachment B. The Program will continue to determine the accuracy of this map. 4. Projects draining to Sunnyvale East or West Channels. Such areas are shown in purple on Figure 1, Attachment B. 5. Projects draining to an underground stonn drain that discharges directly to San Francisco Bay. 6. Projects that demonstrate, upon completion of stream-specific and modeling studies that are consistent with the method used in the HMP Report and its supporting technical documents, that there will be no increase in potential for erosion or other adverse impact to beneficial uses to an)' State Waters. 7. Projects that are less than 50 acres in total project size that are located in areas with < 65- 70% impervious surface9 and 90% or more built-out, as shown in yellow on Figure 1, Attachment B. Such projects shall be encouraged but not required to implement the HMP. 8 See Section 7.7 of the HMP Report for further guidance on operations and maintenance. 9 The map is based on 65% impervious surface; however, impervious surface was determined from aerial photographs taken during the summer, when foliage covered impervious surfaces~ PageA-3 8. Projects that are located in areas with 2:: 65~ 70% impervious surfacelO and 90% or more built-out, as shown in red on Figure 1, Attachment B. Such projects shall be encouraged but not required to implement the HMP. 10 The map is based on 65% impervious surface; however, impervious surface was determined from aerial photographs taken during the summer, when foliage covered impervious surfaces. Page A-4 Attachment B: Figure 1. Key Provisions of the HMP Report, Areas of Applicability --Order R2-2005-0035 -- Page 10 ATTACHMENTD INFORMATION REGARDING REVISED REQUIREMENTS FOR STORM WATER BEST MANAGEMENT PRACTICES (BMPs) FOR LAND DEVELOPMENT PROJECTS WHO: The City of Palo Alto (as well as all other cities in the Santa Clara Valley) will be adopting revised storm water regulations applicable to land development projects. The scope of the regulations will be expanded to include those projects that create an amount of impervious surface equal to or more than one of the following thresholds: 1. One acre (43,560 square feet), or 2. 10,000 square feet if the project is in one of the following land use categories: a. Gas stations; b. Auto wrecking yards; c. Projects containing 10,000 square feet or more of impervious surface used for one of the following land use functions: 1. Loading dock; 11. Surface parking lot; 111. Outdoor vehicle or equipment maintenance areas (including washing and repair); IV. . Outdoor handling or storage of hazardous materials or waste; v. Outdoor manufacturing areas; VI. Outdoor food handling or processing; V11. Outdoor animal care; or VI11. Outdoor horticultural activities. WHEN: The regulations became effective on October 13,2005. WHAT: In order to protect water quality, the Regional Water Quality Control Board has modified the NPDES permit regulating the discharge of storm water runoff to local creeks by Santa Clara Valley municipalities. The new permit provisions mandate that the municipalities expand their regulations reqmrIng owners/developers of applicable projects to install and maintain permanent storm water quality protection measures in accordance with specific design criteria. Palo Alto Municipal Code Chapter 16.11 will be modified to comply with the revised NPDES permit requirements. July 25,2005