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HomeMy WebLinkAboutStaff Report 114-07TO: FROM: DATE: SUBJECT: City of Palo Alto City Manager’s Report COUNCIL CITY MANAGER DEPARTMENT: PUBLIC WORKS JANUARY 22, 2007 CMR: 114:07 APPROVAL AND ADOPTION OF ORDINANCE WITH CHANGES TO PALO ALTO MUNICIPAL CODE CHAPTER 16.28 (GRADING AND EROSION AND SEDIMENT CONTROL) OF TITLE 16 (BUILDING REGULATIONS) TO REGULATE IN-STREAM GRADING AND CONSTRUCTION 7 RECOMMENDATION Staff recommends that Council approve and adopt the attached ordinance (Attachment A) revising the City’s Grading and Erosion and Sediment Control Regulations (Palo Alto Municipal Code [PAMC] Chapter 16.28). The ordinance contains requirements that provide increased protection from the impacts of grading and construction activity between the banks of a stream. The ordinance is consistent with the Guidelines and Standards for Land Uses Near Streams developed by the Santa Clara Valley Water Resources Protection Collaborative and supplements the water resources protection provisions being added to the Zoning Ordinance as PAMC Section 18.40.140. BACKGROUND The Santa Clara Valley Water Resources Protection Collaborative (Collaborative) was convened in February 2003 as an ad hoc working group to address issues related to land use near streams. The Collaborative consists of representatives from 15 municipalities (including the City of Palo Alto), the County of Santa Clara, the Santa Clara Valley Water District (District) and other community and environmental group stakeholders. The Collaborative was formed as a consensus-based forum in which the stakeholders could jointly develop 1) a set of guidelines and standards (G&S) for land uses near streams consistent with their mutual stream protection goals, and 2) an implementation program which clearly delineates the roles of the District and the local agencies in land Use permitting and regulation for properties near streams. In September 2003, Council approved a resolution in support of the Collaborative’s mission to develop and implement watershed resource protection G&S (CMR:431:03). In July 2005, Council approved a resolution supporting the G&S and the Collaborative’s implementation program for revised regulation of land uses in and near streams (CMR:321:05). Many of the proposed G&S address the potential impacts of land development activity adjacent to streams. As a result, staff has recommended incorporating many of the G&S through changes to the Zoning Ordinance (Chapter 18 of the Municipal Code). Planning and Public Works staff have submitted the land use-related G&S to the Planning and Transportation Commission for review and comment, and a recommendation for approval of several zoning regulation changes are being concurrently submitted to Council in a companion staff report (CMRll3:07). This CMR: 114:07 Page 1 of 3 report transmits recommended Ordinance changes based upon the G&S that address the potential impacts of grading and construction activity directly within streams. DISCUSSION Construction of storm drain outfalls, bridges, culverts, and stream bank erosion repair projects can adversely affect streams and the riparian corridor. Flooding, bank erosion, and sedimentation can be exacerbated by construction of these in-stream features unless they are carefully planned and executed. The Collaborative identified several G&S that can minimize the negative impacts of these activities (see Attachment B). Staff has incorporated the Collaborative’s recommendations into several changes to the City’s Grading and Erosion and Sediment Control Regulations (PAMC Chapter 16.28). Recommended changes to the regulations also streamline the permitting of in-stream work by differentiating the permitting authorities of the City and the District in order to eliminate duplicative permitting processes. The recommended changes to the Grading and Erosion and Sediment Control Regulations can be summarized as follows: Grading or construction within a Santa Clara Valley Water District (District) right-of- way or easement will require a District encroachment permit, but will no longer require a City grading permit. Grading or construction outside a Water District right-of-way or easement will be regulated through a City grading permit, and will no longer require a Water District permit. Bridges, culverts, and storm drain outfalls shall be constructed in a manner consistent with the current version of the Santa Clara Valley Water Resources Protection Collaborative User Manual: Guidelines and Standards for Land Uses Near Streams. Stream bank erosion repair shall use the softest possible method appropriate for the stream characteristics. Use of hardscape materials or retaining walls within the banks of a stream shall be avoided. Stream bank erosion repairs shall be constructed in a manner consistent with the current version of the Santa Clara Valley Water Resources Protection Collaborative User Manual: Guidelines and Standards for Land Uses Near Streams. Streams shall not be filled or placed in culverts to accommodate grading and construction for land development projects, except for road crossings. Exception provisions to the stream protection requirements are provided, subject to the discretionary review of the Director of Public Works. RESOURCE IMPACT The proposed regulation changes can be enforced by existing staff as part of the current grading permit review process. POLICY IMPLICATIONS Council adoption of the attached ordinance is consistent with the following Comprehensive Plan policies and programs: Policy N-IO: Work with the Santa Clara Valley Water District and other relevant regional agencies to enhance riparian corridors and provide adequate flood control by use of low impact restoration strategies. PolicyN-11: Preserve the integrity of riparian corridors, CMR:ll4:07 Page 2 of 3 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. ATTACHMENTS Attachment A: Attachment B: Ordinance Excerpts from the Santa Clara Valley Water Resources Protection Collaborative’s Guidelines and Standards for Land Uses Near Streams PREPARED BY: DEPARTMENT HEAD: CITY MANAGER APPROVAL: Senior Engineer GLENN S. ROBERTS Director of Public W~-~ EMIL~S~)~ Assistant City Manager co:Stan Williams, Santa Clara Valley Water District John Gamman, CONCUR CMR: 114:07 Page 3 of 3 ATTACHMENT A ***NOT YET APPROVED*** ORDINANCE NO. ORDINANCE OF THE COUNCIL OF THE CITY OF PALO ALTO AMENDING SECTION 16.28.080 (SPECIFIC EXEMPTIONS) AND ADDING SECTION 16.2.8.321 (CONSTRUCTION OF BRIDGES,CULVERTS AND STORM DRAIN OUTFALLS AND SECTION 16.28.322(STREAM BANK EROSION REPAIR) TO CHAPTER 16.28 (GRADING AND EROSION AND SEDIMENT CONTROL)OF TITLE 16 (BUILDING REGULATIONS)OF THE PALOALTO MUNICIPAL CODE The Council of the City of Palo Alto does ORDAIN as follows: Section i. Findings and Declarations. finds and declares as follows: The City Council (a) In 2003 various agencies, including the City of Palo Alto, formed the Santa Clara Valley Water Resources Protection Collaborative to develop uniform guidelines and standards for land use near streams; (b) In August 2005, the Collaborative developed the Santa Clara Valley Water Resources Protection Collaborative User Manual: Guidelines and Standards for Land Uses Near Streams; (c) In July 2006 further updates.were made tothe User Manual; and (d) The City of Palo Alto desires to conform its land use policies near streams to the User Manual. Section 2. Section 16.28.080 amended to read as follows: (Specific Exemptions) is 16.28.080 Specific Exemptions Sections 16.28.060 and 16.28.070(a) - (f) notwithstanding, the following activities are exempt from the permit requirements of this chapter. (a) An excavation below finished grade for basements and footing of a building, retaining wall, or other structure authorized by a valid building permit. This shall not exempt any fill made with the material from such excavation nor shall it exempt any excavation ~having an unsupported depth greater than five feet after the completion of the structure. 070116 syn 0120044 1 ***NOT YET APPROVED*** (b)Cemetery graves. (c)Refuse disposal sites controlled by other regulations. (d)Excavations for wells, sanitary sewers, water pipes, natural gas pipes, and electrical/communications conduits or Cables.However, when such excavation is performed within a public utility easement, an encroachment permit is required. (e) Mining, quarrying, excavating, processing, stockpiling of rock, sand, gravel, aggregate, or clay, where authorized and regulated by law, provided such Operations do not affect the lateral support or increase the stresses in or pressure upon any adjacent or contiguous property. (f) Exploratory excavations under the direction of soils engineers or engineering geologists. (g)Routine agricultural crop management practices. (h)Emergencies posing an immediate danger to life or property, or substantial flood or fire hazards. (i) Any activity where the total volume of material disturbed, stored, disposed of, or used as fill does not exceed i00 cubic yards and does not obstruct or modify the storm water carrying capacity or characteristics of a drainage course. (j) Sections 16.28.060 and 16.28.070 (a) -(g) notwithstanding, any activity where the total volume of material disturbed, stored, disposed of, or used as fill does not exceed five cubic yards is always exempt from the permit requirements. (k) ~ny grading or construction activity within a Santa Clara Valley Water District right-of-way or easement which requires a Water District encroachment permit. Section 3. Section 16.28.321 (Construction of Bridges, Culverts, and Storm Drain Outfalls) is hereby added to read as follows: 16.28.321 Construction of Bridges, Culverts, and Storm Drain Outfalls (a) Bridges, culverts, and storm drain outfalls shall be constructed in a manner consistent with the Santa Clara Valley Water Resources Protection Collaborative User Manual: Guidelines and Standards for Land Uses Near Streams(Revised July 2006), as amended from time to time. (b) Streams shall not be filled or placed in culverts to accommodate grading and construction for land development projects, except for road crossings. (c) Stream culverts constructed to accommodate road access shall be clear-span whenever possible and shall be constructed in a manner consistent with the Santa Clara Valley Water 070116 syn 0120044 2 ***NOT YET APPROVED*** Resources Protection Collaborative User Manual: Guidelines and Standards for Land Uses Near Streams (Revised July 2006), as amended from time to time. Section 4. Section 16.28.322 (Stream Bank Erosion Repair) is hereby added to read as follows: Section 28.322 Stream Bank Erosion Repair (a) Stream bank erosion repair shall use the softest possible method appropriate for the stream characteristics. Use of hardscape materials or retaining walls within the banks of a stream shall be avoided. Stream bank erosion repairs shall be constructed in a manner consistent with the Santa Clara Valley Water Resources Protection Collaborative User Manual: Guidelines and Standards for Land Uses Near Streams (Revised July 2006), as amended from time to time. (b) Exceptions to this requirement may be granted by the Director of Public Works where the applicant provides an engineering report demonstrating that softer methods have been evaluated and found to be infeasible, that the proposed method will effectively reduce bank erosion, and that the proposed method will not cause erosion or negatively impact proper stream function in other areas. Any use of hardscape under this exception, will require the planting of appropriate native riparian vegetation onsite or at another suitable location to be approved by the Director of Public Works in order to mitigate the impacts of the hardscape. // // // // // // // // // 070116 syn 0120044 3 // ***NOT YET APPROVED*** Section 5. day after the date of its adoption. INTRODUCED: PASSED: AYES: NOES: ABSTENTIONS: ABSENT: ATTESt: This ordinance shall be effective the 31st APPROVED: City Clerk Mayor APPROVED AS TO FORM: Sr. Assistant City Attorney City Manager Director of Public works Director of Planning and Community Environment 070116 syn 0120044 4 ÷ ATTACHMENT B GU|DEL|NES & FOR LAND USE STANDARDS NEAR STREAMS A Manual of Tools, Standards and Procedures to Protect Streams and Streamside Resources in Santa Clara County Prepared by the Santa Clara Valley Water Resources Protection Collaborative August, 2005 IV.EROSION PREVENT|ON AND R:EPA~R IV.A. Erosion Repair IV.A. 1. Root cause of erosion Where known, the root cause and extent of any erosion must be identified, described and reported to the appropriate agency or agencies prior to any attempts to repair erosion site. IV.A. 2. Remediation of erosion Property owner to remediate source of erosion if onsife. IV.A. 3. Evaluation of effects of adjacent properties All repair project proposals should include an evaluation for the potential impacts On both downstream and upstream banks. IV.A. 4. Evaluation of impacts on channel dynamics If erosion protection extends into active channel, evaluate post construction erosion potential due to change in stream dynamics caused by design. IV.A. 5. Hydraulic analysis If the repair method reduces stream cross-section or increases stream roughness, a hydraulic analysis is required to demonstrate no increase in flood elevations. IV.A. 6. Construction on slopes For construction on slope greater than 5%, require implementation of erosion and sediment control measures. (See the "Erosion and Sediment Control Field Manual" developed by the Water Quality Control Board.) ~V.B. PROJECT DESEGN/ CONSTRUCTION IV, B. I. Use of Soft Erosion Repair Techniques Design of erosion protection must utilize the softest possible method appropriate for the stream characteristics; use of hardscape materials or retaining walls within the banks of the watercourse should be avoided. IV.B. 2. Use of Hardscape/ Retaining Walls If hardscape or a retaining wall is to be used, it must be demonstrated that (1) all softer methods have been evaluated, (2) the proposed method will reduce erosion and (3) the proposed method will not cause erosion or negatively impact proper stream function in other areas. IV.B. 3. Use of Hardscape/ Retaining Walls If used, hardscape elements will require project proponents to mitigate impacts by planting appropriate native riparian vegetation onsite or at another suitable location, Mitigation requirements will need approval by regulatory agencies. USER MANUAL: GUIDELINES & STANDARDS FOR LAND USE NEAR STREAMS 3.1 1 Vi. OUTFALLS, PUMP STATIONS AND SiTE DP~AINAGE V.A. Drainage Related to Grading Grading must address drainage. Drainage that avoids the need for ouffalls, or reduces the size and/or number or outfalls is encouraged. V.B. Construction Related to Grading Grading adjacent to streams must be in compliance with NPDES general permit, where applicable, and must at a minimum provide for buffer areas and vegetated swales between the stream and graded areas. In compliance with the statewide General Permit for Construction, grading activities that disturb one acre or more of land require the project proponent to prepare and have on site a Storm Water Pollution Prevention Plan. EXCEPTION: Exceptions are allowed per each municipality’s drainage ordinance and NPDES permits. Exceptions from swale and BMP’s are allowed if there are other run-off controls in place. V.B.2. Construction Related to Grading Recommend that fill be placed adjacent to dry side of the levee to minimize the levee height unless it causes drainage problems, disturb~s wetlands, creates safety concerns, or impacts aesthetics of property. V.B.3. Construction Related to Grading Modifications to levees are allowed if a slope stability analysis is performed and any structure that provides support to the levee is designed with long-term life span (50-100 years). EXCEPTION: Exceptions are allowed (although discouraged) to cuts in levees if for a temporary purpose and repair is completed by the beginning of October and a performance bond is used to assure completion. V.B.4. Construction Related to Grading Grading adjacent to drinking water reservoirs (Calero, Anderson, Lexington, Coyote, Almaden) must be acceptable to the District, which may require water quality monitoring depending on project’s potential for adverse impacts. Consider protective measures in source water protection zones and sensitive areas of reservoir watersheds. Erosion and sediment control measures are required to prevent sediment contribution from the construction area to the reservoir. USEP~ MANUAL: GUIDELINES & STANDARDS FOR LAND USE NEAR STREAMS 3.13 VI.A.1 Site Drainage Runoff must not be directed across stream watershed boundaries as a result of grading or through storm drain system design. VI.A.2 Site Drainage Direct site drainage through vegetated areas or stilling basins prior to discharge or collection in storm drain system. VI.A.3 Site Drainage No concentrated overbank drainage is allowed (e.g. roof overhangs or downspouts). If overbank drainage will occur, use vegetative buffer strips or direct drainage to landscaped areas. VI.B.10utfalls Prefer that there are no new ouffalls, However, if there is no way to avoid new ouffalls then the following applies: 1. Minimize the number of outfalls. New channel outfalls must conform to the local municipality’s drainage master plan. Slope protection for outfalls must meet SCVWD minimum engineering standards using softer slope protection methods if possible (see Standard Details and Specifications). Outfalls should not overhang the bank or bed as this can lead to excessive channel erosion. Minimum diameter is 12 inches and discharge must be oriented downstream and pipe invert should be at least 2 feet above the stream bottom in areas where sediment deposition is anticipated. Flap gates will be installed when 100-year water surface is above adjacent ground at inlet. Outfalls with flap gates require dormers or similar designs to isolate the flap gate and keep them out of flow area (see Standard Details and Specifications). Outfalls on federal projects (Coyote Creek downstream of Montague Expressway, Guadalupe River downstream of Blossom Hill, Llagas Creek downstream of Buena Vista, and Uvas Creek downstream of Santa Teresa) must be submitted to SCVWD to coordinate federal review and approval. In conjunction with new or redevelopment, abandoned outfall pipes and slope protection must be removed and the stream bank restored to similar condition existing upstream and downstream of site. Permits are needed from Dept of Fish and Game, U.St Army Corps, and RWQCB. See Standard Details and Specifications. VI.B.2. Outfalls Discharge must not pollute receiving water or cause channel erosion. Non storm water discharges not already subject to existing NPDES requirement will be subject to approval and permit from RWQCB. VI.C1. Storm Drainage Pump Stations Limit pump discharges to the extent feasible during peak flows to minimize potential impacts from flooding. When a development requires a storm drain pump station that discharges to a stream, require discharge management plan that addresses pump operation during high water (flood) events. 3.14 USER MANUAL: GUIDELINES & STANDARDS FOR LAND USE NEAR STREAMS VII.A. Undergrounding Creeks 1. Streams must not be buried or put into culverts. The exception for culverts only is for road crossings though they should be clear-span whenever possible. If culverts are used they must carry the bankfull flow, accommodate a modified floodplain drainage and where feasible accommodate a 100-year flow rate. This is accomplished with multi-stage culverts with cross-sections designed to carry different flows. Regional debris or sediment basins that will be owned or maintained by SCVWD must be designed for 50-year sediment capacity. Filling creeks to accommodate grading and construction for developments is not permissible until impact avoidance and minimization efforts are maximized. In the event that impacts are determined to be unavoidable, adequate mitigation must be proposed. CEQA document must be prepared to provide mitigation for impacts of burying stream and appropriate regulatory agency permits, such as a Streambed Alteration Agreement (SAA) must be obtained. The clty/ county storm drain system, whether in pipes or roadside ditches, is not included in this standard. VII.B. Open Channel Modification The design must consider stream dynamics and induced flooding. A hydraulic analysis acceptable to SCVWD will be required. Recommend restoration of natural stream processes if possible. Impacts to habitat must be avoided or mitigated. Stream conveyance area must be designed for 100-year design flow with freeboard, if along a SCVWD jurisdictional area. SCVWD may request dedication of right-of-way for stream modification projects, including an 18-22 foot wide maintenance area. Notify and secure appropriate state and regulatory permits, such as a SAA. EXCEPTION: If active channel and floodplain will not contain the design 100- year flow, then the design can be based on existing capacity with the allowance for providing additional active floodplain width in the future to contain the design 100-year flow. Streams to be dedicated to SCVWD must include an 18-22 foot wide maintenance area. In addition, flood capacity less than the 100-year flow is acceptable if the community in the flood zone is willing to accept less protection and ongoing flood insurance requirements. USER MANUAL: GUIDELINES & STANDARDS EOR LAND USE NEAR STREAMS 3.15