CITY OF BELMONT CITY COUNCIL AND BELMONT FIRE PROTECTION DISTRICT BOARD OF DIRECTORS www.belmont.gov NOTICE OF SPECIAL MEETING Tuesday, October 28, 2014 6:00 PM One Twin Pines Lane, City Hall Emergency Operations Center, Second Floor, Belmont, California AGENDA This Special Meeting is called to consider the items of business listed below. 1. ROLL CALL 2. ITEMS OF BUSINESS Persons wishing to orally address the Council on the items of business listed below will be given an opportunity to do so before or during the Council’s consideration of the item. A. STUDY SESSION (1) Informational Report Regarding the Belmont Creek Study Recommendation: Receive information report regarding the Belmont Creek Study on the long-term approach to address the creek maintenance and improvements within the watershed Attachment(s): Staff Report Watershed Map Watershed Study Presentation (Power Point) 3. ADJOURNMENT If you need assistance to participate in this meeting, please contact the City Clerk at (650) 595-7413. The speech and hearing-impaired may call (650)637-2999 for TDD services. Notification in advance of the meeting will enable the City to make reasonable arrangements to ensure accessibility to this meeting. Meeting information can also be accessed via the internet at: www.belmont.gov. All staff reports will be posted to the web in advance of the meeting, and any writings or documents provided to a majority of the City Council/District Board regarding any item on this agenda will be made available for public inspection in the City Clerk's Office, One Twin Pines Lane, during normal business hours and at the Council Chambers at City Hall, Second Floor, during the meeting. Meeting Date: October 28, 2014 STAFF REPORT Agenda Item: Study Session Agency: City of Belmont Staff Contact: Leticia Alvarez, Public Works, 595-7469, [email protected] Afshin Oskoui, Public Works, 595-7459, [email protected] Jonathan Gervais, Parks & Recreation, 595-7488, [email protected] Agenda Title: Informational Report Regarding the Belmont Creek Study Agenda Action: No Action Recommendation Receive informational report regarding the Belmont Creek Study on the long-term approach to address the creek maintenance and improvements within the watershed. Background Belmont Creek dredging between El Camino Real and Old County Road is part of an on-going effort by the City to reduce the potential for flooding in the area during the winter rainy season. The City has dredged this portion of Belmont Creek five times in the last seven years. Because of the potential impact to the creek and the habitat, permits are required from the Department of Fish and Wildlife, U.S. Army Corp. and the Regional Water Quality Control Board San Francisco Bay Region (RWQCB), among others. Additionally, last year Novartis Pharmaceuticals Corporation (Novartis) in San Carlos initiated a dredging project in the creek adjacent to their facilities due to previous flooding problems. During the permitting process for both projects, the permitting agencies required that the Cities of Belmont, San Carlos and the County of San Mateo as well as Caltrans and Redwood City (which are indirectly affected) work in collaboration for a long-term approach to address the on-going maintenance and creek improvements within each jurisdiction. For the last year, staff has been working with the regulatory agencies and the entities involved on a comprehensive watershed study project which was funded by Novartis. Analysis WRECO was the consultant selected by Novartis to perform the study, developed nine conceptual alternatives and presented them to the project stakeholders, including Novartis, RWQCB, Caltrain, Caltrans, San Mateo County, and the Cities of Belmont, Redwood City, and San Carlos. Five alternatives were selected by the stakeholders for further analysis using hydraulic models developed by WRECO. This modeling allowed WRECO to determine the effectiveness of each of the alternatives. These alternatives included improvements of operations and design of Water Dog Lake, an off-line basin and floodplain restoration at Twin Pines Park, a parallel culvert bypass through Harbor Boulevard, flood walls through lower Belmont Creek, and tide gates at Marine Parkway. Page 1 of 2 Through field reconnaissance, creek data gathering, and stakeholders’ input, WRECO developed a hydrologic model of the watershed and hydraulic models of the existing condition and for each chosen alternative. These models showed the impact comparisons for each of the chosen alternatives. The hydraulic models showed that, individually, none of the alternatives would have a significant impact on the flooding of Belmont Creek. WRECO developed a “Preferred Alternative” that took elements of the individual alternatives that showed the most effectiveness in the modeling phase and modified them until modeling indicated that they would significantly reduce the flooding issue for the 10-year storm event. This alternative was achieved by enlarging the by-pass culvert on Harbor Boulevard and restoring the floodplain at Twin Pines Park. Combining the two elements would greatly reduce the sedimentation that has caused issues within the lower Belmont Creek and allow much larger flows to pass through the lower Belmont Creek. In addition, low impact development measures could be incorporated into Harbor Boulevard when it is reconstructed over the by-pass culvert. The measures could include porous pavement and bio-retention areas. This preferred alternative has the most potential for reducing the flood risk in the lower portion of Belmont Creek from Old County Road to Highway 101, while at the same time providing water quality improvements and environmental enhancements. This project has been of great interest to the regulatory agencies due the nature of the evaluation in integrating flood control, water quality protection and habitat restoration for the Belmont Creek watershed. The RWWQCB is very interested in working with the agencies involved for application of grant funding and working with the other regulatory agencies to pursue a potential watershed-based permitting strategy with all the regulatory agencies. Alternatives 1. Take No Action Attachments A. Map – Belmont Creek Watershed B. Belmont Creek Watershed Study Presentation Fiscal Impact No Impact/Not Applicable Funding Source Confirmed: Source: Purpose: Public Outreach: Council Statutory/Contractual Requirement Posting of Agenda Staff Council Vision/Priority Other* Citizen Initiated Discretionary Action Other* Plan Implementation* * Page 2 of 2 ATTACHMENT A MAP OF BELMONT CREEK WATERSHED Dr. Martin Renner, Novartis Grant Wilcox, P.E., CEG, WRECO October 28, 2014 The Belmont Creek Watershed Study is Sponsored by: 2 Today we will discuss: Project History and Background Summary of Initial Alternatives Summary of Studied Alternatives Review of Preferred Alternative Benefits of Preferred Alternative Impacts of Preferred Alternative Mitigation and Additional Benefits of Twin Pines Park Next Steps 3 Novartis Site Background In 2010, Novartis manufacturing was down for over 2-1/2 weeks and the cost of repair was approximately $615,000. Repair costs in 2011 were approximately $100,000. Flood gates Completed in 2011 Cost ~$1.2 million Dredging Completed in September 2013 Cost ~$230,000 Improved local channel capacity from 3.5-year event 4 Recent History of Flooding at Novartis Site 2010 Storm Overbank flows escaped near Old County Road, traveled along Quarry Road, and reached Novartis property April 2010 April 2010 5 Recent History of Flooding at Novartis Site 2010 Storm Creek (northwest side) Lot entrance (northeast side) Quarry Road (south side) Front of facility (northeast side) 6 Sedimentation Build-up Downstream 04/01/14 04/02/14 7 Initial Alternatives Explored Alternative 1: Operations and Design of Water Dog Lake Alternative 2: Upstream Basins at Carlmont Drive, Village Drive, and Carlmont High School Baseball Field Off Club Drive Alternative 3: Low Impact Development Measures Alternative 4: Creek Daylighting Through a Portion of Silverado Senior Living Facility Alternative 5: Floodplain Restoration and Offline Basin for Temporary Storage at Twin Pines Park Alternative 6: Parallel Overflow Pipes from Old County Road down to Harbor Blvd and/or Quarry Rd. with New Culvert at 101 Alternatives 7: New Cross Culvert at Old County Rd., Industrial, and 101 and Channel Improvement with Short Flood Walls on Lower Belmont Creek Alternative 8: Floodgate and Pump at Shoreway Road/Marine Parkway Alternative 9: Floodgates and Pump near Oracle Bridge 8 Alternatives Studied Alternative 1: Operations and Design of Water Dog Lake Alternative 5: Floodplain Restoration and Offline Basin for Temporary Storage at Twin Pines Park Alternative 6: Parallel Overflow Pipes from Old County Road down to Harbor Blvd and/or Quarry Rd. with New Culvert at 101 Alternatives 7: New Cross Culvert at Old County Rd., Industrial, and 101 and Channel Improvement with Short Flood Walls on Lower Belmont Creek Alternative 8: Floodgate and Pump at Shoreway Road/Marine Parkway 9 Preferred Alternative 10 Preferred Alternative Result: Reduces flooding through lower Belmont Creek Sediment Traps with Sumps that can be periodically cleaned out, reducing dredging needs Permeable Pavers can be proposed over removed roadway portions 11 Impacts from Preferred Alternative Estimated Construction Cost: ~$16 million Temporary traffic lane closures Utility relocations 12 Benefits of Preferred Alternative Flood Risk