Flooding from Butano Creek on Pescadero Road

Transcription

1 Developing Solutions to Flooding from Butano Creek on Pescadero Road Chris Bowles, PhD, PE Chris Hammersmark, PhD, PE Ethan Bell, MS October 1, 2013

2 Outline Objectives Funding Qualifications Approach Schedule Permitting Potential Solutions Questions

3 Project Objectives Pi Primary Goal: Identify a long term solution to the flooding of Butano Creek at Pescadero Road that t is: constructible able to obtain permits/permissions/approvals enhances habitat used by native species if possible This effort is not focused on the annual fish kills or the flooding caused by Pescadero Creek

4 Funding for Feasibility Study $240, total t current funding Comprised of: $145,00 County of San Mateo $77,000 Proposition 84 Bay Area IRWMP $18,000 USFWS Coastal Program In the future, results of this effort will be used to seek funding for implementation of a specific potential solution

5 Qualifications of the Multidisciplinary Team cbec eco engineering Primarily focused on the physical aspects (sand and water) Stillwater Sciences Primarily focused on the biological aspects (plants and animals) Our firms have successfully worked together on a number of large and challenging projects Both firms have recent relevant experience with management efforts in Central Coast rivers, streams, floodplains and estuaries

6 cbec eco engineering We specialize in: geomorphology sediment transport hydrology& hydraulics numerical modeling surveying/mapping design restoration/rehabilitation outreach integration communication Ati Actively working on projects on the West tcoast tfrom San Diego to Puget Sound Locally we are working with Santa Cruz RCD on several projects, and in the past our staff have worked on sediment and vegetation managementstudies on the San Lorenzo and Pajaro Rivers, and more

7 Stillwater Sciences Aquatic and terrestrial ecologists Regional experience with steelhead, coho salmon, and tidewater goby Handling permits and experience with red legged frog and SF garter snake Services include: Habitat assessment and suitability Restoration design and planning Permitting and regulatory compliance

8 Stillwater Sciences Habitat evaluations Design recommendations Alternatives evaluation Permitting guidance

9 General Approach Review existing data and collect necessary data Use computer models to evaluate various options Refine and improve potential solutions Work with stakeholders throughout the process to build agreement on an appropriate solution to resolve the flooding

10 Tasks and Schedule Review Existing Information Tech. Memo. submitted September 13, 2013 Collect Necessary Data November, 2013 Build Tools and Evaluate Existing Conditions Tech. Memo. completed by April 1, 2014 Community Meeting ~ June 16, 2014 Identify, Develop and Assess Potential ti lsolutions Final Report completed by September, 2014 Community Meeting ~ September 22, 2014

11 Review of Existing Physical Information Flow and sediment inflow Topography Distribution of sand, silt and gravel

12 Review of Existing Biological Information Central California Coast steelhead Coho salmon Red legged frog Tidewater goby San Francisco garter snake

13 Existing Conditions Analysis Develop a tool (a model) to identify the source of sedimentation and flooding Determine current extent of flooding Verify the model results match the local s observations Determine species use of the area and habitat needs

14 Hydraulic & Sediment Transport Model Inputs: topography, stream flow, sediment size, roughness (amount and type of vegetation) Outputs: t depth, velocity, bed bdelevation, water surface elevation, flood extents, amount of sediment stored and/or transported t Time scale: near term and long term

15 Suisun Creek Interstate 80 City of Fairfield Example of Model Results

16 Sediment Modeling Example San Lorenzo River HWY 1 Laurel St Water St Soquel Ave Riverside Ave SPRR PWA, 2004

17 Sediment Modeling Example San Lorenzo River Current Bed Profiles Future PWA, 2004

18 Impact & Permit Evaluation 1. What permits will likely be needed? USACE 404 permit CDFW 1600 permit NMFS & USFWS ESA Section 7 CEQA & CESA compliance RWQCB 401 certification Coastal Commission CDP San Mateo County 2. What regulated impacts will various solutions have? 3. What protection measures may be necessary?

19 1. Do nothing Alternatives 2. Dredge within the County s right of way 3. Dredge upstream and downstream beyond the County s right of way 4. Dredging concept developed by Sigma Prime 5. Restoration alternative which maximizes habitat protection & enhancement and sediment storage & transport 6. New concepts developed by the consultant team 7. Others?

20 Alternatives

21 Alternatives dredge here

22 Alternatives dredge here

23 Alternatives dredge here

24 Alternatives

25 Alternatives dredge here

26 Alternatives What are other potential solutions?

27 Alternative Evaluation Flood reduction immediately after construction and after a significant storm Impacts and benefits to native species Feasibility cost, constructability, bl lk likelihood lh of obtaining permits, permissions and approvals Operation and maintenance in the future

28 Please share other ideas Chris Bowles Chris Hammersmark com Ethan Bell