Integrating Sea Level Rise Considerations in the South Bay Salt Ponds Restoration Project. Norma J. Camacho Chief Operating Officer, Watersheds

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1 Integrating Sea Level Rise Considerations in the South Bay Salt Ponds Restoration Project Norma J. Camacho Chief Operating Officer, Watersheds

2 Presentation Overview Mission of the District Santa Clara County Flood Hazards Shoreline Study Study objectives Identifying challenges and opportunities Forecasting existing and future conditions Plan formulation Next Steps 2 May 23, 2012

3 Our Purpose Provide comprehensive water management for all beneficial uses, and Provide protection from flooding within Santa Clara County 3 May 23, 2012

4 District Flood Protection Goals Natural flood protection for residents, businesses, and visitors Reduce potential for flood damages 4 May 23, 2012

5 Current Flood Hazards 5 May 23, 2012

6 Figure D-85 from Administrative Draft of Flood Types, History and Hazard Exposure, Santa 6 Clara Footer County

7 Shoreline Study Overview 7 May 23, 2012

8 Shoreline Study Area 8 May 23, 2012

9 Project Purposes Flood Risk Management Ecosystem Restoration Recreation 9 May 23, 2012

10 Study Partners US Army Corps of Engineers Federal sponsor and NEPA co-lead agency California State Coastal Conservancy Non-Federal sponsor and CEQA lead agency Santa Clara Valley Water District Non-Federal sponsor US Fish and Wildlife Service Landowner and NEPA co-lead agency 10 May 23, 2012

11 Study Flood Protection Objectives 1. Reduce potential tidal flood damages. 2. Reduce the risk to public health and human safety due to flooding from tidal sources. Sandbag pickup station in Alviso 11 May 23, 2012

12 Impetus for Considering Sea Level Rise Flood risk Potential economic and environmental flood damages (tidal and fluvial sources) Potential impacts to public safety and health 12 May 23, 2012 Salt Pond levees Alviso, 1983

13 Sea Level Change Engineering Circular USACE coastal investigations required to address sea level change EC , July 2009 Requires examination of three scenarios: Historic NRC Scenario I NRC Scenario III 13 May 23, 2012

14 Major Assumptions 1. Period of analysis Year 0 (Base year): 2017 o South Bay Salt Ponds Restoration Project Phase I Year 50: Salt pond levees are maintained to their existing condition. 14 May 23, 2012

15 Rates of Sea Level Rise Evaluated for Project For period of analysis ( ): o Historic: ft o NRC I: ft o NRC III: ft Initial planning/design will assume highest rate of sea level change analyzed (NRC Curve III, consistent with CA requirements) Final alternatives will also be evaluated against NRC Curve III 15 May 23, 2012

16 Flood Plain Mapping 3 Scenarios 16 May 23, 2012

17 Palo Alto Regional Water Quality Control Plant Sunnyvale Water Pollution Control Plant San Jose/ Santa Clara Water Pollution Control Plant

18 Economic Analysis- Sea Level Change Equivalent annual damages (EADs) were estimated for 14 economic impact areas (EIAs) EIAs with highest EADs EIAs with high EADs under NRC Curve III 18 May 23, 2012

19 EAD Calculations Highest damages are predicted in four EIAs: EIAs 8 and 13 accrue substantial commercial and industrial damages under NRC Curve III ($22.1 M and $17.6 M respectively). 19 May 23, 2012

20 Alviso Ponds and Santa Clara County Interim Feasibility Study Area ~8,000 acres former salt-production ponds USFWS and local land ownership ~15 miles of shoreline Historic subsidence Significant commercial and public facilities 20 May 23, 2012

21 Flood Risk Assessment EIA 11 Residential, industrial, and commercial structures Community of Alviso (2,200 residents, 500 housing units) San Jose/Santa Clara Water Pollution Control Plant * Figure above shows first significant damage 21 May 23, 2012

22 At Risk Urban Development 22 May 23, 2012

23 Cross Section of Alviso with Projected Sea Level Rise 23 May 23, 2012

24 Plan Formulation Initial Plan Formulation - terminology Measures Nonquantified Elements Themes Options Conceptual Alternatives Preliminary Alternatives Quantified Elements Final Alternatives 24 May 23, 2012

25 Plan Formulation (cont.) Measure identification and screening Flood risk management 18 Nonstructural, 16 retained 22 Structural, 14 retained Many measures eliminated because they would address fluvial but not tidal flooding 25 May 23, 2012

26 Evaluating Alternatives, Public Input Analysis of baseline conditions complete Public concerns: Provision of fluvial flood control for adjacent communities Potential flood damage to wastewater treatment plants Protection of wildlife from the effects of recreational access Mercury methylation and its effects on fish and wildlife Reduction of bird strike hazards at Moffett Federal Airfield arising from nearby ponds and mudflats Concerns from local governments regarding potential effects on their facilities, projects, and infrastructure Local government coordination with the study Public meetings held to present preliminary project alternatives August, December 2011 January, February, March, May May 23, 2012

27 Stakeholder Meeting: June 21, May 23, 2012

28 Costs Study Sponsoring Agencies USACE $ 9.1 mill. (50%) Santa Clara Valley Water District California State Coastal Conservancy Total Study Cost $ 7.5 mill. $1.6 mill. $18.2 million 28 May 23, 2012

29 29 May 23, 2012

30 Questions? Norma J. Camacho Chief Operating Officer 5750 Almaden Expressway San Jose, CA (408) ext Ngoc Nguyen Unit Manager 5750 Almaden Expressway San Jose, CA (408) ext May 23, 2012

31 Ponds A19, 20 and 21 (Island Ponds) Status: Restored in May 23, 2012

32 Pond A8 gates opened June 1, May 23, 2012

33 Reusing Sediment for Restoration Efforts Stream Sediment can help jump start tidal marsh restoration 33 May 23, 2012

34 34 May 23,

35 At Risk Critical Infrastructure 35 May 23, 2012

36 Multi-objective Design Flood Protection and tidal restoration 36 May 23, 2012