Flood Prevention Authority. Agency Presentation. Gilroy Meeting. June 3, Pajaro River Watershed. Flood Prevention Authority

Transcription

1 Pajaro River Watershed Flood Prevention Authority Agency Presentation Gilroy Meeting June 3, 2009 Pajaro River Watershed Flood Prevention Authority

2 Presentation Outline Formation and Purpose of the Pajaro River Watershed Flood Prevention Authority Pajaro River Watershed Progress and Successes Confirmation of Lower Pajaro River Assumptions Implementation of Soap Lake Floodplain Preservation Pajaro River Watershed Flood Protection Strategy Flooding History Lower Pajaro River Flood Protection Project Funding Shortfalls

3 Formation and Purpose of the Authority Formation: AB807 (Keeley) Pajaro River Watershed Flood Prevention Authority: Chartered 10/10/99 Purpose: To identify, evaluate, fund, and implement flood prevention and control strategies in the Pajaro River Watershed, on an intergovernmental, cooperative basis.

4 Composition of the Authority Eight Members Appointed by: Monterey County Water Resources Agency San Benito County Water District Santa Clara Valley Water District Santa Cruz County Flood Control and Water Conservation District Monterey County San Benito County Santa Clara County Santa Cruz County

5 Jurisdictional Boundaries of the Authority

6 Watsonville Floods in the Early 1900 s Early 1900 s Photo courtesy of Pajaro Valley Historical Association

7 Watsonville Floods Again in 1937 Early 1900 s Photo courtesy of Pajaro Valley Historical Association

8 Army Corps of Engineers Constructs Levees in 1949 Early 1900 s Levee System Construction is completed along Pajaro River and Salsipuedes/ Corralitos Creeks

9 Levees Breached December 25, 1955 Early 1900 s

10 Flooding Damages Exceeded $95 Million in 1995

11 Pajaro River Watershed Study Four-Phase Study by RMC Funded by $2 Million in State Proposition 13 funds Conducted in

12 Phase 1 Study Objective: Perform hydrologic and sediment modeling to provide a foundation for the development of flood protection strategies Conclusions: Verifies Corps hydraulics Emphasizes importance of Soap Lake and watershed approach Identified additional watershed study opportunities along San Benito River

13 Phase 2 Study Objective: Identify project alternatives that provide a sustainable 100-year level of flood protection, and select the most feasible alternatives for more detailed study in Phase 3. Conclusions: Sustainable 100-year level of flood protection requires downstream levee improvements in conjunction with upstream floodplain management Soap Lake Floodplain Preservation most cost effective approach for upstream floodplain management

14 Soap Lake Floodplain Provides 25% of the Downstream Flood Protection 60,000 cfs Without Soap Lake Soap Lake 44,000 cfs xxx cfs Flood Protection Strategy Levees Current level of flood protection

15 Levee Height Increases Up to Four Feet without Soap Lake at a cost of $100 Million Total estimated Soap Lake Preservation costs of $46 Million Net Cost Savings of $64 Million ($100 M - $46 M)

16 Phase 3 and 4a Objective Objective: Define and document the preferred method to maintain the Soap Lake attenuation and storage capacity, known as the Soap Lake Floodplain Preservation Project (Project). Conclusions: Soap Lake 100-year Floodplain defined Acquisition of floodplain easements preferred alternative Project costs approximately $46 M for 9,100 acres of floodplain easements

17 Over 25% of Soap Lake Floodplain Preserved

18 Proposition 50 Grant will be Leveraged to Maximize Benefits Grant funding total: $4,425,300 Task 1: Administration: $600,300 Task 2: Land/Easement Acquisition: $3,825,000 Land Acquisition funds will be matched dollar for dollar by local partners total acquisition funds $7,650,000 Approximately 1500 acres can be preserved over 20% of remaining floodplain acreage

19 Continued Work and Funds Needed to Provide 100-Year Flood Protection Soap Lake Secure Additional Funding Complete Acquisitions Watershed Study Secure Funding Complete Study New Project? Levee Project Secure Design/ Env Doc Funds Construct Project 100-Year Sustainable Flood Protection

20 Corps Project will Protect along River and Tributaries

21 Currently at 10-Yr Level of Protection along Pajaro River March 1995

22 Currently at 8-Yr Level of Protection along Corralitos and Salsipuedes Creeks March 1997

23 Levee Project will Provide 100-Year Flood Protection Assumes Soap Lake floodplain benefits New levees along River and Tributaries Limited floodwalls through City Habitat enhancements within banks

24 Estimated (2008) Project Costs and Funding COSTS Design/Environmental Construction TOTAL FUNDING Federal Cost Share Local Cost Share TOTAL $10 M $190 M $200 M $150 M $50 M $200 M

25 $50 M Local Cost Share LOCAL FUNDING AB 2348 (Laird) Local Financing TOTAL $25 M $25 M $50 M

26 Together, We Can Avoid Additional $60M in Increased Construction Costs or Future Flood Damage!

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