LOWER CACHE CREEK, YOLO COUNTY WOODLAND AREA FEASIBILITY STUDY

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1 Background LOWER CACHE CREEK, YOLO COUNTY WOODLAND AREA FEASIBILITY STUDY Energy and Water Development Appropriations Act of 1993 Reconnaissance Study completed June 1994 Feasibility Cost Share Agreement signed January 2000 $2.5M Study Sponsors The Reclamation Board City of Woodland

2 Study Area

3 LOWER CACHE CREEK, YOLO COUNTY WOODLAND AREA FEASIBILITY STUDY Study Purpose: Define flood related problems and opportunities, evaluate a full range of alternatives, and recommend a plan to reduce potential flood risk within the City of Woodland and the unincorporated areas of Yolo County. Study Scope Establish specific objectives of a plan to reduce flood damages and protect related environmental resources. Inventory and forecast conditions in the study area. Define criteria and constraints for formulating and evaluating alternatives. Formulate alternatives to reduce flood damages and protect related environmental resources. Compare alternative plans and identify recommended plan.

4 LOWER CACHE CREEK, YOLO COUNTY WOODLAND AREA FEASIBILITY STUDY Topographical Surveying Tasks Completed To Date Baseline Geotechnical Analysis Hydrologic Model and Frequency Curves Environmental Site Assessment (Hazardous Waste) Hydrology &Hydraulic Without Project Modeling (10/00) Floodplain Mapping

5 LOWER CACHE CREEK, YOLO COUNTY WOODLAND AREA FEASIBILITY STUDY Discussion Points Sacramento District is Committed to Meeting Project Schedule WRDA 2002 Authorization City of Woodland s Economic Viability Timeliness of Appropriation for New Construction Continuing Federal Support and Appropriation of Funds

6 Survey & Mapping Completed August 2000 by Corps Photogrammetric & Ground Control 2 Contours Datum: NAVD 88 More Detailed than Reconnaissance Report

7 Hydrology Developed by Corps with HEC-1 Return Period (years) Peak Flow (cfs) 50 yr 53, yr 63, yr 70, yr 78,595 No significant changes compared to Reconnaissance Study

8 Hydraulics UNET - Unsteady, One-Dimensional Flow FLO2D - Unsteady, Two-Dimensional Flow HEC-RAS - Steady, One-Dimensional Flow

9 Existing Cache Creek Levee Design Original Design: 30,000 cfs 3 freeboard 10-year protection

10 Peak Rainflood Frequency Curve Cache Creek at Rd. 94B

11 Non-Damaging Flow Geotechnical Risk-Based Analysis Probable Non-Failure Point 2 Below Top of Levee Probable Failure Point Top of Levee Calculated Flow Below PNP, and Does Not Overtop Existing Bank (30,000 Yolo; 34,000 Rd. 94B)

12 N 65 DRAFT LIMIT OF 8,100 cfs " STUDY Road 17 Yolo ÑÑÑÑ Ñ Ñ Ñ ÑÑÑ Ñ " 85 16,000 cfs Ñ Ñ Ñ Ñ Ñ Ñ ÑÑ ÑÑ ÑÑ ÑÑ 80 " 7,000 cfs (LF) Interstate 5 70 LIMIT OF STUDY 60 9,100 cfs (LF) " " 10,700 cfs (LF) Union Pacif ic Ra ilr oad H ighw ay 113 R oad Cache Creek ± Road 101 Bes t Ranch Rd. Road 18C R oa d 1 02 " Water Surface Elevation Contours Approximate Extent of Overbank Flooding, Existing Conditions Peak Flow R oad 94B Kentuck y Av e. Road 98 Road 99 W. M ain Street Woodland E. M ain Street Cache Creek Settling Basin Yolo Bypass H ighw ay 113 Legend (LF) Levee Failure Highw ay 16 I nterstate 5 35 Road 24 W. G ibs on Rd. E. Gibs on Rd. Vert ical Dat um: NAVD 88 Cache Creek Hydraulic Study Existing Conditions 200-Year Flood Event Feet LIMIT OF STUDY

13 Economic Damages Analysis Table year Floodplain Structure Values ($1,000s) (October 2000 Price Levels) Lower Cache Creek Study Main Reach Total SFR Struct $289,205 $289,205 MFR Struct $21,283 $21,283 Office Struct $10,852 $10,852 Retail Struct $33,403 $33,403 Restaurant $5,377 $5,377 Service Struct $1,150 $1,150 Public Struct $18,377 $18,377 Industrial $354,803 $354,803 Total $734,450 $734,450

14 Economic Damages Analysis Table 9 Without Project Conditions Expected Annual Damages (Base Year Conditions) (In $1,000s) Lower Cache Creek Main Reach Total Aggregated Structures & Contents $12,313 $12,313 Total $12,313 $12,313

15 Environmental Analysis Status of work. Land-use constraints. Endangered species and conservation programs.

16 Plan Formulation and Evaluation Process Define specific objectives to reduce flood damages. Define criteria and constraints for formulating and evaluating alternatives. Identify and assess potential measures to reduce flood damages. Evaluate and screen preliminary alternatives. Evaluate and screen selected alternatives to identify the NED and the LPP plans.

17 Planning Objectives Provide a minimum of 100-year flood protection to the City of Woodland from flooding from Cache Creek. Maximize the use of existing flood reduction facilities prior to constructing new facilities.

18 Planning Constraints Plans will be formulated according to Congressional direction, current applicable laws, regulations, and policies. Plans will be formulated according to the Federal objective of water and related land resource planning. Minimize the operation and maintenance requirements and associated costs of the flood reduction system. Minimize impacts to agricultural lands and to lands adjacent to Cache Creek.

19 Planning Criteria Completeness is the extent to which a given alternative plan provides and accounts for all necessary investments or other actions to ensure the realization of the planning objectives. Effectiveness is the extent to which an alternative plan alleviates the identified problems and achieves the planning objectives. Efficiency is primarily a measure of the planning objectives. It is a measure of the extent to which an alternative plan is the most costeffective means of alleviating identified flood problems. Acceptability is the workability and viability of the alternative plans with other Federal agencies, affected State and local agencies, and public entities given existing laws, regulations, and public policies.

20 Initial Screening Nonstructural Raise/flood proof structures Relocate structures Flood Warning System Structural Storage Channelization Levees/set-back levees Flood bypass

21 Preliminary Alternatives Clearing and grubbing Raise levees Channelization and raise levees Set-back levees Lower Cache Creek Overflow Barrier

22 N RD [PRELIMINARY ALTERNATIVE 1 plan view map] RD 94B I-5 CALIFORNIA NORTHERN RR YOLO RD 18B RD 97A HWY 16 RD 19A RD 98 RD 18 RD 99 RD 99E RD 18A RD 100B RD 18B RD 18C RD 99 HWY 113 RD 101 RD 102 KENTUCKY AVE KENTUCKY AVE Miles LEGEND Cache Creek Existing Project Levee Limits of Clearing and Grubbing HWY 16 MAIN ST WOODLAND HWY 113 MAIN ST CACHE CREEK SETTLING BASIN I-5 RD 24 GIBSON RD GIBSON RD LOWER CACHE CREEK, WO ODLAND, CALIFORNIA AREA FEASIBILITY Preliminary Alternative 1 CHANNEL CLEARING AND GRUBBING SACRAMENTO DISTRICT, CORPS OF ENGINEERS FEBRUARY 2001

23 Preliminary Alternative 1: Channel Clearing and Grubbing Primary Features Clear and grub channel approximately 9.3 miles No bridge replacements Riprap protection Accomplishments Increase level of protection from 10 to 40 years Environmental Impacts Significant removal of valuable riparian habitat Mitigation very difficult

24 N I-5 RD 94B [PRELIMINARY ALTERNATIVE 2 plan view map] 700 RD RD 18B RD 97A YOLO HWY 16 RD 19A RD 98 CALIFORNIA NORTHERN RR RD 18 RD RD 99E 400 RD 99 HWY 113 RD 101 RD RD 18A RD 100B 300 RD 18B RD 18C KENTUCKY AVE KENTUCKY AVE Miles LEGEND Cache Creek Existing Project Levee Raise Project Levee Construct New Levee HWY 16 MAIN ST WOODLAND HWY 113 MAIN ST CACHE CREEK SETTLING BASIN I-5 RD 24 GIBSON RD GIBSON RD LOWER CACHE CREEK, WOODLAND, CALIFORNIA AREA FEASIBILITY Preliminary Alternative 2 RAISE EXISTING LEVEE & CONSTRUCT NEW LEVEE SACRAMENTO DISTRICT, CORPS OF ENGINEERS FEBRUARY 2001

25 Preliminary Alternative 2: Raise Levees Primary Features Raise existing levees 1 to 14 feet for 9.3 miles Replace bridges: I-5, Road 99W, Railroad, 113, Road 102 Riprap protection Accomplishments 200-year level of protection Environmental Impacts Removal of valuable riparian habitat Mitigation very difficult

26 N I-5 RD 94B [PRELIMINARY ALTERNATIVE 3 plan view map] 700 RD RD 18B RD 97A YOLO HWY 16 RD 19A RD 98 CALIFORNIA NORTHERN RR RD 18 RD RD 99E 400 RD 99 HWY 113 RD 101 RD RD 18A RD 100B 300 RD 18B RD 18C KENTUCKY AVE KENTUCKY AVE Miles LEGEND Cache Creek Existing Project Levee Construct New Levee HWY 16 MAIN ST WOODLAND HWY 113 MAIN ST CACHE CREEK SETTLING BASIN I-5 RD 24 GIBSON RD GIBSON RD LOWER CACHE CREEK, WOODLAND, CALIFORNIA AREA FEASIBILITY Preliminary Alternative 3 IMPROVE CHANNEL AND CONSTRUCT NEW LEVEES SACRAMENTO DISTRICT, CORPS OF ENGINEERS FEBRUARY 2001

27 Preliminary Alternative 3: Channelization and Levee Raising Primary Features Approximately 9.3 miles of bench channel to 2-year flow channel 500 to 700-foot terraces at the 2-year water surface elevation Construct new levees on one side to existing heights Replace bridges: Railroad bridge Riprap protection Accomplishments 200-year level of protection Environmental Impacts Removal of agricultural lands Significant removal of valuable riparian habitat (temporary) Potential for on-site mitigation

28 N I-5 RD 94B [PRELIMINARY ALTERNATIVE 4 plan view map] 700 RD RD 18B RD 97A YOLO HWY 16 RD 19A RD 98 CALIFORNIA NORTHERN RR RD 18 RD RD 99E 400 RD 99 HWY 113 RD 101 RD RD 18A RD 100B 300 RD 18B RD 18C KENTUCKY AVE KENTUCKY AVE Miles LEGEND Cache Creek Existi ng Project Levee Raise Exi sting Project Levee Construct New Levee Proposed 1000' Setback HWY 16 MAIN ST WOODLAND HWY 113 MAIN ST CACHE CREEK SETTLING BASIN I-5 RD 24 GIBSON RD GIBSON RD LOWER CACHE CREEK, WOODLAND, CALIFORNIA AREA FEASIBILITY Preliminary Alternative 4 CONSTRUCT SETBACK LEVEES SACRAMENTO DISTRICT, CORPS OF ENGINEERS FEBRUARY 2001

29 Preliminary Alternative 4: Setback Levees Primary Features Approximately 9.3 miles of set-back levees on one side or other 1 to 14 feet high Raise levees on other side, if necessary, from 1 to 7 feet high Replace bridges: Railroad bridge Riprap protection Accomplishments 200-year level of protection Environmental Impacts Removal of agricultural lands Removal of valuable riparian habitat near bridges Potential for on-site mitigation

30 N I-5 RD 94B [PRELIMINARY ALTERNATIVE 5 plan view map] 700 RD RD 18B RD 97A YOLO HWY 16 RD 19A RD 98 CALIFORNIA NORTHERN RR RD 18 RD RD 99E 400 RD 99 HWY 113 RD 101 RD RD 18A RD 100B 300 RD 18B RD 18C KENTUCKY AVE KENTUCKY AVE Miles LEGEND Cache Creek Existing Project Levee Const ruct New Levee HWY 16 MAIN ST WOODLAND HWY 113 MAIN ST CACHE CREEK SETTLING BASIN I-5 RD 24 GIBSON RD GIBSON RD LOWER CACHE CREEK, WOODLAND, CALIFORNIA AREA FEASIBILITY Preliminary Alternative 5 LOWER CACHE CREEK OVERFLOW BARRIER SACRAMENTO DISTRICT, CORPS OF ENGINEERS FEBRUARY 2001

31 N I-5 RD 17 YOLO Miles RD 94B RD 18B RD 97A 600 HWY 16 RD 19A RD 98 CALIFORNIA NORTHERN RR RD 18 RD 99 RD 99E 400 RD 18A RD 100B RD 18B RD 18C RD 99 HWY 113 RD 101 RD 102 KENTUCKY AVE KENTUCKY AVE 250 LEGEND Cache Creek Lower Cache Creek Overflow Barrier 200-Yr Floodplain, Pre-project 200-Yr Floodplain, Post-project HWY 16 MAIN ST WOODLAND HWY 113 MAIN ST CACHE CREEK SETTLING BASIN I-5 RD 24 GIBSON RD GIBSON RD LOWER CACHE CREEK, WOODLAND, CALIFORNIA AREA FEASIBILITY Preliminary Alternative YEAR PRE- AND POST-PROJECT FLOODPLAIN SACRAMENTO DISTRICT, CORPS OF ENGINEERS FEBRUARY 2001

32 N YOLO 9,100 9,100! LF LF Miles 8,100 8,100!! 16,000 16,000 LF! 7,000 7,000! 15,300 15,900! 10,700 10,700 2,600 2,900!! 2,300 3, ,700!! 17,900 32,400 N/A 40,100! LEGEND Existi ng Pro ject! LF Cache Creek Lower Cache Creek Overflow Barrier 200-Yr Floodplain, Pre-Project 200-Yr Floodplain, Post-Project Peak Flow (CFS) Levee Failure! 11,200 N/A CACHE CREEK SETTLING BASIN WOODLAND! 20,300 N/A LOWER CACHE CREEK, W OODLAND, CAL IFORNIA AREA FEASIBILITY Preliminary Alternative (200-YEAR) Existing Conditions Vs. North Woodland Overflow Barrier SACRAMENTO DISTRICT, CO RPS OF ENGINEERS FEBRUARY 2001

33 N 6 HWY ROAD 102 Depth (ft) [PRELIMINARY ALTERNATIVE 3 5 plan view map with 6 pre- 2 and post- hydrographs] 4 ROAD 98 Depth (ft) Time (hrs) Depth (ft) # # # # Time (hrs) Miles LEGEND Cache Creek Existing Conditions With North Woodland Overflow Barrier 200-Yr Floodplain, Pre-proj ect 200-Yr Floodplain, Post-project Time (hrs) I I-5 Depth (ft) Depth (ft) # Time (hrs) Time (hrs) LOWER CACHE CREEK, WOODLAND, CALIFORNIA AREA FEASIBILITY Preliminary Alternatives YEAR PRE- AND POST-PROJECT FLOODPLAIN HYDROGRAPHS SACRAMENTO DISTRICT, CORPS OF ENGINEERS FEBRUARY 2001

34 N I-5 RD 17 YOLO Miles RD 94B RD 18B RD 97A 600 HWY 16 RD 19A RD 98 CALIFORNIA NORTHERN RR RD 18 RD RD 99E 400 RD 99 HWY 113 RD 101 RD RD 18A RD 100B 300 RD 18B RD 18C KENTUCKY AVE KENTUCKY AVE 250 LEGEND Cache Creek Lower Cache Creek OverFlow Barrier Water Depth Contours 10-Yr Floodplain HWY 16 MAIN ST WOODLAND HWY 113 MAIN ST CACHE CREEK SETTLING BASIN I-5 RD 24 GIBSON RD GIBSON RD LOWER CACHE CREEK, WOODLAND, CALIFORNIA AREA FEASIBILITY Preliminary Alternative 5 10-Year Post-Project Floodplain SACRAMENTO DISTRICT, CORPS OF ENGINEERS FEBRUARY 2001

35 Preliminary Alternative 5: Lower Cache Creek Overflow Barrier Primary Features Approximately 6.7 miles of new levee from County Road 96 to the Settling Basin west levee from 4 to 17 feet high. Internal drainage canal on water side Flood warning system Removal of a portion of Settling Basin west levee Accomplishments 200-year level of protection for Woodland Alleviate flooding of Northern California Railroad and Interstate 5 south of flood barrier Environmental Impacts Minimal impacts to agricultural lands and the environment

36 Ranking of Preliminary Alternatives Ranking 1 Preliminary Alternative Lower Cache Creek Overflow Barrier 2 Setback Levees Comparative Cost Investment Cost Annual Cost Environmental Impact Effectiveness Acceptability $27,707,000 $2,028,000 Minimal Excellent High $36,457,000 to $45,615,000 $2,668,000 to $3,339,000 Moderate Good Moderate 3 Channelization $69,201,000 $5,063,000 Extensive Moderate Poor 4 Raise Levees $81,139,000 $5,937,000 Extensive Moderate Poor 5 Clearing & Grubbing $37,383,000 $2,945,000 Extensive Unacceptable Unacceptable

37 Key Issues Existing project Erosion sites--future operation and maintenance Raising existing weir--future operation Removing west levee of settling basin Real estate takings in floodway only for lands significantly impacted Bridge and road impacts--state highways, county roads, and railroads Mercury load

38 LOWER CACHE CREEK, YOLO COUNTY WOODLAND AREA FEASIBILITY STUDY Feasibility Study Milestones January 20,2000 May 23, 2000 March 26,2001 July 2001 December 2001 February 2002 March 2002 April 2002 June 2002 Project Milestones Feasibility Cost share Agreement Signed Public Workshop F3 Conference (without project condition) Determination of Selected Plan Draft Feasibility Report w/eis/eir for Public Review Final Feasibility Report w/eis/eir Final Public Meeting Division Engineer s Notice Chief of Engineer s Report to OMB to Achieve Conditional Authorization in WRDA 2002

39 LOWER CACHE CREEK, YOLO COUNTY WOODLAND AREA FEASIBILITY STUDY Project Milestones Design and Construction Milestones October 2002 March 2005 November 2007 Execute Design Agreement and Initiate Preconstruction, Engineering and Design (PED) Award Construction Contract Complete Construction

40 Conclusions/Concurrences Detailed analysis of overflow barrier and set-back levee alternatives