USACE Flood Risk and Water Supply Activities in the Dallas Fort Worth Area BUILDING STRONG

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1 USACE Flood Risk and Water Supply Activities in the Dallas Fort Worth Area

2 What Do You See? Flood control system Over $70 billion in damages prevented (60 years) $2-3 billion per year Water supply system 6.8 million served

3 May 2015 Flood Rain Storage: 360k ac-ft Flood Pool: 100% Status: S Rain Storage: 260k ac-ft Flood Pool: 100% Status: S Rain Storage: 500k ac-ft Flood Pool: 100% Status: S Rain Storage: 285k ac-ft Flood Pool: 100% Total Storage: 1.6 M ac-ft 75 Days Minimum to Empty I I Rain Storage: 74k ac-ft Flood Pool: 44% Rain 20.1 Storage: 125k ac-ft Flood Pool: 100% I

4 Summary of Projects Averages for CY2014 Reservoir Inflow & Basin Average Precip 100% Resv Inflow Basin Avg Precip 1 Jan 14 Cons Storage 31 Dec 14 Cons Storage 90% 80% 70% Percent of Normal 60% 50% 40% 30% 20% 10% 0% Red Neches Trinity Brazos Colorado Guadalupe

5 Climate Variability/Climate Change within Texas Region of significant climate variability Observations show loss rates vary 70% from 15% to 85% loss for single events 10%-30% of normal annual runoff

6 Climate Variability and Non-Stationary of Watersheds San Jacinto

7 Case Study 1: Brazos River Basin Assessment Background POR analysis used to inform dependable yield, environmental flows, hydropower allocations, recreation levels, flood risk POR may not accurately reflect changes WM strategies should be based on actual flow volumes expected under current watershed conditions POR analysis that include consideration of identified trends and variability would provide a better basis for both short term operational plans and long term planning strategies Goals Determine if human activities or climate change have impacted POR analysis Determine if identified trends can be correlated with other variable such as: Precipitation Temperature Regulation/development of storage Effluent Groundwater changes Land use and range management practices Implementation of water rights Modify period of record simulation data sets to reflect changed watershed conditions Lake Granbury Tend analysis coupled with exponential and log smoothing Determine new expected flow volumes Possum Kingdom Lake Whitney Waco Texas

8 Brazos River at South Bend, TX from 1924 to Total streamflow volume in decade Potential flood storage at end of decade Total streamflow volume, in acre-ft Potential flood storage, in acre-ft Decade

9 Why Perform Watershed Assessments Affects all business lines Flood risk Environmental Hydropower (5 USACE sites) Water supply (USACE % of surface water supply) Recreation Population growth 25 M current 46 M projected (2060) ½ in I35 corridor Significant refinery industry Military installations and supporting industry Climate variability Climate change?

10 Development of Water Supply Storage Texas Texas Water Development Board Plan

11 Sulphur River Basin Study - Wright Patman Reallocation

12 Reallocations or Modifications Completed Waco Whitney Belton Lewisville Lavon Ongoing or future Aquilla Whitney Granger Lavon? Wright Patman Lavon Whitney hydropower reallocation Aquilla reallocation in progress Granger reallocation in FY14 budget submission Wright Patman Sulphur River study Most Brazos Basin projects will be studied for reallocation

13 Hydrologic Network Cooperative program federal, state, local, academia, AE community Over 400 Remote Sensing Stations, approximately 2000 Observers Basic data for operation of the projects Calibration of NWS precipitation estimates Model calibrations, real-time forecasting and hydrologic investigations Jointly funded with USACE direct expenditures of close to $18 million annually, SWF $1 million annually Partnerships USGS, NWS, River Authorities, Counties, Cities $2,000,000 $1,800,000 Coordination and resource sharing to maximize network benefits $1,600,000 $1,400,000 $1,200,000 $700k Actual Cost Leveraged Cost USACE-SWF has leveraged partnerships for $700k $1,000,000 $800,000

14 Trinity River Reservoir System Where is the 7 th flood control reservoir?

15 Corridor Development Certificate Floodplain as a Reservoir WATER SURFACE RIVER CHANNEL Full floodplain conveyance and storage

16 Corridor Development Certificate Floodplain as a Reservoir Downstream flood risk increases Higher flows Higher water surface elevations WATER SURFACE Active Flood Storage Joe Pool Benbrook RIVER CHANNEL Full floodplain conveyance and storage Lavon CDC Corridor BUILDABLE AREA BUILDABLE AREA Grapevine Bad things happen when you do this! Lewisville Ray Roberts RIVER CHANNEL Reduced floodplain conveyance and storage

17 Chronology of the Regulatory Program TREIS 1987 ROD 1988 CDC 1991 Benefits of the CDC Process Establishment of the CDC Process provides a number of benefits and innovations, including the stabilization of flood risk. Common regional criteria State-of-the-art floodplain mapping Hydrologic modeling based on year 2055 Upper Trinity River watershed development A current hydraulic model incorporating CDC permitted floodplain development U.S. Army Corps of Engineers technical review Regional review and comment

18 Corridor Development Certificate Floodplain as a Reservoir WATER SURFACE BUILD AREA BUILD AREA RIVER CHANNEL Full floodplain conveyance and storage Reduces, but does not eliminate, impacts on downstream flood potential (compromise) Approx. 100 projects permitted Leveraging to expand SW management practices STORAGE AREA STORAGE AREA RIVER CHANNEL Recovered conveyance and compensatory storage

19 NOAA Atlas 14 Precipitation Frequency Estimates How much rainfall to expect from: 10 yr storm event 100 yr storm event 100 yr storm event Used to design significant infrastructure Transportation Flood protection Flood plain mapping Precipitation estimates are out of date (1961) Collaboration NCTCOG USACE TXDOT Fort Worth NOAA USGS UCAR Cost $1.6 mil, $533k/yr for 3 years $960,000 pledged.

20 National CWMS Implementation 200+ USACE Watersheds Modern state of the art models for all watersheds (200+) with USACE assets Supports Rainfall-runoff River stage Reservoir system simulation Economic Dam safety, reservoir operation and $125-$150 million nationally Texas ($6 million) Completed (75%) Trinity, Neches, Guadalupe, Colorado Current Brazos Future Sulphur, Cypress Coordination FEMA, USGS, NWS, regional and local governments

21 FEMA Region 6 Federal Partnerships Federal Agency Partnership Universities, NWS and ERDC for review and Research Leverage regional expertise PM & Resourcing USACE SWF FEMA Region 6 Production USGS LA, TX, OK, NM, AR Stations Research & Review NWS Leverage library of exiting studies and models USACE SWF, SWL, SWT, SWG, SPA, ERDC Universities within FEMA Region 6 ERDC

22 WEB Site Questions?