10/5/2015

From Drought of the Century to Statewide Reservoir Development Real-Time Operations and FRM Flood of the Century Background

. Multi-purpose ► Flood control, water supply, hydropower, . Federal, state and local partnership environmental, recreation, navigation . Critical to the early development of ►Real-time operations . Significant federal economic contribution • USGS, NWS-RFC . Planned/constructed dams 111/32 ► 1st - Marshall Ford Dam () 1942 • City of Dallas, TRWD, state and local EM’s ► Last – Cooper (Jim Chapman Reservoir) 1991 ►FRM . 8.8 M ac-ft conservation storage San Jacinto ► 20% - 25% surface water supply • FEMA, state, local . 15.9 M ac-ft flood storage in 31 federal dams • NCTCOG, Steering Committee, FMTF . Costs (2013)  CDC Program ► Construction - $8.2 billion ► Benefits - $76 billion (flood only) • Local governments ► B/C ratio – 9.3 . Annual recreation visits – 22 M

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What Do You See? Seventh Flood Control Reservoir – RESERVOIR ALLOCATIONS CDC Regulatory Program Top of Dam

Maximum Design Surface Active Flood Storage Freeboard

Surcharge Benbrook Top of Flood Control Joe Pool 15.9 million ac-ft $2-3 billion/yr damages prevented, $76 billion total Top of Conservation Lavon CDC Corridor th Water Supply, Fish & Wildlife, Recreation Where is the 7 flood control reservoir? • Municipal Spillway Crest Grapevine West Fork • Agricultural • Industrial 8.8 million ac-ft Trinity TRWD Spillway Lewisville Ray Roberts and Whitney • Hydropower 5.8 ac-ft water supply 20-25% surface water Crest 50% supply

• Flood control system Perched Reserve Power Pool • Over $70 billion in WATER SURFACE SWF - 214 GWH/yr @ 5 locations damages prevented (60 Low Flow years) Top of Inactive Pool Sedimentation Pool • $2-3 billion per year • Water supply system Streambed • 6.8 million served RIVER CHANNEL

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Plans of Regulation Hydrologic Network

. Cooperative program – federal, state, local, . Peak flow vs. volume academia, AE community . Follow published plans of regulation for . Over 400 Remote Sensing Stations, each project approximately 2000 Observers . Store flood producing runoff to protect . Basic data for operation of the projects Surcharge Operations downstream areas . Calibration of NWS precipitation estimates . Uncontrolled areas . Model calibrations, real-time forecasting . Project Safety – can we store it? Surcharge and hydrologic investigations releases? . Jointly funded with USACE direct . Forecasts - reservoir managers, surcharge expenditures of close to $18 million What was the largest historical releases annually, SWF $1 million annually . Evacuate flood water to prepare for . Partnerships dam failure catastrophe? subsequent flooding events ► USGS, NWS, River Authorities, Counties, . Coordinate with other dam operators $2,000,000 Cities $1,800,000 . Retain full conservation pools and ► Coordination and resource sharing to $1,600,000 $1,400,000 $700k Actual Cost Leveraged Cost additional supplies on a temporary basis to maximize network benefits $1,200,000 support drought (deviation) ► USACE-SWF has leveraged partnerships $1,000,000 $800,000 . Controls for $700k

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Summary of Projects Averages for CY2014 Maintaining Perspective On Water Surcharge Operations Reservoir Inflow & Basin Average Precip Resv Inflow Basin Avg Precip 1 Jan 14 Cons Storage 31 Dec 14 Cons Storage Management Rare! 100%

. Historical Disasters . Most likely from ensemble events 90% . Dams have limited capability to ► S. Fork Dam, Johnstown, Pennsylvania (Operational Issues) 80% • May 1889, 2209 dead, $17 mil damages store runoff, 100-yr, SPF, PMF, ensemble 70% ► St Francis Dam, California (Operational & Design) . Once full spillway activation likely • March 1928, 450 dead, several towns destroyed 60% ► Buffalo Gap, Virginia Tailings Dams (Operational & Des.) . Control point flows no longer Proctor Lake • Feb 72, 125 dead (COE Involvement) applicable 50%

► Teton Dam, Idaho (Design Issues) . Dam safety 40% PercentofNormal • June 1976, 11 dead, $.5 billion damages . Spillways 30% ► Banqiao & Shimantan Dams (Ru & Hong Rivers, China)(Design ► Uncontrolled

Issues) • Rare 20% • August 75, 85,000 dead, 11 million affected • Damages 10% ► Tainter gates Lavon Lake • Requires SWF internal decision 0% Red Neches Trinity Brazos Colorado Guadalupe BUILDING STRONG®

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May 1- 5 25.00 Typical Rainfall Patter May – June 2015 Event Rain Gage at DFW Airport

In the month of May, the upper 20.00 . Ended 2014 in significant drought received 20”-30” of rain across the entire watershed. Ray Roberts . TRWD projects on West Fork 10+ ft. low I=0.88 in

98 C Lavon 15.00 I=0.44 in . 20” – 30” rainfall across entire upper Trinity River Lewisville I=0.65 in

. Surcharge operations at 10 reservoirs (Neches/Trinity/Brazos) 15 Grapevine F 7 F I=0.70 in . Damage inducing surcharge releases at Lewisville, Grapevine 10.00 93 and Lavon C

. flooding (excess of 100-yr event) (inches) Precipitation Total 5.00 Benbrook 83 I=0.41 in 10 C Joe Pool F . 15” – 18” rainfall on Brazos Basin (Waco, Whitney, Aquilla) I=0.35 in . Whitney was at 48%C when event began 0.00 . Sequential events with little opportunity to make releases 1-Apr 8-Apr 15-Apr 22-Apr 29-Apr 6-May 13-May 20-May 27-May 3-Jun 10-Jun 17-Jun 24-Jun . Few significant single events *Pool percent taken on the last day BUILDING STRONG® BUILDING STRONG® BUILDING STRONG®

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Storm Event May 6-12 Storm Event May 13-19 Storm Event May 20-25

Ray Roberts Ray Roberts Ray Roberts I= 9.45 in I=4.36 in I=4.74 in C= 10.33 in C=14.69 in C=19.43 in Lavon 86 Lavon 93 Lavon F I=3.61 in 100 Lewisville F I=5.57 in I=5.04 in Lewisville C=9.62 in Lewisville I= 7.04 in C=6.01 in I=3.57 in I=4.15 in C=14.66 in C= 7.69 in C=11.26 in C=15.41 in Grapevine 59 74 Grapevine F 37 Grapevine F 57 100 I=6.74 in F F 82 F I=3.74 in I=3.37 in C=7.44 C=11.18 in C=14.55 in 25 44 F F 71 F

Benbrook Benbrook I=4.61 in Benbrook I=3.44 in 11 2 F 18 I=2.01 in Joe Pool C=5.02 Joe Pool F 51 C=10.47 in 18 F F I =4.24 in F Joe Pool 79 F I=3.72 in C=7.03 in C =8.31 in I=5.25 in C=4.07 C=13.56 in

*Pool percent taken on the last day *Pool percent taken on the last day *Pool percent taken on the last day BUILDING STRONG® BUILDING STRONG® BUILDING STRONG®

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Storm Event May 26-31 Variations is Loss Rates for Forecast Modeling Tropical Storm Bill June 13-23 Upper Trinity River – Dallas, Fort Worth Area

Ray Roberts I=4.84 in 2.3 Million (ac-ft) Ray Roberts C=24.27 in I=4.78 in stored in the 6 C=29.45 in Lavon projects Lavon 100 Lewisville 100 I=3.12 in I=5.07 in I=4.38 in C=17.78 in Lewisville C=22.93 in C=19.79 in I=4.70 in C=24.86 in Grapevine 100 100 100 Grapevine 100 I=4.33 in I=6.46 in C=18.88 in C=25.76 in 100 100 70% variation in loss rates Benbrook I=3.79 in Benbrook C=14.26 in Joe Pool I=5.16 in 40 F 100 Joe Pool I=6.52 in 100 C=19.43 in I=3.03 in 100 C=20.08 in C=23.11 in

RSR & LOL 70k-80k cfs 10yr – 20 yr event

*Pool percent taken on the last day *Pool percent taken on the last day BUILDING STRONG® BUILDING STRONG® BUILDING STRONG®

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FM 2499 Closure Total Rainfall for May-June 2015

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Mass Rainfall at Whitney Lake Storm Event May 17-31 Anticipating Bill, June 16 25 Whitney Aquilla 21000 611 1453 0 Whitney 48% C Waco 4230 Spring 2015 Events Belton When event began 206 1641 Georgetown 20 27 258 0 Granger Whitney 2820 Whitney and Aqulla Lakes received Aquilla 0 9.3 in I around 18” of basin average rainfall. 8.5 in I 15.5 in C Waco Lake received around 15” of basin 14.8 in C 15 23,000 average rainfall. 600 CFS CFS •Whitney, Waco Lake and 56F Aquilla were significantly in the 42 F flood pool. 10 •The Corps of Engineers was in Waco 24 hour operations in the path 8.2 in I of Tropical Storm Bill. 12.6 in C th Total Precipitation (inches) Precipitation Total 5 •At 11 pm on June 16 the 6,000 CFS Corps of Engineers reduced Flood Pool 35F Waco Gage releases at 6 reservoirs in Stream Gage 29,000 CFS anticipation of the storm. This action prevented flooding in 0 1-Apr 8-Apr 15-Apr 22-Apr 29-Apr 6-May 13-May 20-May 27-May 3-Jun 10-Jun 17-Jun 24-Jun Waco and other areas.

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Tropical Storm Bill June16-18 Pool-Elevation Frequencies Damages Prevented

Reservoir Return Interval . Red River Basin $5.2 million . Sam Rayburn 14 Whitney . Benbrook 7 . Basin $99.7 million 2.7 in I Aquilla 18.2 in C 3.1 in I . Joe Pool 125 . Trinity River Basin $6.7 billion 1,500 CFS 18.3 in C 1 CFS . Ray Roberts 167 . Basin $173.5 million . Lewisville 100 12 F 31 F . Grapevine 40 . Basin $59.9 million . Lavon 55 Waco . Basin $23.7 million 2.4 in I . Bardwell 125 15.3 in C . Navarro 40 . Total $7.1 billion 200 CFS Flood Pool 10 F Waco Gage . Somerville 70 Stream Gage <5,000 CFS

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Inundation Mapping Requests

Important Changes and Lessons *Word was out that we have these new HEC-RAS models for CWMS spanning hundreds of river miles. . Significant new technology Flood Inundation Scope of Inundation Requests: . Not enough gages ~ 1,500 River Miles . Loss rate variations – 24 hour forecast time Mapping . 13 River Basins/Reaches . Plans of regulation do not address multiple . 7 Reaches (~500 river miles) requested by (Our Unforeseen Mission) USACE’s EOC [Impacted by simultaneous surcharge operations USACE reservoir surcharge releases]

. Forecast were frequently superseded . 6 Reaches (~1,000 river miles) . Inundation mapping necessary requested by the State of Texas . Staff performance – AMAZING! Suspense Schedule? Right Now!

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How Requests Were Met Final Map Products CWMS Implementation . Existing HEC-RAS Models for ~ 200 River Miles ► HEC-RAS models available for ~900 of the requested 1,500 river miles . 200+ USACE watersheds . $150 M investment, nationally ► Credible geo-referenced HEC-RAS models available for only ~200 requested river miles (good geometry, primarily from previous study . $6 M for Texas models; well calibrated) . 6+ year plan ► Remainder of RAS reaches primarily based on 10-meter DEM data . Supports (nominally +/- 5-ft accuracy) with few bridges and levees incorporated ► Dam safety, operations (forecasting), can be leveraged (FEMA) . FESM (Flood Evaluation Simulation Model) Tool from Apartment Complex . 2014 on Sandy Lake Rd USACE’s MMC to map ~1,300 River Miles ► Colorado, Neches, Guadalupe, Trinity, San ► Straight-line interpolation between NWS forecast points for the water Jacinto () surface profile. No hydraulic modeling involved. . GIS Shapefiles . 2015 ► Mapped on 30-meter DEM ► Brazos . Google Earth Files . MetVue -> HMS-> . MMC created all publishable map products. RiverWare-> RAS-> FIA . PDF Map Books in DFW

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Lessons Learned Customer Feedback on Inundation Mapping FEMA Support: Wimberley, TX #1: Our new CWMS modeling suites are a great start. Not ready for prime time, especially with regard to supporting accurate inundation mapping. ~ 200 River Miles based on credible HEC-RAS models: #2: A significant investment will be required to develop and maintain HEC- May 2015 Flood . Positive Feedback from Emergency Management Community RAS models capable of supporting accurate real-time inundation maps. . 9 Deaths . Helped Focus Emergency Response Resources in Dallas-Forth Worth #3: Flood forecasts can change many times during the course of a prolonged . 350 Homes Washed Away . Make better Reservoir Release decisions: Who would be impacted? flood event, and inundation mapping must be continually updated. . River rose 26 feet in 1 hour #4: Need More Organization for Future Efforts: . Few Errors  Areas to Improve Models . Estimated Peak Flow of . Policy/Guidance: Any River, Anywhere? Accuracy Level Standards? 175,000 cfs How to Communicate Uncertainty? The Other ~1,300 River Miles . Infrastructure: Sufficient experienced staff & computing power . USACE Division – Why is this not a better (more accurate) product? . Funding sources . State of Texas – Not useful. Mapping showed inundation behind non- #5: Is this a role that USACE should be filling? overtopped levees.

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Discharge-Frequency Curves: FEMA Support – Wimberley, TX How Much Gage Record Do You Need Blanco River at Wimberley to Estimate the 100-yr Discharge? May 2015 Flood - Blanco River at Wimberley: 355 Square Miles, 88 years of record . High Water Marks 5-10 feet above current BFEs . Floodplain Maps driven by 100-yr (1%) Flow Estimate

149,000 cfs 2015 Gage 100-yr Est

126,000 cfs 2013Gage 100-yr Est Dashed Yellow Line = Actual 100-yr (1%) Discharge Solid Yellow Line = Estimate of 100-yr (1%) Discharge based on previous years of record

What is the true 100-yr (1%) Flow at Wimberley? 300 to 400 years of Record before 100-yr Estimate Converges

Credit: Beth Faber at USACE-HEC

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How Much Uncertainty Do You Have Conclusions with 100 years of Record? . 100 years of Record may not be enough! . Watershed models can help compensate for non-representative samples in the WEB Site gage record . Need to use reasonable loss rates that consistent with observed events www.swf-wc.usace.army.mil

Sliding Window = 100 years of Record 23,000 cfs difference in 100-yr estimate after Solid Yellow Line = Estimate of 100-yr (1%) Discharge 1 Flood Event Questions? 100-yr (1%) Estimate varies from 100,000 to 450,000 cfs with 100 years of Record

Credit: Beth Faber at USACE-HEC

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