1. BUILDING STRONG ® Trinity COMMON VISION Steering Committee September 10, 2015

2. BUILDING STRONG ® Trinity River COMMON VISION  What is the program about, and why is it important? ► The program was developed in the late 1980’s and is a cooperative management effort among local governments, NCTCOG, and the USACE, along the Trinity Corridor, that results in a comprehensive and regional approach in addressing flood damage reduction, recreation, and environmental quality.

3. BUILDING STRONG ® NINE CITIES: ArlingtonCarrolltonCoppell DallasFarmers BranchFort Worth Grand PrairieIrvingLewisville THREE COUNTIES: DallasDentonTarrant TWO SPECIAL DISTRICTS: Tarrant Regional Water District Trinity River Authority NCTCOG TRINITY RIVER CORRIDOR INTERLOCAL AGREEMENT est. 1989

4. BUILDING STRONG ® Timeline and Background Discussion  Pre 1970’s - Dallas and Fort Worth Floodways constructed by USACE  1972 – Clean Water Act involving USACE permits  1980’s – Cumulative impact of floodplain reclamation projects identified as a concern  1988 – National Environmental Policy Act (NEPA) drives USACE Environmental Impact Statement (EIS) & Record of Decision (ROD)  1988 - Member cities come forward to form the NCTCOG Trinity River COMMON VISION Steering Committee  1990 – Upper Trinity River Basin Reconnaissance Report – common permit strategy based on interest of the locals  1990 –Interlocal Agreements signed by member cities & Congress authorizes the Upper Trinity River Feasibility Study (UTRFS)  Flood Management Task Force formed and CDC criteria developed based on ROD  May 1991 - 1st Edition of the Corridor Development Certificate (CDC) Manual  Today - Approximately 100 projects permitted and four CDC manual updates since 1991

5. BUILDING STRONG ® Historical Background – EIS & ROD  Regional Environmental Impact Statement Trinity River and Tributaries (1988) ► Cumulative impact of development is “Measurable and Significant” ► Record of Decision (ROD) (1988) Applied through 404 permit process No rise in 100-yr water surface elevation No rise in SPF water surface elevation No loss of valley storage for 100 yr Up to5% loss of valley storage allowed for SPF

6. BUILDING STRONG ® CDC Program Goals  Limits (but does not eliminate) the impact of floodplain encroachments for regulated streams on downstream areas  Establishes a consistent regional criteria and review process  Provides a funding stream for updates and state-of-the-art models and modeling tools  Provides oversight for projects constructed in the 100 yr floodplain  Allows development in the floodplain  Allows all FMTF members to review projects for the entire regulatory footprint

7. BUILDING STRONG ® Flood control system Over $70 billion in damages prevented (60 years) $2-3 billion per year Trinity Corridor Development Certificate (CDC) Where is the 7 th flood control reservoir?

8. BUILDING STRONG ® Corridor Development Certificate Floodplain as a Reservoir RIVER CHANNEL WATER SURFACE Full floodplain conveyance and storage 1990 1949 1989

9. BUILDING STRONG ® Corridor Development Certificate Floodplain as a Reservoir  Downstream flood risk increases ► Higher flows ► Higher water surface elevations RIVER CHANNEL WATER SURFACE Full floodplain conveyance and storage Reduced floodplain conveyance and storage RIVER CHANNEL BUILDABLE AREA Bad things happen when you do this!

10. BUILDING STRONG ® 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 TREIS 1987ROD 1988 CDC 1991 Chronology of the Regulatory Program

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

12. BUILDING STRONG ® Questions or Comments?

13. COMMON VISION Activities GIS Mapping Application Link: http://www.nctcog.org/envir/SEEsafe/fpm/cdc/index.asphttp://www.nctcog.org/envir/SEEsafe/fpm/cdc/index.asp

14. COMMON VISION Activities  Ongoing Support Activities  Ongoing Trinity River COMMON VISION Information and Task Force Committee Support  Ongoing Corridor Development Certificate (CDC) Process and mapping support  Continued sponsorship of FEMA’s NFIP training courses  Continued effort toward a Consolidated CDC Model  Ongoing effort to explore partnership and outreach opportunities  Continued exploration of regional cooperative detention/retention strategies  Floodplain Management Seminars for Policy Makers

15. Trinity River COMMON VISION Work Program FY16 Special Projects  Highlights:  Continued effort toward a Consolidated CDC Model  Collection of data from May 2015 weather events  Design and distribution of promotional materials

16. Related Activities Update  Cooperating Technical Partnership  Community Rating System Users Group  Atlas 14

17. Cooperating Technical Partnership In 2002, NCTCOG was named CTP and provided technical information and outreach to assist FEMA in their map modernization efforts. In 2009, NCTCOG crafted an Upper Trinity River Basin Mapping Needs Assessment Tool for the Texas Water Development Board and FEMA. In 2013, NCTCOG served to perform Discovery for two basins- the Lower West and Elm Forks of the Trinity. (We also supported Dallas’ efforts in the Upper Trinity.) For 2015, FEMA is funding NCTCOG for technical production of updated floodplain engineering for portions of the Bear Creek Watershed in Tarrant County, within the Lower West Fork Trinity watershed.

18. Cooperating Technical Partnership Bear Creek Watershed Flood Risk Identification Project The key communities are already working together. Residents of the Bear Creek watershed and their property are continually threatened by severe storm events. Colleyville & Southlake have 350+ flood insurance policies and over $500,000 paid out in flood losses over the past several decades. Floodplain analyses for Bear Creek are outdated and do not represent the flood risk in the watershed. Stakeholders will be able to accomplish the flood risk reduction goals that could not have been achieved by any one entity alone.

19. FEMA’s Community Rating System (CRS)  Voluntary incentive program that recognizes and encourages community floodplain management activities that exceed the minimum NFIP requirements.  Partnership between Floodplain Managers and Elected Officials is essential  Flood insurance premium rates are discounted to reflect the reduced flood risk resulting from the community actions meeting the three goals of the CRS:  Reduce flood damage to insurable property;  Strengthen and support the insurance aspects of the NFIP, and  Encourage a comprehensive approach to floodplain management.

20. North Central Texas CRS Users Group DateTitle 10/22/2014 Developing Outreach Projects (Activity 330) 11/19/2014Flood Warning & Response (Activity 610) 12/17/2014 Developing a PPI, CIP, and Using FloodSmart 01/20/2015Preparing for a Verification Visit 02/17/2015Introduction to CRS 03/18/2015Developing a PPI and CIP 04/22/2015 Drainage System Maintenance (Activity 540) 05/20/2015CRS and Higher Regulatory Standards 06/17/2015CRS and Natural Floodplain Functions 07/22/2015Preparing an Impact Adjustment Map 08/19/2015Preparing an Annual Recertification

21. BUILDING STRONG ® NOAA Atlas 14 Precipitation Frequency Estimates  Used to design: ► Storm water run-off facilities ► Size of detention basins and outlet structures ► More accurately designed drainage for Texas roads and Highways ► Bridges and Culverts  Modeling: ► Flood Risk Management studies ► Flood plain mapping

22. BUILDING STRONG ® NWS Technical Paper No. 40 (1961) NWS Technical Paper No. 49 (1964) NWS Hydro-35 (1977) Available Precipitation Frequency Products NOAA/NWSUSGS Atlas of Depth-Duration Frequency of Precipitation Annual Maxima for Texas (2004) Note: based on data from 1998 study (data from 1994)

23. BUILDING STRONG ® NOAA Atlas 14 Volume for Texas  More accurate, reliable and robust ► More observing locations, longer period of record ► Better statistical methods ► Objective, high resolution spatial interpolation ► Peer review  De-facto national standards ► Local, state and federal agencies  Consistency between states and agencies (equity)  Web based electronic delivery ► Precipitation Frequency Data Server ► Extensive documentation ► Linkage to modern software (HEC)

24. BUILDING STRONG ® Record Lengths & Additional Stations  Development is based on historical observations ► 50+ years to original NOAA studies ► 20+ years to USGS ► Many new rainfall stations

25. BUILDING STRONG ®. Duration Average recurrence interval (ARI) 1251025501002005001,000 5-min 10-min 15-min 30-min 60-min 2-hour 3-hour 6-hour 12-hour 24-hour 2-day 3-day 4-day 7-day 10-day 20-day 30-day 45-day 60-day  PFDS operates from a set of ASCII grids (30-arc sec resolution) Duration and ARI coverages USGS project coverage

26. BUILDING STRONG ® Current Financial Outlook Current Partners TxDOT City of Fort Worth U.S. Army Corps of Engineers NCTCOG Harris County Flood Control District