Smart Infrastructure Investment: Evalua2ng Demand Trends & Weighing Risks

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1 Smart Infrastructure Investment: Evalua2ng Demand Trends & Weighing Risks David Marshall, P.E. Engineering Services Director Tarrant Regional Water District 1/23/14

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3 TRWD Overview Formed in 1924 from an act of the Texas Legislature and Governed by a 5 member Board of Directors Guidance provided by four primary wholesale customers: Arlington, Fort Worth, Mansfield and the Trinity River Authority. Main functions are flood control ($21 MM annual budget) and water supply ($116 MM annual budget) Ultimately serves 70 cities in an eleven county service area. Current service population is 1.8 million; projected to increase to 4.3 million by 2060 District should deliver about 370,000 acre feet of untreated water this year

4 IPL Pipeline A joint transmission project with Dallas

5 TRWD System Op2miza2on and Risk TRWD balances opera2ng costs and reliability in our op2miza2on using a daily 2me step Our opera2ng policies are flexible: policy sets are developed using the short term climate parerns (6 months) to adapt to condi2ons These dynamic policy sets are then used to simulate the system to determine system reliability for daily opera2ons Demands are based on responses to the climate but demand responses to drought measures are not es2mated We also simulate the system on a monthly 2me step to see frequencies of shortages, pumping, lake levels and other opera2ng parameters to guide is in planning.

6 TRWD Reliability Modeling

7 Risk of Climate Variability Tree ring records show extreme droughts in the past Clima2c parern changes add another uncertainty in supply planning

8 Climate Variability - Palmer Index History

9 Demand Forecas2ng Region C s methodology Each Water User Group (WUG) projects popula2on and demand based on a number of categories This is done for each decade for 5 forward decades The process accounts for conserva2on in the plumbing code in the demands through lower per capita demands

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11 Western is Bridgeport and Eagle Mountain Eastern Cedar Creek and Richland Chambers

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13 TRWD Demands Over Time

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15 From Water Research Founda2on Webcast Founda2on Knowledge Webcast: Assessing Changes in Single Family Water Use 12/6/2011

16 Growth in Popula2on & Water Consump2on 210 1,400, Population 1,200, Non-Rev Total Consumption 1,000,000 Annual MGD Billed Consumption 800, ,000 Population , ,

17 So, what are our demands? Reflec2ng back to the methodology used in the 1984 and 1990 State Water Plan, we have to bracket them We s2ll may not capture the future Con2nued conserva2on ac2vi2es Escala2ng price impact Uncertainty in popula2on gain Future demands are one of the major sources of uncertainty in the process

18 Looking for the Next Source

19 Finding New Sources

20 Exploring alterna2ve new sources Expanded conserva2on Reuse Dual systems (Cape Coral, FL) Direct reuse (Big Spring) Indirect reuse (TWRD, NTMWD Wetlands) Rainwater harves2ng Tucson rebate program Simple landscape terracing Water sharing with adjacent agencies (Dallas, NTMWD) Reservoir augmenta2on/off channel storage capturing flood flows ASR for drought con2ngency

21 Cost es2mates from Region C 2011 Regional Water Plan

22 Evalua2ng the Best Strategy A number of factors need to be considered in developing the plan: Future popula2on and demands Risk tolerance of our customers Legal risks for a new source Cost to develop the source Cost to deliver the water Environmental considera2ons Social considera2ons Partnering op2ons Time to develop the resource

23 Considering a number of factors complicate the decision process

24 Char2ng the Course Combining all the informa2on will not lead to a single course of ac2on there is too much uncertainty in the future Risk analysis in system modeling iden2fies the poten2al 2ming water shortages, the volume of those shortages and the frequency of those shortages Develop a decision tree that charts the best course based on choices of the driving forces As 2me progresses and uncertain2es reduced, the tree will guide the u2lity to the best path

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27 TRWD s Future The best path may have many forks - a long- term decision process will con2nue to evolve Con2nue to ac2vely pursue conserva2on Con2nue to plan with our regional partners Further develop our system simula2on for risk evalua2on to include climate varia2on and demand response to drought

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