A Robust Water Supply System:

Transcription

1 A Robust Water Supply System: Incorporating Climate Variability, Climate Change & Uncertainty in Decision Making Tirusew Asefa Ph.D., P.E., D.WRE Co-Chair, Florida Water Climate Alliance ( Manager, Planning & System Decision Support Tampa Bay Water ( September 13 th, 216

2 Overview Wholesale drinking water to six governments 2.6 Million Residents mgd annual average Seasonal to multi-year variable climate 2

3 Who We are (Cont.) Desal Water Ground Water Surface Water 15 BG Reservoir

4 The Florida Water and Climate Alliance Initially funded by NOAA Climate Program Office: CSI and SARP. Now funded by local partners. Goal: Increase the regional relevance and usability of climate and sea level rise models for the specific needs of water suppliers and resources managers in Florida.

5 Develop a collaborative working group Actionable climate science - Data/models/tools relevant to water supply operations and management Domain Community Learning together Practice Public water suppliers, resource managers, climate, social and hydrologic scientists, local planners Workshops, projects, research, website, reports, s, personal communication, outreach Based on: Wenger, Etienne, Communities of Practice, May 29

6 Phase 1: Hydrologic Implications of Dynamically Downscaled Climate Predictions What we did Used dynamically-downscaled bias corrected retrospective and future climate projections (CMIP3) to evaluate potential impacts of future climate change on hydrology in the Tampa Bay region Why we did it Want to understand implications of future changes in temperature and precipitation over Tampa Bay region on long term water supply planning What we found

7 Validation of the Downscaled Retrospective GCM Output for Streamflow Prediction Key Finding Mean streamflow (m 3 /s) Obs ( ) Cal ( ) CCSM_retrospective_BC HadCM3_retrospective_BC GFDL_retrospective_BC Alafia River Historic Streamflow seasonal cycles preserved using retrospective GCM predictions Mean streamflow (m 3 /s) Obs ( ) Cal ( ) CCSM_retrospective_BC HadCM3_retrospective_BC GFDL_retrospective_BC Hillsborough River

8 Temperature Dynamic Downscaling Climate Modeling Results obs_tmax Retro. _Tmax Future_Tmax obs_tmin Retro. _Tmin Future_Tmin mean temperature ('C) Bias corrected results CCSM T max T min mean temperature ('C) T max Jan Feb Mar Apr May Jun T min HadCM3 Jul Aug Sep Oct Nov Dec mean temperature ('C) mean temperature ('C) 45 GFDL T max T max T min GFDL T min Key Findings: 1. Global Climate Models reproduce seasonal cycles of observed mean monthly temperatures 2. Global Climate Models predict about 1 to 3 degree C increase in average monthly Temperature for the future period

9 Bias corrected results Precipitation Dynamic Downscaling Climate Model Results mean precipiatation (mm) obs Retro. _BC Future_BC CCSM obs Retro. _BC Future_BC HadCM obs Retro. _BC Future_BC GFDL Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Future projections for rainfall vary considerably in the summer rainy season

10 Future Projection of Streamflow Lithia gage) CCSM Very low river flow predictions Mean streamflow (m3/s) Future simulations Obs ( ) Alafia River Cal ( ) CCSM_21st_BC1 CCSM_21st_delta Mean streamflow (m3/s) Streamflow Change (Future-retro.) CCSM_21st 2th_BC1 CCSM_21st 2th_delta Alafia River HadCM3 About the same as today Mean streamflow (m3/s) Obs ( ) Cal ( ) HadCM3_21st_BC1 HadCM3_21st_delta Alafia River Mean streamflow (m3/s) HadCM3_21st 2th_BC1 Alafia River HadCM3_21st 2th_delta 2 GFDL Higher late spring and summer flows Mean streamflow (m3/s) Obs ( ) Cal ( ) GFDL_21st_BC1 GFDL_21st_delta Alafia River Mean streamflow (m3/s) GFDL_21st 2th_BC1 Alafia River GFDL_21st 2th_delta 2

11 Phase 2: Hydrologic Implications of Statistically Downscaled Climate Predictions Statistically downscale CMIP5 retrospective and future predictions for 1-15 GCMs and 3 RCP trajectories Quantify the uncertainty in future temperature, precipitation and reference ET projections for the Tampa Bay Region among the GCMs and RCPs Estimate agricultural and urban irrigation demand projections for retrospective vs future climate in the Tampa Bay Region Evaluate potential impacts of climate change on future water supply availability in the Tampa Bay region

12 Relationship Between ET-Rainfall Simulated Annual Total ET, inches y =.1658x R 2 = Percentage of Annual Rainfall as Simulated Annual Total ET, % y = x R 2 = Annual Rainfall, inches Annual Rainfall, inche s Calibration Calibration Verification Verification Linear Trend (Calibration & Verification) (a) Linear Trend (Calibration & Verification) (b)

13 Reconciling short-term decision making with long-term planning

14 How can we integrate short-term management into long-term infrastructure planning? Haasnoot et al (213). "Dynamic adaptive policy pathways: a method for crafting robust decisions for a deeply uncertain world." Global Environmental Change 23(2):

15 How can we integrate short-term management into long-term infrastructure planning? Long-term infrastructure sequencing often times neglects impacts of short-term management decisions Short-term management decisions assumes static structural environments Instead of optimizing actions, models develop rules that integrate new information

16 Monitoring Risk of Failure (ROF) The probability of getting into a Water Supply Crisis in the next 3-month

17 Use of ROF to make a decision to trigger Infrastructure Storage range >9%.%.%.%.%.%.%.%.%.%.%.%.% 8-9%.%.%.%.%.%.%.1%.1%.4%.1%.%.% 7-8%.%.%.%.%.%.4%.6%.9% 2.% 4.1% 4.1%.3% 6-7% 3.1% 4.% 7.4% 5.3% 1.3% 2.2% 2.2% 3.4% 7.7% 18.1% 22.1% 1.5% 5-6% 19.% 21.6% 3.2% 25.9% 7.1% 5.4% 5.6% 6.9% 14.9% 42.5% 52.5% 32.% 4-5% 44.% 46.7% 57.1% 48.2% 16.4% 1.6% 8.2% 11.7% 27.% 61.% 71.% 57.6% 3-4% 52.2% 61.8% 73.3% 65.9% 26.9% 16.% 14.2% 19.4% 4.5% 76.8% 83.1% 73.8% 2-3% 71.1% 74.% 8.2% 7.7% 33.1% 23.1% 16.% 27.1% 59.% 87.1% 92.1% 83.1% 1-2% 75.4% 81.5% 86.9% 74.9% 34.8% 26.3% 2.7% 38.8% 69.9% 93.2% 95.2% 91.6%

18 Updated Water Shortage Mitigation Plan Uses seasonally adjusted reservoir target levels Phase III: Regional Supply Shortage Curve Phase IV: Water Supply Crisis Curve 18

19 Probability of Shortage Crisis in the next 3-month: Illustrative Example Water shortage phase for Apr 27: Phase III RMD flow: Indicator value (mgd) Threshold Value (mgd) -3-1 Forecasted Reservoir Elev (5 th percentile): Indicator value (ft) Threshold Value (Apr)

20 Key Takeaways A robust water supply system is resilient to demand/supply shocks Short-term adaptive management strategies should be tied to long-term planning and vice versa Community-building lessons (Florida Water and Climate Alliance): Provide rigorous science Understand user perspective and context Ensure sustainability (November 16 th, 216, Peace River Facility, Arcadia, FL)

21 Thank You! Questions? Contributors: Tampa Bay Water University of Florida Water Institute Alison Adams, PhD., P.E., Chief Technical Officer Nisai Wanakule, PhD., P.E., Lead Engineer Jeff Geurink, PhD., P.E., Principal Engineer Hui Wang, PhD., Water Res. Sys. Engineer Wendy Graham, PhD, Director & Professor Seungwoo (Jason) Chang, UF, PhD student Cornell University Civil & Env. Eng. Patrick Reed, PhD, Professor