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Climate Change Impact on Water Availability in NYC Water Supply. Adao Matonse 1 , Allan Frei 1 , Donald Pierson 2 , Mark Zion 2 , Elliot Schneiderman 2 , Aavudai Anandhi 1 , and Hampus Markensten 3. 1 CUNY Institute for Sustainable Cities, Hunter College
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Climate Change Impact on Water Availability in NYC Water Supply Adao Matonse1, Allan Frei1, Donald Pierson2, Mark Zion2 , Elliot Schneiderman2, AavudaiAnandhi1, and Hampus Markensten3 1 CUNY Institute for Sustainable Cities, Hunter College 2 Bureau of Water Supply, New York City Department of Environmental Protection 3 Upstate Freshwater Institute Water Quality New York City Department of Environmental Protection Bureau of Water Supply
02 Presentation Outline • Introduction • What is OASIS ? • The OASIS Model Framework • The NYC Water Supply System • Climate Change Simulations for OASIS • Selected Results • Summary • Preliminary Conclusions • Next Steps • Discussion
03 IntroductionWhat is OASIS with OCL? NODES • It has a Graphical User Interface (GUI) • Control data entry into database • Helps manage simulation runs • Helps access to output files • Graphical display of the system (schematic) • Routes water from a system of nodes & arcs Reservoir Demand Junction ARCS
04 IntroductionWhat is OASIS with OCL? • Software by HydroLogics, Inc. • Modeling operations of water supply systems • Generalized program • Data-driven: specify features and rules without altering source code • Use Operations Control Language (OCL) to set operating rules • Simulates routing by solving a Linear Program (LP)
05 The OASIS Modeling FrameworkOverview - Climate Change Simulations Default Input Other Measured GCM Simulation Watershed Model W Quality Model OASIS How to do it? LP System Design Rules - Constraints - Goals What to do? OCL Integrated System System Descriptors Driving Elements Demand Climate Change
06 IntroductionThe NYC Water Supply System West Of Hudson East Of Hudson Areas in green • Delaware • [1012 sq. mi.] • Cannonsville • Pepacton • Neversink • Rondout • Catskill • [571 sq. mi.] • Schoharie • East Ashokan • West Ashokan Croton [375 sq. mi.] • Present focus on WOH but, • OASIS has feedback to what is happening in • - Croton and • lower Delaware • Croton and Lower Delaware are run with • present climate
07 IntroductionClimate Change Simulations for OASIS • GCM Simulations • GCMs: ECHAM, GISS, NCAR • Emission Scenarios: A1B, A2, B1 • Time Slices: • Baseline: 1980 – 2000 • Future: 2046 – 2065; 2080 – 2100 • Monthly delta-change GCM air temperature and precipitation as input in: • GWLF Watershed Model • Generate inflow data for OASIS
08 Selected Results • Identify Relevant System Descriptors • West Of Hudson Subsystems • Inflow from GWLF simulations • Drought Conditions • Probability of Subsystem Refill • Storage levels – Inflow – Spills • Focus on Delaware Results. Catskill results have similar patterns • Results are preliminary
09 ResultsAnnual Inflow Baseline Median
10 ResultsMonthly Inflow Baseline Future-4665 Future-8099
11 ResultsAverage Number of Days per Year in Drought Condition - Delaware Subsystem
12 ResultsAverage Number of Days per Year inDrought Condition Delaware Subsystem Catskill Subsystem Days per Year Days per Year FutureScenarios FutureScenarios Baseline Baseline
13 ResultsProbability of Refill by June 1st • Function of: • Current day’s storage levels • Expected system diversions • Inflow Forecast between today and Jun 1st
14 ResultsInflow – Storage – SpillBaseline Future • Future Inflow more uniform and high in winter months • Future storage and Spill increase during Fall and winter • Future and current storage similar in summer but with less variability for future
15 Summary • Climate projections from 3 GCMs, 3 emission scenarios, 1 baseline and 2 future time slices applied in this study • Monthly delta-change method for climate projections • Projected air temperature and precipitation used in GWLF to generate inflows used in OASIS • Simulations for future on WOH watersheds • Croton and Lower Delaware run on present climate • Rules and Demands were assumed stationary
16 Preliminary ConclusionsInflow • Most GCMs project increased Winter and reduced early Spring inflows due to earlier snow melt • Inflow patterns for all scenarios are similar but GISS and NCAR are of a greater magnitude • Inflows for 2046-2064 and 2080-2100 time slices appear similar on annual basis • Seasonal changes more pronounced in the 2080 - 2100 simulations
17 Preliminary ConclusionsSystem Indicators • Reduction in number of days per year system is under Drought Watch, Warning and Emergency with high variability between GCM predictions • Increase in Subsystem Probability of Refill by Jun 1st for future scenarios • Increased spills during winter • Increased future storage levels during winter months while similar storage levels with less variability in late Spring and Summer
18 Next Steps • Improve Quality of Input data • Apply Climate Change Data to EOH and Lower Delaware • Project Future Demands Under Climate Change • Optimize OASIS Rules • For Each of Above: • Generate Indicators • Evaluate System Performance and Sensitivity • Integrate New Selected Indicators Into OASIS