Analysis and Simulation of Conjunctive Water Use for Agricultural Settings with the Farm Process for MODLFOW

Transcription

1 Analysis and Simulation of Conjunctive Water Use for Agricultural Settings with the Farm Process for MODLFOW Randy Hanson 1, and Wolfgang Schmid 2 1 U.S. Geological Survey 2 University of Arizona Resource Development and Management of Regional Aquifer Systems Sustainability of Resources is subject to changing Demands and Supplies that are integrated through Conjunctive Use FLOWS PAY THE BILLS! Demand Development Supply Replenishment & Storage Water-Resource Management & Conjunctive Use are subject to: Social Constraints Water Rights, Conservation, Land-Use Planning Economic Constraints Water Markets, Industrial/Urban/Agriculture/Tourism Water Quality Natural & Anthropogenic Contamination Land-Use Conversion of Agriculture to Urban Land Use or Habitat Mitigation Ecological Requirements Climate Change & Variability Toward Sustainable Groundwater in Agriculture An International Conference Linking Science and Policy June 2010 San Francisco, California Current Features of FMP Supply-Constrained--Demand Driven Mass Balances USGS s s MODFLOW MODULAR EXPANSION Ground--water Flow Model Full Hydrologic Model Wide Range of Applications and Hydrologic & Political Settings

2 (1) Precipitation input (FMP) (2) Irrigation demand supplied in order of decreasing priority by (a)non-routed deliveries (FMP), (b)semi- or fully routed surfacewater deliveries streamflow or surface-water rights constrained stream diversions (FMP and SFR), (c)groundwater pumpage from capacity- or head-constrained singleor multi-node wells (FMP and MNW), (d)potential other external water supplies (FMP); (3) Uptake from groundwater (FMP) with groundwater flow simulated by MODFLOW s Groundwater Flow (GWF) Process (4)Transpiration through vegetation of water derived from precipitation, irrigation, and groundwater sources separately (FMP) (5) Evaporation from bare soil of water derived from precipitation, irrigation, and groundwater sources separately (FMP); (6) Surface returnflows from precipitation and irrigation in excess of consumptive use as overland runoff to stream network (FMP and SFR); (7) Sub-surface returnflows as instant deep percolation or delayed recharge (FMP and UZF) and optionally also as well injections (FMP and MNW) Simulation of Conjunctive Use Two types of Interdependency head-dependent dependent flows and flow-dependent flows Simulation of both Natural and Anthropogenic coupled Demand/Supply Flows (1) Irrigation Demand (2) Identify Delivery (3) MF-FMP (4) Check Constraints (5) Returnflow Climate Change Analysis Central Valley, California Conjunctive Use in Central Valley Virtual Farms, Plumbing, & Land Use 21 Virtual Farms 43 Rivers/66 Diversions 22 Crop Groups Including urban Native/Riparian 5 Land-use windows Climate periods Crop coefficients (Faunt et al., 2009, USGS Professional Paper 1766) Central Valley Conjunctive Use Stream Network Inflows (43) Diversions (66) Deliveries 64 to Virtual Farms 2 diverted outside of model Deliveries/diversions (first 6 virtual farms )

3 Central Valley Water Use: Total Use Through Time (Water Years ) Paleo- Extreme Climate Events Central Valley, California Mega-Droughts > 100 years long Mega Drought Medieval Drought Faunt et al., 2009 (USGS PP 1766) Historical Change in Groundwater Storage (Water Years ) CLIMATE CHANGE ANALYSIS Coupled Hydrologic Models Provide a Physically-Based Platform to Simulate/Analyze Conjunctive Use and Movement of Water Faunt, C.C., Hanson, R.T., Belitz, Kenneth, and Rogers, Laurel, 2009, California s Central Valley Groundwater Study: A Powerful New Tool to Assess Water Resources in California's Central Valley: U.S. Geological Survey Fact Sheet , 4 p. ( DSS & LINKAGE BETWEEN GCM and BCM & CVHM Supply-Constrained/Demand-Based Hydrologic Model System Run GCM Model (CM2/PCM) Statistical Downscaling 12km 4km Bias Corrected 270m Precipitation, Temperature, & Ref-ET (Constructed Analogs) Mountain Runoff/Recharge to Rivers & Reservoirs (Basin Characteristic Model (BCM) of all Central Valley Watersheds) CLIMATE VARIABILITY within CHANGE Precipitation Stationarity & Weak-Stationarity? Cumulative Precipitation Shows A2 Scenario at Davis with the potential for sustained droughts in the 21 st Century Potential Decadal-length Droughts or Dry Periods (GFDL-A2) Run Central Valley Hydrologic Model (MODFLOW-FMP) DSS Analyze Groundwater, Surface-water, & Landscape Budgets RESAMPLING onto Valley-Wide Grid Build Farm Process (FMP) Input for Monthly Precipitation & Reference ET To Simulate Agricultural Demand Build Stream Routing/Deliveries 41 River Inflows, 66 Diversions, 42 Nonrouted deliveries (Reservoir Releases, Unregulated Streamflows & Project Water Deliveries) DSS Analyze Groundwater Levels, Streamflow, & Land Subsidence Estimate Reservoir Releases Sac & San Joaquin (Not Used) (CALSIM/CALVIN/Regression) Estimate Reservoir Releases Tulare Basin (Regression outside of CALSIM) (Not Used) (King,Kaweah,Tule, Kern) DSS Analyze Drought Response & Adaptation Davis- Measured Potential Multi-Decade Decline in Precipitation Davis-Measured Davis-GFDL/A Mean 17.3 in 13.7 in Variance 37.8 in in 2 >PDO-AMO 43 yr (79%) 52 yr (87%) PDO 18 yr (14%) 19 yr (10%) MON-PE 9 yr (3%) 9 yr (2%) ENSO 2 6 yr (4%) 2 6 yr (1%)

4 Sustained Drought Intermittent Droughts Predominantly Surface-water Deliveries Irrigation Supply/Demand Predominantly Groundwater Deliveries Delta Outflow to San Francisco Bay Canals Used for Surface-water Delivery System Land Subsidence & Differential Subsidence may disrupt or damage Canals & Rivers & Runoff Preliminary Results Subject to USGS approval and modification (Hanson et al, 2010) Aquifer-Storage & Recovery with Coastal Delivery System Pajaro Valley, California AQUIFER STORAGE & RECOVERY SYSTEM COUPLED TO: SUPPY CAPTURE LOCAL RUNOFF DEMAND COASTAL DISTRIBUTION SYSTEM (CDS) Harkins Slough Deliveries 4.3 Million m 3 (3,470 ac-ft) CDS Deliveries 2.6 Million m 3 (2,100 acft) 61% of Recharged Water ASR Deliveries 21% of Recharged water & 35% of CDS Delivery Local Recharge occurring as well as ASR operation Recycled Water Contribution up to 16% of Total Agricultural Water Demand 54.6 million m 3 /yr (44,230 acre-ft/yr) SIMULATION OF ASR and CDS RELATED PROJECTS Agricultural Conjunctive Use Simulation of Supply & Demand of ASR and CDS and Reduced pumpage from Coastal Regions Simulation of Delivery Simulation of Reduced Coastal Pumpage 3 Farms 2-3 Sources Priority of Water Supply for Farm Balance of Flows per Stress Period (each Month) 1) Recovery wells 2) Recycled Water Facility (2008) 3) City Connection 4) Blend Wells 5) On farm wells will make up remainder of demand 1 Farm 1Source 2 Farms 2 Sources Preliminary Results Subject to USGS approval and modification

5 Misnomers & Differences FMP has many options but is easy to use (especially in data deficient settings) Not all FMP options have to be used Start simple! FMP options can be implemented incrementally and easily changed FMP makes you think about hydrology plus all of the flows, climate, soils, & vegetation FMP requires more analysis (flows and heads) FMP requires more associations (wells, diversions, rivers, etc) FMP SUMMARY OF FEATURES AND ADVANTAGES MODEL FEATURES MADE EASY Estimates Irrigation Demand Estimates Surface-Water Deliveries Estimates Ground-water Pumpage Estimates Net Recharge Estimates all for ET, Runoff, and Deep Percolation Complete Linkage to Ground-water and Surface-water Flow ADVANTAGES FOR MODELERS No need for indirect estimates of Pumpage, Recharge, ET, Runoff, or Surfacewater deliveries Uses Natural Data Easy to Update Model Saves time and money for constructing, operating, and updating models Facilitates Operational and Forecasting Simulations FMP is easy to build FMP can be estimated from simple and primary data MODFLOW Interdependency of Flows and Heads Recent MODFLOW Developments More Linked & Complete Hydrologic Models More Realistic Simulations Better Analysis of Linked Flows (Conjunctive Use) within the entire Hydrologic Cycle of Regional Hydrologic Systems Linked Model Architecture Decision Support Tools & Self-Updating Models Ground-Water Flow Features ( Packages ) THE END FINAL COMMENTS & DISCUSSION? THANKS! Ground-Water Processes (Transport-GWT/ MODPATH, Management-GWM/FMP, Parameter Estimation-UCODE/Pest, Landscape-FMP ) Integration with Other Models in Hydrologic Cycle (Atmospheric-GCMs, Runoff-PRMS(GSFLOW)/BCM/VIC, Water-Allocation Models (ex. CALVIN), Reservoir Operation Models) Integration with Other Processes Ecological & Biogeochemical Models & Agro-Economic Models CONJUNCTIVE USE GROUND-WATER SUSTAINABILITY = STRAWBERRY FIELDS FOREVER? rthanson@usgs.gov (619)