Will Conjunctive Use Solve California’s Water Demand Problems?

1. Will Conjunctive Use Solve California’s Water Demand Problems? • Definitions • History • Conjunctive use programs • Components • California water plan • Opportunities & state funding • Constraints • And the bottom line is…. Carl Hauge Chief Hydrogeologist, DWR Retired tuleluke@earthlink.net

2. What is conjunctive use? The planned and managed operation of a groundwater basin and a surface water storage system combined through a coordinated conveyance infrastructure to optimize water quantity and quality After DWR Bulletin 118-2003, California’s Groundwater

3. Conjunctive use vs water banking • Storage of groundwater and extraction for use • Within the basin = conjunctive use • Export from the basin = water banking

4. Central Valley Project • Recharging groundwater along the east side of San Joaquin Valley since 1940s by means of unlined canals and watercourses

5. California Water Plan, 1957 • An estimated potential yield of 9 million acre feet per year • Requirements • More dams & reoperation of existing dams • More conveyance facilities • More wells • Inter-agency cooperation • Resolution of political, legal, institutional, technical and economic issues

6. Successful conjunctive use programs • Chino basin—injection wells • Coachella Valley Water District • Fresno • Friant-Kern Water Users Authority • Kern County (some banking) • Kern Water Bank, Bakersfield City, Pioneer, Berrenda Mesa WD

7. More successful programs • Orange County Water District • Santa Clara Valley Water District • Semitropic Water Storage District (banking)—in lieu recharge • United Water Conservation District • Water Replenishment District of Calif

8. Attempted programs • San Joaquin County • Madera County

9. Technical components • A water supply • Surface water storage—dams or setback levees • Conveyance facilities—canals, pipelines, pumps, wells • Storage capacity in the aquifer • Hydraulic continuity between the recharge point and the point of use • A monitoring program designed for the hydrogeology of the site—sw & gw quantity and quality over time

10. Setback levees on rivers can improve natural floodplain functions by: • Restoring habitat • Attenuating flood flows • Recharging groundwater if hydrogeologic conditions are suitable

12. Political, legal, institutional & economic components • Different for each project • 22 types of agencies that deal with water • Surface water • Groundwater • Statutory authority varies • Surface water rights • Overlying landowner rights • Personalities

13. Likely locations • Southern California • San Joaquin Valley

14. Southern Calif and SJV • No appreciable surface water in streams • Empty storage capacity in the aquifer • Available imported or local surface water supplies • Extensive infrastructure—canals, pipelines, pumps, water wells • Some history of cooperation • NEEDED—thru Delta conveyance facility

15. Sacramento Valley is completely different • Aquifers are generally full • If groundwater is extracted the water is recharged by surface water from live streams • Surface water rights can be contravened • When you extract gw you are borrowing against future surface water • USBR & DWR make up the deficit

16. Sacramento Valley • Conjunctive use is technically difficult • The aquifer must first be emptied • Will affect other water rights • Data needed • Stream flow • Aquifer gradients • Extraction amounts • Source and amount of recharge

17. Ag water use eff Urban water use eff Conveyance System reoperation Water transfers Conjunctive use & gw storage Desalination Precip enhancement Recycled water Sw storage Treatment & distribution Gw/aquifer remediation Quality to use Pollution prevention Urban runoff mgmt Ag lands stewardship Economic incentives Ecosystem restoration Floodplain mgmt Recharge areas protection Urban land mgmt Water recreation Watershed mgmt California water plan lists 25 resource management strategies

18. 3 resource management strategies deal with groundwater • Conjunctive use and groundwater storage • Will increase water supply • Groundwater/aquifer remediation • Will improve water quality • Recharge areas protection • Will be good resource stewardship

19. Conjunctive use will help meet these water management objectives • Provide water supply benefits • Improve drought preparedness • Improve water quality • Provide operational flexibility & efficiency • Reduce flood impacts • Provide environmental benefits • Reduce groundwater overdraft _____________________________ • Energy benefits • Recreational opportunities

21. How much water can be produced by each strategy? (maf/yr) • Precipitation enhancement 0.3 - 0.4 • Conveyance 0.3 - 0.4 • Desalination—ocean & brackish 0.3 - 0.5 • Agricultural efficiency 0.2 - 0.8 • CALFED surface storage 0.1 - 1.0 • Recycled water 0.9 - 1.4 • Conjunctive use 0.5 - 2.0 • Urban efficiency 1.2 - 3.1

22. Opportunities for conjunctive use • Funding from propositions administered by DWR has been used by local agencies to help develop a number of conjunctive use programs • Some areas have been identified where hydrogeologic conditions might be suitable for a conjunctive use program • NEEDED—thru Delta conveyance facility

23. Proposition 13 loans & grants • GW Storage Grants $168 million • GW Storage FS Grant $1.1 million • GW Storage Pilot Projects $8.9 million • GW Recharge Construction Loans $26.2 million • GW Recharge FS Grants $1.4 million ______________________________ • Total State Grants and Loans = $205.6 million • Total local, other state, & federal funding = $744 million • Total Project Costs = $1 billion

24. Other programs • Previous programs funded 128 projects • Grants totaled $28 million • Applications for AB 303 grants this year total 122, a record • Total funds requested = $6.7 million • Total funds available = $6.4 million

25. Estimated groundwater yield of funded projects • Prop 204 7,000 acre-feet per year • Prop 13 340,000 acre-feet per year • TOTAL 300,000 to 350,000 af/yr

26. Constraints • Recharge method • Political, legal, institutional issues • Water quality • Energy requirements • Rights to local & imported sw & to gw

27. Recharge method • Natural • In lieu • Injection wells • In channel • Off channel

28. Santa Ana River in-channel & off-channel recharge

29. Fragmented basin mgmt Legal rights of water users & water agencies Public trust resources Ecological concerns Bookkeeping—whose water is it? How much water must be left behind? Reoperation of dams Mitigation of potential impacts Rights to use of the aquifer Rights to vacant aquifer space Local gov’t land use decisions Working toward consensus Political, legal, institutional issues

31. Water quality • Native water • Imported water • Changes in quality • Treatment may be required • Recycled water

32. Energy requirements • Conveyance pumps • Pump lift in water wells • Treatment, if necessary

33. Rights to local & imported surface water, & to groundwater • Keeping tabs on imported vs local gw • When sw recharges gw, what happens to the sw right on file with SWRCB? • How much groundwater must be left in the aquifer? • 10 to 15 percent of the water that is recharged—Kern Water Bank

34. When you use groundwater you are borrowing against future surface water • Developing conjunctive use programs is a political, legal, institutional problem • A thru Delta conveyance facility is needed

35. And the bottom line is…. • More conjunctive use programs could increase California’s water supply • But there are some problems to overcome • Political, legal, institutional, technical & economic issues must be resolved • Still, we estimate that between 500,000 & 2,000,000 af per year could be made available • The potential is high, but the achievable is unknown

36. Laws of ecology • Everything is connected to everything else • Everything must go somewhere • Nature knows best • There is no such thing as a free lunch Barry Commoner