California’s water problems as global problems – pitfalls and solutions

1. California’s water problems as global problems – pitfalls and solutions • A litany of challenges: • Population pressures (demands) • Regional growth patterns (demands) • Supply options • Supply vulnerability • Climate change/variability • Ecological concerns • Urban vs. agricultural competition

2. Population growth and water • California’s population is projected to increase by more than 50% by 2025 (1995 as base year) – faster than any other state. • This rate-of-growth = roughly half a million new residents per year (Department of Finance, 2007). • Over half this growth will occur in hotter inland counties. This is likely to increase urban water demands 50-60%. Significance? • These are areas characterized by high evapo-transpiration rates. • Also, regions where water conservation methods not widely utilized.

3. Precipitation patterns in California 1961-1990 – Cal DWR

4. Per capita water use by region of state

5. Supply options for California Likely future Source: California Water Plan Update, 2005 (CA DWR)

6. Traditional solutions - more dams? Number and size of reservoirs completed by decade

7. Supply vulnerability • Between 20 - 30 million Californians rely on: • State Water Project (SWP) • Central Valley Project (CVP) • Both are vulnerable from events that could precipitate sudden disruptions in supply (e.g., seismic events, floods, acts of terrorism). • 17 million rely on Colorado River: • California must reduce its previous reliance on 4.4 million acre/feet to under 3 million acre feet. • Draws attention to need for “new” sources of water (e.g., waste-water reuse, conservation).

8. Diamond Valley Reservoir – one example of how to respond to vulnerability • Built in Riverside county (1999) to provide “critical water storage for MWD of S. California,” south of Delta and West of San Andreas fault. • Capacity at full pool = 800,000 acre/feet or enough water for 3.2 million (enough for 6 months emergency supply in event of an earthquake.)

9. Climate change impacts to California’s water • 1. less spring snowmelt • 2. more winter runoff • 3. runoff not storable due to flood control needs • 4. Less snowmelt = lower early summer storage; less hydro-power • 5. Sea level rise: levee problems in Delta; more saltwater intrusion; adverse effects on coastal marshes, wildlife.

10. California, water, and climate change • Likely to change precipitation patterns – already difficult to forecast in a state where 80% of water goes for agriculture. • Climate change could raise the elevation of snow levels with reduced spring snowmelt and more winter runoff: • Added winter runoff not storable because of flood control needs. • Less snowmelt = lower early summer storage at foothill reservoirs. • Less hydroelectric power production. • Higher temperatures + reduced snowmelt = less suitable cold water habitat for salmon; higher temperatures will increase demand for water by plants. • Greater frequency of large damaging fires. • Sea level rise.

11. Sea level rise Source: California EPA – Golden Gate tidal gauge at entrance to San Francisco Bay • Sea level rise: • Affects Sacramento/San Joaquin Delta levees; more saltwater intrusion. • Could adversely affect many coastal marshes and wildlife reserves.

12. Integrated water management • Goal: balance water supply and demand by identifying feasible alternatives that meet the test of least cost without sacrificing other needs. • Principal Methods: • Demand management by utilities (e.g., conservation pricing) – discussed previously. • Depleted aquifer recharge/seasonal groundwater recharge. • Wastewater reuse/recycling. • Regional planning & collaboration to capitalize on existing resources, eliminate duplication, manage growth, avoid cost of new supplies.

13. Aquifer recharge • Becoming more popular – locally as well as world-wide • Orange County, Los Angeles • Advantages: • Permits sensible storage, seasonally-needed supplies. • Re-fill during wet seasons; use during dry periods – “conjunctive use.” • Storage serves multiple purposes (e.g., preventing salt water intrusion). • Disadvantages: • Costly – can be more expensive than surface water storage.

14. Anaheim Lake, Orange County Water District recharge basin. • One of 9 deep recharge basins in O.C – on Santa Ana River. • Fishing and recreation permitted. • Shoreline is a “conservation easement” designed to control development, ensure high-quality runoff.