Climate Change A n o t h e r F a c t o r i n M a n a g i n g S o u t h e r n C a l i f o r n i a s W a t e r R e s o u r c e s Lauma M. Jurkevics - DWR, Southern Region Senior Environmental Scientist USEPA-Region IX, Extreme Events and Climate Adaptation Planning Workshop April 1, 2015
Topics to Cover California Climate Current Trends and Observations Projections and Impacts Adaptation Wrap-Up
California Climate
California s topography affects our weather and climate Mediterranean climate (warm, dry summers & cool, wet winters) Lots of variability
Annual Precipitation Map
Storms and California Water Supply Just a few storms each year are the core of California s water supplies Dettinger et al., 2011
Key Phenomena Affecting California Water Supply/Flooding Storm Track changes Cyclogensis L Flooding & water supply MJO/Tropical Convection Easterly Wave ENSO The Size of the AR Results from the Alignment of Key Processes The Absence of AR Activity Important to Drought
Current Trends and Observations
High variability, no trend 11 year Mean WRCC s California Climate Tracker
Decadal Scale Variability 70 60 50 40 30 20 10 0 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Los Angeles County Sonoma Mendocino 8 Station Index 5 Station Index
Other Observations Warming Trend Less snow/more rain; changing snow thresholds Less Snowpack Earlier snowfed streamflow Earlier greenup dates; more tree mortalities; enhanced wildfires Animals moving north Mike Dettinger, USGS and SIO/UCSD
Indicators of Climate Change in California 36 indicators Decreasing spring snowmelt runoff Rising sea levels along the coast Shrinking glaciers Increasing wildfires Warming lakes and ocean waters Gradual migration of many plants and Cal/EPA and Health Hazards animals to higher elevations
GISS analysis of global surface temperature change. Base period = 1951 1980. Green vertical bar is estimated 95% confidence range. Source: update of Hansen et al., GISS analysis of surface temperature change.
South Coast Hydrologic Region Temperature Increases (F) During Past Century 4 3.5 3 2.5 2 1.5 1 Coastal Lo Coastal Hi Interior Lo Interior Hi 0.5 0 Avg Temp Nighttime Min Daytime Max Western Region Climate Center, 2013
Runoff (million acre-ft) Monthly Average Runoff in San Joaquin River System 1.6 1.4 Runoff is dominated by snowmelt 1901-1955 1956-2007 1.2 1.0 Increasing winter runoff, decreasing spring runoff 0.8 0.6 0.4 0.2 0.0 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Month
Projections and Impacts
Heat Days (Greater than City of Los Angeles 95 F)
Heat Days (Greater than 95 F) Southern CA
Declining Snowpack in SoCal (source: Sun, et. al, 2012, UCLA & LARC) With Mitigation of GHGs Without Mitigation of GHGs
In the Next 35 Years 25-40% reduction in snowpack Less summer runoff More intense wet and dry periods Increased salinity in the Delta Less supply and predictability of water resources for urban, agricultural and environmental uses More frequent and intense wildfires 5 to 24 inches rise in sea level
Five Major Impacts to Water Resources in CA Shift in runoff patterns resulting in more winter runoff and less spring and early summer runoff Sea level rise with levee and salinity problems in the Delta and low coastal areas Bigger floods due to larger winter rainflood producing areas and more water vapor in storms Somewhat higher crop and landscape water needs Water temperature problems for cold water fish like salmon and steelhead
Adaptation
Statewide Strategies Practice and promote integrated flood & water supply management Enhance and sustain ecosystems Expand water storage and conjunctive management of surface and groundwater resources Fix Delta water supply, quality and ecosystem conditions
http://www.water.ca.gov/climatechange/cchandbook.cfm
CC Handbook for Regional Water Planning Vulnerability Assessment Checklist Water Demand Water Supply Water Quality Sea Level Rise Flooding Hydropower Ecosystem and Habitat Vulnerability
Climate Change and Water Management Adaptation Strategies Urban infrastructure upgrades Water use efficiency Groundwater recharge Watershed restoration Floodplain restoration to improve hydrologic function Wetland, vernal pool, riparian restoration Invasive species management Native plant revegetation
California Water Plan, Update 2013 Climate Change Content Volume 1: CA Water Today Statewide Adaptation and Mitigation Volume 2: Regional Reports Volume 3: Resource Management Strategies
Water and Energy Connection Blue circles: Water in Energy Orange Circles: Energy in Water
Wrap-Up
http://www.water.ca.gov/climatechange/
For More Information California Department of Water Resources Data http://www.water.ca.gov/nav/index.cfm?id=106 California Data Exchange Center (CDEC) Basin-specific climate data Water quality Groundwater California Water Update 2013 http://www.waterplan.water.ca.gov/cwpu2013/final/ index.cfm
Take Home Points Variability (climate, topography, elevation) in California Trends evident (temp, runoff, snowpack) Strategies and resources exist to adapt to changes