California's Water Supplies

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California's Water Supplies

• 75 of runoff occurs in north
• 72 of consumptive use in south

Sacramento-San Joaquin Delta Watershed
http//www.water.ca.gov/maps/allprojects.html
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NORTH
San Joaquin R
Delta
Sacramento R
Bay
In today's State-scale water-supply system, the
Delta is the critical, but weak, link between
North South
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• The Delta is a 2200 km2 maze of
• Farms
• Channel sloughs
• Marshlands
• Suburban
• Encroachment

all sitting very near sea level with water held
in place by aging, poorly engineered levees
50 km
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High quality Sacramento River
Delta as the North-South Meeting Place of Waters
?
Salty seawater
Low quality San Joaquin River
Water pumped south
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• The Big Gulp
• In the event of several major levee breaches,
  sea water is expected to flow in and cutoff
  passage for southbound freshwater flows to the
  export pumps in the southern Delta ()
• Sea-level rise, increased flood flows, aging
  levees, earthquakes together offer an estimated
  60 chance of this happening by 2050 (Mount
  Twiss, 2005)

The Big Gulp
Florsheim Dettinger, 2005
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ECOSYSTEMS Endangered fisheries, shrinking
wetlands declining landscapes have devastated
the once-rich ecosystems of Central California.
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DRIVERS of DELTA CHANGE

• Land subsidence
• Invasive species
• Population growth urbanization
• Earthquakes
• Climate change
• Sea level rise

Pelagic organism declines (POD) Less reliable
water supplies Deteriorating water
quality Threats to agriculture, communities
infrastructure corridors
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CALFED AGENCIES
California Resources Agency DWR, DFG, Reclamation
Board, Delta Protection Commission, Dept of
Conservation, SF Bay Commission California
EPA State Water Resources Control Board Cal Dept
Health Services Cal Dept Food Ag Western Area
Power Administration
US Dept Interior Bureau of Reclamation, Fish
Wildlife, Geological Survey, Bureau of Land
Mgmt US EPA Army Corps of Engineers US Dept of
Agriculture NRCS, Forest Service US Dept of
Commerce National Marine Fisheries Service
CALFED GOALS

• Restore ecosystems
• Improve levee stability

• Improve water supply reliability
• Protect water quality

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What should the future Delta look like?
Mount, Twiss Adams, 2006
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• Business as Usual?
• Ecosystem's piece of the Pie?
• Crumbling Levees "The Big Gulp"

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• Fortress Delta?
• Astronomical cost!
• Sea-Level Rise Receding Targets
• Ecosystems are adapted to variable flows
  salinity (not Delta as concrete canal)

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• Abandoned Delta?
• Peripheral Canal !
• (Voters rejected in 1982)
• Ecosystem or sewer?
• 560,000 acres of prime agriculture 2B
  (in-Delta) agricultural economy

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• Restored Delta?
• Restored to what?
• Sea level rise, invasive species sediment
  supply
• Would this provide water supply reliability?
  Infrastructure corridors?

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What should the future Delta look like?
Mount, Twiss Adams, 2006
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• Some Lessons Learned
• Sediment budget is critical for both (estuarine)
  sustainability restoration. Indeed, budgets
  (water, sediments, "food", land use, hydrodynamic
  power, chemical, ) generally are key and
  difficult integrative measures/controls on S R.
• Estuarine ecosystems, water quality
  sustainability require variability (no single
  optimal state)
• Hydrodynamic residence times!
• Levees not only aren't really sustainable
  framework but also do harm to ecosystems
• Protection of quality of sources (water,
  sediment, etc) is always more efficient than is
  remediation
• All solutions are provisional and should include
  the seeds of their own future adaptations/revision
  s

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Delta Visions

• 3. Re-governance the Delta
• 4. STOP suburbanization!
• 5. Armored levees where needed (human life),
  abandoned levees for ecosystems over-toppable
  levees for agriculture
• 6. Variable flow regimes geomorphology
• 7. Leaky peripheral canal variable salinity
  Delta
• 8. Carbon "farms"?

• Coequal water supply ecosystem goals
• 2. Dual conveyance facilities (instead of BAU or
  isolated Delta, both!)

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But, do we know enough to redesign the Delta this
way? Designing the information sources flows
is key!