California Water . California Association of Food Banks October 14, 2010 By: Adan Ortega, Jr. California’s Major Water Users:. Agriculture – irrigated farm land, a huge economic engine for the state. Environment – fish and other wild life have specific water requirements.
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California Association of Food Banks
October 14, 2010
By: Adan Ortega, Jr.
An acre-foot equals the amount of water needed to cover an acre of land to the depth of one foot (326,000 gallons) and is approximately the amount of water used by an average family of four during one year.
The deficit between pumped water from a groundwater basin and the long-term recharge.
Where Southern CaliforniaGets its Water
Water Banking / ExchangesTransfers & Storage
State Water Project Supplies
Colorado River Aqueduct Supplies
Geologic Tug #1: The North 75%– 25% South precipitation distribution circumstance
Geologic Tug #2: The Coast Range and Sierra Nevada Mountains rain shadow effects
Geologic Tug #3: The Drought/Flood cycles – El Nino and La Nina
Geologic Tug #4: Calif. is the number 1 ground water using state, but has little regulation
Water Use Tugs
Water Use Tug #1: 80% of water demand occurs south of Sacramento North versus South
Water Use Tug #2: There is also an East versus West use conflict
Water Use Tug #3: Water demand is highest in the summer when availability is lowest
Water Use Tug #4:Environmental water use conflicts with agriculture, urban need.
Water Use Tug #5:Agriculture versus Urban use: who gets how much and when, etc.?
Water Use Tug #6:What are the water rights for various interest groups in the future?
California’s ground water
California’s groundwater basins store about 850 million acre-feet of water. (Less than 50% is unavailable for use due to depth of water table.)
For long term sustainability, groundwater cannot be removed that will not be replenished.
15 million acre-feet of groundwater is pumped each year.
20% of the state’s water requirements are met with pumped groundwater.
CA is operating on a 1.3 million acre-foot overdraft.
CA groundwater is recharged by:
1) Nature – rain & snow (7 million acre-foot annually)
2) After usage – agriculture & industry (6.65 million acre-feet /yr.)
3) Recharge programs – Los Angeles municipal water
Comes from an average annual statewide precipitation of almost 24 inches. (Ranging from almost nothing in the deserts to more than 100 inches in the northern mountains)
Sixty percent of the precipitation is evaporated or transpired by trees and vegetation.
The remaining forty percent equals about 71 million acre-feet of stream flow (in an average rainfall year).
Colorado River flows diverted to California supply 4.8 million acre-feet.
Inflow streams from Oregon add an addition 1.4 million acre-feet.
This means in an average year California has available slightly more than 78 million acre-feet of water.
However, not all of this water can be collected for use (almost 29 million acre-feet occurs in the north coast region alone and much of it is unavailable for use).
80% of developed supply (reservoir storage, irrigation districts, state and federal water projects)
28-35 million acre-feet depending on yearly rainfall
Irrigated acreage is declining due to urban growth and water cut backs by federal/state projects.
A large percentage of agriculture water percolates back into ground or streams (around 5 million acre-feet contributes to re-charge)
CA urban use is about 7.8 million acre-feet.
One acre of houses uses approximately the same amount of water as an acre of agriculture crops (what happens to this water?)
26 million acre-feet is diverted to environmental uses during normal years less in drought years)
9.56 million acre-feet for the Delta
17.8 for wild and scenic river flows
This amount is expected to increase
Central Valley 19 million acre-feet
Sacramento River 11.7 million acre-feet
South Coast 4.6 million acre-feet
Colorado River 4 million acre-feet
California, there are two major arteries serving as the sources of surface water for urban and agricultural areas: