190 likes | 503 Vues
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.
E N D
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. • Families – human factor, showers, dishes, swimming pools and golf courses. • Manufacturing – processing, cooling produce jobs for the state which generate a tax base.
Water Terminology Acre-foot 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. Overdraft The deficit between pumped water from a groundwater basin and the long-term recharge.
Where Southern CaliforniaGets its Water Water Banking / ExchangesTransfers & Storage Local Supplies LA Aqueduct State Water Project Supplies Colorado River Aqueduct Supplies Recycling Conservation Groundwater
California’s Tug of Water Geologic Tugs 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
California’s Tug of Water 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 Water Supply 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
California’s surface 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.
California’s surface water continued… 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).
Agriculture’s Water 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)
Urban and Environmental Water Use 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
Regional Water Use 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
Sources of Water • Rain and Snow replenishes the surface water and underground aquifers • Ground Water (aquifers) • Surface Water (rivers, lakes, reservoirs)
Sources of Surface Water California, there are two major arteries serving as the sources of surface water for urban and agricultural areas: • The Sacramento-San Joaquin Delta (Bay-Delta) and • The Colorado River
The Delta • Delta serves as a major water source for approximately two-thirds of the state – over 22 million people • The region is fed by two major rivers: the Sacramento from the north and the San Joaquin from the south
Federal Central Valley Project • FDR and U.S. Reclamation Service looking for projects, took over CVP in 1935, began construction in 1937 • Eventually completed in 1950’s • Final cost more than $500 million • Distributes more than 3,000,000 acre feet of water • Almost all used for agriculture • No connections to Southern California initially
The Colorado River • Colorado River winds its way through the southwestern United States before terminating in the Gulf of California in Mexico. • Provides water to seven states including California, with each state's water use determined by the Colorado River Compact of 1922. • California permitted to use 4.4 million acre-feet annually. • For over a decade, California has been using well beyond the 1922 allotment. • As water conditions have tightened in several of the other states, agreements were reached in 2003 requiring that California reduce its use of the Colorado River - a major challenge to river water users.