Transcript - Catalyst

Water Wars in California
“Whiskey’s for drinkin’ and water’s
for fighting for….”
Mark Twain
Definition
• An acre foot is enough water to cover 1 acre
with 1 foot of water
– Roughly 360,000 gallons or 1 million liters
• NGO - non governmental organization
• ESA Endangered Species Act
California sources of water
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Rainfall
Snow melt from mountains
Groundwater
Imports from Colorado River
• Most rainfall is in
the north where
there is little
demand and
runs to the
ocean
• There is little
rainfall or snow
in the
agricultural
areas or the
populated places
California Water Facts of Life
• The rainfall is 75% in the north
• The coast range provides a rain shadow for the
central valley
• Great year to year variation in rainfall due to El
Nino and La Nina climate changes
– So there are very wet and very dry years, dry years are
when the water crunch hits
– El Nino is associated with particularly wet years
– La Nina produces mixed results, dryer over most of
the state but wetter in the N. coast
Hydrologic region
Annual precipitation
Annual runoff
North Coast
55,900,000 acre feet
28,900,000 acre feet
Sacramento River
52,400,000 acre feet
22,400,000 acre feet
North Lahontan
6,000,000 acre feet
1,900,000 acre feet
San Francisco Bay
5,500,000 acre feet
1,200,000 acre feet
San Joaquin River
21,800,000 acre feet
7,900,000 acre feet
Central Coast
12,300,000 acre feet
2,500,000 acre feet
Tulare Lake
13,900,000 acre feet
3,300,000 acre feet
South Lahontan
9,300,000 acre feet
1,300,000 acre feet
South Coast
10,800,000 acre feet
1,200,000 acre feet
Colorado River
4,300,000 acre feet
200,000 acre feet
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.
Central valley agriculture
• On 1 percent of US farmland 8 percent of the
value of US crops are produced
• Initial development was in the delta where
there was plenty of fresh water but later
development provided irrigation to almost all
the valley
To get the water where the need is
• Three major projects
• The Central Valley Project: moves water from
the Sacramento River to the south about 7
million acre feet almost all to agriculture
• The State Water Project: 2.3 million acre feet
70% goes to urban use
• Colorado River diversions, about 4 million acre
feet per year
Another look at the delta
Farming in the delta
On the ground projects: dams
Diversions
The result
• In dry years the San Joaquin river goes dry
• In dry years when pumps are running at full
power, the delta flows backwards, towards the
pumps, not towards S.F. Bay
Environmental impacts
• Fish
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Loss spawning habitat
Reduced flows – slower migration
Changed ecosystem
Direct mortality at pumping stations
Changes in the delta with reduced flows
Erosion
Pollution
Salinization
Lost Habitat
Steelhead
Winter run chinook
Spring run chinook
Delta smelt
Fall run chinook
Discussion question
• If the only way to continue exporting water to
farms and communities will lead to the
extinction of the delta smelt
• A. The food and water for communities is too
important and this species should be allowed
to disappear
• B. We have to cut back water use in order to
save the species.
Pollution
• The irrigation water carries great quantities of
fertilizer, herbicides and pesticides into the
ground water and rivers
The transformation of the delta
• Levees and farming have totally changed the
ecosystem
• Exotic species have replaced most native
species, from striped bass to the zooplankton
• Water withdrawals have totally changed the
hydrology
Subsidence in the delta
Subsidence from groundwater
pumping near Santa Ana
Salinization
Erosion
• Irrigation increases rates of soil erosion
The water wars
• Primary battles are North vs South
– Further projects
• Water users (agriculture and cities) vs
environmental concerns represented by NGOs
and Federal and State agencies
– ESA (Endangered Species Act) listing of delta
smelt, and several runs of chinook salmon
– The main conflict is in dry years
Summary
• California agriculture is a miracle of modern
technology, providing a significant portion of
the nations fruits and vegetables
• But it has come at a very considerable
environmental cost
• What is the right balance?
Take away points
• In many places water is in short supply,
demand exceeds supply
• There are trade-offs between food production
and impact on the environment
• Water use is inefficient – we can have our cake
and eat it too if we had better ways or
allocating water
Other water wars in U.S.
• Columbia River – fish vs power, agriculture,
and barge traffic
• Colorado River – fights over who gets the
water
• Ogallala Aquifer in great plains
– Fights over who gets it
Study Guide
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What are the major sources of water for California agriculture? Rainfall, runoff from snow melt in the mountains,
groundwater, imports from the Colorado River.
Where does most of the precipitation fall in California? In the north coast and in the mountains.
What is the importance of El Nino, La Nina to California agriculture? In El Nino years there is above average
precipitationl
What is the importance of the delta to California agriculture? It is an important producing area, and provides the
source of most water withdrawn to send to southern agriculture and cities.
What is the difference between water allocation in wet and dry years? In dry years the amount of water used for
cities and agriculture increases slightly, causing a major reduction in the amount of water available for
environmental flows.
How do the major water projects affect chinook salmon? Dams eliminate spawning habitat, water withdrawals
impede migration and cause direct mortality when juvenile salmon are sucked into water diversions.
How many acre feet per acre of land are applied as irrigation water in central valley farms? 2 to 3 acre feet per
acre.
What is subsidence? The dropping of soil levels because of groundwater withdrawals and diking and farming.
How does salinization occur and what are its consequences? Salinization is the accumulation of salts in the soil
from irrigation -- the irrigation water has salts in it, the water evaporates and leaves the salts. As salt
concentrations increase, the soil becomes less suitable for crops and yields decline.
sources
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Biological Assessment on the Continued Long-term Operations of the Central Valley Project and the State Water Project.
U.S. Department of the Interior Bureau of Reclamation