Download presentation
Presentation is loading. Please wait.
Published byHugo Houston Modified over 8 years ago
1
Water Wars in California “Whiskey’s for drinkin’ and water’s for fighting for….” Mark Twain
2
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
3
California sources of water Rainfall Snow melt from mountains Groundwater Imports from Colorado River
4
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
5
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
6
Hydrologic regionAnnual precipitationAnnual runoff North Coast55,900,000 acre feetacre feet28,900,000 acre feetacre feet Sacramento River52,400,000 acre feetacre feet22,400,000 acre feetacre feet North Lahontan6,000,000 acre feetacre feet1,900,000 acre feetacre feet San Francisco Bay5,500,000 acre feetacre feet1,200,000 acre feetacre feet San Joaquin River21,800,000 acre feetacre feet7,900,000 acre feetacre feet Central Coast12,300,000 acre feetacre feet2,500,000 acre feetacre feet Tulare Lake13,900,000 acre feetacre feet3,300,000 acre feetacre feet South Lahontan9,300,000 acre feetacre feet1,300,000 acre feetacre feet South Coast10,800,000 acre feetacre feet1,200,000 acre feetacre feet Colorado River4,300,000 acre feetacre feet200,000 acre feetacre feet
7
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.
8
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
9
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
15
Another look at the delta
16
Farming in the delta
18
On the ground projects: dams
19
Diversions
20
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
22
Environmental impacts Fish – Loss spawning habitat – Reduced flows – slower migration – Changed ecosystem – Direct mortality at pumping stations Changes in the delta with reduced flows Erosion Pollution Salinization
23
Lost Habitat
24
Steelhead
25
Winter run chinook
26
Spring run chinook
27
Delta smelt
28
Fall run chinook
30
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.
31
Pollution The irrigation water carries great quantities of fertilizer, herbicides and pesticides into the ground water and rivers
32
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
33
Subsidence in the delta
34
Subsidence from groundwater pumping near Santa Ana
35
Salinization
36
Erosion Irrigation increases rates of soil erosion
37
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
38
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?
39
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
40
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
41
Study Guide 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.
42
sources 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
Similar presentations
© 2024 SlidePlayer.com. Inc.
All rights reserved.