California Water IssuesCalifornia Water Issues

AGST 3000AGST 3000Agriculture, Society and the Natural WorldAgriculture, Society and the Natural World

www.water-ed.org/cabriefing.aspwww.water-ed.org/cabriefing.aspwww.dwr.water.ca.gov/www.dwr.water.ca.gov/

Look at the those websites and…Look at the those websites and…

From the first site, read…”A Briefing on California Water Issues”From the first site, read…”A Briefing on California Water Issues”

Search the second sight and provide details on the Central Valley Search the second sight and provide details on the Central Valley Project:Project:

Who is the Central Valley Project operated by?Who is the Central Valley Project operated by? How many reservoirs are part of the CVP and how many acre feet How many reservoirs are part of the CVP and how many acre feet

do they hold and are delivered in an average year?do they hold and are delivered in an average year? In contrast, How many reservoirs are part of the State In contrast, How many reservoirs are part of the State Water Project and how many acre feet do they hold and are Water Project and how many acre feet do they hold and are

delivered in an average year?delivered in an average year? How many farmed acres does the CVP irrigate?How many farmed acres does the CVP irrigate? How many people does the CVP provide drinking water for?How many people does the CVP provide drinking water for? In contrast, what percentage does the SWP deliver to urban vs. In contrast, what percentage does the SWP deliver to urban vs.

agriculture?agriculture?

Water TerminologyWater Terminology

Acre-feet Acre-feet

An acre-foot equals the amount of water needed An acre-foot equals the amount of water needed to cover an acre of land to the depth of one foot to cover an acre of land to the depth of one foot (326,000) and is approximately the amount of (326,000) and is approximately the amount of water used by an average water used by an average family of four during family of four during two year period.two year period.

OverdraftOverdraft

The deficit between pumped water from a The deficit between pumped water from a groundwater basin and the long-term groundwater basin and the long-term recharge.recharge.

California’s Tug of WaterCalifornia’s Tug of Water

Geologic TugsGeologic Tugs

Geologic Tug #1:Geologic Tug #1: The North 75%– 25% South The North 75%– 25% South precipitation distribution circumstanceprecipitation distribution circumstance

Geologic Tug #2:Geologic Tug #2: The Coast Range and Sierra The Coast Range and Sierra Nevada Mountains rain shadow effectsNevada Mountains rain shadow effects

Geologic Tug #3:Geologic Tug #3: The Drought/Flood cycles The Drought/Flood cycles

Geologic Tug #4:Geologic Tug #4: Calif. is the number 1 ground Calif. is the number 1 ground water using state, but has little regulationwater using state, but has little regulation

California’s Tug of WaterCalifornia’s Tug of Water

Water Use TugsWater Use Tugs

Water Use Tug #1Water Use Tug #1: 80% of water demand occurs south of : 80% of water demand occurs south of Sacramento North versus SouthSacramento North versus South

Water Use Tug #2Water Use Tug #2: There is also an East versus West use : There is also an East versus West use conflict conflict

Water Use Tug #3Water Use Tug #3: Water demand is highest in the : Water demand is highest in the summer when availability is lowestsummer when availability is lowest

Water Use Tug #4:Water Use Tug #4: Environmentalists idea on water use Environmentalists idea on water use versus water developers ideasversus water developers ideas

Water Use Tug #5:Water Use Tug #5: Agriculture versus Urban use: who Agriculture versus Urban use: who gets how much and when, etc.?gets how much and when, etc.?

Water Use Tug #6:Water Use Tug #6: What are the water rights for various What are the water rights for various interest groups in the future?interest groups in the future?

Figure 1. Freshwater Consumption as a Percentage of Local Figure 1. Freshwater Consumption as a Percentage of Local Average Annual Precipitation. (Source: USDA-NRCS, 2001) Average Annual Precipitation. (Source: USDA-NRCS, 2001)

California’s Water SupplyCalifornia’s Water Supply

California’s ground waterCalifornia’s ground water California’s groundwater basins store about 850 million California’s groundwater basins store about 850 million

acre-feet of water. (Less than 50% is unavailable for use acre-feet of water. (Less than 50% is unavailable for use due to depth of water table.)due to depth of water table.)

Groundwater cannot be removed that will not be Groundwater cannot be removed that will not be replenished.replenished.

15 million acre-feet of groundwater is pumped each year.15 million acre-feet of groundwater is pumped each year. 20% of the state’s water requirements are met with 20% of the state’s water requirements are met with

pumped groundwater.pumped groundwater. CA is operating on a CA is operating on a 1.3 million acre-foot overdraft.1.3 million acre-foot overdraft. CA groundwater is recharged by:CA groundwater is recharged by:

1) Nature – rain & snow (7 million acre-foot annually)1) Nature – rain & snow (7 million acre-foot annually) 2) After usage – agriculture & industry (6.65 million acre-feet 2) After usage – agriculture & industry (6.65 million acre-feet

annually)annually) 3) Recharge programs3) Recharge programs

California’s surface waterCalifornia’s surface water Comes from an average annual statewide Comes from an average annual statewide

precipitation of almost 24 inches. (Ranging from precipitation of almost 24 inches. (Ranging from almost nothing in the deserts to more than 100 almost nothing in the deserts to more than 100 inches in the northern mountains)inches in the northern mountains)

Sixty percent of the precipitation is evaporated Sixty percent of the precipitation is evaporated or transpired by trees and vegetation. The or transpired by trees and vegetation. The remaining forty percent equals about 71 million remaining forty percent equals about 71 million acre-feet of stream flow.acre-feet of stream flow.

Colorado River flows diverted to California Colorado River flows diverted to California supply 4.8 million acre-feet.supply 4.8 million acre-feet.

California’s surface water continued…California’s surface water continued…

Inflow streams from Oregon add an addition 1.4 Inflow streams from Oregon add an addition 1.4 million acre-feet.million acre-feet.

This means in an average year California has This means in an average year California has available slightly more than 78 million acre-feet available slightly more than 78 million acre-feet of water.of water.

However, not all of this water can be collected However, not all of this water can be collected for use (almost 29 million acre-feet occurs in the for use (almost 29 million acre-feet occurs in the north coast region alone and much of it is north coast region alone and much of it is unavailable for use).unavailable for use).

Agriculture is the largest user of CA Agriculture is the largest user of CA water supply.water supply.

80% of developed supply80% of developed supply

28-35 million acre-feet depending on yearly rainfall28-35 million acre-feet depending on yearly rainfall

Irrigated acres Irrigated acres 20022002-8,709,353-8,709,353 19971997-8,886,693-8,886,693

Irrigated acreage is declining due to urban growth Irrigated acreage is declining due to urban growth

A large percentage of agriculture water percolates A large percentage of agriculture water percolates back into ground or streams (around 5 million acre-back into ground or streams (around 5 million acre-feet contributes to re-charge)feet contributes to re-charge)

California Water Balance Summary

For Water Years 1998, 2000 and 2001 

Where the Water Goes 1998 (Wet Year) 2000 (Avg Year) 2001 (Dry Year)

Total Supply

335.8 maf ** 194.2 maf 145.5 maf(Precipitation & Imports)

Dedicated Supply (Includes Reuse) 97.5 maf 82.5 maf 65.1 maf

Distribution of Dedicated Supply to Various Applied Water Uses

Urban Uses 7.7 maf (8%) 8.8 maf (11%) 8.6 maf (13%)

Agricultural Uses 27.7 maf (28%) 34.3 maf (42%) 34.1 maf (52%)

Environmental Water * 62.1 maf (64%) 39.4 maf (47%) 22.4 maf (35%)

* Environmental water includes instream flows, wild & scenic flows, required Delta Outflow and managed wetlands water use.

** million acre-feet

CA CA urbanurban use is about 7.8 million acre-feet. use is about 7.8 million acre-feet. One acre of houses uses approximately the same One acre of houses uses approximately the same

amount of water as an acre of agriculture cropsamount of water as an acre of agriculture crops

26 million acre-feet is diverted to 26 million acre-feet is diverted to environmentalenvironmental uses during normal years less in drought years)uses during normal years less in drought years) 9.56 million acre-feet for the Delta9.56 million acre-feet for the Delta 17.8 for wild and scenic river flows17.8 for wild and scenic river flows This amount is expected to increaseThis amount is expected to increase

Regional water use:Regional water use:

Central ValleyCentral Valley 19 million acre-feet19 million acre-feet Sacramento River Sacramento River 11.7 million acre-feet11.7 million acre-feet South Coast South Coast 4.6 million acre-feet4.6 million acre-feet Colorado River Colorado River 4 million acre-feet4 million acre-feet

The earth’s water supplyThe earth’s water supply……

Salt Water 97.2%Salt Water 97.2% Fresh Water 2.8%Fresh Water 2.8% Ground Water 0.6%Ground Water 0.6% Lakes and Streams 0.01%Lakes and Streams 0.01% Glaciers and Icecaps 2.2%Glaciers and Icecaps 2.2% Water Vapor 0.001%Water Vapor 0.001%

Chronology of Water in Chronology of Water in CaliforniaCalifornia

Refer to the handoutRefer to the handout

Class Discussion…after reviewing the Class Discussion…after reviewing the handout, in your opinion…handout, in your opinion…

What are some of the most significant What are some of the most significant events?events?

What is the most striking aspect of the What is the most striking aspect of the entire list of events?entire list of events?

WATER RESOURCE PROBLEMSWATER RESOURCE PROBLEMS

Too Much Water… Too Much Water…

Untimely precipitation: India gets 90% of Untimely precipitation: India gets 90% of its rainfall from June-Sept. – Monsoon its rainfall from June-Sept. – Monsoon Season results in:Season results in:

FloodsFloods Water logged soilsWater logged soils Leaches soil nutrientsLeaches soil nutrients Soil erosionSoil erosion

Figure 2. Excessive Erosion on Cropland, 1997. Each red dot represents 5000 Figure 2. Excessive Erosion on Cropland, 1997. Each red dot represents 5000 acres of highly erodible land and each yellow dot represents 5000 acres of acres of highly erodible land and each yellow dot represents 5000 acres of non-highly erodible non-highly erodible (USDA-NRCS(USDA-NRCS 20012001))

Floods are also beneficial…Floods are also beneficial…

Provide nutrients to farmland located in Provide nutrients to farmland located in the flood plainthe flood plain

Recharge groundwaterRecharge groundwater Refill wetlandsRefill wetlands Keep waterways flooding during droughtsKeep waterways flooding during droughts Provide fish and wildlife habitatProvide fish and wildlife habitat

Floodplains… Floodplains… a magnet for human settlementa magnet for human settlement

Fertile soilFertile soil Close to water for domestic and agricultural uses Close to water for domestic and agricultural uses

and as source of transportation and as source of transportation Usually a flat area suitable for farming, buildings, Usually a flat area suitable for farming, buildings,

highways, railroads, etc..highways, railroads, etc.. But, these areas are referred to as floodplains But, these areas are referred to as floodplains

for a reasonfor a reason Floods kill many people annually and are Floods kill many people annually and are

responsible for billions of $ in property damageresponsible for billions of $ in property damage

Too Little Fresh Water…Too Little Fresh Water…

DroughtsDroughts Most damaging natural hazard Most damaging natural hazard Since 70’s, 24,000 people/yr. killedSince 70’s, 24,000 people/yr. killed 40% of world’s pop. live in 80 arid/semiarid 40% of world’s pop. live in 80 arid/semiarid

countriescountries

At risk areas include…At risk areas include… N. Africa, parts of India, N. China, Middle East, N. Africa, parts of India, N. China, Middle East,

Mexico, parts of W. U.S., & much of former U.S.S.R.Mexico, parts of W. U.S., & much of former U.S.S.R.

Potential causesPotential causes DeforestationDeforestation OvergrazingOvergrazing DesertificationDesertification Natural vegetation replacementNatural vegetation replacement

Impact of global warmingImpact of global warming Water will be a foreign policy issueWater will be a foreign policy issue

Water IssuesWater Issues

Allocating more water for fish and wildlifeAllocating more water for fish and wildlife Population GrowthPopulation Growth Water ConservationWater Conservation The Bay-DeltaThe Bay-Delta Colorado RiverColorado River Water MarketingWater Marketing Groundwater Overdraft and ContaminationGroundwater Overdraft and Contamination Agricultural DrainageAgricultural Drainage Class Discussion…Class Discussion…