Return to Water Management
Introduction
|
Water management in California has evolved from the early days of indigenous populations and the first foreign settlements to our current standing as the most populous state in the nation. Because much of the state does not receive enough rainfall to sustain the growing population of early California, early inhabitants were motivated to develop water management and delivery mechanisms.
Prior to the 1900’s, Native Americans and early Californians settled within close proximity to streams, rivers and other fresh water sources, to satisfy their fresh water needs. When cities like Los Angeles and others (especially in Southern California) were booming, and agriculture surged as a top industry, construction of complex statewide systems was necessary to transport and store water. |
|
Where's the water?
Californians enjoy drinkable water (often called potable) from a variety of sources, but are primarily from surface water and groundwater.
Surface water
Approximately 70% of California’s fresh water supply originates in Northern California from precipitation and snowpack primarily from the Sierra Nevadas but also from the Klamath Mountains and lower Cascades.
The state’s largest surface ‘reservoir’ is the Sierra Nevada snowpack, and therefore, much attention is given to annual snowfall as an indicator of water supply levels. The Department of Water Resources conducts monthly snowpack surveys throughout the winter and into spring to estimate annual water supply.
Approximately 70% of California’s fresh water supply originates in Northern California from precipitation and snowpack primarily from the Sierra Nevadas but also from the Klamath Mountains and lower Cascades.
The state’s largest surface ‘reservoir’ is the Sierra Nevada snowpack, and therefore, much attention is given to annual snowfall as an indicator of water supply levels. The Department of Water Resources conducts monthly snowpack surveys throughout the winter and into spring to estimate annual water supply.
|
Groundwater
During a normal year, groundwater makes up around 30% of the total state water supply but this varies based on annual rainfall and drought (groundwater has supplied up to 60% of the state’s water in periods of drought). Some communities rely heavily on groundwater as their main potable water source. Groundwater aquifers across the state have a storage capacity of over 10 times that of the surface supply. These aquifers recharge through the water cycle as precipitation infiltrates into the soil and through manmade groundwater recharge systems. |
|
Water storage and distribution
|
Water is collected and stored in reservoirs throughout the state, where it can then enter the conveyance systems to transport it to where it’s needed. As you can see from the map, there are hundreds of reservoirs, aqueducts and canals throughout the state, which are all part of California's complex web of storage and conveyance systems. What isn’t shown on the map, and a point many people overlook, is that California’s water supply network also includes hundreds of pipelines, pump stations, and hydropower facilities.
|
Click to enlarge
|
Reservoirs
This melted snow and rain flows through streams and rivers and is ultimately captured and stored in lakes and manmade reservoirs formed by dams. By constructing a dam across a river, natural flow is constricted creating a reservoir behind it.
This melted snow and rain flows through streams and rivers and is ultimately captured and stored in lakes and manmade reservoirs formed by dams. By constructing a dam across a river, natural flow is constricted creating a reservoir behind it.
California has hundreds of reservoirs that supply water across the state. In addition to providing water storage, reservoirs also provide flood protection for downstream communities by controlling discharge flows. Dams also produce hydroelectric power, providing around 15% of California’s annual energy supply.
Conveyance System
In Southern California, water is stored in state reservoirs. In addition, water is transported from Lake Havasu on the Arizona/California border via the 200-mile Colorado River Aqueduct. The State Water Project, the nation’s largest state-built water and power development and conveyance system provides water to approximately 25 million Californians. The California aqueduct, just on piece of the project approved in 1960, meanders along interstate 5, 444 miles. Starting at the delta formed at the confluence of the Sacramento and San Joaquin rivers, water is carried to the San Joaquin Valley and on to the city of Los Angeles. |
The downsides of reservoirs Engineered reservoirs also have some undesired consequences. When a dam is constructed, the river valley behind it floods, triggering many impacts.
|
Water Management
Water management is complex, but can be simplified into three main categories: water quality, water rights, and water distribution. Several agencies, ranging from federal, state, and local levels can be involved in each of the categories
|
Water quality
As stated in Action 1, water quality is regulated at the federal level by the EPA through the Safe Drinking Water Act. The EPA relies on agencies at the state level to oversee compliance. In California that agency is the State Water Resources Control Board (State Water Board). |
|
Water rights
Since most of California’s water supply needs to be transported to end users (oftentimes long distances), who has rights to the water is a complicated issue. In early settlements, water rights were granted to individuals that owned land adjacent to the water body, called riparian rights. Later, as cities were developing further away from water sources, water rights were claimed separately and unassociated with land ownership in a first come, first serve fashion — called appropriative rights.
Disputes over water rights have plagued the state and are still a hot topic today. However, under the Water Commission Act of 1914, the California Water Board has the authority to administer water rights for California’s surface water, and is the only agency authorized to do so.
Since most of California’s water supply needs to be transported to end users (oftentimes long distances), who has rights to the water is a complicated issue. In early settlements, water rights were granted to individuals that owned land adjacent to the water body, called riparian rights. Later, as cities were developing further away from water sources, water rights were claimed separately and unassociated with land ownership in a first come, first serve fashion — called appropriative rights.
Disputes over water rights have plagued the state and are still a hot topic today. However, under the Water Commission Act of 1914, the California Water Board has the authority to administer water rights for California’s surface water, and is the only agency authorized to do so.
Water distribution
Major water managers in California
You can probably imagine that it takes extraordinary effort to carry water across the state, requiring large scale infrastructure to be built and maintained (much of it built in the early to mid-1900’s). There are three agencies that manage the largest water distribution systems in California — the Central Valley Project, under federal jurisdiction, the State Water Project, managed by the state, and the Colorado River Aquaduct, managed by the Metropolitan Water District. The remainder of surface water supply is distributed by a combination of regional wholesalers or local public agencies.
You can probably imagine that it takes extraordinary effort to carry water across the state, requiring large scale infrastructure to be built and maintained (much of it built in the early to mid-1900’s). There are three agencies that manage the largest water distribution systems in California — the Central Valley Project, under federal jurisdiction, the State Water Project, managed by the state, and the Colorado River Aquaduct, managed by the Metropolitan Water District. The remainder of surface water supply is distributed by a combination of regional wholesalers or local public agencies.
|
The Central Valley Project, managed by the United States Bureau of Reclamation, consists of a number of major reservoirs and conveyance systems that were initially built to provide irrigation water and flood protection to the Central Valley, but has expanded today to provide municipal supplies to the Greater Sacramento and San Francisco Bay Areas. Shasta Lake, the largest reservoir in the state, is part of the Central Valley Project.
|
|
The State Water Project is the largest surface water supply in California, providing water to around 27 million Californians, and is managed by the California Department of Water Resources. The State Water Project encompasses many of the reservoirs, canals and aqueducts that supply water to Southern California, including the second largest reservoir, Lake Oroville, and the longest aqueduct in the state at over 400-miles, the California Aqueduct.
|
Surface water from both the Central Valley Project and the State Water Project collect in the Sacramento River and discharge into the Sacramento-San Joaquin Delta where is distributed through a network of aqueducts and canals to local water suppliers or wholesalers. The Delta is the largest distribution site of California’s surface water supply.
|
The Metropolitan Water District of Southern California is a regional wholesaler that manages water from the Colorado River Aqueduct, delivering a significant and critical water supply to Southern California. The MWD provides water to member agencies enveloping Los Angeles, Orange, Riverside, San Bernardino, San Diego and Ventura counties.
|
Water Distributors
The federal and state agencies provide water to contractors, which are regional wholesalers, public utility agencies, cities, counties, and/or municipal water districts. Depending on the contractor, they may provide water directly to residents and end users, or they may provide water to member agencies (made up of cities and local water agencies), who then in turn provide water to end users.
The hierarchy of water management from manager to end user is shown on the following graphic.
The federal and state agencies provide water to contractors, which are regional wholesalers, public utility agencies, cities, counties, and/or municipal water districts. Depending on the contractor, they may provide water directly to residents and end users, or they may provide water to member agencies (made up of cities and local water agencies), who then in turn provide water to end users.
The hierarchy of water management from manager to end user is shown on the following graphic.
With all of the engineered water systems constructed to supply fresh water to Californians, environmental protection of ecosystems and sensitive habitats is a top priority.
Multiple agencies conduct regular water quality monitoring of all surface waters under the jurisdiction of the State Water Board, as well as implement extensive restoration projects to repair existing impacts, particularly to fish populations in streams, rivers, and the Sacramento-San Joaquin Delta.
Multiple agencies conduct regular water quality monitoring of all surface waters under the jurisdiction of the State Water Board, as well as implement extensive restoration projects to repair existing impacts, particularly to fish populations in streams, rivers, and the Sacramento-San Joaquin Delta.
Instructions
Your local water supply
Depending on where you live, your surface water supply could originate from a local reservoir, or it could travel hundreds of miles to get to your tap. In this action, you will take a closer look at the Water Supply and Storage in California map to locate the origin of the surface water supply where you live.
Depending on where you live, your surface water supply could originate from a local reservoir, or it could travel hundreds of miles to get to your tap. In this action, you will take a closer look at the Water Supply and Storage in California map to locate the origin of the surface water supply where you live.
- Print this Data Collection Sheet, and grab a pencil.
- View the Water Supply and Storage in California map.
- Follow the instructions on the data sheet to locate your local surface water supply.
- Report back to the city by clicking on the SUBMIT FINDINGS link below.
Evaluate and Report
Please submit your results to help your community plan for the future.
