Water

A precious, contested resource.

Watershed Health Index

The map below is about the ability of our watersheds to support ecosystems and habitats. While some drinking water systems in Southern California rely on their own watersheds, many do not.

Water Icon

The map above shows a clear relationship between urbanization and poor water quality (light blue areas). Impermeable surfaces where water can’t penetrate are part of the problem—creating lack of groundwater recharge and water filtration as well as increased flood risk.

Click on the map to find out where your neighborhood stands. Explore solutions like de-paving, daylighting, permeable surface materials, and expanding urban greenspace. Collectively, we can turn more of this map dark blue!

Where does Southern California water come from?

Water reflects everything about us. It's part of us...approximately 98% part! The water cycle is the ultimate closed loop system. But with so many compromises along the way (toxins, melting, evaporation, innundation, saline contamination), how we adapt to our changing water system is increasingly important.

Anatomy of Water Sources in Southern California

State Water Project: California Aqueduct

While the SWP produces hydropower, it is also the largest consumer of power in California with a net usage of 5,100 GWh.

Length: 705 miles
Supply: Dependent on allocation

InfrastructureUses
34 reservoirs and lakes
701 miles of aqueducts
5 power plants
24 pumping plants
27 million people
residential, municipal, industrial (66%)
750,000 acres farmland (34%)
6,500 GWh hydroelectric power annually

Southern California has a history of expanding its capacity for population growth through hydrological projects that extract water from distant watersheds. While the entire state of California is about 104 million acres, the City of Los Angeles alone accesses over 140 million acres of watershed area to supply water to its residents and businesses. Southern California is in a state of "ecological debt"--but it's a debt that is never paid back. Despite a three-fold increase in population, water savings measures such as low-flow toilets and showerheads, lawn replacements, and water catchment systems have limited water use increases, which, ironically, have occurred most recently during times of severe drought.

Los Angeles Aqueduct(s)

Owens Lake has remained (mostly) dry since the inception of the LA Aqueduct, requiring Los Angeles Department of Water and Power to spend over $1 billion in attempts to prevent the lakebed's dust from affecting the respiratory health of locals.

Length: 460 miles
Supply: 260 million gallons daily

Infrastructure Uses
34 reservoirs and lakes
701 miles of aqueducts
5 power plants
24 pumping plants
27 million people
residential, municipal, industrial (66%)
750,000 acres farmland (34%)
6,500 GWh hydroelectric power annually

Colorado River Aqueduct (California)

While California is legally entitled to 4.4 million acre feet of the Colorado River, the state has historically drawn more than its allotment. The effort to bring water from the river westward has not occured without environmental casualties. An engineering mistake in 1905 caused water from the Colorado river to breach an irrigation canal and create the Salton Sea. Further, instead of pumping water over or around Mount San Jacinto, a tunnel was blasted directly through such that water flows underneath the mountain with a seemingly unrestrainable flow that has periodically project water into various directions within the mountain.

Length: 242 miles
Supply: 1 Billion gallons daily

InfrastructureUses
150 miles of canals
5 pumping plants
90 miles of tunnels
Municipal

 

The Colorado River Basin

The Colorado River Basin, spanning around 246,000 square miles, is one of the most heavily developed basins in the world. Around 80% of the water supply is replenished by snowmelt each year; however, aridification is posing a threat to this supply, as snowpacks decrease and evaporation increases. The over-allocation of its waters have also put serious strain on the water storage of the basin, as it is shared by seven states (Colorado, New Mexico, Utah, Wyoming, Arizona, Nevada and of course, California) all with different water politics. The Colorado River is also the source of a longstanding dispute between the United States and Mexico. The river no longer drains at the Gulf of Mexico, as the flow is dry after the dam at the US-Mexico border.

Length: 1450 miles

Dams Uses
15 along main river
hundreds along tributariess
40 million people served

Local LA Rivers 

Southern California's local rivers, streams and creeks were originally used by Indigenous groups, with many villages being built along prominent rivers. Multiple rivers and creeks stll exist in Southern California, many of them have been "altered"--meaning that waterways are controlled, paved, shifted, and changed. Manh of our native rivers and creeks flowed seasonally, shifting to underground for parts of the year. Local water can't supply enough water to serve the region's needs, although familar water company names such as Yosemite (named for Yosemite Avenue in Highland Park, not for Yosemite National Park) and Sparkletts still bottle and sell local water. To date, there is no reliable inventory of how much water Southern California has on its own. Many creeks are channelized and indistiguishable from storm drains--where the water flows uselessly to "water the ocean," as Jenny Price once put it. These rivers are the underrepresented water sources of Southern California.

River Length (miles)
Mojave River 110
Santa Ana River 96
Santa Clara river 83
San Gabriel River 58
Whitewater river 54
LA River 51
San Jacinto River 42
Santiago Creek 34
Santa Gertrudis Creek (Tucalota creek) 24 (estimate)
San Margarita River 30
Temescal Creek 29
San Juan River 29
Arroyo Seco 25
San Dieguito River 24
Arroyo Trabuco 22
San Mateo Creek 22
Aliso Creek 20

Zanjas

Zanjas were the premier water system for El Pueblo de Los Angeles from the late 1700's to early 1900's, established by Spanish colonizers and the residing Indigenous groups. The Zanja Madre was the original aqueduct that supplied water to Angelinos residents and farmers. The Zanja Madre was collectively built and diverted water from what was at that time known as the Río de Porciúncula (LA River). In addition the Zanja Madre, there came to be nearly a hundred zanjas in and around the Los Angeles area, built and largely controlled by the hands of Angelenos themselves. Even then, conflict over the water in these ditches was ripe and sometimes violent. The Zanjero, a revered importante official, was the overseer of the water system who often patrolled the zanjas with a shovel in hand to remediate issues on the spot. In the late 1800's, European American ideals of closed and purportedly cleanlier water pipe systems began competing with the open air-open access ditches championed by Mexican American values of community. Eventually, the area's population and sanitation needs outgrew the zanja system completely.

Reducing our Debt

Overreliance on water resources from outside of Southern California creates a situation of “ecological debt.” Essentially, this means we are living beyond our means—a problem we have solved by taking water from other regions. Water challenges aren’t exclusive to Southern California. Increasingly, So Cal water sources from a variety of locations are also changing. But cities like Los Angeles have goals to reach 100% local water through water capture, water recycling, and water conservation. Go LA!

The Color of Water

Did you know that there are many different kinds of water? Some colors (green, blue, grey, black, and purple, below) are how we designate water types. Other color terms (red, orange, yellow, even pea soup!) are reflective of off-color water due to algal blooms or a high presence of minerals like iron.

Flip the color boxes below to find out how some of the colors of water are connected and others are connected to climate change and out-of-whack ecosystems.

Green Water

Green water is water for plants! It's in the soil where we humans and animals can't get it. That's a good thing! Imagine plant roots as special kinds of straws that the plants use to suck water and soil nutrients into their stems and leaves. Think of the term moisture. That's what green water is.

Blue Water

Blue water is water that is accessible and drinkable by you, your dog, a coyote, bugs, butterflies, and everyone else. It's on the earth's surface and can be pooled in ponds, flow along in streams and rivers, or be contained in reservoirs for human consumption. Blue water is life giving and precious!

Purple Water

Welcome to the wonderful land of water recycling! Purple pipe water is used, contaminated water that has been treated and purified and gets back out there for consumption. This system mimics what nature does, because all water is recycled through the water cycle. Sometimes people are a bit suspicious of purple pipe water, and so it tends to be used for irrigation instead of coming into people's homes. But it's an excellent and also underutilized water source that can make us less reliant on outside water imports and unneeded energy expenditures!

Pea Soup!

Pea Soup usually means an algal bloom--dangerous for human and animal health. Pea soup can be lots of different colors, odors, and textures...but it general means that the water ecosystem is way off. Increased heat is throwing ecosystems out of wack and an increase in algal blooms is a signal of some serious issues. 

Grey Water

Grey water is an underutilized water resource. Grey water can come from rainfall on your roof, your bathtub or laundry, and then can be utilized to water your garden. Grey water morphs right into green water. Given how much water our homes and businesses we use daily and how much water we use for landscaping, grey water is a double win. Using grey water also reduces energy consumption. Plants naturally filter out the impurities in grey water, which then goes back into the water cycle.

Black Water

Black water has to do with, you guessed it, poop. It's what gets flushed from your toilet down through the sewer system.  But guess what? Water treatment plants can turn black water into various other water types.

Orange/Red Water

Orange or reddish water may mean the presence of minerals such as iron. Did you know that a river turned orange in Alaska recently? Because permafrost is melting, the amount of iron in the water increased dramatically! With climate change and older infrastructure, water that changes color is increasingly common.

Yellow Water

We know what you're thinking...

And no it's not about pee. There is no simple answer to this one. Like its orange/red cousins, yellow can also mean iron. Or Manganese. Or chlorine. Or that the water systems has been recently flushed. It can mean there is decaying vegetation...so many causes of yellow water. It's usually safe to drink but try a water filter if you're uncomfortable!

Archival Resources

https://library.ucr.edu/collections/water-resources-collections-archives
https://www.csusb.edu/special-collections/collections/joseph-andrew-rowe-water-resources-archives

Get to know the Metropolitan Water District

By Celia Malone '24

 

Water as a Human Right

The Human Right to Water is one expression of the idea that "water is life/agua es vida." Explore below human causes and effects of water toxicity, availability, and stress. Our history of pesticide-heavy agriculture, military land uses, and groundwater overdraft and contamination combine with drought and climate change make water quality one of Southern California's key issues.

Adelanto: Water Justice in the High Desert

More of our favorite water projects…

Owl Swimming (1)