California's Water Problem

California's Water Problem
Table of Contents
Table of Contents

California, a state with a population of around 40 million, is grappling with a severe water crisis that has far-reaching implications for its people, agriculture, and economy. In this engaging exploration, we'll delve into the root causes of the crisis, examining the state's unique geography, climate, and the demands of its massive agricultural industry to understand this complex issue.

Historical Perspective

From ancient times, California has faced water issues mainly due to its uneven distribution of water resources. The northern third of the state, with only 20% of the population, receives around 75% of the state's water supply. In contrast, the lower two-thirds, housing the remaining 80% of the population, relies on a mere 25% of the water supply. This inherent imbalance has necessitated an intricate network of canals, aqueducts, and pipes to transfer water from the north to the south.

Thirsty Giant: California's Agricultural Industry

California's agricultural industry consumes a staggering 80% of the state's water supply. With an annual value of $50 billion, it produces about one-third of America's vegetables and two-thirds of the country's fruits and nuts. The central valley alone contributes more than 8% of America's entire agricultural output by value and provides roughly 25% of the nation's food supply while adding $20 billion into California's economy.

Over 250 different crops are grown in California, with almonds being the most high-profile, accounting for 80% of the worldwide supply and worth around $5 billion per year. Almonds alone consume about 17% of California's total water supply, while all nuts account for around 20%. Additionally, 15% of the water is used to grow alfalfa for cattle feed, and 9% is utilized for livestock pasture. Despite the high water usage, demand for almonds has grown tremendously in recent years, with production increasing by over 8 times since 1995. Today, almonds make up about 25% of California's entire agricultural exports and are in high demand in faraway places like India, East Asia, and Europe.


California's water challenges can be traced back to its unique geography and climate. The state receives most of its water from rain and snow, brought by westerly winds from the Pacific Ocean. These winds initially impact California's high mountain ranges, such as the Sierra Nevada, the Cascades, and the Klamath Mountains. The air rises, cools, and forms precipitation, making some of the rainiest parts of the state the western-facing sides of these mountain slopes.

The Rain Shadow Effect: A Tale of Two Climates

Northwestern California has a temperate climate, with average annual rainfall rates of 1,300 millimeters - more than double the average rainfall in London. However, the rain shadow effect caused by the state's mountainous geography leads to much drier conditions east of these mountains. The westerly winds carrying moisture cannot climb higher than the tall peaks, resulting in substantially less rainfall and snowfall in these areas. Consequently, the Sonoran and Mojave deserts make up most of the land east of the mountains.

The Water Distribution Puzzle

North vs. South: About 75% of California's water supply comes from the northern third of the state, where only 20% of its population resides. Conversely, 80% of California's population lives in the lower two-thirds of the state, where only 25% of its water supply originates. This uneven distribution necessitates the transfer of massive water volumes from the north to the south to meet the larger demand.

On average, California receives approximately 200 million acre-feet of water per year through precipitation and imported water. About half of this amount is lost through natural processes such as evaporation or runs off into the Pacific Ocean. The remaining half is consumed by humans, with agriculture accounting for approximately 80% of the water usage and other activities using the remaining 20%. This means that humans use around 100 million acre-feet of water per year in California, although this number can vary greatly depending on the amount of precipitation received in a given year. In fact, this amount can fluctuate by up to 40 million acre-feet or about 40%, which is equivalent to the amount of water needed to submerge the entire state of West Virginia under a foot of water.

California's Water Engineering Solutions

During the early and mid-20th century, California built an extensive network of canals, aqueducts, and pipes to address the uneven water distribution. The Central Valley Project and the California State Water Project are the backbone of this system, designed to move water southward for agriculture and the heavily populated areas of Los Angeles, Orange County, the Inland Empire, and San Diego.

The Los Angeles Aqueduct and the Colorado River Aqueduct supplement this system, drawing water from the Owens River in the Eastern Sierra Nevada and the Colorado River, respectively.

The city of Los Angeles came up with a clever idea to use "shade balls" around 96 million of them to help prevent evaporation and harmful chemical reactions caused by sunlight.

Lake Mead

Lake Mead is an essential source of water and hydroelectric power for millions of people in the western United States, including California. The state relies on Lake Mead for a significant portion of its drinking water, irrigation for agriculture, and power generation. However, the ongoing drought conditions and increased demand for water have caused the lake's water levels to decline, which has led to concerns about potential water shortages in California. The recent "Minute 323" agreement between the US and Mexico has allowed for the release of water from Mexican reservoirs into Lake Mead, providing some relief to the drought conditions in the region and ensuring a continued water supply for California.

How Minute 323 benefits Mexico 

Firstly, it provides the country with a reliable means of storing water in Lake Mead, which is located on the border between Arizona and Nevada. This helps Mexico to better manage its own water resources by allowing the country to store water during times of plenty and withdraw it during times of scarcity.

Secondly, the agreement allows Mexico to continue to meet its own water needs while also fulfilling its obligation to deliver water to the United States under a separate agreement called the 1944 Water Treaty. This ensures that both countries are able to meet their water needs and fulfill their obligations under the treaty in a sustainable and equitable manner.

Finally, the agreement includes provisions for environmental restoration projects in the Colorado River Delta region of Mexico. This will help to restore critical habitats and ecosystems in the area and improve the health of the delta's ecosystems, benefiting both Mexico and the United States.

The Ongoing Mega Drought: Straining Water Resources

Since 2000, the American Southwest has experienced a "mega drought," with the 22-year period being the driest on record. This drought has severely impacted California's water supply, causing reservoirs like Lake Shasta, Lake Oroville, and Lake Mead to approach dangerously low levels. In 2021-2022, snowmelt into California's rivers, streams, and reservoirs was just 38% of its usual volume.

La Nina and Its Effects on California

La Nina has played a significant role in exacerbating California's water crisis. This meteorological event, characterized by cooler-than-usual northern Pacific waters, reduces evaporation rates and nudges the polar jet stream further north across British Columbia and Washington state. This shift dramatically reduces the winds and moisture that typically reach California from the Pacific, leading to less rainfall and higher temperatures. The resulting atmospheric temperature increase intensifies evaporative stress, quickly depleting soil moisture and leading to even hotter temperatures. This creates a vicious cycle that is challenging to break short of the La Nina event itself coming to its natural conclusion, which can often take months or even years.

California's water crisis is a complex problem rooted in the state's geography, weather patterns, and agricultural demands. The years long mega drought, coupled with La Nina events and the state's intricate water distribution system, has strained California's water resources to a breaking point. On the brighter side, in 2023 California had a great stormy winter season that caused 12 of the 17 reservoirs filled to their historical averages.

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