Coachella Valley Groundwater Replenishment

Aquifers Refill Naturally

Groundwater Replenishment of underground aquifers is a topic which many areas do not have to discuss. In a natural normal cycle, without human intervention, this is never a concern. Natural rainfall percolates into the ground and keeps the aquifer filled.

Above: Thomas E. Levy Groundwater Replenishment Facility (TEL). In June of 2009, the TEL began percolating imported Colorado River water into the Indio Subbasin.

Aquifers In Deserts

In arid climates, such as Coachella Valley, with increasing human population, overdrawing from the underground aquifer is possible. Using more water than is percolated in is a common concern. Obtaining fresh water for human use can be an expensive undertaking. Once obtained, storage of the fresh water for the local population has options, all of which have related costs. The most expensive option is to build surface tanks to hold water. The lower cost option is to purposefully replenish or refill the local underground aquifers. Refilling local underground aquifers utilizes the existing subterranean basins and eliminates the need for building massive water tanks.

Specifically In Coachella Valley

The topic of refilling local underground aquifers is discussed on the Coachella Valley Water District (CVWD) webpage: Groundwater Replenishment & Imported Water | Coachella Valley Water District – Official Website ( There they report that Coachella Valley gets an annual average of 3 inches of rain and based on 99 years of rainfall records starting in 1922 through 2021, yes, Coachella Valley’s has received an annual average of 3 inches of rain.

Coachella Valley is the location of Palm Springs, CA. A place known for large estates, grand golf courses, and plenty of farms. All in all, this desert is bustling with human activity.

Statistics Can Be Problematic

A problem in Coachella Valley is that using the 99-year average rainfall may be causing an unintended miscalculation of the water potential. Factoring in the changing climate, looking at the data more critically, and viewing the data along its timeline instead of the whole 99-year history, Coachella Valley experiencing decreasing rainfall. In the last 20-years the average rainfall is only 2 inches rain. This is 1/3rd less rain than the historical average records.

Above is a plot of the annual rainfall for Coachella Valley, using a 20-year average applied to all the available data from 1922 to 2021. Notice how the average rainfall is decreasing over time.

Where Does Rain and Snow Come From?

When people talk about rainfall and snowpack, they do not often consider where the rain and snow originate. Of course, it comes from the sky, but where does the moisture come from to create the rain and snow. In the case of the Coachella Valley, much of that moisture originated from the Salton Sea.

When we talk about the Salton Sea, we are reminded that it is an artificial inland sea created by a 1905. Prior to its creation, the Salton Sink was a dry place, evaporating all of its annual moisture accumulation.

This is so simple. Rain comes from evaporation. What evaporates up, must rain down.

How Much Moisture

We postulate that the large surface area of the original Salton Sea was a grand evaporation pond which provided atmospheric moisture and encouraging more rain and snow for the Coachella Valley. The rainfall records we have available today begin in 1922, 17-years after the Salton Sea was created, records before that date do not exist, so we will never be able to prove this postulation. However, using the records we do have we can make a comparison of the Salton Sea surface level and the Coachella Valley annual rainfall.

Above is a plot of the Salton Sea surface level, using a 20-year average applied to all the available data from 1905 to 2021. Notice how the surface level is decreasing over time.

Compare The Two Charts

Take note of how the two charts resemble each other. As the Salton Sea surface level is decreased the annual rainfall also diminishes.

A Problem At The Salton Sea

Today, the Salton Sea surface level is steadily decreasing and may soon lose all its water and become a dry desert depression. Note that as the lake’s surface level increases, so also does its surface area. The more surface area the more evaporation occurs. Evaporation infuses the air with moisture which is needed for rain and snow in the Coachella Valley. If the natural rain and snow in Coachella Valley can be increased, the costly need for infusing water into the aquifer can be reduced. In Coachella Valley artificial replenishment/recharge of the aquifers is necessary in the short-term, but this process always has the potential to contaminate the aquifer. Natural replenishment/recharge is much better option because it preserves the aquifer water quality.

Past and projected change in Salton Sea if no intervention occurs.

Fix The Problem

It appears that increasing the surface level of the Salton Sea would benefit the people of Coachella Valley by reduced costs of aquifer recharging. Increasing the surface level of the Salton Sea has been discussed for decades, but there seems to be no interest by the Government of California to accomplish that goal.

Loss of the water in the Salton Sea has multiple detrimental side effects. The first explained above with the loss of moisture in the local atmosphere. The second is the polluted dust left behind by the evaporating water. This dust becomes airborne and becomes a human health hazard to all who live downwind from sea.

Inadequate Government Intervention

The government of California is addressing the Salton Sea, but all efforts to increase the water surface level have been dismissed. Instead, all efforts have been toward diminishing the airborne contaminants, this is called dust mitigation. This sounds like a good thing to accomplish, and billions are being spent to gain this goal, however, this is a waste of taxpayer dollars.

The dust mitigation effort is accomplished by extracting water from the Salton Sea basin and relocating that water over a larger surface area with the hope of encouraging plants to grow and thus holding the dust to the ground. The simple fact is that increasing the surface area of the water encourages more evaporation which will ultimately dry the Salton Sea sooner than if left to its natural course. Once dry, dust mitigation using the existing water will be impossible, and the Salton Sea will return to its previous state as the Salton Sink. The dust will become a human health hazard to everyone downwind from the Salton Sink.

A Better Soultion

It would be much better for the good people of Coachella Valley if California would focus on increasing the Salton Sea surface level as the best practice of dust mitigation, instead of its current ill-advised undertakings.

The Coyote Canal is dry, but reversing the flow and extending it to the Salton Sea would benefit many.

A plan is proposed to refill Salton Sea with ocean water from the Gulf of California. This plan would use gravity flow to move ocean water into the sea. The only energy expended to accomplish this goal is that used to construct the canal to carry the water. After the canal is constructed, the refiling of the Salton Sea is energy neutral.

The first step in this plan is to reverse the flow of the Coyote Canal and allow gravity flow of ocean water into Laguna Salada, Baja, MX. Once that is accomplished the Coyote Canal would be extended from Laguan Salada to the Salton Sea. This is a relatively simple and low-cost engineering and construction project. Once completed, natural processes will deliver increased rain and snow to Coachella Valley for decades into the future.

Spread The Word

Spread the word that the Salton Sea must be saved and refilled to its historic level. This will benefit the people of Coachella Valley as well as all the people in Southern California who live and work downwind of the Salton Sea. By refilling the Salton Sea many benefits will be delivered, including a positive attack on Climate Change.

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2 thoughts on “Coachella Valley Groundwater Replenishment”

  1. Thank you for shedding light on this important topic.
    As a resident of Julian, CA in Northeastern San Diego County, I pay close attention to the geographic and environmental issues of California’s southern region.
    My wife and I visit the Salton Sea from the fall through spring. Julian is in the mountains of SD county at an elevation of about 4500 feet. Winters are cold here.
    However, if we drive down the Banner grade we can get to Borrego Springs in about 40 minutes. From here, it is only another 20 minutes to drive the S22 to Salton City ( a little desert town on the western shores of the Salton Sea ).
    California’s largest lake has been shrinking since the San Diego County Water Authority started buying Imperial County farmers’ ag runoff in the early millennium. Otherwise, the agricultural runoff would naturally find its way to the Salton Sea (the lowest depression in the area).
    Without the influx of new water, evaporation outpaces infiltration.
    Many say the lake should just be allowed to dry up.
    The new lithium ion extraction companies would have more exposed playa to build more mining plants upon.
    However, as this article points out, the downsides to allowing the Salton Sea to evaporate are many.
    The Salton Sea contains many heavy metals and pesticides due to a century of farming and maquiladoras. The latter contributed pollutants into seasonal rivers that drain into the Salton Sea from Mexico.
    The citizens of Imperial County have some of the highest rates of respiratory disease and pulmonary cancer in the nation.
    The result of allowing the Salton Sea to become a dust bowl would be catastrophic and make state and federal governments liable for billions in lawsuits and reparations.
    In addition, the Salton Sea plays an important role in bird migration. It gives countless species a necessary habitat to break up their long flight.
    Also, moisture from the surface of the Salton Sea helps add to the Summer monsoon rain. Providing much needed rain to the region.

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