Groundwater Simplified

Did you know that new water cannot be created? The water that we have on earth is the same water that existed billions of years ago. It goes through the water cycle and is naturally recycled over and over again. In this manner, water cycles through the Santa Ana River Watershed. The Watershed flows over 100 miles, starting in the San Bernardino Mountains, combines with snow melt and eventually ends up in Huntington Beach. It is the largest coastal stream system in Southern California. Along the Watershed, there are several groundwater basins that collect and store water as it travels west.

What exactly is groundwater? Have you heard this term being used, but still questioned what exactly it means? With California’s historic drought sweeping the state, groundwater is often at the forefront of this topic. Put simply, groundwater is water that is stored beneath the soil.


According to The Groundwater Foundation, “Groundwater is the water found underground in the cracks and spaces in soil, sand and rock. It is stored in and moves slowly through geologic formations of soil, sand and rocks called aquifers.” What does this mean?

Beneath the surface of the soil, lie underground aquifers. Aquifers contain water and saturated sand, rock, gravel or silt. Water in the aquifer is stored between the rock particles where it can later be extracted, cleaned and used for drinking water. When it rains or snowpack becomes snowmelt, the water drains into the soil or enters the aquifer through cracks in rocks. The water is then stored for later use.


The depth of an aquifer can vary from being deep beneath the earth or merely a few feet from the topsoil. Because of the spaces between the rock and permeable elements in the aquifer, water is able to travel through it. The speed of the water traveling through the aquifer depends upon the size of the spaces.

The top layer of the aquifer is known as the water table or groundwater table. This is the area where the soil or rocks are always saturated with water. Aquifers can be found just about anywhere in the world with conditions causing water levels to fluctuate. Factors that influence the fluctuation of water include rain, snowmelt or groundwater pumping. Pumping or extracting groundwater from an aquifer more quickly than it is replenished or “recharged,” by rain or snowmelt, can cause shortages in groundwater supplies. Pollution from landfills, pesticides, fertilizers and septic tanks can also affect groundwater.


Naturally, groundwater can be released into streams and lakes through underground springs. Groundwater can also be extracted through drilling a well and pumping the water out from the underground aquifer. The process of drilling a well includes inserting a pipe into the aquifer where it can be pumped to the surface. A screen removes particles from the water supply that can clog well pipes. If a water table is not recharged and water supplies dwindle lower than the pipe of the well, the well can run dry.

The Groundwater Foundation states, “Over 50% of the United States population depends on groundwater for drinking water.” With limited local groundwater supplies, Southern California is highly reliant on imported water from the Colorado River and the California State Water Project. The State Water Project is responsible for delivering water to 25 million Californians, much of which flows down to Southern California for direct delivery and recharge of groundwater basins. Limited rain, snowpack and snowmelt pose challenges for groundwater recharge and resources.

Once the groundwater is extracted it is used to for public consumption, domestic, commercial, agricultural, industrial, irrigation, livestock, aquaculture, mining and thermoelectric purposes. Groundwater is a necessary source for the recharge of rivers, lakes and wetlands.

For an easy to understand video on groundwater, click here: 

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