#SummerScienceFriday | Energy-Water Nexus Series: Our Water Supply

We often think of energy and water as separate resources, each being indispensable to human life. However, they heavily depend on one another and can pose a threat to our supply of these resources when we don't make an effort to conserve them . For this week’s #SummerScienceFriday, we begin our Energy-Water Nexus Series, where we explore the link between water and energy and learn ways that we can conserve them.

Where does our water come from?

Even though water is easily accessible through our sinks and faucets, it actually travels a long way before it reaches our homes. Los Angeles’ water supply comes from three sources: the State Water Project, the Los Angeles Aqueduct, and the Colorado River Aqueduct. When available, groundwater wells pump water from groundwater basins to the surface. Through the State Water Project (a system of reservoirs, pump stations, power plants, pipes, and canals), water is mainly collected as snowmelt in Northern California (Owens River and Mono Lake Basin) and the Sierra Nevada Mountains. As the snowpack melts, the water turns into streams and rivers that run into lakes and aqueducts and then transported to LA through the Los Angeles Aqueduct (1). The groundwater basins also rely on seasonal processes to replenish the water basins. When it rains, the ground becomes saturated with water, which subsequently flows through the soil, forming large pockets of water underground. Today, many of LA’s water basins are refilled by stormwater capture projects and some spreading grounds replenish the basins.

The transport and usage of water heavily relies on energy. According to UC Davis, 20% of all energy in California and 30% of natural gas consumption goes to water (2). The large quantity of energy and gas are used to transport, pump, heat , cool, and purify water. Therefore, it is crucial that we work towards conserving these resources.

Stresses in Southern California

Southern California is already a water-stressed region due to its Medeterranian climate, but urbanization and climate change both pose an additional threat to our water supply. Urbanized areas are characterized as having a large amount of impermeable surfaces such as concrete and asphalt. When it rains, water is not allowed to slowly spread and sink into the water table and instead flows into waterways as runoff. This decreases groundwater recharge. Since climate change is predicted to cause warmer temperatures and changes in precipitation patterns, our water supply and is at an even greater risk. Warmer temperatures will reduce the snowpack in the Sierra Nevada Mountains and changes in precipitation, coupled with impermeable surfaces, will degrade our water quality, pro-long drought periods, and intensify flooding, which threatens our safety, property, ecology, and economy (3).

What can we do to conserve energy and water?

A few simple changes to your everyday routine can go a long way like:

Taking shorter showers, turning off the water while scrubbing dishes and brushing your teeth, and checking for leaks in plumbing
Include native, drought tolerant landscaping and high efficiency appliances in your homes. Drought tolerant, native plants often require less maintenance and water. Newer, more efficient appliances like toilets, dishwashers, and washing machines use less water and energy.
Reduce your meat consumption. While it's not realistic for everyone to switch to a plant-based diet, we can save a lot of water by being part-time vegetarians! Check out our previous blog post about water-saving tips to learn more!
Plug electronics into a power strip and turn it off when not in use. Turn off all lights, appliances, and the air conditioning when you are out of the house!