ABOUT WATER IN THE CITY OF LOS ANGELES
Life without water is unimaginable. Earth is covered approximately 75% in water. Interestingly, the human body is made up of approximately 75% water. Water is an essential and important part of our lives at both the planetary and human scale. We rely on it not only for our survival but also everyday needs of bathing, washing, and gardening. Of all the Earth's water, only 3% is fresh water. The remaining 97% is salt water. This means that the world's drinking water is a valuable and limited resource. In a semi-arid climate like Los Angeles, local groundwater provides only minimal amounts of drinking water. In fact, historically up to 87% of Los Angeles' water has been imported.
Looking at these numbers, it is easy to see why water conservation is an important goal. Los Angeles is doing its part by looking into sustainable management practices that will recharge water into our local aquifers. This will ease the need for so much imported water and the City of Los Angeles would have a buffer during drought years. For more water supply information go to www.ladwp.com/ladwp/cms/ladwp001620.jsp.
Angelenos can do their part by following simple water conservation steps at their homes. Did you know that landscaping accounts for about half the water Californians use at home, while showers account for another 18%, and toilets use about 20%? We need to use water wisely and efficiently in order to maximize its potential for ourselves, our homes, and our city.
The Water Cycle
The movement of water in and around the Earth as it changes states from solid ice, to liquid water, to water vapor is the basis of the ever important water cycle. As the sun beats down on the oceans it heats the liquid water at the surface that then evaporates, becoming water vapor in the atmosphere. The vapor then rises and cools with the lower temperatures of the atmosphere causing it to condense into clouds, and after enough condensation clouds become saturated with water vapor and precipitation occurs in which water as a liquid or solid falls back to Earth's surface. Solid water that falls as snow on the Earth's ice caps or glaciers provide great stores of frozen water; while liquid water that falls as rain over the land's surface faces two processes. Water that falls on land either creates surface runoff by flowing through rivers into lakes and oceans, or is stored as groundwater in aquifers after it moves through the Earth by infiltration. However, all of this water continues to travel and restart the continuum of the water cycle.
The water cycle is integral to our use of water and our lives; and it is our job to protect and conserve it as individuals and, together, as a City. The City of Los Angeles has taken numerous steps to improve our use and protect the remaining water resources we have left. Water resource projects represent approximately 20% of the 10-year capital budget within the Department of Water and Power, with over half allocated for environmental activities in the Owens Valley.
Some of the active projects include:
- maintaining historic groundwater supplies
- increasing recycled water supplies
- rehabilitating the Los Angeles Aqueduct
- environmental restoration activities in the Eastern Sierra
For more information on LADWP and its water improvement projects:
For more information on the water cycle:
Water Infiltration in Los Angeles
Part of the water that falls as precipitation infiltrates the ground and fills empty spaces between soil particles and rock fragments. Some water that infiltrates will stay in the ground, where it will gradually move through the soil and subsurface material. Water that infiltrates deep enough will recharge groundwater aquifers, which can be thought of as underground lakes or rivers. If the aquifers are porous enough to allow water to move freely through it, people can drill wells into the aquifer and use the water. Water may travel long distances or remain in groundwater storage for long periods before returning to the surface or seeping into other water bodies, such as streams and the oceans.
Because water is such a precious commodity in Los Angeles, it is increasingly important to capture all that we can. Building materials and construction practices commonly used in the 1900s, though, caused much of Los Angeles' land area to become impermeable. Roofs of buildings, streets, and parking lots now cover enormous swaths of land, preventing infiltration of rainwater. This loss of infiltration not only reduces our available groundwater supply, but it also increase the risk of flooding during major storms. As a result, Los Angeles must lead the way in finding ways to increase the amount water infiltration that can occur. One way to do this is through reducing the amount of impermeable surfaces used in construction.
Another benefit of infiltrating water is that natural processes can clean or filter the water that is infiltrated. By infiltrating stormwater, many contaminants that the water may have picked up in its path can be removed through the natural action of plants.
How can you do your part to reduce water use? Doing simple things like turning off the faucet while you are brushing your teeth or shaving will save 3 gallons of water a day. That adds up to over 1,000 gallons a month per person! Wondering how much water you can save with other simple tips? Here's a quick list to start saving water:
- Check pipes, faucets, and toilets for leaks; a small drip can waste more than 20 gallons per day.
- Every dishwasher load uses about 15 gallons of water and a washing machin uses up to 60 gallons per load to clean your clothes, so try to run both with full loads only.
- Replace you toilet with an ultra-low flow flushing toilet and you will save not only water but also money.
- Water your yard in the morning or evening to avoid the strong heat of the sun that accelerates evaporation.
- Reducing sprinkler use during the rainy season is also a simple water saver.
- Consider using native and drought-tolerant plants in your garden to reduce outdoor water consumption.
- Using a pool cover could save 1,000 gallons a month in evaporated water.
Maintaining a safe water supply is of great concern to the City of Los Angeles. Water sources are tested regularly by a crew of field and laboratory personnel who sample and test the water every day of the year, including weekends and holidays. In fact, LADWP collects more samples than required by law to ensure high water quality. To get more information or check out frequently asked questions about water quality go to http://www.ladwp.com/ladwp/cms/ladwp000442.jsp. For information on California water issues go to the State Water Resources Control Board website at http://www.swrcb.ca.gov/. Another great source of statewide water information is the Association of California Water Agencies website at www.acwa.com.
Water History of Los Angeles
The history of the City of Los Angeles is intertwined with the history of water in the area. The needs of a growing city meant that Los Angeles would require a greater water supply. Since there was not sufficient local groundwater to supply the expanding city, other water sources needed to be identified. In 1913 William Mulholland, chief engineer and general manager of the city-owned Bureau of Water Works and Supply (now the Water System of the Los Angeles Department of Water and Power), brought drinking water from the Owens Valley to the thirsty young city. Another aqueduct was completed in 1970. Together, the two aqueducts are capable of delivering up to 430 million gallons per day to the City of Los Angeles. In the past, Los Angeles relied on Owens Valley water to meet almost 90 percent of the City's demand for water. Today, however, Owens Valley water accounts for less than half of the City's need. To learn more about William Mulholland and the early water history of Los Angeles, go to http://www.ladwp.com/ladwp/cms/ladwp000506.jsp for information on the aqueduct history.