A Study in Leaks: Everything’s Connected
According to the San Diego County Water Authority, we import approximately 80-90 percent of our San Diego water supply (about 50 percent comes from the Colorado River, and the remainder of the imported water comes from the Bay-Delta in Northern California). So how does it get from the source to your tap and what is the cost?
From the Oroville Dam in Northern California (the Nation’s’ tallest dam) the water supply we enjoy in San Diego begins a 700 mile journey. It takes an enormous amount of energy to import our water along the way, which travels through canals, reservoirs, pumping stations and power plants. At one point along the way, water is pumped up 2000 ft. At the Edmonston Pumping plant, an electric generator pumps the water using enough energy to power a small city. This is just one piece of a very large and intricate system that expends energy to get water to your taps.
According to the California Energy Commission, importing water across the state accounts for 19 percent of California’s electricity, consumes 32 percent of natural gas resources and consumes 88 million gallons of diesel fuel.
Once the water reaches San Diego, it goes through several additional water treatment processes to ensure it is safe for residential uses, such as coagulation, flocculation, sedimentation, filtration, disinfection, and corrosion control.
Coagulation is the chemical process of rapidly mixing coagulants to the water coming into the treatment plant. The source water contains particles with negative charges. Coagulation changes the particles to a neutral state.
Flocculation takes coagulated water and mixes it causing the particles to collide and form floc. The floc is like a snowflake substance and traps the particles (removing them from the water).
Sedimentation is the process when mixing stops and allows the floc (which is heavier than water) to gradually fall into the sedimentation basin. Once the floc is collected, clear water is collected and sent to filters.
Filtration takes the water and passes it through filtration beds. The filtration beds remove extremely small particles left from the other treatments.
Disinfection (primary) removes pathogens and bacteria. Two methods of water disinfection are ozone and chloride treatment producing clear, pure fresh tasting water.
Secondary disinfection creates chloramines in the water to protect against microbial contamination in the water distribution system.
Corrosion Control adjusts the water pH level.
By the time you turn on your tap in San Diego, the water you use for bathing, drinking, washing dishes and laundry has already traveled several hundred miles and gone through multiple processes to make it safe.
And in San Diego, with looming water mandates and drought conditions, we have to be conscious of how we are conserving, not only water but energy resources as well.
The ways in which we can each do a small part in protecting our resources are easy and small. Conduct your own water audits and understand how much your household is using, make sure that any leaks, minor or major, are not neglected, and educate yourself and community on water saving efforts.
If you believe you have a leak, or want more information about ways in which you can check your household for hidden leaks, call 1-800 Bill Howe (245-5469).