Technology and East Bay Municipal Utility District operations

EBMUD

Technology and "EBMUD"

Technology plays a significant role at the East Bay Municipal Utility District (EBMUD). EBMUD is a publicly owned water company that supplies water service for 1.3 million people that live on the eastern side of San Francisco Bay. It provides water and wastewater treatment for Alameda and Contra Costa Counties which include cities such as Oakland and Berkeley. ("About East Bay"). As EBMUD's responsibilities to the public have grown, so has its use of technology from its inception to the present.

Before EBMUD was created, private water companies in the district had already completed two reservoirs: the San Leandro Reservoir in 1866 and the San Pablo Reservoir in 1916. After recurring droughts and a ten-fold increase in population in a span of just 40 years - from 15,000 in 1870 to 150,000 in 1910, the Municipal District Utility Act of 1921 was created which permitted government agencies to provide service to the public in a region. EBMUD was formed in 1923. It purchased the East Bay Water Company, a private firm, in 1928. By 1930 the population in the area swelled to 460,000, and EBMUD built several more reservoirs to cope with the increasing population. What was then the highest dam in the world, Pardee dam, was completed at about the same time as the Mokelumne Aqueduct, which brought in water from the Sierra Mountains ("About East Bay"). The aqueduct system provides 50% of EBMUD's water supply (Dodge).

Unfortunately, a risk that arises with elevated and buried aqueduct pipelines is that structural damage and major disruptions of water service could occur in the event of an earthquake. Pipeline failure could lead to a critical loss of water with thousands of gallons of water being released into the ground. The faults, such as the San Andreas, Concord, Hayward and the Coast Range -- Central Valley (CRCV), are potential seismic sources. EBMUD used the faults to calculate the probability of different events occurring each year and compared them to an earthquake to design structural parameters (Dodge).

In 1999, EBMUD adopted a seismic improvement program to upgrade "the largest of three aqueducts that carry water from the Sierra Nevada foothills to the urban East Bay of San Francisco" (Dodge). The Mokelumne Aqueduct System is made up of three parallel pipelines. Aqueduct 3 was built in 1963 and supplies 100 million gallons of water every day. Aqueduct 2 was built in 1949. Its diameter is about 67 inches and is smaller than Aqueduct 3 by 20 inches. Aqueduct 1 has the smallest diameter (61 inches) and was built in 1929. EBMUD upgraded the newest pipeline to withstand an earthquake with a magnitude of 6.7 on the Richter scale. Stronger and larger pipelines would replace the two older aqueducts if destroyed by an earthquake (Dodge).

Besides damaging the pipelines, an earthquake could cause floods at three rivers crossings if the embankments cracked. EBMUD upgraded these water storage reservoirs by anchoring and reinforcement ("About East Bay"). The levees were strengthened at the river crossings by such methods as lengthening the existing sheet pile wall; constructing a shoring and bracing system; replacing the pipe and backfilling; and flattening the levee on the land side slope. In addition to those methods, a narrow ledge was added to each side of the pipes and the existing pipe joints were strengthened (Dodge).

To prepare for disruption of water transport by earthquakes or for drought relief (which is expected for 30% of the years), EBMUD is also testing a project called the East Bay Ground Water Storage Masterplan that would create a reservoir underground. The district could "inject treated water into local groundwater and withdraw it later from the same spot with only minor changes in water quality" (Stewart). "Groundwater injection/storage and recovery projects have been implemented and used throughout the United States and other countries for many years" ("About East Bay"). EBMUD determined that the deeper aquifers that are protected by clay layers are suitable for storing potable water. Thus, in the event of low water supply, the underground reservoirs would supply 15 to 30 million gallons of water each day. The first pilot project drilled a 600 ft-deep test well at Ora Loma Waste Treatment Center. There was some degradation in water quality upon retrieval, but despite the necessary water reprocessing, it would still be less expensive than building other storage facilities (Leslie).

Along with advances in water supply technology, EBMUD is investing in alternative sources of power. To reduce its reliance on electricity at its administration center, EBMUD is installing 60-kilowatt natural gas microturbines, and at its operations center, a 30-kW photovoltaic solar system on the roof. These improvements will reduce the district's operating costs and its energy use by 35% (Doyle).

There are also advancements being made in EBMUD's water treatment methods. The water that EBMUD delivers must be potable. It was once treated with chlorine to kill disease-causing organisms such as bacteria and viruses. But on February 1998, EBMUD switched from chlorine to chloramine. Chloramine is produced from ammonia and chlorine and has been in use since 1930 in other cities. Though chloramine is a weaker disinfectant than chlorine, it is more stable. Its stability provides better protection against bacterial regrowth, which can occur in large storage tanks. Chloramine has another advantage over chlorine because it is less reactive to organic material, which causes odor and bad tasting water. Because of chloramine's lower reactivity, there is also a lower incidence of by-products. By-products such as trihalomethanes (THMs) and haloacetic acids (HAAs) have adverse health effects when they occur at high levels ("Disinfecting Drinking Water").