Historically referred to as the filtration plant, the Aberdeen Water Works was built in 1934 on the banks of the Elm River 7 miles northeast of Aberdeen near the small village of Ordway. The state-of-the-art lime softening plant was a marvelous improvement to a town used to drinking the bad tasting, mineral laden well water from the Middle James aquifer. The facility dependably served the community for 25 years before it was expanded to accommodate the increasing water demands of a growing community.

Twenty years later, the facility began to show its age, and the second upgrade included major expansion provisions designed to meet the needs of a city of 50,000 residents. Completed in 1981, the second upgrade relied on the same conventional treatment technology and therefore did not improve upon the process used to chemically and physically treat the water.

Today we are engaged in our most ambitious and extensive renovation to the water treatment plant, yet. Brought on, in part, by the ever increasing demands of the EPA water quality requirements, our improved water treatment plant will incorporate the first advancements to the treatment process since the foundation was first laid. More consistent water quality will be the result, and consumers can expect better tasting, colorless water during those periods when the Elm River is particularly difficult to treat.

The water treatment plant uses a three-stage clarification process including lime and soda ash softening. Clarification is a physical and chemical process which causes the suspended particles found in untreated water to agglomerate together and settle to the bottom of the tanks. Clarification is followed by dual media filtration, and disinfection is achieved through the use of chloramines and occasionally, chlorine dioxide. Fluoride is added to retard tooth decay, and a stabilizing compound is included to prevent the corrosion of water pipes.

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The Water Source

Aberdeen's water supply begins in the headwaters of the Maple and Elm Rivers south of Jamestown in La Moure County, North Dakota. The five water storage dams, including Elm Lake Dam and Willow Creek Dam were built in the 1930's to hold back 6.5 billion gallons of water for the City of Aberdeen. An additional low-head dam and pumping station was constructed in 1976 to divert water from the Maple River into Willow Creek Reservoir during dry seasons. The Elm River is well known throughout the region for its fickle flow rates and ever changing water quality. This makes the surface water extremely complicated to process. However, our record of effectively facing these challenges has earned the community a solid reputation throughout the state for consistently making safe water from the most complex water supply in South Dakota.

The watershed contributing to the Elm River and its tributaries is heavily influenced by agricultural practices. The City of Aberdeen is cooperating with the South Dakota Department of Environment and Natural Resources (DENR) in the EPA's source water protection program to identify and minimize sources of agricultural waste and pollution in our surface water supply.

Additionally, Aberdeen's surface water supply is occasionally supplemented by well water pumped from the Elm Aquifer at the Eyestone Pit well field. The wells primarily function as a reserve water supply for dry seasons, however at times the cleaner ground water from the wells is blended with surface water when the Elm River is particularly muddy or deeply colored.

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The Surface Water Treatment Rule

The Surface Water Treatment Rule involves several tests including turbidity. Turbidity has no health effects. However, turbidity can interfere with disinfection and may provide a medium for microbial growth. Turbidity may indicate the presence of disease causing organisms. These organisms include bacteria, viruses, and parasites that can cause symptoms such as nausea, cramps, diarrhea, and associated headaches.

For a few hours on March 1, 1998 when the Elm River was an extraordinarily deep brown color, our treatment process was unable to remove all the color from the water. Color is another factor influencing turbidity measurements. Subsequently, the treated water flowing from the water plant exceeded the maximum turbidity limit of 0.5 NTU. This constituted a treatment technique violation. Extensive bacteriological testing of the drinking water throughout the distribution system in the days and weeks to follow discovered no presence of disease causing organisms.

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The Water Quality Tests

Aberdeen drinking water is routinely tested as it leaves the water treatment plant, at various locations throughout the distribution system, and at least 29 times a month from faucets in homes and businesses all over town. Many water samples are tested in our own laboratory every day, however more than 360 samples are mailed to the state health lab in Pierre throughout the year.

These samples are analyzed for various substances either occurring naturally in the environment or produced from human activities. As water travels over the surface of the land or through the ground, it dissolves naturally-occurring minerals, radioactive material if present, and can pick up substances resulting from animal life processes and human activity. Contaminants that may be in our source water before we treat it can be categorized as follows:

• Microbial Contaminants, such as viruses and bacteria, result from plant and animal life processes and are naturally occurring in all surface waters. Typical sources of microbial contaminants are sewage treatment plants, septic systems, livestock, and wildlife.
• Radioactive Contaminants are usually naturally occurring and come from certain minerals as water passes over or through them. Mining and oil/gas production are also typical sources.
• Inorganic Contaminants such as salts and metals are either found naturally in our soils, leach from corroding pipes, result from manufacturing, or runoff from fertilizer use.
• Synthetic Organic Contaminants primarily result from the use of pesticides and herbicides. Runoff from landfills and factory waste also can cause these contaminants to be found in water sources.
• Volatile Organic Contaminants occur in drinking water primarily due to industrial discharges, stormwater runoff, and petroleum spills.

The EPA prescribes regulations which limit the amount of certain contaminants in water provided by public water systems. Food and Drug Administration regulations establish limits for contaminants in bottled water which must provide the same protection for public health. Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the EPA's Safe Drinking Water Hotline at 800-426-4791.

Some people may be more vulnerable to contaminants in drinking water than the general population. Immuno-compromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly and infants can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. EPA/CDC guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline at 800-426-4791.


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