Clean drinking water is one of the most important services a city provides to its residents, and Rapid City Water Superintendent Jeff Crockett said that responsibility is one he and his staff take seriously.
To recognize Public Works Week, the city hosted a media tour of Jackson Springs Water Treatment Plant earlier this week. The facility opened in 2013 and has the ability to process up to eight million gallons of water per day.
Jackson Springs is one of two water treatment plants in the city; the other is Mountain View. Together, the two facilities processed nearly three billion gallons of water in 2019.
Crockett said the majority of Rapid City's water supply comes from the Pactola and Deerfield reservoirs in the Black Hills, traveling down the Rapid Creek watershed. The city also operates nine wells that draw water from the Minnelusa and Madison aquifers.
"We are very lucky to have extremely clean water supplies here in Rapid City and we take the stewardship of that water supply to heart," Crockett said.
At the Jackson Springs plant, raw water comes from Rapid Creek and the Jackson Springs Infiltration Gallery. An intake structure along the banks of Rapid Creek sends the water to the plant across the street. A separate pipe routes the water from Jackson Springs Infiltration Gallery.
Once the water arrives at the plant, Crockett said a pretreatment process begins to reduce organic carbon, iron and manganese deposits, as well as microscopic particles.
"It's a multi-step process designed to clean the water and meet all standards from the EPA and state regulators," Crockett said.
During the first step, the water is strained to remove large particles. The water then moves to a rapid mix structure that disperses coagulant for further treatment.
The coagulant assists in the next two processes, flocculation and sedimentation.
"Flocculation facilitates bonding between particles in the raw water, causing them to become larger. That makes them easier to separate," Crowell said. "When the water moves to the sedimentation tank, gravity causes those larger particles to be removed from the water."
The final step in producing water is an intense filtration system where membrane panels remove any remaining particles, bacteria, viruses and parasites.
"The membranes remove 99.9% of all foreign substances out of the water before we bring it to the distribution network," Crowell said.
After the membrane filtration, very small amounts of sodium hypochlorite are added to the water supply to provide disinfection. Crowell said fluoride is also added to supplement the natural fluoride in the water.
Once treated, Rapid City's water is distributed through 511 miles of water mains to 19 storage reservoirs throughout the area before arriving to faucets in residents and businesses.
"It really is an impressive system and we take the health and safety of our water supply very seriously," Crockett said. "We constantly monitor the entire system to make sure we are keeping up with demand and make adjustments when needed."
In 2019, the average daily use of water was more than 8.1 million gallons, Crockett said. The peak usage in one day was 15.1 million gallons of water.
Contact Assistant Managing Editor Nathan Thompson at firstname.lastname@example.org.
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