Crozet’s water supply system is being overhauled with the long view in mind, says Rivanna Water and Sewer Authority (RWSA) Executive Director Bill Mawyer. “We are gathering usage data and growth projections for the area, and our goal is to make one plan that will cover all of the necessary modifications,” he said. That blueprint, called the Drinking Water Infrastructure Plan (DWIP), will be finalized this year, and parts of it are already underway.
Crozet’s water is supplied by Beaver Creek Reservoir and is independent from the rest of the county and the city of Charlottesville, which draws its water largely from the Moormans and Mechums rivers. In 2011, the RWSA’s Regional Water Supply Plan forecasted a water demand of 1 MGD (millions of gallons per day) on average for the Crozet service area to satisfy the community’s needs for the next 30 to 50 years, based in part on the Crozet Master Plan population projections. The Crozet water treatment system’s current capacity is about 1 MGD.
Over the last six years, Crozet has experienced strong residential and commercial growth, and the Albemarle County Service Authority (ACSA), which handles the retail water customer side, reports a 35 percent increase in new connections since 2010. Average daily use is currently about 500,000 gallons, but daily peaks above 800,000 gallons have been recorded several times in every year since 2013, and have sparked a revision of the water supply plan.
Ramping up both capacity and quality
Four ongoing, interrelated projects will address Crozet’s increased water needs for the future.
Pump station. A new finished-water pumping station to replace an outdated one is currently under construction at the Crozet Water Treatment Plant on Rt. 240. It will increase pumping capacity from its current 1 MGD to 2 MGD. Dave Tungate, Crozet resident and water manager for the RWSA, says the new pump station, slated to be complete in April, will be a significant improvement over the original 1967 station.
“We’re proud of this project and how it turned out,” said Tungate. “The new pumps will each have one and a half times the capacity of the old ones, with variable frequency drives, and we’ll have a much more efficient use of the water.” The station is sited uphill from the old location, which will make getting trucks and equipment in and out easier as well. Another part of the $4 million project is replacing a diesel generator (that serves as backup power for the plant) with a more muffled one to keep the noise down for residents of the nearby neighborhoods.
Tungate is especially proud of the RWSA’s above-and-beyond preventative maintenance program, which involves continually spot-checking the system, stocking spare parts, and running the backup generator under full load once a month to keep it tuned up.
Treatment plant. Designs are about 30 percent complete to increase the plant’s water treatment capacity from 1 to 2 MGD as well, which will take several years to complete. To process water for drinking, raw water from the Beaver Creek Reservoir is pumped and piped over to the treatment plant, where the first step is to add a coagulant to make the particulate in the water—dirt, bacteria, and organic matter from leaves and logs—stick together and settle to the bottom of the treatment tanks. Another important part of the process treats and filters the water for two micro-contaminants: giardia and cryptosporidium, both of which are parasites that can cause sickness in humans and pets.
This larger project, projected to cost about $7 million, will be tricky to implement because the treatment processes must continue to run during the changeover. “We have two sets of filters, each of which can handle a million gallons,” said Tungate, “so we can take half of the system down and work with just one set at a time. We plan to time the upgrades to take place mostly during the winter months when water demand is lower.”
Carbon filters. The most visible improvement along Rt. 240 is the big red structure erected last fall. Inside the building, whose color was chosen specifically for its rural charm by the county’s Architectural Review Board, is a new “granular activated carbon” filtration system that is being installed in all five of the RWSA treatment plants. The Crozet project’s cost is $3.4 million, and the system is slated to come online at all locations this coming April or May.
“Each of the two filtration tanks is filled with 20,000 pounds of granular carbon, which looks like black Grape Nuts,” said Tungate. “The carbon is activated by super-heating it, causing micro-fractures that create adsorption, a molecular adhesion process.” The water is filtered in this “polishing” step before adding the disinfection chemicals, and the carbon serves to minimize the acid byproducts created in that final treatment. As with the rest of the system, these filters will be able to handle the overall 2 MGD capacity in the plant.
Dam modifications. Beaver Creek Dam, the 59-foot earthen levee topped by Browns Gap Turnpike, has recently been reclassified by the Virginia Department of Conservation and Recreation as a “high hazard dam.” The classification does not imply that the dam itself is unsafe, but rather that a dam failure would have serious and damaging effects on people and property downstream.
Beaver Creek Dam may be brought into compliance with the more stringent state standards by, for example, enlarging the spillway below the dam (or “armoring” it with concrete) to minimize the downstream impact, or by raising the height of the dam itself. Depending on the solution, the roadway and/or the raw-water pump on the lower side of the dam may have to be rebuilt or moved. RWSA engineers estimate the cost of modifications to the dam could be as much as $10 million.
For all of these projects, the RWSA is trying to coordinate the work to maximize efficiency. An outside consultant, Hazen and Sawyer Engineers, is preparing demand forecasts for Crozet that will determine whether the maximum yield of the reservoir needs to be increased (again, potentially by raising the dam height). If such a change is needed, the RWSA wants to combine that work with the dam compliance modifications. The RWSA expects to return to the CCAC to present and discuss the consultant’s findings in March.
The expense of the combined projects is significant, and the RWSA is funded mostly through a portion of end users’ water bills. Larger projects such as the pump station and treatment plant upgrades require bond funding and thus debt servicing, which increases those bills, but the costs are spread over the entire system and not paid only by Crozet residents.
“The price of water here is tiny compared to all over the state,” said Albemarle County Board of Supervisors White Hall representative Ann Mallek, “and we have spectacular quality, which makes me proud.” Still, she’d like to see more protections on all of the area’s reservoirs. “When people back boat trailers covered with oil and muck down into the reservoir to offload their boats, we don’t need that in the water. We are going to have to raise our standards about what’s allowed.”
Mallek describes the work in Crozet as a team effort between the RWSA and the ACSA, and lauds the efforts of both to make decisions about the future well before problems arise. “The RWSA is planning ahead and I always appreciate that,” she said. “It often takes longer to accomplish these things than we anticipate.”