It's common practice for new communities to set up water purchase agreements with bordering communities. While such agreements usually benefit all those involved, one sells excess water at cost while the other pays for a reliable resource, at what point should budding communities create their own water independence?
Drilling Wells in Sampson County, North Carolina
In an area where water is a diminishing resource, the choice to create water independence can be beneficial to every community. Both surface water and well systems are used in eastern North Carolina, and Sampson County has purchased from both systems - leaving them with little control over source and cost. The historical success of well systems in the area, paired with Sampson County's location just outside a capacity use area, naturally led to the development of their own safe, reliable water supply.
We helped Sampson County develop their own well system to keep them from relying on others' resources. After designing test wells in Upper and Lower Cape Fear, a hydrogeologist observed 24-hour pump tests from both sites to determine their individual safety and reliability. With this information, we were able to set the pump production rate for potential full-scale wells in each location.
The county then drilled two wells that produced 1,200 gallons per minute (GPM) - more than double the expected 500 GPM. The aquifer's water quality was so good that only disinfection was required. With such an abundance of quality water from fresh reservoirs, Sampson County could now set up purchase agreements with the adjacent communities it once bought from, supporting their own needs and those of adjacent communities during times of drought.
Designing a Raw Water Pipeline in Loudoun County, Virginia
When Loudoun Water was in need of a reliable water supply in 1959, they contracted with the City of Fairfax to provide roughly five million gallons per day (MGD). By the mid 2000s, Loudoun Water had purchased an additional 50 MGD of capacity from Fairfax Water. Now, Loudoun County is the seventeenth fastest growing population in the U.S., and its water needs have increased again.
Loudoun Water looked at the cost effectiveness of increasing their purchase capacity from Fairfax in comparison to building their own treatment plant. The decision wasn't as simple as comparing a new plant to purchasing additional capacity; Loudoun's water lines were moving farther west. Pushing water from Fairfax (bordering Loudoun's eastern lines) further west and into higher elevations would be expensive. It would also be necessary to increase transmission capacity with bigger pipes and expand existing pumping stations, additional costs to borne by Loudoun Water.
When increased costs and independence were considered, Loudoun Water determined that building a new plant was the best option, leading to development of six major elements: river intake, pump station, transmission main, quarry storage, treatment, and finished water transmission. We designed the raw water transmission main that runs roughly six miles through the heart of Loudoun County.
