Montgomery County's Sole Source Aquifer - The Good Gift
“Our aquifer is the bloodstream for all farmers in the Agricultural Reserve. It’s what sustains us.” Gene Kingsbury, Kingsbury’s Orchard
This article is excerpted from the Spring 2024 issue of Plenty Magazine. We present the initial portion of the article. You may then link to Plenty’s website to read the remainder of the piece, and see the charts and photos that accompany it.
More often than not, when asked, folks in the D.C. metro region do not really have a fix on where the water that flows from their faucets comes from. Sure, residents and businesses know that they pay Washington Suburban Sanitary Commission (WSSC) for their water and sewage service, and they may know that the origin of their water is the mighty Potomac River. But as to the details—filtration plant operations, the infrastructure that delivers the water from plants to homes and businesses, what happens when there is prolonged drought, these bits are hardly known.
More mysterious to many is where roughly 25-30,000 homes, businesses and farm enterprises get their water from in the nearly one-third of Montgomery County that is wholly outside the WSSC service area by design. And that is the story I aim to share in two parts.
Consider this first installment an introduction to the groundwater aquifer that sustains the Agricultural Reserve and the rural communities that surround it. My aim is transparent: To know our sustaining water resources is to value them, and to value them is to foster necessary collaborative stewardship.
The water beneath our feet
Maryland’s Piedmont Sole Source Aquifer (SSA, see map) was first afforded protective SSA status from the US Environmental Protective Agency (EPA) in 1980 and was extended southward through the municipality of Poolesville in 1998 due to tenacious efforts of Reserve community members beginning two years earlier. This federal designation acknowledges that the groundwater serve at least 50% of the water use in an area and that there is no economic alternative drinking water source available. While not a panacea for protection for the groundwater, the designation does provide that any land and use projects within the SSA area that receive federal funding will be subject to EPA review to ensure that they will not compromise the integrity of the resource, creating hazard to the public. Moreover, advocates for stewardship of the aquifer utilize the designation to educate as to its importance and fragility.
Within the SSA footprint, individual groundwater wells varying in depth from under 100 feet to hundreds of feet, and draw good quality water in widely varying amounts. However, the Piedmont Aquifer with thin soil cover and rapid flow in fractured rock geology is vulnerable to potential contamination. Hydrologist and Reserve resident Bob Tworkowski explains that the unconfined aquifer is in “direct communication with the ground surface, where what is spilled above will more readily percolate through the thin soil seeping into the aquifer.” Moreover, he explains, water in an unconfined aquifer is also subject tp losses through evaporation and plant uptake—think thirsty forests.
Where does the water come from?
The Piedmont Aquifer is fed by rain and snow. An individual well is “recharged” by the precipitation that falls within the nearby watershed. The most effective recharge comes from gradual snow melt or low velocity rain allowing water to slowly percolate through soil and rock to the aquifer below. This process differs from groundwater in Maryland’s coastal plain which travels significant distances from where it enters the system to where it is withdrawn from an individual well.
Bob Tworkowski notes, “The healthiest land use for good recharge to the aquifer is to keep the land as natural open space to minimize the impervious surfaces. Recharge can be affected by a number of items which include the type of soils, the slope of the topography, the vegetation cover, etc. The trick is to hold the water from running off and allow it to sink into the ground where it can contribute to the aquifer.”
The good news is that the Reserve and the low-density rural communities that surround it have retained a significant amount of pervious land that allows for recharge. In those areas where development is dense, recharge is limited, and a greater withdrawal of water may challenge the sustainability of the resource.
Those of us served by groundwater wells here in the Agricultural Reserve and communities like Barnesville, Poolesville, Sugarland, Darnestown, Martinsburg, Damascus, Dickerson, Boyds, Etchison, Clarksburg, and western Potomac are closely tied to out groundwater. We consider ourselves very fortunate as the water is clean and cold, without additives and without per gallon charge, though we maintain our own well infrastructure. This good gift comes with responsibility. We track the seasons and precipitation, or lack thereof, ready to implement water conservation methods such as limiting laundry loads, landscape irrigation, and celebratory showers.
Farmers also utilize practices that will hold water as best as possible on the land, avoiding storm water runoff and enabling recharge of precipitation into the aquifer. We know that squandering this resource spells disaster for our farms and counties. Imagine if farms had to source their water from WSSC, paying per gallon. The additional operating cost would break a number of farm operations. Remember, it was noted that the rural part of Montgomery County is outside the WSSC service area, as laid out on the County’s comprehensive water supply and sewage systems plan updated in 2022 by design. This plan aimed to hold public cost down and, importantly, contain sprawl development that relies on public water and sewer infrastructure. It is a solid plan with a good purpose.
The Piedmont Sole Source Aquifer of central Maryland covers roughly a 130 square-mile area, outlined in green in the map. In 1998, the delineation was extended to include the area around Poolesville. The federal sole source aquifer designation aims to provide a layer of protection for this irreplaceable resource.
Where does the water come from?
The Piedmont Aquifer is fed by rain and snow. An individual well is “recharged” by the precipitation that falls within the nearby watershed. The most effective recharge comes from gradual snow melt or low velocity rain allowing water to slowly percolate through soil and rock to the aquifer below. This process differs from groundwater in Maryland’s coastal plain which travels significant distances from where it enters the system to where it is withdrawn from an individual well.
Bob Tworkowski notes, “The healthiest land use for good recharge to the aquifer is to keep the land as natural open space to minimize the impervious surfaces. Recharge can be affected by a number of items which include the type of soils, the slope of the topography, the vegetation cover, etc. The trick is to hold the water from running off and allow it to sink into the ground where it can contribute to the aquifer.”
The good news is that the Reserve and the low-density rural communities that surround it have retained a significant amount of pervious land that allows for recharge. In those areas where development is dense, recharge is limited, and a greater withdrawal of water may challenge the sustainability of the resource.
Those of us served by groundwater wells here in the Agricultural Reserve and communities like Barnesville, Poolesville, Sugarland, Darnestown, Martinsburg, Damascus, Dickerson, Boyds, Etchison, Clarksburg, and western Potomac are closely tied to out groundwater. We consider ourselves very fortunate as the water is clean and cold, without additives and without per gallon charge, though we maintain our own well infrastructure. This good gift comes with responsibility. We track the seasons and precipitation, or lack thereof, ready to implement water conservation methods such as limiting laundry loads, landscape irrigation, and celebratory showers.
Farmers also utilize practices that will hold water as best as possible on the land, avoiding storm water runoff and enabling recharge of precipitation into the aquifer. We know that squandering this resource spells disaster for our farms and counties. Imagine if farms had to source their water from WSSC, paying per gallon. The additional operating cost would break a number of farm operations. Remember, it was noted that the rural part of Montgomery County is outside the WSSC service area, as laid out on the County’s comprehensive water supply and sewage systems plan updated in 2022 by design. This plan aimed to hold public cost down and, importantly, contain sprawl development that relies on public water and sewer infrastructure. It is a solid plan with a good purpose.
Caroline Taylor serves as executive director of Montgomery Countryside Alliance and lives with her family in the Reserve. She completed the petition for the Poolesville Sole Source Aquifer designation in December of 1996 with her young son fidgeting merrily on her lap.
Up next in part 2 of The Good Gift—a discussion of looming challenges to the aquifer, including issues around climate change and future development in Montgomery County, and how we might get ahead of them, together.