Work by Friends of the Shenandoah River volunteers has set off a mystery of sorts in Round Hill.
The group conducts voluntary E. coli stream testing as part of a broader stream monitoring program. Recently, it found elevated levels at a testing site on the town’s Goose Creek, near its crossing under East Loudoun Street at the eastern edge of town. So far, there’s no evidence the contamination is coming from a leak in the town’s sewer system, but the town is examining its pipes to confirm that.
A more likely source, it appears, is a large tree that towers above the testing site—a favorite roosting site for a committee of vultures, which can be seen sunbathing in its branches with widespread wings.
Subsequent testing by the town staff found lower contamination levels upstream at the town’s Niels Poulsen Park and an area north of town near Kedleston Court—effectively eliminating the possibility of contamination coming from agricultural uses or residential septic tanks. The highest levels were found in the pool area just before the creek passes through a culvert under East Loudoun Street.
The town operates a water treatment plant nearby, south of East Loudoun Street, but that only treats water pulled from two wells in the area and discharges downstream of Sleeter Lake. The town found no threat to the public drinking water.
The town does have a gravity sewer line that runs adjacent to this creek. According to a staff report, “it is unlikely that this line would be the source of contamination because gravity sewer doesn’t normally have much potential to discharge into the stream. The lines are typically deeper than the stream and the pipes are not full.”
Town staff members walked the sewer line that runs along the creek with two sewer camera companies to do a visual survey of the line finding no sign of a leak or overflowing manhole. The town planned to contract to have a camera down the sewer line to confirm the findings.
The vultures have been roosting in the tree for at least 15 years. Preliminary research by the town staff did find citations that vulture droppings can be the source of fecal coliform bacteria contamination in water supplies.
“The only item out of normal that could be leading to this issue is the large amount of waste from the vulture tree located right at the entrance to the Town on Loudoun Street. This area of the roadway and ditch line is white from this [vulture] fecal matter and all stormwater in this area drains right into the creek. The vulture nesting area is less than 50 feet from the creek. The Town couldn’t find any other visual source of potential contamination,” according to the staff report.
In addition to using cameras to confirm the sewer pipe is not leaking, town leaders said they would alert the county Health Department to the concern, as the creek flows beyond the town boundaries into the county.