50 Years of the Occoquan Watershed Monitoring Laboratory

Fifty years ago, the Virginia State Water Control Board adopted the Occoquan Policy, establishing an advanced water reclamation plant to treat wastewater in northern Virginia’s Occoquan watershed and provide for its reuse as drinking water. The policy came in response to concerns of point source pollution, as treated sewage was being discharged into the watershed in the 1960s and draining into the Occoquan Reservoir.

Designed to preserve the reservoir as a valuable water source for future generations, the Occoquan Policy was the first large-scale, planned, indirect potable water reuse initiative in the country for surface water augmentation. Via its Occoquan Reservoir and Potomac River plants, Fairfax Water now provides water for nearly two million residents.

With the policy’s enactment came the need for a consistent source of Occoquan water quality insights over time. In 1972, Cliff Randall, then a professor in civil and environmental engineering at Virginia Tech, established the Occoquan Watershed Monitoring Laboratory to create an unbiased source of scientific monitoring and information on water quality in the watershed’s streams and reservoirs and in stormwater. Tom Grizzard served as the lab’s founding director from 1974 to 2014. 

Since its founding, the lab has collected a rich supply of historic data with impact not only for water monitoring in the northern Virginia region, but for the country on the whole. The lab serves as a model for similar facilities throughout the United States.

“The establishment of the lab was a monumental moment for all water quality professionals,” said Tom Faha, the regional director for the Virginia Department of Environmental Quality. “It was important not only for Virginia, but for the nation.”

Fifty years of data

The lab’s first sample was taken in January of 1974 and analyzed in a lab space located in a storefront in Manassas Park. Since then, researchers at the lab have recorded thousands of samples in a growing database. “We have a huge database upon which we can base scientific decision-making,” said Adil Godrej, the lab’s co-director.

The lab moved to its current location in Manassas in 1982 and has expanded in physical space multiple times. The number of staff to operate the lab has also grown since that first sample was collected. There are now nine automated stream sampling stations, eight Occoquan Reservoir sampling locations, 14 rain gauge stations, and one full weather station. The facilities are located all over the watershed, stretching from the southern boundary of the Dulles Airport in the north to portions of the Quantico Naval Base in the south, and from the town of Warrenton in the west to the town of Occoquan in the east.

While other labs do similar monitoring, few, if any, have the historical data that the Occoquan Watershed Monitoring Laboratory does.

Fifty years of samples have proven that indirect potable water reuse, or the process of using reclaimed wastewater discharged to a reservoir and then used for drinking water, is safe and effective, said Godrej. He added that data can also guide decisions and inform predictions regarding land use and climate change as they affect the Occoquan reservoir and drinking water for the area.

This innovative research has been possible for decades because of the stakeholders that help to fund the lab, including Fairfax Water, Fairfax County, Fauquier County, Loudoun County, Manassas City, Manassas Park City, and Prince William County.

“The Occoquan Watershed Monitoring program provides unbiased scientific information to the watershed jurisdictions, decision-makers, and other stakeholders to assist them in managing water quality to provide for safe and reliable drinking water, protection of public health, and enhancement of the aquatic and terrestrial environment of the Occoquan watershed,” Godrej said.

Beyond Occoquan: solving grand challenges

Facilities at the lab have paved the way for pioneering research done by students and staff, making an impact beyond studying the local environment alone.

In 2021, Micron announced the expansion of its memory chip plant in Manassas. The plant is the only one in the United States where semiconductor memory storage is manufactured. Originally, area residents were concerned about the organic compounds that might be discharged to the reservoir from the plant.

Modeling and analysis conducted at the Occoquan Watershed Monitoring Lab determined that the only compound of concern was sodium, which prompted the plant to change their processes to lower that risk. “Without the lab’s data and modeling, that change wouldn’t have happened,” said Godrej.  

The lab’s co-director, Stanley Grant, hopes to explore more opportunities for this kind of research going forward. “I see the opportunity to put the Occoquan lab at the forefront of some really exciting research opportunities in the future,” said Grant. “Right now, our goal is to engage a diverse group of stakeholders, researchers, scientists, and the general public to work together to solve environmental grand challenges.”

One of those challenges is salinization, or too much salt, in the country’s streams, lakes, and reservoirs. This additional salt threatens ecosystem health and the security of drinking water and food supplies.

The Occoquan Watershed Monitoring Laboratory, other universities, research foundations, and government agencies are collaborating to address the problem, with support from a National Science Foundation grant in its Growing Research Convergence Program.

A bottom-up approach to resource management can be self-managed effectively by local stakeholders to achieve salt budgets in inland freshwaters like the Occoquan Reservoir, Grant explained. “Bringing together diverse groups to tackle such a challenge will allow us to work in a way that is productive and leads to practical solutions,” he said. “Everybody wants to be able to turn their tap on and have clean water come out.”

Grant believes the tools that are being developed through this project reach beyond the problem of salinization, and can be applied to other challenges that involve how humans and nature interact. The ultimate goal is for the lab to start these conversations and serve as a national and international model for ways to solve environmental challenges.

A new space

One way the lab will expand its research is by further expanding its physical spaces. Currently, the lab’s primary focus is on monitoring. With a new addition, the size of the lab will allow space for more research activities for stakeholders and students. The space will include a classroom facility; offices for graduate students, post-docs, and faculty; a collaborative space to facilitate interactions between students, faculty and practitioners; wet laboratory space; and a high-ceiling hydraulics lab for conducting near-field scale experiments.

“The expansion of the lab is exciting for our department as we look to focus on experiential learning for graduate and undergraduate students,” said civil and environmental engineering department head Mark Widdowson. “This additional space will allow for more opportunities to give students real-world, hands-on experiences.”

Photos and video by Peter Means