Water Quality

Looking for macroinvertebrates in a creek to determine water quality

NPS Photo

Prince William Forest Park (PRWI) falls within the Quantico Creek watershed, a roughly 30-square-mile area and an important tributary of the Potomac River. Surface runoff and streams move through the landscape and carry with them whatever they pick up along the way. Therefore, land use activities in and around the park can have a significant impact on water quality throughout the watershed and beyond.

The water quality monitoring program at Prince William Forest Park began in the 1990s. It allows natural resources managers to assess the health of surface waters in the park, understand how these sensitive ecosystems are changing over time, and identify when there is a problem that needs further investigation.

Through this program, managers conduct regular assessments of three different water quality indicators:

 

Macroinvertebrates: Diptera larvae and beetle larvae

NPS Photo

Benthic macroinvertebrates

Macroinvertebrates are small organisms that do not have a backbone and can be seen with the naked eye. Benthic macroinvertebrates, such as aquatic insects and crayfish, live at the bottoms of lakes, rivers, oceans, and streams. Their size makes them easy to collect and their sensitivity to environmental change makes them excellent indicators of ecosystem health.

Fecal coliforms

Fecal coliforms, such as E. coli (Escherichia coli), are a type of bacteria that live in the intestines of warm-blooded animals including wildlife, farm animals, pets, and humans. Concentrations of fecal coliforms can increase after heavy storms which lead to high volumes of runoff into surface waters. Prince William Forest Park tests their lakes and streams frequently to ensure that they meet strict water quality standards for the health of ecosystems and visitors, alike.

How can you help? Visitors can help us maintain good water quality in Prince William Forest Park by picking up after their pets throughout the park and disposing of their pet's waste in appropriate garbage receptacles.

Water chemistry

Scientists assess water chemistry by examining a variety of factors. Through sample analysis and the use of special equipment, they measure electrical conductivity, dissolved oxygen levels, nutrient concentrations, acidity, clarity, and more. Wildlife, especially amphibians, are very sensitive to changes in water chemistry, so keeping an eye on these changes is essential to protecting wildlife in the park.


Monitoring these three indicators in Prince William Forest Park gives scientists a clearer picture of overall water quality, helps them identify potential sources of pollution, and allows managers to maintain the integrity of ecosystems within the park.