Water-Quality Monitoring in Paint Branch, Maryland

Objectives

1. Establish a station for stream gaging and water-quality monitoring on Paint Branch sited on the the property of the U.S. Army Research Laboratory in Adelphi, Maryland.

2. Collect samples for nutrients, suspended sediment, and bacteria using integrated equal-width sampling and with an autosampler over a range of hydrologic conditions.

3. Deliver water-quality samples to the WSSC laboratory in Laurel, Maryland. Document quality-assurance practices and certifications at the WSSC laboratory.

4. Review water-quality data for inclusion in the USGS National Water Information System (NWIS) database and in the Annual Data Report of the MD-DE-DC Water Science Center.

Statement of Problem

Paint Branch is a major tributary to the Anacostia River with stream segments that require Total Maximum Daily Loads (TMDLs) for nutrients, sediment, biological integrity, and bacteria. The Montgomery County Department of the Environment (MCDEP) has requested the U.S. Geological Survey (USGS) collect data for water quality to be used to calculate the TMDLs and for interpretation on the status of nutrient enrichment and bacterial contamination coming from the watershed.

Strategy and Approach

USGS in cooperation with the U.S. Army Research Laboratory and the Montgomery County government will build and establish a gage and station house to measure stream flow and to collect water-quality samples.

USGS will collect discrete samples for nutrients (total Kjeldahl Nitrogen, total Phosphorus, and Nitrate/Nitrite), suspended sediment, and bacteria. Base-flow samples will be collected monthly using integrated equal-width sampling techniques for nutrients and by dip sample at the center of flow for bacteria. Twelve storms per year will be collected using an autosampler to capture multiple samples over each storm event (rising, peak, and falling limb). At least two storms sampled in each quarter should be greater than or equal to 0.6 inches of rain in 24 hours, which is the one month/24 hour frequency storm for this area. The collection of storm samples may be modified due to weather conditions. Samples for quality assurance will be collected as needed and evaluated with the other data.

Samples for microbiological analyses will be collected with the autosampler using techniques to minimize contamination and appropriate quality assurance to verify the accuracy and precision of the measurements. When USGS is on site collecting base-flow or occasional stormflow samples from the river, a separate sample for bacteria will be collected from near the center of flow and delivered with other samples to the WSSC laboratory. Some storms that trigger the autosampler may be missed for bacteria due to the unpredictability of the weather. USGS also will collect a concurrent sample at each event for the measurement of suspended sediment at the USGS Sediment Laboratory in Louisville, Kentucky.

Samples will be delivered by USGS to the WSSC laboratory in Laurel, Maryland for chemical and bacteriological analysis. These data will be reviewed and published in a USGS annual data report and presented on the USGS website - NWISurface WaterEB. Cost estimates include building a structure to house all of the equipment and that has electrical power and cellphone capability, installation of equipment to measure streamflow, collect water-quality samples, and to log data for transmission to the USGS database in Balimore, Maryland. Successful completion of data collection will be contingent on the development of a technique to collect bacteria with an autosampler, power connections to the site that will be arranged between the ARL and MontCo, and certification of the WSSC laboratory. Contacts have been made with Rosalinda Pineta at the WSSC lab, and they are willing to work with USGS to document their lab certification.

There are a number of potential users of these data including the Washington, D.C. Department of the Environment (DDOE), the Chesapeake Bay Program, and the Maryland Departments of Natural Resources and the Environment.