Water-Resources Investigations Report 02-4067

Water Quality, Sediment Quality, and Stream-Channel Classification of Rock Creek, Washington, D.C., 1999-2000

By Anita L. Anderson, Cherie V. Miller, Lisa D. Olsen, Edward J. Doheny, and Daniel J. Phelan


This report is available as a pdf.



Rock Creek Park is within the National Capital Region in Washington, D.C., and is maintained by the National Park Service. Part of Montgomery County, Maryland, and part of the District of Columbia drain into Rock Creek, which is a tribu-tary of the Potomac River. Water quality in Rock Creek is important to biotic life in and near the creek, and in the Potomac River Basin and the Chesapeake Bay. The water quality of the Rock Creek Basin has been affected by continued urban and agricultural growth and development. The U.S. Geological Survey, in cooperation with the National Park Service, investigated water quality and sediment quality in Rock Creek over a 2-year period (19982000), and performed a stream-channel classification to determine the distribution of bottom sediment in Rock Creek.

This report presents and evaluates water quality and bottom sediment in Rock Creek for water years 1999 (October 1, 1998 to September 30, 1999) and 2000 (October 1, 1999 to September 30, 2000). A synoptic surface-water assessment was conducted at five stations from June 23 to June 25, 1999, a temporal surface-water assessment was conducted at one station from February 18, 1999 to September 26, 2000, and bed-sediment samples were collected and assessed from three stations from August 17 to August 19, 1999. The synoptic surface-water assessment included pesticides (parent compounds and selected transformation products), field parameters, nutrients, and major ions. The temporal surface-water assessment included pesticides (parent compounds and selected transformation products) and field parameters. The bed-sediment assessment included trace elements and organic compounds (including low- and high-molecular weight polycyclic aromatic hydrocarbons, polychlorinated biphenyls, pesticides, and phthalates). Some, but not all, of the pesticides known to be used in the area were included in the synoptic water-quality assessment, the temporal water-quality assessment, and the bed-sediment assessment. In addition to the water-quality and sediment-quality assessments, a Rosgen stream-channel classification was performed on a 900-foot-long segment of Rock Creek.

In the synoptic water-quality assessment, two pesticides were found to be above published criteria for the protection of aquatic life. In the temporal water-quality assessment, four pesticides were found to be above criteria for the protection of aquatic life. In the bed-sediment assessment, 8 trace elements, 12 polycyclic aromatic hydrocarbons, 6 pesticides or transformation products, 1 phthalate compound, and total polychlorinated biphenyls were found to be above criteria for the protection of aquatic life. In the Rosgen classification, a comparison to a previous classification for this segment showed an increase in sands and other fine-grained sediments in the creek bed.





Purpose and scope

Previous investigations

Current investigation

Description of study area




Land-use patterns

Sources of fertilizers and pesticides to Rock Creek Park

Potential sources outside the park

Potential sources within the park


Methods of investigation

Site selection

Sampling and field methods

Analytical methods

Quality assurance and quality control

Stream-channel classification

Water-quality data

Synoptic surface-water sampling.27

Temporal surface-water sampling32

Sediment-quality data

Data analysis and comparison of stream-channel classifications

Summary and conclusions

References cited


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For more information about USGS activities in Maryland, Delaware and the District of Columbia contact:


MD-DE-DC Water Science Center
U.S. Geological Survey
8987 Yellow Brick Road
Baltimore, MD 21237
Telephone: (410) 238-4200
Fax: (410) 238-4210


or access the USGS Water Resources of Maryland, Delaware, and District of Columbia home page at:

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