USGS

 

U.S. GEOLOGICAL SURVEY

Scientific Investigation Report 2004-5056


Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 19522002

By Allen C. Gellis, William S.L. Banks, Michael J. Langland, and Sarah K. Martucci

 

This report is available as a pdf.

 

ABSTRACT

U.S. Geological Survey suspended-sediment data from 1952 to 2002 from selected stream-gaging stations draining the nontidal parts of the Chesapeake Bay Watershed were summarized to identify areas in the Watershed with high suspended-sediment loads, yields, and concentrations. The suspended-sediment load data were separated into two periods, 19521984 and 19852001. In 1985, the Chesapeake Bay Program began recommending sediment regulations, so 1985 represents an important break in the data. The instantaneous suspended-sediment concentration data were examined for the period 19852002.

Suspended-sediment load data collected from 43 stations from 19521984, with a minimum of 3 years of record, indicated that the two highest average annual suspended-sediment loads were for stations on the main stem of the Potomac and Susquehanna Rivers. The highest average annual sediment yields and discharge-weighted sediment concentrations were for streams draining the metropolitan Washington, D.C. area, possibly related to urbanization. Data from 1985 through 2001 that were collected from 35 stations with a minimum of 3 years of record showed that the highest average annual suspended-sediment loads were also on the main stem of the Potomac and Susquehanna Rivers. Four of the six highest average annual sediment yields and discharge-weighted sediment concentrations for 19852001 were for stations draining to the Conestoga River, a tributary of the Susquehanna River.

Examination of percentiles (10th, 50th, and 90th) of instantaneous suspended-sediment concentrations for 51 stations with a minimum of 3 years of data and at least 10 samples in a year indicated that streams that drain to the Conestoga River had the highest suspended-sediment concentrations. Sediment-transport curves for the 51 stations were separated into classes by drainage-area size. Five of the eight drainage-area classes showed that streams draining the Susquehanna River Basin had the highest suspended- sediment concentrations. Three of the Susquehanna River Basin drainage-area classes were in the Conestoga River Basin. Agriculture is the dominant land use in the Conestoga River Basin and may be an important source of sediment leading to the high sediment yields and instantaneous suspended-sediment concentrations, but further research is needed to quantify the importance of agriculture in relation to other sources of sediment in the Conestoga River Basin.

 

TABLE OF CONTENTS

Abstract

Introduction

Purpose and scope

Previous studies

Methods of study

Limitations of data and methods of analysis

Summary of sediment loads, yields, and discharge-weighted sediment concentrations

River Input Monitoring station data, 19852001

Suspended-sediment data, 1952 through 1984

Suspended-sediment data, 1985 through 2001

Instantaneous suspended-sediment concentrations

Sediment-transport curves

Summary and conclusions

References cited


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

 

Director
U.S. Geological Survey
Maryland, Delaware, D.C. Water Science Center
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:  http://md.water.usgs.gov/.




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