The U.S. Geological Survey (USGS) is studying five watersheds across the Nation to better understand how natural factors 

and agricultural management practices (AMPs) affect the transport of water and chemicals. Natural factors include climate and 

landscape (soil type, topography, geology), and AMPs include 

practices related to tillage, irrigation, and chemical application. 

The study approach is similar in each watershed so that we can 

compare and contrast the results and more accurately predict 

conditions in other agricultural settings. 

 Study objectives

 • Understand the links between the sources of water and 

agricultural chemicals (nutrients and pesticides) and their 

behavior and transport through the environment 

 • Predict the behavior and transport of water and agricultural 

chemicals in other agricultural areas not being studied

 • Evaluate what the study results mean for management of 

water and water quality in a variety of agricultural settings 

 Why study the Morgan Creek watershed?

 Morgan Creek and the other four watersheds represent 

nationally important agricultural settings (chemical use, crops, 

and AMPs) and natural settings (climate, geology, topography, 

and soils). Morgan Creek, which is part of the Chesapeake Bay 

watershed, is representative of corn and soybean row cropping in 

the Atlantic Coastal Plain. Other features relevant to this study:

 • Use of agricultural chemicals: Chemicals used include herbicides such as atrazine, simazine, metolachlor, and glyphosate; 

and fertilizers, both organic and inorganic. 

 • Distinct natural setting: The nearly flat topography, porous 

soils, and a permeable surficial aquifer allow water and 

chemicals to move downward to the water table, discharge 

to streams, and then move downstream to Chesapeake Bay. 

The wooded riparian zone along Morgan Creek retards runoff 

from fields and allows chemicals to break down. 

 • Variety of agricultural management practices: AMPs include 

tillage and no-tillage; maintenance of stream buffer zones and 

grassy waterways (swales); construction of storm retention 

ponds; use of central pivot irrigation.

 • Water-quality issues on the Delmarva Peninsula: Herbicides 

have been frequently detected in streams and ground water, 

including drinking-water wells (findings of USGS studies 

since the 1990s). Some herbicide concentrations were among 

the highest in agricultural areas sampled across the Nation. 

Nitrate was frequently detected in domestic drinking-water 

wells, many of which had nitrate concentrations greater than 

the Federal drinking-water standard (Judy Denver, USGS). 

 We appreciate your help 

 We are working with local growers and land owners to 

gain access to study sites. We also need information about the 

watershed and about current as well as historical agricultural 

management practices—past practices also affect concentrations 

of agricultural chemicals in ground and surface water. 

 We will report the findings of the study in public meetings 

and in publications. These findings will provide information that 

will be useful for improving agricultural management locally 

and nationally, and will guide future studies in other watersheds.

 Morgan Creek Watershed Selected for a National Water-Quality Study

 The Morgan Creek 

watershed on the 

Delmarva Peninsula is one of 

five watersheds 

selected by the USGS 

National WaterQuality Assessment 

(NAWQA) Program 

for a special study 

of agricultural 

chemicals and water 

quality. 

U.S. Department of the Interior

U.S. Geological Survey

 Fact Sheet 080-03

Printed on recycled paper August 2003 

White-Great and

Little Miami

River Basins

Central Nebraska

Basins

San Joaquin-Tulare

River Basins

Central Columbia PlateauYakima River Basin

Potomac River Basin and

Delmarva Peninsula
What kind of data Why the data are collected How often

Meteorological data, including rainfall, 

wind speed, solar radiation, and air temperature. Soil temperature and moisture

To determine amount of precipitation and how 

much water from land surface reaches the water 

table, how much is lost to evapotranspiration

Continuously for 2 years

Amount of streamflow at Morgan Creek 

near Kennedyville, MD, gaging station

To interpret water-quality data correctly 

(the amount of water in streams affects chemical 

concentrations) 

Continuously since 1951 (realtime data available at

http://waterdata.usgs.gov/md/nwis/

uv?01493500 )

Quality of stream water, runoff water, 

rain water1

To quantify the transport and behavior of natural 

and agricultural chemicals

Several times a year (>14 

samples) for 2 years, with intensive sampling during application 

season

Ground-water levels in wells To determine direction of ground-water flow, 

which affects transport of chemicals

At least quarterly in some wells, 

continuously in others for at least 

1 year

Quality of ground water, soil water, and 

shallow water in and around streambed/

riparian zone1

To quantify the transport and behavior of natural 

and agricultural chemicals

At least quarterly for 1 year

Quality of sediment in streambed and soils 

in agricultural fields1

To quantify the storage, behavior, and transport of 

water and chemicals in the soils and sediment

At least once during study

 1

In this study, water-quality and sediment-quality data include concentrations of nutrients (nitrogen and phosphorous), pesticides and pesticide breakdown 

products, and natural constituents and properties, including major ions (calcium, magnesium, chloride, etc.), organic carbon, dissolved oxygen, and temperature. 

 Data Collection in the Morgan Creek Watershed, 2003–2004

 We would like to thank

 U.S. Dept. of Agriculture

 Maryland Dept. of Agriculture, Kent County 

Soil Conservation District 

 University of Maryland Cooperative 

Extension, Kent County office

 Judy Denver, Project Chief, 

Potomac-Delmarva NAWQA study unit

(302) 734-2506 ext 229

jmdenver@usgs.gov

 NAWQA Program 

 http://water.usgs.gov/nawqa 

 For more information

 Tracy Hancock, Lead Scientist, 

Morgan Creek study 

(804) 261-2618, thancock@usgs.gov

 Paul Capel, Team Leader, National study

(612) 625-3082, capel@usgs.gov

 The USGS provides reliable scientific information to describe and understand the Earth; minimize loss of life and property 

from natural disasters; manage water, biological, energy and mineral resources; and enhance and protect our quality of life.

 At a typical study site, several methods 

are used to collect water and chemical 

samples from the air, soil, surface 

water, and ground water.

After being applied to the land 

surface, agricultural chemicals can 

move upward into the atmosphere, 

downward through the soil to shallow 

ground water and underlying aquifers, 

eventually discharging to streams, or 

run off across the land into streams, 

eventually moving downstream to 

reservoirs and coastal waters. This 

process can take days, weeks, or even 

decades if water moves underground 

through the ground-water system. 

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