Environmental Setting of the Morgan Creek 

Basin, Maryland, 2002-04

By Tracy Connell Hancock and Michael J. Brayton

Open-File Report 2006-1151

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

Dirk Kempthorne, Secretary

U.S. Geological Survey

Mark Myers, Director

U.S. Geological Survey, Reston, Virginia: 2006

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Suggested citation:

Hancock, T.C., and Brayton, M.J., 2006, Environmental Setting of the Morgan Creek Basin, Maryland, 2002-04: 

U.S. Geological Survey Open-File Report 2006-1151, 28 p.
iii

Contents

Abstract............................................................................................................................................................1

Introduction.....................................................................................................................................................1

Purpose and Scope...............................................................................................................................2

Previous Studies....................................................................................................................................2

Environmental Setting: Physical and Cultural Features, Climate, and Hydrology................................4

Physical Features..................................................................................................................................4

Physiography.................................................................................................................................4

Geology...........................................................................................................................................7

Soils ............................................................................................................................................8

Cultural Features..................................................................................................................................11

Land Use.......................................................................................................................................11

Population....................................................................................................................................15

Climate...................................................................................................................................................15

Hydrology..............................................................................................................................................17

Surface Water.............................................................................................................................20

Ground Water..............................................................................................................................22

Floods and Droughts..................................................................................................................23

Water Use....................................................................................................................................23

Summary........................................................................................................................................................23

References Cited..........................................................................................................................................24

Figures

1-3. Maps showing:

1. The Delmarva Peninsula and Morgan Creek Basin, Maryland................................................3

2. Hydrogeomorphic regions in the surficial aquifer on the Delmarva Peninsula................... 5

3. Topography and hydrography of the Morgan Creek Basin, Maryland...................................6

4. Composite hydrostratigraphic sequence of central Kent County, Maryland.................................7

5. Cross section showing generalized hydrostratigraphy across central Kent County,

Maryland.............................................................................................................................................8

6-8. Maps showing:

6a. Soil drainage descriptions in Morgan Creek Basin, Maryland..............................................9

6b. Soil textures in the Morgan Basin, Maryland.........................................................................10

7. Land use and land cover in the Morgan Creek Basin, Maryland........................................12

8. Population density for the Morgan Creek Basin, Maryland.................................................16

9-11. Graphs showing:

9. Average daily high and low temperatures for 2003 and 2004 at National Weather

Service, Station 181750, Chestertown, Maryland...........................................................18

10. Annual precipitation over time at National Weather Service, Station 181750,

Chestertown, Maryland........................................................................................................18

11. Mean monthly precipitation for 2003 and 2004 at National Weather Service, Station

181750, Chestertown, Maryland.........................................................................................18
iv

12. Location of Morgan Creek and tributaries in relation to the streamflowgaging station..................................................................................................................................19

13-15. Graphs showing:

13. Long-term annual discharge at the Morgan Creek streamflow-gaging station, 

 water years 1952-2004....................................................................................................20

14. Mean daily discharge and mean monthly discharge at the Morgan Creek 

 streamflow-gaging station, water years 2003 and 2004 ............................................21

15. Summary of daily mean streamflow characteristics at Morgan Creek 

 streamflow-gaging station, water years 1952-2004 showing percent of 

 time that daily mean streamflow was greater than or equal to the discharge 

 value shown, in cubic meters per second ....................................................................22

Tables

1. Summary of crops and animal operations in the Morgan Creek Basin, 2003-04 ........................11

2. Summary of fertilizers used, crops treated, application method, area of application, and 

total elemental mass applied in the Morgan Creek Basin, 2003-04.......................................13

3. Summary of herbicide use in the Morgan Creek Basin, 2003-04...................................................14

Conversion Factors and Vertical Datum

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

millimeter (mm) 0.03937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

meter (m) 1.094 yard (yd) 

Area

square meter (m2) 0.0002471 acre 

square kilometer (km2) 247.1 acre

hectare (ha) 0.003861 square mile (mi2) 

square kilometer (km2) 0.3861 square mile (mi2)

Volume

liter (L) 0.2642 gallon (gal)

cubic meter (m3) 264.2 gallon (gal) 

cubic meter (m3) 0.0002642 million gallons (Mgal) 

liter (L) 61.02 cubic inch (in3) 

cubic meter (m3) 35.31 cubic foot (ft3)

Flow rate

cubic meter per second (m3/s) 35.31 cubic foot per second (ft3/s)

cubic meter per second (m3/s) 22.83 million gallons per day (Mgal/d) 

Mass

milligram (mg) 35.27 ounce, avoirdupois (oz)

gram (g) 0.03527 ounce, avoirdupois (oz)

kilogram (kg) 2.205 pound avoirdupois (lb)
v

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F=(1.8×°C)+32

Vertical datum: In this report, vertical coordinate information is referenced to the National 

Geodetic Vertical Datum of 1929 (NGVD 29) and (where noted) to the North American Datum of 

1983 (NAD 83).

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) 

or micrograms per liter (μg/L).

Water year is the 12-month period between October 1 through September 30. The water year is 

designated by the calendar year in which it ends and which includes 9 of the 12 months. Thus, 

the year ending September 30, 2003, is called the “2003 water year.”
vi
Abstract

The Morgan Creek Basin is a 31-square-kilometer 

watershed in Kent County, Maryland on the Delmarva 

Peninsula. The Delmarva Peninsula covers about 

15,500 square kilometers and includes most of the State 

of Delaware and parts of Maryland and Virginia east of the 

Chesapeake Bay. The Morgan Creek Basin is one of five 

sites selected for the study of sources, transport, and fate by 

the U.S. Geological Survey (USGS) National Water-Quality 

Assessment (NAWQA) Program’s: Agricultural Chemicals: 

Sources, Transport and Fate study team (Agricultural Chemicals Team, ACT). A key component of the study is identifying 

the natural factors and human influences affecting water 

quality in the Morgan Creek Basin. 

The Morgan Creek Basin is in the Coastal Plain 

Physiographic Province, which is a nearly level seawardsloping lowland with areas of moderate topographic relief. 

The study area lies within a well-drained upland region with 

permeable and porous soils and aquifer sediments. The soils 

are well suited to most field crops.

Agriculture is the principal land use in the Morgan Creek 

Basin, as well as throughout the entire Delmarva Peninsula. 

Most agricultural land is used for row crops such as corn, 

soybeans, and small grains, and slightly less land is used for 

pasture and hay production involving alfalfa, clover, and various perennial grasses. There are several animal operations in 

the study area. Farm management practices include fertilizer 

and herbicide applications, different tillage practices, addition 

of lime, forested riparian buffers, grassed waterways, and sediment retention ponds. Irrigation in the study area is minimal.

The climate of the Morgan Creek Basin is humid and 

subtropical, with an average annual precipitation of 

1.12 meters. Overall annual precipitation is evenly distributed 

throughout the year, from 76 to 101 millimeters per month; 

however, the spring and summer (March – September) tend to 

be slightly wetter than the autumn and winter (October – 

February). Anomalously high precipitation can occur in 

summer/early autumn due to occasional hurricanes and 

tropical storms. Thunderstorms can also produce relatively 

high localized precipitation over the Morgan Creek Basin 

during the summer months.

Mean daily streamflows for Morgan Creek are highly 

variable, and somewhat flashy due to the relatively small area 

of the basin. The long-term median base flow for Morgan 

Creek is 59 percent of total flow, indicating that total streamflow is most often dominated by a sustained ground-water 

contribution. Surface runoff accounts for the other 41 percent 

of the water in total streamflow and dominates during and just 

after precipitation events. 

The surficial aquifer in the study area consists of 

permeable quartz-rich sand and gravel and is underlain by 

less permeable marine sand, silt, and clay. The depth to water 

table ranges from less than 0.4 meters below land surface in 

the floodplain to 12 meters below land surface in upland areas. 

Ground water generally flows from uplands toward the 

Morgan Creek floodplain at a variety of depths and time 

scales. Because the soils and sediments are permeable and 

porous, some fraction of chemicals applied to the land surface 

tend to move downward to the water table where they are 

transported to discharge areas near Morgan Creek. 

Introduction

The Morgan Creek Basin is located in Kent County, 

Maryland on the Delmarva Peninsula (fig. 1), which covers 

about 15,500 km2 (square kilometers) and includes most of 

the State of Delaware and parts of Maryland and Virginia east 

of the Chesapeake Bay. The Morgan Creek Basin is one of five 

sites selected for the study of sources, transport, and fate by 

the U.S. Geological Survey (USGS) National Water-Quality 

Assessment (NAWQA) Program’s: Agricultural Chemicals: 

Sources, Transport and Fate study team (Agricultural 

Chemicals Team, ACT). The primary goal of the ACT study 

is to identify the natural and human factors affecting the 

Environmental Setting of the Morgan Creek Basin, 

Maryland, 2002-04

By Tracy Connell Hancock and Michael J. Brayton 
transport and fate of agricultural chemicals in different 

environmental settings nationwide. 

The other agricultural basins in the ACT study included 

Mustang Creek Basin and the lower Merced River Basin in 

central California, Leary Weber Ditch Basin and Sugar Creek 

Basin in central Indiana within White River Basin, DR2 Drain 

Basin and the Granger Drain Basin in south-central Washington within the Yakima River Basin, and Maple Creek Basin 

in Nebraska. Additionally, two more studies began in 2005 

in Iowa and Mississippi. As the studies progress, additional 

basins will likely be added. The basins in the studies represent 

a range of agricultural settings—with varying crop types and 

agricultural practices related to tillage, irrigation, artificial 

drainage, and chemical use—as well as a range of landscapes 

with different geology, soils, topography, climate, and hydrology. Consistent methodology and analysis allow comparisons 

among the different basins. This study design leads to an 

improved understanding of the many factors that can affect 

the movement of water and chemicals in different agricultural 

settings. There was an attempt to keep the local study designs 

as consistent as possible, but only the study components that 

were locally pertinent were included. 

Purpose and Scope

To understand the sources, transport, and fate of 

agricultural chemicals on a basin level, intensive chemical 

sampling was conducted in the Morgan Creek Basin from 

2002 through 2004. Samples were collected from each 

environmental “compartment” within the basin and specifically from a single agricultural field along the creek. Environmental compartments sampled included precipitation, unsaturated zone water, surface water, ground water, and riparian 

zone seepage water. The report provides a description of major 

natural (physiography, geology, soils, climate, and hydrology) 

and human components (land and water use, population, and 

modifications to the natural hydrology) of the environmental 

setting. 

Previous Studies

Several previous investigations characterized the surface- and ground-water quality of the Delmarva Peninsula. 

In 1986, the USGS NAWQA Program began pilot studies to 

assess the quality of the Nation’s surface- and ground-water 

resources. A regional ground-water quality assessment of the 

Delmarva Peninsula was one of the pilot studies conducted for 

the NAWQA Program (Shedlock and others, 1993). The study 

focused on the surficial aquifer and used both existing data 

and newer data collected from 1988 to 1991 (Hamilton and 

others, 1991; Hamilton and others, 1993; Shedlock and others, 

1999; Koterba and others, 1993) to characterize ground-water 

quality on the Delmarva Peninsula. 

Later studies of the Morgan Creek Basin established 

an understanding of the effects of hydrogeology on surfacewater quality and the interaction between surface and ground 

water on water quality. Böhlke and Denver (1995) evaluated 

the history and fate of nitrate contamination of ground water 

using age dating, chemical, and isotopic analyses. They documented the occurrence of denitrification in shallow subsurface 

geologic formations, and assessed the effect of denitrified 

discharge water on the chemical composition of stream base 

flow. The U.S. Environmental Protection Agency developed 

analytical and numerical models of ground-water flow and 

nitrate transport, and assessed the basin capacity for nitrogen 

reduction (Hantush and Cruz, 1999; Hantush and Marino, 

2001). Bachman and others (2002) described the hydrogeology, ground-water geochemistry, and assessment of nitrogen 

yield from base flow in Morgan Creek.

Ator and others (2000; 2003) related previously 

collected shallow ground-water-quality data in the MidAtlantic Coastal Plain and newly collected stream-waterquality data in the study area to surficial hydrogeology. Ator 

and others (2005) delineated different hydrogeologic settings 

for the Mid-Atlantic Coastal Plain on the basis of geomorphology, and the thickness and texture of surficial sediments and 

underlying confining beds. 

The NAWQA Program conducted a follow-up assessment of water quality, Cycle II, in ground water and streams 

on the Delmarva Peninsula from 1999 to 2001 (Denver and 

others, 2004). In a similar manner to the pilot study from 1988 

to 1991, water quality was assessed at many scales–from local 

ground-water flow paths to regional ground-water networks, 

and in surface water. In this Cycle II NAWQA study, trends in 

water quality were evaluated with respect to changes in 

chemical sources, land use, and chemical transport and fate. 

Water discharge data have been continuously collected 

by the USGS at one fixed streamflow-gaging station in the 

Morgan Creek Basin since 1951: USGS Station 01493500, 

Morgan Creek near Kennedyville, Maryland. The streamflow-gaging station on Morgan Creek is in Hydrologic Unit 

02060002. This site consists of a telemetered water-stage 

recorder, which provides near real-time data via the Internet 

(http://waterdata.usgs.gov/md/nwis/uv?01493500). A concrete 

control weir forms a small pool, and a few hundred yards 

below this pool, the stream becomes tidal. During unusually 

strong storms, when southwesterly winds are sustained, water 

can mound on the eastern side of the Chesapeake Bay and be 

forced into tributaries. The result is a higher-than-normal high 

tide that affects the gage pool with backwater, raising the stage 

so as to inaccurately reflect the actual discharge. During these 

infrequent and short-duration tidal events, stream records can 

be estimated by removing tidal effects using downstream 

tide-gage data.

Surface-water quality data have been collected in several 

previous studies at both the Morgan Creek streamflow-gaging 

station (located in the southwest portion of the Morgan Creek 

Basin), and other upstream locations (Böhlke and Denver, 

1995; Bachman and others, 2002; Ator and others, 2003). As 

part of the NAWQA National Trends Monitoring Program, a 

continuous in-stream monitor was operated in Morgan Creek 

   Environmental Setting of the Morgan Creek Basin, Maryland, 2002-04
D E L A W A R E

B A Y

DELAWARE

RIVER

River

RIVER

Patuxent River

Patapsco River

Severn River

Bush

SUSQUEHANNA

Gunpowder R.

Middle R.

EASTERN BAY

Nanjemoy Cr.

Prettyboy Res

Loch Raven

Res

Liberty

Lake

Wicomico River

Pocomoke River

CHINCOTEAGUE BAY

Manokin

River

Choptank River

Nanticoke River

L. Choptank R.

Fishing

Bay

Bay

Bay

Wicomico R.

Nassawango

Creek

Indian River

Rehoboth

Choptank River

Leipsic River

St. Jones R.

Murderkill River

Marshyho ep Creek

Broad Creek

Tuckahoe

Creek

Unicorn Br. Elk

River

River

C & D

Christina River

Smyrna

River

Sassafras

CANAL

Chester

River

Monocacy

River

WesternRun

Triadelphia

Res

Patuxent

River

Gunpowder Falls

Morgan Run

Gillis Falls

Deer

Creek

Tinkers Cr.

Piscataway Cr. Mattawoman Cr.

Zekiah Swamp

Run

POTOMAC

RIVER

Rappahannock

River

York River

Occoquan

Res

Occoquan Creek

Accotink Cr.

Mill

Cr.

Reedy Cr.

Piscataway

Cr.

Mattaponi

River

Kent

Island

NEW

CASTLE

TALBOT

Prince

Frederick

Heathsville

Accomac

Eastville

Cambridge

Salisbury

Princess

Anne Snow Hill

Dover

Georgetown

Centreville

Denton

Easton

WILMINGTON

Elkton

Chestertown

Bel Air

Towson

Westminster

Ellicott City

Rockville

ANNAPOLIS

Upper

Marlboro

La Plata

Leonardtown

Annandale

King George

Montross

Warsaw

Lancaster

Bowling Green

Tappahannock

Saluda

ACCOMACK

NORTHAMPTON

SOMERSET

DORCHESTER

WICOMICO

WORCESTER

CAROLINE SUSSEX

KENT

QUEEN

ANNES

KENT

CECIL HARFORD

BALTIMORE

CARROLL

FREDERICK

BALTIMORE

CITY

HOWARD

MONTGOMERY ANNE

ARUNDEL

PRINCE

GEORGES

CALVERT

CHARLES

ST. MARYS

FAIRFAX

GEORGE

WEST MORELAND

RICHMOND

NORTHUMBERLAND

LANCASTER

CAROLINE ESSEX

KING AND

WILLIAM

KING

QUEEN

MIDDLESEX

MATHEWS

PENNSYLVANIA

MARYLAND

NEW JERSEY

DELAWARE

MARYLAND

MARYLAND

VIRGINIA

VIRGINIA

MARYLAND

WASHINGTON,

D.C.

0

0 10

10

20

20

30 KILOMETERS

30 MILES

77°00′ 76°00′ 75°00′

39°00′

38°00′

37°00′

FALL

GENERALIZED FALL

LINE

GENERALIZED

LINE

COASTAL PLAIN

PIEDMONT

EXPLANATION

DELMARVA PENINSULA

STUDY AREA

298 298

213

213

444

Kennedyville

Locust

Grove

Shrewsbury Neck

Shellcross

Chesterville

292

A’

A

0 1.5 3 KILOMETERS

0 1.5 3 MILES

291

National Weather

Station 181750

Figure 1. The Delmarva Peninsula and Morgan Creek Basin, Maryland.

Introduction 
at the streamflow-gaging station from April 2002 to October 

2004, to measure temperature, specific conductance, dissolved 

oxygen, and pH. 

Denver and others (2004) found that on the Delmarva 

Peninsula in 2001, nitrogen concentrations were greater than 

3 mg/L (milligrams per liter) in about half of the headwater 

streams sampled during base-flow conditions in the spring. 

At the same time, in the surficial aquifer, the median nitrate 

concentration in 48 ground-water wells was 5.8 mg/L as N 

(nitrogen). In well-oxygenated areas of the surficial aquifer, 

this concentration increased by an average of 2 mg/L between 

1988 and 2001. Concentrations of nitrate were above 10 mg/L 

as N, the Federal standard for drinking water (U.S. Environmental Protection Agency, 2002), in about one-third samples 

from 29 wells in the part of the aquifer used for domestic 

water supply.

Denver and others (2004) also found that phosphorus was 

transported to streams and rivers on the peninsula, primarily 

with overland runoff during storms. Concentrations of total 

phosphorus were typically less than 0.1 mg/L at base flow 

in well-drained areas. Phosphorus strongly attaches to soil 

particles in well-drained agricultural soils and, as a result, 

concentrations of dissolved phosphorus in ground water in the 

surficial aquifer rarely exceed 0.1 mg/L in spite of relatively 

large phosphorus applications. 

Atrazine was one of the most frequently detected 

herbicides in streams and surficial ground water throughout 

the Delmarva Peninsula (Denver and others, 2004; Ator and 

others, 2004) and the Nation (Kolpin and Kalkoff, 1993). 

Denver and others (2004) frequently observed metolachlor and 

simazine in surficial ground water and streams throughout the 

Delmarva Peninsula. 

Environmental Setting: Physical 

and Cultural Features, Climate, and 

Hydrology

The Morgan Creek study area is in central Kent County, 

Maryland in the northwest region of the Delmarva Peninsula 

(fig. 1). It is situated between the tidal Chester and Sassafras 

Rivers, about 15 km (kilometers) northeast of Chestertown, 

Maryland. Morgan Creek is a small stream which drains a 

31-km2 basin and flows directly into the tidal part of the Chester River. It is surrounded by rural farmland and flows past the 

village of Kennedyville. Forested riparian zones border most 

areas of the creek and many of its tributaries. Morgan Creek 

flows 9.8 km toward the southwest from its source in the upper 

northeast portion of the basin to the streamflow-gaging station 

(USGS Station 01493500), and a total of 18.8 km from its 

source to the confluence with the Chester River (fig. 1). 

Physical Features

The Delmarva Peninsula covers about 15,500 km2 and 

includes most of the State of Delaware and parts of Maryland 

and Virginia east of the Chesapeake Bay. The entire peninsula 

lies within the Coastal Plain Physiographic Province, which is 

locally a broad central upland with flat to gently rolling topography, flanked by low plains that slope toward surrounding 

water bodies (Denver and others, 2004). The highest elevation 

on the Delmarva Peninsula is 151 m (meters) above sea level, 

in the northern part (National Elevation Dataset, 1999). 

The peninsula is underlain by a series of unconsolidated 

deposits of sand, silt, clay, gravel, and seashells. This wedge of 

unconsolidated sediments underlying the peninsula thickens to 

the south and east. The thickness ranges from virtually zero in 

the northern part of the peninsula to more than 2,400 m along 

the Atlantic Coast of Maryland. Cushing and others (1973) 

divided these deposits into a complex aquifer system consisting of a series of confined aquifers of coarse sediments (sands 

and gravels) and associated confining units of finer sediments 

(silts and clay). 

Several different hydrogeologic settings have been 

delineated within the Delmarva Peninsula (fig. 2) at several 

different scales by different methods (Shedlock and others, 

1993; Bachman and others, 2002; Ator and others, 2000; Ator 

and others, 2005). Each hydrogeologic setting has a unique 

set of geologic, geomorphology, drainage patterns, soils, and 

land-use patterns. 

Physiography

The Morgan Creek Basin is characterized by flat and 

gently rolling topography (fig. 3) (White, 1982). The majority of the study area is from 18 to 25 m above sea level and 

consists of nearly level or undulating land that is dissected in 

places by ravines. The study area lies within a well-drained 

upland region (fig. 2), which includes permeable soils and 

aquifer sediments that are deeply incised by stream valleys 

(Hamilton and others, 1991; Shedlock and others 1993). The 

valleys are sometimes inundated by water during periods of 

heavy rainfall or high tides.

The drainage network for Morgan Creek (fig. 3) includes 

a series of tributaries that originate in the central upland 

regions of the basin. In general, surface drainage in the study 

area is good. Ponds are fairly common in the basin and most 

of them were constructed for sediment retention from farm 

runoff. Grassed waterways are prevalent and serve to route 

water off fields and control eroding sediment during rain 

storms (Natural Resources Conservation Service, 2005). Most 

of these grassed waterways lead to sediment retention ponds 

that are often not lined (Craig McSparron, University of 

Maryland, Cooperative Extension, oral commun., 2005). 

   Environmental Setting of the Morgan Creek Basin, Maryland, 2002-04
76°00′

A

T

L

A

N

T

I

C

O

C

E

A

N

0

0

20 40 MILES

20 40 KILOMETERS

10 30

10 30

75°00′ 74°00′

38°00′

39°00′

PENNSYLVANIA

MARYLAND

MARYLAND

DELAWARE

WELL-DRAINED UPLAND

EXPLANATION

HYDROGEOMORPHIC REGIONS

FROM HAMILTON AND OTHERS 1993

SURFICIAL CONFINED REGION

FINE GRAINED LOWLAND

INNER COASTAL PLAIN

BEACHES, TIDAL MARSHES, LAGOONS

AND BARRIER ISLANDS

POORLY DRAINED LOWLAND

POORLY DRAINED UPLAND

MORGAN CREEK BASIN

Figure 2. Hydrogeomorphic regions in the surficial aquifer on the Delmarva Peninsula (from Hamilton and others, 1993; modified from 

Shedlock and others, 1999).

Environmental Setting: Physical and Cultural Features, Climate, and Hydrology 
76°00′ 75°55′

39°20′

39°15′

0

0

1 2 MILES

1 2 KILOMETERS

EXPLANATION

RANGE IN ELEVATION

STREAMS

USGS GAGE

AND NUMBER

MINIMUM ELEVATION 9 FEET

MAXIMUM ELEVATION 82 FEET

HIGH

LOW

01493500

Morgan

Creek

MORGAN CREEK

BASIN BOUNDARY

01493500

Figure 3. Topography and hydrography of the Morgan Creek Basin, Maryland.

 Environmental Setting of the Morgan Creek Basin, Maryland, 2002-04
Geology

The geology of the Morgan Creek Basin, like that of the 

peninsula, includes a series of coarse and finer sediments in 

unconfined aquifers and confining units. The regional confining layer is a low-permeability clay bed in the Severn Formation (fig. 4). This unit lies more than 50 m below land surface 

throughout most of the study area (Bachman and others, 

2002). Above this confining layer, there are two lithologically 

similar, coarsening upward sequences of marine glauconitic 

sands with varying amounts of silts and clays, which dip and 

thicken to the southeast. Specifically, these consist of fine-tomedium quartz sands with abundant (30 to 50 percent) glauconite grains in a silt-clay matrix and are light olive-brown with 

dark reddish-brown flecks of glauconite. The lower of these 

units is the Paleocene Hornerstown Formation (Bachman and 

others, 2002), and above that is the upper Paleocene Aquia 

Formation (figs. 4 and 5). 

Throughout the study area, the Hornerstown Formation 

is generally 16 m thick. The top of this formation ranges from 

10 m above sea level in the northwest part of the study area 

to more than 20 m below sea level in the southeast part of the 

study area. The contact between the Aquia and the Hornerstown Formations is usually not a distinctive lithologic break 

and is commonly identified on gamma logs as the transition 

between the silt-clay-rich parts at the bottom of the Aquia and 

the sandy top part of the Hornerstown (fig. 4) (Bachman and 

others, 2002). The Aquia Formation subcrops within 3 to 5 m 

of land surface in a band that strikes southwest to northeast 

across the northern edge of the study area, but its exact location is poorly known (Bachman and others, 2002). This formation thickens from 5 to 25 m from northwest to southeast. 

COLUMBIA

AQUIFER

AQUIA

AQUIFER

HORNERSTOWN

AQUIFER

HORNERSTOWN

CONFINING

LAYER

AQUIA

CONFINING

LAYER

SEVERN

CONFINING LAYER

MONMOUTH

AQUIFER

SURFICIAL AQUIFER

HYDROSTRATIGRAPHIC

UNITS

UPPER

MIOCENE (?)

LOWER

PLIOCENE (?)

PENSAUKEN

FORMATION

AQUIA

FORMATION

HORNERSTOWN

FORMATION

SEVERN

FORMATION

MT. LAUREL

FORMATION

UPPER

PALEOCENE

LOWER

PALEOCENE UPPER CRETACEOUS

LITHOSTRATIGRAPHIC

UNITS

e peak gamma response in

Aquia confining layer

j-k sandy bed in upper Severn

Formation

k top of Severn confining layer

m base of Severn confining

layer, top of Monmouth

aquifer

l peak gamma response in

Severn confining layer

i peak gamma response in

Hornerstown confining layer

j base of Hornerstown

confining layer

g top of sand of the

Hornerstown aquifer

h base of Hornerstown aquifer,

top of Hornerstown confining

layer

f base of Aquia confining layer,

top of Hornerstown Formation

d top of tight Aquia confining

layer

a land surface

b base of Pens uken Formation,

top of Aquia Formation

a

c base of Aquia aquifer, top of

Aquia confining layer

HORIZONS

ON GAMMA LOG

i

HORNERSTOWN

CONFINING

LAYER

SEVERN

CONFINING

LAYER

MONMOUTH

AQUIFER

HORNERSTOWN

AQUIFER

AQUIA

CONFINING LAYER

AQUIA

AQUIFER

COLUMBIA

AQUIFER

Well KE Be 186 Well KE-94-0146

k

m

l

j

g

h

f

d

e

a

c

e

g f

d

a

b

c

NATURAL GAMMA RAY LOG

b

10

50

40

30

20

60

80

70

0 20 40 60 80 100

GAMMA, IN COUNTS PER SECOND

DEPTH BELOW LAND SURFACE, IN METERS

0

Figure 4. Composite hydrostratigraphic sequence of central Kent County, Maryland (modified from Shedlock and others, 1999; 

Bachman and others, 2002).

Environmental Setting: Physical and Cultural Features, Climate, and Hydrology 
The upland regions of the Morgan Creek Basin are 

capped by a gravelly, coarse sand known as the Pensauken 

Formation (figs. 4 and 5), which is thought to be late Miocene to early Pliocene (Owens and Denny, 1979; Owens and 

Minard, 1979). The Pensauken Formation is lithologically 

similar to the Columbia Formation (Jordan, 1962, 1964) and 

some references use these interchangeably. The Pensauken 

Formation includes medium-to-coarse sands and gravels with 

common cobbles and less common boulders (Bachman and 

others, 2002). The sediments are poorly sorted and deeply 

weathered; the dominant colors are yellowish-orange, light to 

very light brown (tan), and light gray. These sediments were 

deposited in a braided-river system that covered most of the 

central peninsula. Fluvial erosion during the deposition truncated older sediments resulting in a regional angular unconformity at the base of the Pensauken (Bachman and others, 

2002). The Pensauken is typically 6 to 15 m thick in the study 

area and the base is between 12 to 15 m above sea level, but is 

irregular because of channelization and scouring. 

The youngest sediments in the Morgan Creek Basin are 

the incised valley fill. These Holocene alluvial sediments were 

derived from erosion of the adjacent upland and are dominantly coarse sands with gravels interbedded with some peat 

layers and trace amounts of glauconite (Bachman and others, 

2002). Although the thickness of this alluvium is inferred 

because of limited core data, Bachman and others (2002) 

indicate there may be as much as 4 to 6 m in the stream axis 

of Morgan Creek. Silty overbank deposits form the modern 

floodplain and contain organic matter accumulated from the 

riparian forest (Bachman and others, 2002).

Soils

Soils in the Morgan Creek Basin are predominantly 

well- to moderately well-drained (fig. 6a) fine silt loams 

(fig. 6b) that have some clay (Maryland Department of State 

Planning, 1973; White, 1982; U.S. Department of Agriculture, 

2005). These soils have formed in the upland regions and in 

sloped parts of the study area. Fine loam soils have formed 

along the wooded regions near the creek, tributaries, and other 

drainages, and in some upland regions in the southeast part of 

the study area. Coarse loam soils are typically found in and 

near the stream channels. 

Soils in the uplands and side-sloped regions of the study 

area, including fine silt loams and fine loams (fig. 6b), are 

generally 1.5 to 1.9 m deep (including the substratum), fineto-medium textured, well-drained (fig. 6a), and have moderate 

to low permeability (White, 1982). Available water capacity is 

moderate to high. In cultivated areas, the potential for runoff is medium and the hazard of erosion is mostly moderate, 

although in some soils it is slight. The soils are strongly to 

EXPLANATION

GEOLOGIC CONTACT

Dashed and queried where uncertain

AQUIFER ?

CONFINING LAYER

0 0.5 1 MILE

0 0.5 1 KILOMETER

VERTICAL SCALE GREATLY EXAGGERATED

NGVD 29

(South)

A A'

(North)

100

50

25

-25

75

-50

-75

-100

FEET

NGVD 29

30

20

10

-10

-20

-30

METERS

HORNERSTOWN FORMATION AQUIA FORMATION

AQUIA AQUIFER

HORNERSTOWN AQUIFER

? ?

OLD CHURCH

FORMATION (?)

LAND SURFACE

COLUMBIA AQUIFER PENSAUKEN FORMATION

Chesterville

(Morgnec Road)

Locust Grove

Road

Blacks Station

Road

Augustine Herman

Highway

Morgan Creek

Figure 5. Cross section showing generalized hydrostratigraphy across central Kent County, Maryland (modified from 

Bachman and others, 2002; Ator and others, 2005). Location of A-A’ shown in figure 1.

 Environmental Setting of the Morgan Creek Basin, Maryland, 2002-04
MORGAN CREEK

BASIN BOUNDARY

Morgan

Creek

01493500

76°00′ 75°55′

39°20′

39°15′

0

0

1 2 MILES

1 2 KILOMETERS

MODERATELY

WELL DRAINED

POORLY DRAINED

SOMEWHAT

EXCESSIVELY DRAINED

WELL DRAINED

EXPLANATION

SSURGO

DRAINAGE DESCRIPTION

LAKES

STREAMS

01493500

USGS GAGE

AND NUMBER

Figure 6a. Soil drainage descriptions in the Morgan Creek Basin, Maryland, based on the Soil Survey Geographic (SSURGO) Database 

for Kent County, Maryland (from U.S. Department of Agriculture, 2005).

Environmental Setting: Physical and Cultural Features, Climate, and Hydrology 
Morgan

Creek

MORGAN CREEK

BASIN BOUNDARY

01493500

76°00′ 75°55′

39°20′

39°15′

0

0

1 2 MILES

1 2 KILOMETERS

WATER

COARSE-LOAMY

FINE-LOAMY

FINE-SILTY

LOAMY

NO DATA

STREAMS

EXPLANATION

SSURGO

TEXTURE DESCRIPTION

01493500

USGS GAGE

AND NUMBER

Figure 6b. Soil textures in the Morgan Creek Basin, Maryland, based on the Soil Survey Geographic (SSURGO) Database for Kent 

County, Maryland (from U.S. Department of Agriculture, 2005).

10 Environmental Setting of the Morgan Creek Basin, Maryland, 2002-04
extremely acidic under natural conditions, although most areas 

with crop production have been repeatedly treated with lime. 

These soils are classified as prime farmland (White, 1982) and 

are well suited to most field crops; however, many of the soils 

are also well suited for woodland.

Soils in the floodplains are level to nearly level and are 

poorly drained (fig. 6a) coarse loams (fig. 6b) (White, 1982). 

These soils are generally 1.5 m deep (including substratum) 

and have moderate permeability. Available water capacity 

is high, and surface runoff is low. These soils are frequently 

flooded, especially in winter and early spring, and strongly 

acidic throughout the profile. Poor drainage, flooding, and the 

narrow shape of the areas makes them generally unsuitable 

for most field crops, and well suited to woodland and wetland 

habitat.

Cultural Features

The Delmarva Peninsula is mostly a rural setting with 

several small cities and towns. Agriculture is the main land use 

and most agricultural land is used for row crops such as corn, 

soybeans, and small grains. There are also poultry and dairy 

operations scattered throughout the peninsula. 

Land Use

Because of the fertile, well-drained soils, agricultural 

crop production is the main activity in the Morgan Creek 

Basin (fig. 7; table 1). A few dairy operations and poultry 

houses are scattered throughout the study area. The only 

nonrural area within the study area is the village of 

Kennedyville (fig. 7) along the northwest edge of the Morgan 

Creek Basin. Woodlands and wetlands are predominantly 

located in steep valleys along Morgan Creek and its tributaries.

Farm management practices for the 2 years of study 

(water years 2003 and 2004) were documented by gathering 

information from local farmers, commercial applicators of 

farm chemicals, and the University of Maryland, Cooperative 

Extension, Kent County Office. This information included 

fertilizer and herbicide applications on production crops, 

applications of lime, animal operations, different tillage 

practices, irrigation, forested riparian buffers, grassed waterways, and sediment retention ponds. The information was 

subsequently used with public records (Alexander and Smith, 

1990; Aspelin and Grube, 1999; Bandel and others, 1990; 

Cornell University, 2005a,b; E.I. du Pont de Nemours and 

Company, 2005; Gianessi and Puffer, 1991; Information 

Ventures, Inc., 1995a,b,c; Poole, 2004; Spectrum Laboratories, 

Table 1. Summary of crops and animal operations in the Morgan Creek Basin, 2003-04. 

[Information gathered from local farmers, commercial applicators, and the University of Maryland, Cooperative 

Extension, Kent County Office (Craig McSparron, University of Maryland, Cooperative Extension, oral commun., 

2005; Michael Bandstra, Horizon Organic Dairy, oral commun., 2004). Bold values represent totals for particular 

categories (row crops or animal operations)]

Activity Area 

(hectares)

Percent of 

agricultural 

land

Percent of 

total watershed 

area

Row Crops 2249.5 80.1 59.1

Corn 1079.0 38.4 28.3

Soybeans 1148.0 40.9 30.2

Small Grains 22.5 0.8 0.6

Pasture, Hay 490.0 17.4 12.9

Nursery, Orchard 56.4 2.0 1.5

Animal Operations 13.3 0.5 0.3

Dairy Operations 8.0 0.3 0.2

Chicken Houses 5.4 0.2 0.1

Environmental Setting: Physical and Cultural Features, Climate, and Hydrology 11
Morgan

Creek

MORGAN CREEK

BASIN BOUNDARY

76°00′ 75°55′

39°20′

39°15′

0

0

1 2 MILES

1 2 KILOMETERS

WATER

URBAN

FOREST

AGRICULTURE

WETLAND

STREAMS

EXPLANATION

01493500

USGS GAGE

AND NUMBER

01493500

Figure 7. Land use and land cover in the Morgan Creek Basin, Maryland (modified from light detection and ranging (LIDAR) imaging 

and National Elevation Dataset, 1999).

12 Environmental Setting of the Morgan Creek Basin, Maryland, 2002-04
2003; Toth and Stinner, 2005; U.S. Department of Agriculture, 

2002; Vance Communication Corporation, 2004), area reconnaissance, and extrapolation to calculate amounts of herbicides 

and fertilizers applied to the basin for each field in the study 

area.

Approximately 2,300 hectares of the Morgan Creek 

Basin are used for row crops such as corn, soybeans, and small 

grains, and approximately 500 hectares are used for pasture 

and hay production involving alfalfa, clover, and various 

perennial grasses (table 1) (U.S. Department of Agriculture, 

2002). Small grains such as wheat, barley, and rye are often 

used as cover crops and for silage, grazing, and hay (Poole, 

2004). One of the most common crop rotation practices in the 

basin involves planting corn in 1 year, then wheat (or other 

crops), followed by soybeans. In this area of Kent County, 

wheat, barley, or hay is planted in the fall, then soybeans are 

planted later in the spring or summer (Poole, 2004). 

The majority of row-cropped fields in the Morgan Creek 

Basin undergo conservation no-tillage practices. This significantly reduces soil erosion and nutrient runoff, and often produces higher crop yields and more efficient utilization of plant 

nutrients (Craig McSparron, University of Maryland, Cooperative Extension, oral commun., 2005; Bandel and others, 

1990). In no-tillage practices, cover crops are typically used in 

the late fall through winter and into early spring to reduce the 

growth of weeds and prevent soil erosion. Prior to planting in 

the spring, a pre-emergent application of herbicides is often 

used as a dessicant to “burn-down” the winter cover crop. 

Applications of fertilizer and lime also occur in the spring. 

The farm machinery that is often used to sow the spring crop 

seeds will disc or knife the soil, turning the winter cover crop 

debris into the near-surface soil, so the winter cover crop 

debris can be used as “green fertilizer” for the spring crop.

Nitrogen, phosphorus, and potassium are the most 

commonly applied fertilizers in the study area (table 2) and the 

source of these is commercial inorganic fertilizers and animal 

manures (Bandel and others, 1990; Alexander and Smith, 

1990; Denver and others, 2004). Potash is commonly used as 

Table 2. Summary of fertilizers used, crops treated, application method, area of application, and total elemental mass 

applied in the Morgan Creek Basin, 2003-04. 

[Information gathered from local farmers, commercial applicators, and the University of Maryland, Cooperative Extension, Kent County Office 

and from specific sources (Craig McSparron, University of Maryland, Cooperative Extension, oral commun., 2005; Michael Bandstra, Horizon 

Organic Dairy, oral commun., 2004; Alexander and Smith, 1990; Bandel and others, 1990; Toth and Stinner, 2005; Poole, 2004; and U.S. 

Department of Agriculture, 2002)]

2003 2004

Fertilizers and 

other soil 

additives

Crops 

treated

Application 

method(s)

Area of 

application 

(hectares)

Total mass 

(kilograms)

Area of 

application 

(hectares)

Total mass 

(kilograms)

Nitrogen

mostly corn, 

little on 

soybeans, 

rarely on 

pasture/hay

pre- and postemergent 

surface 

application

3,260 265,000 3,400 226,300

Phosphorus

mostly corn, 

little on 

soybeans, 

rarely on 

pasture/hay

pre- and postemergent 

surface 

application

3,160 120,000 3,050 145,000

Potassium

mostly corn, 

little on 

soybeans, 

rarely on 

pasture/hay

pre- and postemergent 

surface 

application

3,160 150,200 3,180 166,500

Sulfur

mostly corn, 

little on 

soybeans, 

rarely on 

pasture/hay

pre- and postemergent 

surface 

application

2,980 57,300 2,730 52,500

Environmental Setting: Physical and Cultural Features, Climate, and Hydrology 13
Table 3. Summary of herbicide use in the Morgan Creek Basin, 2003-04. 

[Information gathered from local farmers, commercial applicators, and the University of Maryland, Cooperative Extension, Kent County Office and from specific sources (Aspelin and Grube, 1999; Cornell University, 2005a,b; E.I. du Pont de Nemours and Company, 2005; Gianessi and Puffer, 1991; Information Ventures, Inc., 1995a,b,c; Spectrum Laboratories, 2003; Toth and Stinner, 2005; Poole, 2004; U.S. Department of Agriculture, 2002; Vance Communication Corporation, 2004)]

2003 2004

Herbicides Crops treated Application method(s)

Area of 

application 

(hectares)

Total mass 

(kilograms)

Area of 

application 

(hectares)

Total mass 

(kilograms)

atrazine corn pre- and post-emergent surface application 1,310 2,740 1,630 3,460glyphosate soybeans post-emergent surface application 1,660 2,460 1,350 2,160simazine corn, small grains pre- and post-emergent surface application for corn; pre-emergent surface application for small grains 1,160 1,340 1,860 2,160paraquat soybeans, corn pre-emergent surface application 1,850 2,100 1,940 2,100metolachlor corn pre-emergent surface application 1,270 1,780 1,470 2,0002,4-D soybeans, corn, pasture/hay pre-emergent surface application 1,720 1,960 1,510 1,800thifensulfuron 

methyl corn, small grains

post-emergent surface application for break-through 

weeds in corn; pre-emergent surface application for small grains

700 6.8 620 5.7

rimsulfuron corn, small grains

post-emergent surface application for break-through 

weeds in corn; pre-emergent surface application for small grains

430 7.5 530 9.3

dicamba corn post-emergent surface application for break-through weeds in corn 150 23 430 66dimethenamid corn pre-emergent surface application 33 16.5 70 33difluenzopyr corn post-emergent surface application for break-through weeds in corn 153 9 430 26tribenuron methyl small grains pre-emergent surface application 390 2.4 220 1.6chlorimuron ethyl small grains pre-emergent surface application 120 17.4 160 24sulfentrazone small grains pre-emergent surface application 120 21 160 29metsulfuron methyl pasture surface application 320 5.5 330 5.6

14 Environmental Setting of the Morgan Creek Basin, Maryland, 2002-04
a fertilizer because it is a source of soluble potassium. Sulfur 

is also commonly applied with commercial inorganic nitrogen 

fertilizer mixtures in the form of ammonium sulfate. 

Nitrogen fertilizers are applied to nearly all the corn in 

the study area. Little nitrogen or other fertilizers are applied 

for soybean production; however, depending on results of 

field-soil analysis, some fertilizers may be used. Nitrogen 

applications in the study area are commonly in the form of 

either an ammonium sulfate or a urea-ammonium nitrate 

(UAN) solution. These nitrogen forms are applied to field 

crops throughout the growing season such as the pre-emergent 

herbicide applications, during seeding of the crop, and as a 

post-emergent sidedressing to growing crop (Craig McSparron, University of Maryland, Cooperative Extension, oral 

commun., 2005). Most post-emergent sidedressed applications 

of nitrogen to corn occur as a 28-35 percent UAN solution 

(Bandel and others, 1990). Some dairy waste is applied to 

row crops and pasture/hay fields for fertilizer and disposal. 

Composted poultry litter is also used for fertilizer, albeit 

infrequently in this part of the Delmarva Peninsula (Craig 

McSparron, University of Maryland, Cooperative Extension, 

oral commun., 2005). 

Numerous years of fertilizer applications on the 

Delmarva Peninsula have led to increased soil concentrations 

of phosphorus that often exceed crop uptake needs (Sprague 

and others, 2000). For this reason, phosphorus is not used as 

often, or in as high quantities, as nitrogen on the Delmarva 

Peninsula (Alexander and Smith, 1990; U.S. Department of 

Agriculture, 2002). 

A herbicide is a type of pesticide used to kill plants. 

Herbicides are the most widely used pesticides in the Morgan 

Creek Basin and on the Delmarva Peninsula where they are 

used for weed control (Denver and others, 2004). Metolachlor 

and simazine are often used in combination with atrazine for 

corn production (table 3). Glyphosate and paraquat are the 

major herbicides applied to soybeans in the study area 

(table 3). Numerous other herbicides are used in the production of row crops, pasture, hay, and nursery stock (table 3). 

There is no record of fungicide and insecticide use in the study 

area for the water years 2003 and 2004.

There are a few dairy operations scattered throughout 

the Morgan Creek Basin and fewer poultry houses. The dairy 

operations cover a total of 8 hectares of land in the study area 

and the poultry houses cover a total of 5.4 hectares (table 1). 

Most dairy operations implement agricultural management 

practices such as stream fencing to keep cattle out of the creek, 

open grazing in pastures, and spraying of liquid lagoon waste 

and disposal of solid waste on fields for fertilization of forage 

and silage crops. There is at least one location on Morgan 

Creek where cattle cross the stream. Most dairy operations 

have approximately 100 adult females and varying numbers of 

calves. Only half of the waste lagoons in the study are 

lined and most are emptied twice a year (Craig McSparron, 

University of Maryland, Cooperative Extension, oral 

commun., 2005).

There is a large commercial organic dairy operation in 

the Morgan Creek Basin, which consists of a primary farm of 

72 hectares located along the southwest edge of the basin. As 

of 2002, the primary farm had over 600 adult female cows, 

several waste lagoons, and 49 hectares in various rotations 

of corn, perennial rye grass, clover, and alfalfa. The organic 

dairy operation also uses another property in the basin. Of 

the 89 hectares on this second property, 65 hectares are used 

for alfalfa and 18.2 hectares are used for pasture. As of 2002, 

approximately 75-100 calves were raised on this smaller 

property (Michael Bandstra, Horizon Organic Dairy, oral 

commun., 2004).

The organic dairy employs the practice of no-tillage, 

unless weed problems are encountered, in which case 

conventional tillage is used. There is some spraying of liquid 

waste on the primary farm fields. During periods of heavy 

precipitation, lagoons on the main farm may overflow and run 

overland into Morgan Creek. Solid waste is disposed of on the 

smaller organic dairy property and at a local nursery. At the 

nursery, the solid waste is combined with unsold trees to 

create compost, which is used in the production of nursery 

stock (Michael Bandstra, Horizon Organic Dairy, oral 

commun., 2004). 

Less than 2 percent of the Morgan Creek Basin contains 

nursery crops (table 1); however, 30 percent of an adjacent 

basin is used for cultivation of plant nursery stock (Bachman 

and others, 2002). This nursery, located in the northern part of 

the Morgan Creek Basin and adjacent basin, most commonly 

grows a variety of ornamentals including premium 

Root Pruned Holly, Juniper, Arborvitae, Taxus, and Flower 

Carpet Roses (James Kohl, Angelica Nursery, oral commun., 

2004).

Population

In 2000, about 1.1 million people lived on the Delmarva 

Peninsula; the population is increasing in the urban area 

around Wilmington, Delaware and near vacation resorts along 

the Atlantic coastline (fig. 1) (U.S. Bureau of Census, 2004). 

In general, there are at least 327 people per km2 throughout the 

study area, except in the village of Kennedyville, where there 

are over 327 people per km2 (fig. 8). The population in Kent 

County, Maryland, increased approximately 10 percent from 

1990-2004 to 19,600 (U.S. Bureau of Census, 2004).

Climate

The climate of the Morgan Creek Basin is humid and 

subtropical, with an average annual precipitation of 1.12 m. 

The mean temperature in January, the coldest month, is 0.6 °C 

(degrees Celsius), and mean temperature in July, the warmest 

month, is 25.2 °C (National Weather Service, 2004).

Monthly mean high and low temperatures were 

generally lower than the long-term average for the first 

6 months of 2003, and similar or greater than the long-term 

Environmental Setting: Physical and Cultural Features, Climate, and Hydrology 15
Figure 8. Population density for the Morgan Creek Basin, Maryland (based on the U.S. Bureau of Census, 2004).

Kennedyville

76°0′0′′ 75°55′

39°20′

39°15′

0

0

1 2 MILES

1 2 KILOMETERS

EXPLANATION

PEOPLE PER SQUARE KILOMETER

12 OR LESS

13 OR MORE

STREAMS

01493500 USGS GAGE

AND NUMBER

Morgan

Creek

MORGAN CREEK

BASIN BOUNDARY

01493500

16  Environmental Setting of the Morgan Creek Basin, Maryland, 2002-04
average for the second half of 2003 and all of 2004 (fig. 9). 

The only exception was in January 2004, when temperatures 

were much colder than the long-term average. Extreme 

temperatures for the study period were marked by a high of 

36.7 °C on July 5, 2004, and a low of minus 15  ̊C on 

January 10, 2004.

At the National Weather Service monitoring station at 

Chestertown, Maryland, located 8.3 km from the Morgan 

Creek streamflow-gage, mean annual precipitation was 

112 cm (centimeters) for the period 1975-2004. Precipitation 

during 2003, 162 cm, was much greater than the long-term 

average, and precipitation during 2004, 100 cm, was slightly 

less than the long-term average (fig. 10). On average, annual 

precipitation is evenly distributed throughout the year, from 

7.3 to 11.1 cm per month (fig. 11); however, the spring and 

summer period (March – September) tends to be slightly 

wetter than the autumn and winter period (October – 

February). Anomalously high precipitation can occur in late 

summer/early autumn due to occasional hurricanes and 

tropical storms. Thunderstorms can also produce relatively 

high localized precipitation during the summer months.

Monthly precipitation during 2003, a relatively wet year, 

was above normal for all months except January and April. 

February, June, and September had nearly twice the normal 

precipitation (fig.11). In 2004, which was drier than normal, 

precipitation for most months was near or below normal, 

except for April and November (fig.11). In water year 2003, 

there were more frequent storms than in water year 2004.

Hydrology

The hydrology of the Morgan Creek Basin can be 

described by partitioning the annual mean precipitation of 

112 cm into a basic water budget. 

PPT = SW + GW+ ET,

where

PPT is annual precipitation, 112 cm

SW is streamflow loss = 28 percent, 31.4 cm

GW is ground-water loss to adjacent basins = 

2 percent, 2.2 cm

ET is evapotranspiration loss = 70 percent, 

78.4 cm

Evapotranspiration is predominant during the growing 

season from April through September, whereas simple evaporation is more likely to occur from October through March. 

JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEP. OCT. NOV. DEC. JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEP. OCT. NOV. DEC.

2003 2004

-10

-5

0

5

10

15

20

25

30

35

AIR TEMPERATURE, IN DEGREES CELSIUS

30 YEAR MONTHLY MEAN HIGH AND LOW

MONTHLY MEAN HIGH AND LOW

Figure 9. Average daily high and low temperatures for 2003 and 2004 at National Weather Service, Station 

181750, Chestertown, Maryland (from National Weather Service, 2004). Location of station is shown in 

figure 1.

Environmental Setting: Physical and Cultural Features, Climate, and Hydrology 17
1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004

0

20

40

60

80

105

120

140

160

180

ANNUAL PRECIPITATION, IN CENTIMETERS

ANNUAL PRECIPITATION STATION 181750

30 YEAR MEAN, 112 CENTIMETERS

Figure 11. Mean monthly precipitation for 2003 and 2004 at National Weather Service, Station 181750, 

Chestertown, Maryland (from National Weather Service, 2004).

Figure 10. Annual precipitation over time at National Weather Service, Station 181750, Chestertown, 

Maryland (from National Weather Service, 2004).

0

4

6

8

10

12

14

16

20

22

MEAN MONTHLY PRECIPITATION, IN CENTIMETERS

18

2

JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEP. OCT. NOV. DEC. JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEP. OCT. NOV. DEC.

2003 2004

30 YEAR MEAN

MONTHLY

18  Environmental Setting of the Morgan Creek Basin, Maryland, 2002-04
Morgan

Creek

MORGAN CREEK

BASIN BOUNDARY

75°55′

39°20′

39°15′

0

0

1 2 MILES

1 2 KILOMETERS

76°00′

PONDS

STREAMS

EXPLANATION

01493500

USGS GAGE

AND NUMBER

01493500

Figure 12. Location of Morgan Creek and tributaries in relation to the streamflow-gaging station.

Environmental Setting: Physical and Cultural Features, Climate, and Hydrology 19
An estimate for recharge to ground water is 18 cm; while 

runoff contribution to streamflow is 15.5 cm.

Natural hydrologic processes dominate water movement 

in the basin; however, there are some non-natural modifications that affect streamflow conditions and water quality. 

These features include grassed waterways that direct overland 

runoff, and small (less than 0.04 hectares) sediment retention 

ponds, which are common on many farms. There are limited 

ground-water withdrawals for both agricultural and municipal 

uses, as well as some permitted surface discharges to Morgan 

Creek.

Surface Water

Water discharge data were continuously collected by the 

USGS at one fixed streamflow-gaging station in the Morgan 

Creek Basin: USGS Station 01493500, Morgan Creek near 

Kennedyville, Maryland (fig. 12). The streamflow-gaging 

station on Morgan Creek is in Hydrologic Unit 02060002.

Mean annual discharges for water years 2003 (0.52 m3/s 

[cubic meter per second]) and 2004 (0.45 m3/s) were both 

greater than 0.31 m3/s, the long-term mean annual discharge 

for Morgan Creek (fig. 13). Interannual variation in discharge 

is fairly common. Mean annual discharge for water year 2003, 

for example, was almost three times greater than for water 

year 2002 (0.19 m3/s), which was a drought year. Seven of the 

last 10 water years have been near or greater than the longterm mean annual discharge, indicating a relatively wet period 

of time.

Mean monthly discharges for water year 2003 were 

greater than the long-term mean monthly discharges for all 

months except October and January (fig 14). In water year 

2004, mean monthly discharges were again equal to or greater 

than normal for all months, except January, March, and 

August (fig 14). 

Mean daily discharges (logarithmic scale), plotted with 

mean monthly discharges, show the relative frequency and 

duration of storm events, and the general pattern of other flow 

variations within each month. Mean daily discharge for Morgan Creek can be highly variable, and somewhat flashy due to 

the relatively small area of the basin. A successive sequence 

of storms (rainfall events) is capable of sustaining high mean 

daily discharges. In water year 2003, there were more frequent 

storms than in water year 2004; however, some of the storms 

in water year 2004 were much larger (more intense and(or) 

with greater total rainfall amounts) than those in water year 

2003. Frequent rainfall events tend to maintain saturated 

conditions in near-surface soils, resulting in sustained greater 

than average streamflow. 

1955 1959 1963 1967 1971 1975 1979 1983 1987 1991 1995 1999 2003

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

8.0

DISCHARGE, IN CUBIC METERS PER SECOND

ANNUAL DISCHARGE

01493500 MORGAN CREEK AT KENNEDYVILLE, MD

YEAR

ANNUAL DISCHARGE

MEAN DISCHARGE, 0.31

Figure 13. Long-term annual discharge at the Morgan Creek streamflow-gaging station, water years 

1952-2004 (from U.S. Geological Survey, 1952-2004).

20 Environmental Setting of the Morgan Creek Basin, Maryland, 2002-04
2.5

2.0

1.5

1.0

0.5

0.0

O N D J F M A M J J A S O N D J F M A M J J A S

MEAN MONTHLY DISCHARGE, IN CUBIC METERS PER SECOND

100.0

10.0

1.0

0.1

0.0

MEAN DAILY DISCHARGE, IN CUBIC FEET PER SECOND

2002 2003 2004

MEAN DAILY DISCHARGE

MEAN MONTHLY DISCHARGE

LONG-TERM MEAN MONTHLY DISCHARGE

Figure 14. Mean daily discharge and mean monthly discharge at the Morgan Creek streamflow-gaging station, 

water years 2003 and 2004.

Daily mean streamflow characteristics for the Morgan 

Creek Basin are summarized for water years 1952-2004 

(fig. 15). Flow duration computations show the relative percent 

of time that the daily mean streamflow exceeded the discharge 

value shown. Low flows are discharges less than 0.09 m3/s 

(90-percent exceedance), and high flows are discharges greater 

than 0.85 m3/s (5-percent exceedance).

Using steamflow-component separation techniques 

(HYSEP, local minimum method, Sloto and Crouse, 1996) for 

water years 1952-2004, the long-term median base flow for 

Morgan Creek was calculated to be 59 percent of total flow. 

This indicates that total streamflow is most often dominated by 

sustained ground-water contribution. Surface runoff accounts 

for the other 41 percent of total streamflow and dominates 

during and just after precipitation events. Streamflow separation calculations support the estimates of runoff and recharge 

in the total water budget.

Wetlands constitute less than 5 percent of the Morgan 

Creek Basin and occupy low-lying and relatively flat areas, 

mostly the floodplain and main channel of Morgan Creek and 

its tributaries (fig. 7). Many wetland areas are also forested 

and the combined forest and wetland land use is close to 

9 percent of the total study area. Because soils in the wetlands 

are frequently flooded, especially in winter and early spring, 

and poorly drained, these areas are generally unsuitable for 

most field crops. The high organic content of these soils 

creates favorable conditions for denitrification; however, other 

forms of microbial and chemical degradation of agricultural 

chemicals may occur as surface water flows through the 

forested wetlands during and after rainfall, and as ground 

water discharges in and near these areas (Böhlke and Denver, 

1995; Bachman and others, 2002). 

Ponds are fairly common in the Morgan Creek Basin and 

most were constructed for sediment retention on farm fields. 

Secondary use of these ponds is for hunting and recreation. 

As of 2002, there are 30 known retention ponds, ranging in 

size from 0.2 to 4.9 hectares. In sum, these ponds cover an 

estimated surface area of 36.8 hectares, or 1.1 percent of 

Environmental Setting: Physical and Cultural Features, Climate, and Hydrology 21
the total basin land area. Most ponds were constructed with 

design assistance from the Natural Resources Conservation 

Service (2005). Although the actual surface area of the ponds 

is relatively small, the total contributing areas to these ponds 

is considerable. These farm field ponds may increase potential 

evaporation, and can also serve as areas of focused recharge if 

unlined. 

The formation of natural ponds in uplands is inhibited 

by the presence of well-drained soils; however, some transitory ponds form in the main stem of Morgan Creek and some 

tributaries. These ponds are created by the buildup of channel 

debris, or more likely, from beaver activity, and may persist 

for weeks or even years in extreme cases. Ponds formed 

in the mainstem channel affect streamflow by delaying the 

movement of water downstream. Aside from effective use in 

sediment retention, ponds tend to slow down the traveltime of 

water in the basin, which allows for settling of other particulate matter and greater time for nutrient uptake by vegetation. 

Ground Water

In the Morgan Creek Basin, the surficial aquifer consists 

of permeable quartz sand and gravel of the Pensauken 

Formation and fine-to-medium quartz sands and glauconite 

in a silt-clay matrix of the upper part of the Aquia Formation 

(fig. 5). The depth of the surficial aquifer ranges from 15 m 

above sea level at the northern edge of the study area to near 

sea level at the southern edge (fig. 4) (Bachman and others, 

2002). Depth to the water table ranges from less than 0.4 m 

below surface in the floodplain to 12 m below land surface in 

upland areas (Bachman and others, 2002). Ground water flows 

generally from uplands toward the Morgan Creek floodplain 

at a variety of depths and time scales (Bachman and others, 

2002). In the upper reaches of the basin where the floodplain 

is narrow and floodplain sediments are thinner, direct 

discharge of ground water to the stream is possible. In the 

lower reaches of the basin, where the floodplain is wider, 

direct contribution of ground water to the stream is more 

limited, and perennial seeps along the fringes of the broad 

floodplain are a major source of ground-water discharge.

There is a wide range of ages and sources of ground 

water discharging to the Morgan Creek floodplain. Along the 

fringes of the floodplain, recently recharged water less than 

5 years old is common. Toward the middle of the floodplain, 

closer to the stream channel, ground waters traveling along 

longer and deeper flow paths are encountered, ranging in age 

from 10 to more than 30 years old, based on recent age-date 

sampling (Bachman and others, 2002). For the entire Morgan 

Creek Basin, there is regional ground-water loss via the deepest flow paths in a southeasterly direction toward an adjacent 

Figure 15. Summary of daily mean streamflow characteristics at Morgan Creek streamflow-gaging 

station, water years 1952-2004 showing percent of time that daily mean streamflow was greater than 

or equal to the discharge value shown, in cubic meters per second.

100

PERCENT OF TIME

75

50

25

0

DISCHARGE, IN CUBIC METERS PER SECOND

0.01 0.1 1 10

22 Environmental Setting of the Morgan Creek Basin, Maryland, 2002-04
basin, consistent with the overall dip and strike orientation of 

subsurface geologic units (Leon Kauffman, USGS, oral 

commun., 2005).

Floods and Droughts

Hydrologic conditions such as floods and droughts can 

be inferred, in part, from examining streamflow records. 

Morgan Creek has sustained flows typically ranging from 0.13 

to 0.27 m3/s. In the context of streamflow, a storm event for 

Morgan Creek is considered a discharge greater than 0.48 m3/s 

(10-percent exceedance), and is typically generated by 

15-25 mm (millimeters) of rainfall within a 24-hour period. 

On occasion, precipitation of great intensity and(or) long 

duration (large storm event) will create flooding conditions. 

Because Morgan Creek Basin is relatively small, large storm 

events can inflate the overall monthly, or even yearly mean 

discharges. This occurred during February 2004, when one 

storm event raised the overall mean monthly total to more than 

twice the long-term average (fig. 14).

High flows, greater than 0.85 m3/s (5-percent 

exceedence), are almost always attributed to storms and will 

visibly transport sediment. Direct field observation of streamflows greater than 2.8 m3

/s (1-percent exceedance) showed 

inundation of parts of the floodplain. Flooding events, defined 

for Morgan Creek as discharges exceeding 2.8 m3/s, were 

more common in water year 2003 (8 separate days), than in 

water year 2004 (3 separate days). The greatest instantaneous 

discharge ever measured at Morgan Creek was 317 m3/s during 

Hurricane Floyd, on September 16, 1999 (gage height, 4.6 m). 

Most examples of extreme flooding are related to hurricanes 

passing near the area.

Low streamflows are considered to be discharges less 

than 0.07 m3/s (95-percent exceedance). During the study 

period, low-flow conditions existed only during early October 

of water year 2003, a remnant of drought conditions during 

the summer of 2002. During the remainder of the study period, 

discharges never dropped below 0.14 m3/s (fig. 13). The smallest instantaneous discharge ever recorded for the period of 

record at the streamflow-measurement gage was 0.017 m3/s on 

August 28-29, 1966, during the drought of 1966. A drought is 

difficult to define solely based on low streamflow; however, as 

it also requires measurement of soil moisture, and measured 

lack of precipitation. 

Water Use

Both surface- and ground-water uses are permitted in 

the Morgan Creek Basin by the Maryland Department of the 

Environment. Because of the relatively high yielding aquifers, 

water quantity is plentiful. Ground-water quality is dependent on specific location. Regionally, water quality is highly 

affected by past and present agricultural land use (Denver and 

others, 2004).

Within Kent County, permitted ground-water withdrawals 

range from 0.38 to 30 cubic meters per day (m3/d) for small 

users and 30 to 2,700 m3/d for large users (U.S. Geological 

Survey, 1985). Small-scale uses include livestock watering, 

seasonal pond filling, and irrigation of lawns, gardens, and 

recreation fields. There are also limited withdrawals for 

drinking water for small businesses and restaurants. Largescale ground-water uses include farm irrigation, livestock 

watering and sanitation, and the Kent County Sanitary District 

at Kennedyville.

Surface-water withdrawals are limited, and primarily

used for farm irrigation. Most agricultural operations in the 

study area rely on natural rainfall. There is center pivot 

irrigation in some areas of the study area where there are welldrained soils (University of Maryland, 2005). There are no 

known or permitted surface-water withdrawals that are 

used for drinking water. 

The Kent County Sanitary District is permitted to 

discharge treated wastewater to Morgan Creek from its 

Kennedyville road facility. Most water withdrawn is either 

recharged back to ground water or is lost to evapotranspiration; very little water leaves the basin through interbasin 

transfer (Leon Kauffman, USGS, oral commun., 2005).

Summary

The Morgan Creek Basin is one of five sites selected 

for the study of sources, transport, and fate of agricultural 

chemicals by the Agricultural Chemicals Team as part of the 

U.S. Geological Survey’s National Water-Quality Assessment Program. This basin is in Kent County, Maryland, in the 

northeast region of the Delmarva Peninsula. Morgan Creek is a 

small stream that drains a 31-square-kilometer basin and flows 

directly into the tidal portion of the Chester River. It is 

surrounded by farmland and bordered by wooded riparian 

zones. There are no large towns in the basin.

Morgan Creek Basin lies within the Coastal Plain 

Physiographic Province, which is a generally flat, seawardsloping lowland with areas of moderate topographic relief. 

The basin lies within a well-drained upland region, which 

includes permeable soils and sediments that are incised by 

stream valleys. This region contains a mixed sequence of 

unconsolidated deposits of sand, silt, clay, gravel, and shells.

Soil types in the Morgan Creek Basin are predominantly 

silt loams that have some clay, but have a higher proportion 

of silts and sands. These are often found in the upland regions 

and in sloped areas away from drainages. Over half of the soils 

in the study area are classified as well drained and moderately 

well drained. Available water capacity is moderate to high. 

In cultivated areas, the potential for surface-water runoff is 

medium and the hazard for soil erosion is mostly moderate. 

The soil is strongly to extremely acidic in areas where limed 

is added. These soils are classified as prime farmland and are 

Summary 23
well suited to most crops, including row crops, pasture, hay, 

and specialty crops such as nursery stock. 

Agriculture is the main land use in the study area. Most 

agricultural land is used for row crops such as corn, soybeans, 

and small grains, and, slightly less is used used for pasture 

and hay production involving alfalfa, clover, and various 

perennial grasses. Conservation no-tillage practices are commonly employed in the row cropping of corn and soybeans. 

The major growth enhancer used is nitrogen. The majority of 

nitrogen applied comes from inorganic ammonium sulfate and 

urea-ammonium nitrate applications; however, some liquid 

dairy and solid poultry waste is used on a few fields. Glyphosate and paraquat are the major chemical herbicides used in 

soybean production and atrazine and metolachlor are the major 

chemicals used in corn production. Insecticides are rarely used 

in the study area. Irrigation is minimal. 

The Morgan Creek Basin exhibits moderate temperatures 

ranging from a mean of 25.2 degrees Celsius in July to a mean 

of 0.67 degrees Celsius in January. The mean annual precipitation is 1.12 meters. Generally, precipitation is evenly distributed throughout the year, with total amounts in spring and 

summer slightly exceeding that of fall and winter. Evapotranspiration plays a large role in the water budget. In the study 

area, an annual average of 78.4 centimeters of moisture moves 

into the atmosphere as a result of evaporation and transpiration, and this occurs predominantly during the growing season 

from April to September. 

A streamflow-gaging station on Morgan Creek was used 

to measure discharge in the study area—Morgan Creek near 

Kennedyville, Maryland (Station number 01493500). Mean 

daily streamflows for Morgan Creek are highly variable, and 

somewhat flashy due to the relatively small area of the basin. 

Frequent storm events that maintain saturated conditions in 

the basin help to sustain greater than average streamflow. The 

long-term median base flow for Morgan Creek is 59 percent 

of total flow, indicating that total streamflow is most often 

dominated by sustained ground-water contribution. Surface 

runoff accounts for the other 41 percent of total streamflow 

and dominates during and just after precipitation events. 

Ponds are fairly common in the Morgan Creek Basin, and 

most were constructed for sediment retention on farms. Some 

transitory ponds form in the main stem of Morgan Creek and 

some tributaries. These ponds are created by the buildup of 

channel debris, or more likely, from beaver activity, and may 

persist for weeks or even years in extreme cases. Aside from 

effective use in sediment retention, ponds tend to slow down 

the travel time of water in the basin, which allows for settling 

of other particulate matter and greater time for nutrient uptake 

by vegetation. 

The surficial aquifer in the study area consists of 

permeable quartz sand and gravel and is underlain by less 

permeable silt and clay. Depth to the water table ranges from 

less than 0.4 meters below land surface in the floodplain to 12 

meters below land surface in upland areas. Ground water generally flows from uplands toward the Morgan Creek floodplain 

at a variety of depths and time scales. In the upper reaches of 

the basin where the floodplain is narrow and 

floodplain sediments are thinner, direct discharge of ground 

water to the stream is possible. In the lower reaches of the 

basin, where the floodplain is wider, direct contribution of 

ground water to the stream is more limited, and a major source 

of ground-water discharge is perennial seeps along the fringes 

of the broad floodplain. 

Flooding in the Morgan Creek Basin occurs occasionally 

when precipitation is of great intensity and(or) long duration. 

High flows are almost always attributed to storms and stormflows will infrequently inundate parts of the floodplain. The 

greatest instantaneous discharge ever measured at Morgan 

Creek was 317 cubic meters per second during Hurricane 

Floyd, on September 16, 1999. Most examples of extreme 

flooding are related to hurricanes passing near the area. 

During the study period, low-flow conditions existed only 

during early October of water year 2003, a remnant of drought 

conditions during the summer of 2002. The smallest discharge 

ever recorded for the gage period of record (1951 to 2004) was 

0.017 cubic meters per second on August 28-29, 1966, during 

the drought of 1966. 

Both surface- and ground-water use is permitted in the 

Morgan Creek Basin by the Maryland Department of the 

Environment. Within Kent County, permitted ground-water 

withdrawals range from 0.38 to 30 cubic meters per day for 

small users and 30 to 2,678 cubic meters per day for large 

users. Small-scale uses include livestock watering, seasonal 

pond filling, and irrigation of lawns, gardens, and ball fields. 

There are also limited withdrawals for drinking water for 

small businesses and restaurants. Large-scale ground-water 

uses include farm irrigation, livestock watering, and sanitation. Surface-water withdrawals are limited, and used for farm 

irrigation. There are no known or permitted surface-water 

withdrawals for use as drinking water. 

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26  Environmental Setting of the Morgan Creek Basin, Maryland, 2002-04
Coordination with agencies and organizations in the Delmarva Peninsula was integral to the success of this study. We thank those 

agencies and organization that cooperated with data-collection efforts and contributed information. 

Federal Agencies

U.S. Department of Agriculture

 National Resources Conservation Service

State and Local Agencies

Delaware Department of Agriculture

Maryland Department of the Environment

Universities

University of Maryland

 Cooperative Extension, Kent County Office

We also thank the following individuals for contributing to this effort.

The numerous property and business owners who provided information on their farm management practices and allowed us access 

to their fields, wells, and streams for reconnaissance studies and sampling. 

Judith Denver, Jeffrey Barbaro, William Guertal, Scott Ator, Matt Ferrari, Leon Kauffman, William Fleck, J.K. Böhlke, Mark Sandstrom, 

Richard Healy, Tom Nolan, Larry Puckett, and Paul Capel of the U.S. Geological Survey who helped with study design and provided 

scientific advice and oversight. 

Deb Bringman, George Zynjuk, Bill Stearns, Joe Beman, Jim Jeffries, Holly Weyers, Eric Lang, Matt Baker, and James Broadwater, 

Maria Gieske, Steven Schriver, and Wade Kress of the U.S. Geological Survey who provided data collection and technical support. 

Mark Nardi, Betzaida Reyes, Mike Wieczorek, and Ted Samsel of the U.S. Geological Survey for graphics production and geographical 

information systems support. 

Glenn Berwick, Jeff Grey, Art Baehr, Tim Reilly, and Pat Mills of the U.S. Geological Survey for well-drilling services.

Report reviewers include: Paul Capel, Wesley Stone, and Wayne Newell of the U.S. Geological Survey.

For additional information, contact:

Director, Virginia Water Science Center

U.S. Geological Survey

1730 East Parham Road

Richmond, VA 23228

References Cited 27