National Capital Parks–East 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2008/039 

National Park Service 

U.S. Department of the Interior 

Natural Resource Program Center 
THIS PAGE: THIS PAGE: 

Mountian Laurel, Greenbelt Park, Maryland. Mountian Laurel, Greenbelt Park, Maryland.

ON THE COVER: ON THE COVER: 

Oxon Hill Farm, Part of Oxon Cove Park, Maryland. Oxon Hill Farm, Part of Oxon Cove Park, Maryland.

NPS Photos by John Grubka and Bill Clark. NPS Photos by John Grubka and Bill Clark.
National Capital Parks–East 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2008/039 

Geologic Resources Division 

Natural Resource Program Center 

P.O. Box 25287 

Denver, Colorado 80225 

June 2008 

U.S. Department of the Interior 

Washington, D.C.
The Natural Resource Publication series addresses natural resource topics that are of interest 

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series include vital signs monitoring plans; "how to" resource management papers; 

proceedings of resource management workshops or conferences; annual reports of resource 

programs or divisions of the Natural Resource Program Center; resource action plans; fact 

sheets; and regularly- published newsletters. 

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Printed copies of reports in these series may be produced in a limited quantity and they are 

only available as long as the supply lasts. This report is also available from the Geologic 

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gre_publications) on the internet, or by sending a request to the address on the back cover. 

Please cite this publication as: 

Thornberry- Ehrlich, T. 2008. National Capital Parks–East Geologic Resource Evaluation 

Report. Natural Resource Report NPS/NRPC/GRD/NRR—2008/039. National Park Service, 

Denver, Colorado. 

NPS D- 28, June 2008 
 NACE Geologic Resource Evaluation Report iii

Table of Contents 

List of Figures .............................................................................................................. iv

Executive Summary ...................................................................................................... 1

Introduction ................................................................................................................... 2

Purpose of the Geologic Resource Evaluation Program ............................................................................................2

Geologic Setting .........................................................................................................................................................2

Geologic Issues........................................................................................................... 10

Recreational Demands .............................................................................................................................................10

Erosion, Sediment Load, and Channel Storage........................................................................................................10

Water Issues.............................................................................................................................................................11

General Geology ......................................................................................................................................................12

Landscape Change ..................................................................................................................................................13

Geologic Features and Processes............................................................................. 14

Cretaceous Age Fossils............................................................................................................................................14

Geology and History at National Capital Parks–East................................................................................................14

Map Unit Properties .................................................................................................... 19

Map Unit Properties Table........................................................................................................................................20

Geologic History.......................................................................................................... 25

Taconic Orogeny ......................................................................................................................................................25

Acadian Orogeny......................................................................................................................................................26

Alleghenian Orogeny ................................................................................................................................................26

Triassic Extension to Cenozoic Deposition...............................................................................................................26

Quaternary Landscape Evolution .............................................................................................................................27

Glossary....................................................................................................................... 34

References................................................................................................................... 37

Appendix A: Geologic Map Graphic .......................................................................... 40

Appendix B: Scoping Summary................................................................................. 43

Appendix C: Report of the NPS Monitoring Workshop ........................................... 46

Appendix D: Geoindicators Report............................................................................ 56

Attachment 1: Geologic Resource Evaluation Products CD 
 NPS Geologic Resources Division iv 

List of Figures 

Figure 1: Physiographic provinces and regions of Maryland..........................................................................................5

Figure 2 Map of Fort Washington Park visitor use facilities............................................................................................6

Figure 3: Map of Greenbelt Park visitor use facilities .....................................................................................................7

Figure 4: Map of Kenilworth Aquatic Gardens and Marsh as part of Anacostia Park.....................................................8

Figure 5: Photograph of Oxon Cove Park and Oxon Hill Farm ......................................................................................9

Figure 6: Drawings of Astrodon johnstoni tooth............................................................................................................16

Figure 7: Drawing of the Maryland State Dinosaur.......................................................................................................16

Figure 8: Drawing showing the location of the series of forts belonging to the Fort Circle Parks .................................17

Figure 9: Drawing of Fort Dupont.................................................................................................................................18

Figure 10: Geologic time scale.....................................................................................................................................29

Figure 11: Geologic time scale specific to Virginia-Maryland. ......................................................................................30

Figures 12–14: Geologic evolution of the Appalachian Mountains in the National Capital area.........................31,32,33
 NACE Geologic Resource Evaluation Report 1

Executive Summary 

This report accompanies the digital geologic map for National Capital Parks–East, which 

the Geologic Resources Division produced in collaboration with its partners. It contains 

information relevant to resource management and scientific research. 

National Capital Parks–East provides a natural haven for 

the urbanized Washington, D.C., area. This collection of 

parks lies within the Atlantic Coastal Plain physiographic 

province and contains a wedge- shaped sequence of 

mixed sedimentary rocks and deposits of Cretaceous to 

recent age. They include sandstones, clay beds, gravel 

deposits, and silts. They form part of a thick mantle of 

relatively young rock debris, alluvium, regolith, slope 

deposits, and soils that covers the underlying 

metamorphic bedrock. This wedge of sediments can be 

as much as 3,000 m (10,000 ft) thick near the Maryland 

coast. These deposits (specifically the Arundel Clay of 

the Potomac Formation) contain fossilized remains of 

the Maryland State Dinosaur, the sauropod Astrodon 

johnstoni, as well as other Cretaceous- age plants, 

mollusks, and shark teeth. 

The experience of National Capital Parks–East begins 

with the geology and with the processes from which 

today’s environments, history, and scenery arose. 

Knowledge of the geologic resources can beneficially 

influence resource management decisions related to the 

park. Geologic processes gave rise to rock formations, 

hills, and valleys. The results of these processes played a 

prominent role in the history of the Potomac River valley 

and Washington, D.C. and influenced human use 

patterns as they developed the modern landscape. Land 

management issues include air and water quality, 

urbanization, flood risk, wildlife populations and 

invasive species, future scientific research projects, 

interpretive needs, and economic resources. Because 

many of the 98 sites that compose National Capital 

Parks–East are monuments or areas too small to contain 

significant geologic resources, regional descriptions are 

presented here with issues and recommendations for 

certain specific units. 

National Capital Parks–East protects a vast array of 

geological resources that warrant consideration in land 

use planning and in managing visitor use in the parks. 

Production of a detailed geologic map, wayside exhibits, 

and a road or trail log, along with a guidebook that ties 

National Capital Parks–East to the other parks in the 

Central Appalachian region, would help meet visitor 

information needs. These items would enhance visitor 

appreciation of the geologic history and dynamic 

processes that created the natural landscape of the parks. 

Humans have significantly modified the landscape 

surrounding the parks as well as the geologic system of 

the area. Urban developments threaten the health of the 

ecosystem. The dynamic system is capable of noticeable 

change within a human life span. 

The following features, issues, and processes have 

geological importance and a high level of management 

significance within the parks: 

• Recreation Demands 

National Capital Parks–East provides a substantial, 

heavily visited protected area between urbanized 

Washington, D.C., and Baltimore, Maryland. The 

cumulative effect of visitation places increasing 

demands on protected areas within the parks. Visitor 

use includes hiking, camping, picnicking, biking, and 

horseback riding. The landscape response to potential 

visitor overuse is a resource management concern and 

includes visitor safety, especially along stream edges, 

roads, and near waste facilities. 

• Erosion, Sediment Load and Channel Storage 

Erosion from surrounding areas and developments 

within National Capital Parks–East increases the 

sediment carried into the park by rivers and streams. 

Sediment loads and distribution affect aquatic and 

riparian ecosystems. Sediment loading can change 

channel morphology and increase the frequency of 

overbank flooding. Fine- grained sediments transport 

contaminants in a water system. Sediment loading 

typically follows a seasonal cycle and may deserve 

further investigation. 

• Water Issues 

Many small streams crossing the landscape within 

units of National Capital Parks–East, combined with 

their associated hydrogeologic system as part of the 

Anacostia River watershed, are a primary resource at 

these units. The overall quality of the streams is 

threatened by the constantly increasing urban 

development in the Maryland–Washington, D.C., 

metro area. Threats include contamination by waste 

products and road salts, deforestation along the river 

edges that increases erosion and sediment load, and 

acidification from acid rain and snow. A working 

model of the hydrogeologic system within and 

between the parks is needed to predict environmental 

responses to contaminants and to help remediate 

affected areas. 

Included with the geologic issues are a description of 

some of the cooperative geologic research efforts 

currently underway and a list of suggested action items 

related to management issues in National Capital Parks–

East. 
 NPS Geologic Resources Division 2 

Introduction 

The following section briefly describes the National Park Service Geologic Resource 

Evaluation Program and the regional geologic setting of National Capital Parks–East. 

Purpose of the Geologic Resource Evaluation Program 

The Geologic Resource Evaluation (GRE) Program is 

one of 12 inventories funded under the NPS Natural 

Resource Challenge designed to enhance baseline 

information available to park managers. The program 

carries out the geologic component of the inventory 

effort from the development of digital geologic maps to 

providing park staff with a geologic report tailored to a 

park’s specific geologic resource issues. The Geologic 

Resources Division of the Natural Resource Program 

Center administers this program. The GRE team relies 

heavily on partnerships with the U.S. Geological Survey, 

Colorado State University, state surveys, and others in 

developing GRE products. 

The goal of the GRE Program is to increase 

understanding of the geologic processes at work in parks 

and provide sound geologic information for use in park 

decision making. Sound park stewardship relies on 

understanding natural resources and their role in the 

ecosystem. Geology is the foundation of park 

ecosystems. The compilation and use of natural resource 

information by park managers is called for in section 204 

of the National Parks Omnibus Management Act of 1998 

and in NPS- 75, Natural Resources Inventory and 

Monitoring Guideline. 

To realize this goal, the GRE team is systematically 

working towards providing each of the identified 270 

natural area parks with a geologic scoping meeting, a 

digital geologic map, and a geologic report. These 

products support the stewardship of park resources and 

are designed for non- geoscientists. During scoping 

meetings the GRE team brings together park staff and 

geologic experts to review available geologic maps and 

discuss specific geologic issues, features, and processes. 

The GRE mapping team converts the geologic maps 

identified for park use at the scoping meeting into digital 

geologic data in accordance with their innovative 

Geographic Information Systems (GIS) Data Model. 

These digital data sets bring an exciting interactive 

dimension to traditional paper maps by providing 

geologic data for use in park GIS and facilitating the 

incorporation of geologic considerations into a wide 

range of resource management applications. The newest 

maps come complete with interactive help files. As a 

companion to the digital geologic maps, the GRE team 

prepares a park- specific geologic report that aids in use 

of the maps and provides park managers with an 

overview of park geology and geologic resource 

management issues. 

For additional information regarding the content of this 

report and up to date GRE contact information please 

refer to the Geologic Resource Evaluation Web site 

(http://www2.nature.nps.gov/geology/inventory/). 

Geologic Setting 

National Capital Parks–East is a collection of parks and 

sites that encompass over 8,000 acres of protected land 

in the Washington, D.C., area. The group includes 

Greenbelt Park, Anacostia Park, Kenilworth Park and 

Aquatic Gardens, Kenilworth Marsh, Mary McLeod 

Bethune Council House National Historic Site, Frederick 

Douglass National Historic Site, Capitol Hill Parks, Fort 

Circle Parks also known as the Civil War Defenses of 

Washington (including several Civil War forts, Fort 

Foote, Fort Stanton, Fort Dupont, etc.), Fort Washington 

Park, Shepherd Parkway, Oxon Cove Park and Oxon Hill 

Farm, Oxon Run Parkway, Sewall- Belmont House 

National Historic Site, Baltimore- Washington Parkway, 

Suitland Parkway, Piscataway Park (with Hard Bargain 

and National Colonial Farms), Harmony Hall, and others 

located over 98 sites. 

These NPS units protect natural areas for recreation, 

parkway corridors, archaeological sites, wetlands, river 

valleys, forests, wildlife, vegetation, historical artifacts 

and structures, springs and seeps. These parks and sites 

hosted 1,311,087 recreation visits in 2007, not including 

the millions of commuters that use the parkways each 

day. National Capital Parks–East units extend from Anne 

Arundel County, Maryland at the northern terminus of 

the Baltimore- Washington Parkway, through portions of 

the District of Columbia and Prince George’s County, 

Maryland, then southeast to its southernmost point at 

Piscataway Park in Charles County, Maryland. 

The land covered by National Capital Parks–East shelters 

a haven of natural beauty in the heavily urbanized 

Washington, D.C., area, all within the Atlantic Coastal 

Plain physiographic province (fig. 1). This area includes 

small portions of approximately 20 streams, several of 

which emerge from underground pipes into the 

watershed as part of storm water management facilities. 

Principal waterways include Henson, Fort Dupont, 

Deep, and Still creeks, Pope and Watts branches, and 

Oxon Run. Most of the streams are part of the Anacostia 

River watershed, which in turn is part of the greater 

Potomac River system. At 616 km (383 miles) in length, 

the Potomac River is the second largest contributor to 

the Chesapeake Bay. The Potomac watershed covers 

38,018 square km (14,679 square miles) across Maryland, 

Pennsylvania, Virginia, the District of Columbia, and 

West Virginia. 

The following larger parks with in National Capital 

Parks–East are described in more detail as they contain 
 NACE Geologic Resource Evaluation Report 3

significant geologic resources identified during the GRE 

scoping meeting in 2001. 

• Fort Washington (fig. 2) once guarded the water 

approach to the nation’s capital. The existing fort was 

completed on October 2, 1824. It sits on high ground 

above the Potomac River on the Maryland shore 

providing views of Washington, D.C., and Virginia. 

The park is located 17 km (11 miles) south of 

Washington, D.C., in Prince George’s County. The 

park protects 341 acres of historical and natural 

significance on a point of land between the 

confluences of Swan Creek and Piscataway Creek with 

the Potomac River. 

• Piscataway Park, located in Prince George's and 

Charles counties, Maryland, was created as part of a 

project to protect the river view of Mount Vernon and 

to preserve its appearance from George Washington’s 

time. This 4,625- acre park stretches 10 km (6 miles) 

from Piscataway Creek to historic Marshall Hall (circa 

1725 plantation of Thomas Marshall) on the Potomac 

River. 

• Greenbelt Park (fig. 3) covers more than 1,176 acres in 

Maryland as a haven of natural beauty in Prince 

George’s County. It was acquired and designated a 

national park in August 1950 under Public Law 643. In 

June 2000, one of the park’s trails was designated a 

millennium trail, and in June 2001, another was 

designated an American discovery trail. The park is 

located entirely within the Atlantic Coastal Plain 

physiographic province and in the western shore 

uplands region. Approximately 1.8 km (1.1 miles) wide 

and up to 2.1 km (1.3 mile) long, it extends southward 

from Capitol Drive to Good Luck Road and straddles 

Deep and Still creeks. These streams flow into the 

Northeast Branch of the Anacostia River below Indian 

Creek. The Baltimore- Washington Parkway 

(described below) bisects the park. Landforms within 

the park are rolling to steep hills with ravines 

associated with the two creeks. Elevation ranges from 

8 to 60 m (25 to 200 ft) above sea level (National Park 

Service 2003). 

• Baltimore- Washington Parkway bisects Greenbelt 

Park and provides a 47- km (29- mile) scenic corridor 

between the urban areas surrounding Washington, 

D.C., and Baltimore, Maryland. Thousands of 

commuters use this parkway each day. The parkway 

opened in 1954 after approval in 1902, but was 

conceived by Pierre L’Enfant in his 18th century plan 

to create Washington, D.C., as a city of beautiful parks. 

The National Park Service manages the portion 

between Washington, D.C, and Fort Meade, 

Maryland. 

• Oxon Run Parkway is located between Mississippi and 

Southern Avenues, and 13th Street SE within 

Washington, D.C. The 126 acres of protected area 

include wetlands, floodplains, springs, and forests in a 

natural sanctuary within the urban area. 

• Fort Circle Parks or Civil War Defenses of Washington 

including Fort Dupont, Fort Foote, Fort Stanton, Fort 

Mahan, Fort Carroll, Fort Davis, and Fort Chaplin 

were all part of the Union Civil War defenses of 

Washington, D.C. Fort Dupont covers 376 acres of 

rolling woodland in Washington, D.C., east of the 

Anacostia River. The forts themselves are almost all 

earthworks. 

• Oxon Cove Park and Oxon Hill Farm (fig. 4) preserve 

an early 20th century landscape in eastern Maryland. 

The park and farm straddle the boundary between 

Washington, D.C., and Prince George’s County, 

Maryland. The landscape at Oxon Cove Park and 

Oxon Hill Farm ranges from high river terraces to flat 

river shorelines to intermediate rolling hills created by 

the remediation of a landfill in the 1970s. 

• Anacostia Park protects more than 1,200 acres in 

Washington, D.C. It is one of the region’s largest and 

most visited recreation areas. As an urban park, 

Anacostia includes a sports area, a golf course, a boat 

launch, and performance facilities. Natural resources 

within the park include riparian forests and wetlands, 

river shoreline, and floodplain areas. 

• Kenilworth Park and Aquatic Gardens and Kenilworth 

Marsh (fig. 5) cover some 700 acres within Anacostia 

Park. These parks owe their origins to both the 1791 

L’Enfant Plan for the District of Columbia and the 

McMillan Plan of 1901 that recommended protecting 

public parklands along the Anacostia River. In 1938, 

Kenilworth Aquatic Gardens became the only 

National Park Service unit devoted to the propagation 

and demonstration of aquatic plants. This park is a 

living laboratory for investigating coalification 

processes (O’Connor 1980). The Kenilworth Marsh 

covers 77 acres and surrounds the aquatic gardens on 

three sides. This tidal marsh is all that remains of the 

once vast tidal wetland areas within the capital. Much 

of Kenilworth is underlain by a land fill which emits 

methane used for heating the greenhouse. 

• Suitland Parkway, now a scenic highway used by 

numerous commuters and visitors, was built during 

World War II to connect Andrews Air Force Base, 

Bolling Air Force Base, the Pentagon, and downtown 

Washington, D.C. The parkway opened on December 

9, 1944. Suitland Parkway Legislation was enacted in 

1949 (63 stat 612). It extends 15 km (9.35 miles) from 

Washington to Maryland Route 4 in Prince George’s 

County. The National Park Service manages the 10 km 

(6 miles) of parkway and 610 acres in Maryland. The 

landscape is forested with ample water provided by 

numerous streams, and includes wetlands associated 

with Henson Creek. Among the cultural features in the 

park are stone road works and nine stone- faced 

bridges. 

• Shepherd Parkway is named for the popular post–Civil 

War mayor of Washington, D.C., responsible for many 

of the city’s modern upgrades. The Parkway was 

originally part of the ill- fated Fort Circle Drive 

proposal, which would have connected the preserved 

Civil War defenses of Washington, D.C., in a scenic 

parkway setting. However, delayed by world wars and 

other national issues, the logistics of the drive proved 

too difficult to complete. Today, Shepherd Parkway 

runs parallel to the eastern side of Interstate Highway 
 NPS Geologic Resources Division 4 

295 from Lebaum Street SE to Irvington Street SW in 

the Congress Heights area of the city. This stretch 

provides a natural haven for bald eagles nesting in the 

vicinity. 

• Harmony Hall in Prince George’s County, Maryland, 

was acquired by the National Park Service in 1966 

under the provisions of the Capper- Crampton Act of 

1930. This 18th century Georgian country house was 

listed on the National Register of Historic Places in 

1980 and appears much as it did in 1766 (estimated 

construction date). 

• Frederick Douglass National Historic Site (formerly 

known as Frederick Douglass Home) was designated 

on February 12, 1988. This site commemorates the 

home of the leading 19th century African American 

spokesman who lived there between 1877 and 1895. 

The home (named Cedar Hill) and surrounding 

landscape cover 9 acres within Washington, D.C. 

A general description follows of several of the different 

physiographic provinces of the eastern United States, 

relevant to understanding the geologic history of the 

National Capital Parks–East region (fig. 1). 

Atlantic Coastal Plain Province 

The Atlantic Coastal Plain province is primarily flat 

terrain with elevations ranging from sea level to about 

100 m (300 ft) in Maryland. It extends from New York to 

Mexico. Sediments eroding from the Appalachian 

highland areas to the west formed the province. 

Intermittent deposition during periods of higher sea level 

over the past 100 million years resulted in a wedgeshaped sequence of soft sediments more than 2,400 m 

(7,900 ft) thick at the Atlantic Coast. The deposits were 

reworked by fluctuating sea levels and the continual 

erosive action of waves along the coastline. 

The province continues as the submerged Continental 

Shelf for another 121 km (75 miles) to the east. The 

Coastal Plain province stretches from the Fall Line east 

to the Chesapeake Bay and Atlantic Ocean. Large 

streams and rivers in the Coastal Plain province, 

including the James, York, Rappahannock, and Potomac 

rivers, continue to transport sediment and to extend the 

Coastal Plain eastward. 

Piedmont Province 

The “Fall Line” or “Fall Zone” marks a transitional zone 

where the softer, less consolidated sedimentary rock of 

the Atlantic Coastal Plain to the east intersects the 

harder, more resilient metamorphic rock to the west, 

forming an area of ridges, waterfalls, and rapids 

(Withington and Coulter 1964). This zone covers over 27 

km (17 miles) of the Potomac River from Little Falls Dam, 

near Washington, D.C., west to Seneca, Maryland. 

Examples of this transition are present in the Potomac 

Gorge of the Chesapeake and Ohio Canal National 

Historic Park and at Great Falls Park. The Piedmont 

physiographic province encompasses the Fall Line 

westward to the Blue Ridge Mountains. 

The eastward- sloping Piedmont formed through a 

combination of folding, faulting, metamorphism, uplift, 

and erosion. The result is a landscape of gently rolling 

hills in the east starting at 60 m (200 ft) in elevation. The 

hills become gradually steeper toward the western edge 

of the province where they reach 300 m (1,000 ft) above 

sea level. The Piedmont is composed of hard, crystalline, 

igneous, and metamorphic rocks including schists, 

phyllites, slates, gneisses, and gabbros. 

A series of Triassic age extensional basins occur within 

the Piedmont. These basins were formed by normal 

faults during crustal extension. The faults opened basins 

(grabens) that were rapidly filled with roughly horizontal 

layers of sediment. Examples include the Frederick 

valley in Maryland and the Culpeper valley of northern 

Virginia. 

Blue Ridge Province 

The Blue Ridge province extends from Pennsylvania to 

Georgia along the eastern edge of the Appalachian 

Mountains. Its highest elevations occur in North 

Carolina near Great Smoky Mountains National Park. 

Precambrian and Paleozoic igneous, sedimentary, and 

metamorphic rocks were uplifted during several 

orogenic events to form the steep, rugged terrain. 

Resistant Cambrian age quartzites form Blue Ridge, Bull 

Run Mountain, South Mountain, and Hogback Ridge in 

Virginia (Nickelsen 1956). South Mountain and Catoctin 

Mountain, both anticlines, are two examples of the 

pervasive folding in the Blue Ridge province. Eroding 

streams have narrowed the northern section of the Blue 

Ridge Mountains into a thin band of steep ridges, 

climbing to heights of more than 1,200 m (4,051 ft at 

Hawksbill in Shenandoah National Park). The Blue 

Ridge province is typified by steep terrain covered by 

thin, shallow soils that result in rapid runoff and low 

groundwater recharge rates. 

Valley and Ridge Province 

Long, parallel ridges separated by valleys characterize the 

landscape of the Valley and Ridge physiographic 

province. The valleys formed where more easily eroded 

shale and carbonate formations occur between resistant 

sandstone ridges. The province contains strongly folded 

and faulted sedimentary rocks in western Maryland. 

Areas dominated by carbonate formations exhibit karst 

topography. Karst describes landscapes of irregular 

topography with features such as sinkholes, 

underground streams, caves, and springs formed by 

water percolating through water- soluble rock. The 

karstic eastern portion of the Valley and Ridge province 

is part of the Great Valley (Shenandoah Valley). The 

Valley and Ridge province connects to the Piedmont 

province by streams that cut through the Blue Ridge 

Mountains. 
 NACE Geologic Resource Evaluation Report 5

Figure 1: Physiographic provinces and regions of Maryland showing the rough location of National Capital Parks–East. Graphic is

adapted from Maryland Geological Survey (2001). 
 NPS Geologic Resources Division 6 

Figure 2: Map of Fort Washington Park’s visitor use facilities. Graphic is courtesy of the National Park Service. 
 NACE Geologic Resource Evaluation Report 7

Figure 3: Map of Greenbelt Park’s visitor use facilities. Graphic is courtesy of the National Park Service. 
 NPS Geologic Resources Division 8 

Figure 4: Map of Kenilworth Aquatic Gardens and Marsh as part of Anacostia Park. Map shows visitor use facilities. Graphic is 

courtesy of the National Park Service. 
 NACE Geologic Resource Evaluation Report 9

Figure 5: Photograph of Oxon Cove Park and Oxon Hill Farm showing surrounding rural landscape and rolling topography. Photograph 

is courtesy of the National Park Service. 
 NPS Geologic Resources Division 10 

Geologic Issues 

A Geologic Resource Evaluation scoping session was held for National Capital Parks–

East on April 30–May 2, 2001, to discuss geologic resources, address the status of geologic 

mapping, and assess resource management issues and needs. In addition two other 

meetings–one held on July 9–11, 2002 focused on monitoring and the other held on May 

20, 2002 focused on the influence of geologic processes and humans– are referenced in 

the following section. This section synthesizes results of these meetings, with emphasis on 

those issues that may require attention from resource managers. 

Recreational Demands 

The National Park Service has a mission to protect park 

resources for the enjoyment of current and future 

generations. National Capital Parks–East provides 

numerous recreational possibilities including hiking on 

14 km (9 miles) of trails, ball fields, golfing (in Anacostia 

Park), swimming, musical performances and ice skating 

(at Fort Dupont’s outdoor summer stage and indoor ice 

rink), boat ramp access, fishing, farm activities, 

backpacking, bird watching, camping, horseback riding, 

jogging, nature walks, interpretive programs, bicycling, 

picnicking, cross- country skiing, and photography. The 

parks promote activities that do not damage resources or 

endanger visitors. 

More than 1,300,000 people made recreational visits to 

National Capital Parks–East units in 2007. This number 

does not include many commuters and other drivers 

passing through the parks on the Baltimore- Washington, 

Shepherd, Suitland, and Oxon Run parkways. The large 

number of visitors places increasing demands on the 

resources of the parks. Management concerns include 

trail erosion, water quality, meadowland health, and 

riverbank erosion. 

Many trails wind through preserved biologic, historic, 

and geologic environments at the parks. Many of these 

environments are fragile, and off- trail hiking promotes 

their degradation. The unconsolidated soils and 

sediments along the more than 20 rivers and streams (e.g. 

Deep and Still creeks in Greenbelt Park, Oxon Run in 

Oxon Cove Park, Pope and Watts branches in 

Kenilworth Park, Henson Creek at Suitland Parkway and 

Harmony Hall, Fort Dupont Creek at Fort Dupont Park, 

Anacostia River in Anacostia Park) in National Capital 

Parks–East are often exposed on slopes with sparse 

vegetation. This exposure and/or flooding render them 

highly susceptible to erosion and degradation. 

The parks use designated trails and picnic areas to 

concentrate the impacts of recreation (figs. 2- 4). Trails 

include the Blueberry, Azalea, Perimeter, and Dogwood 

trails in Greenbelt Park, and River Trail in Kenilworth 

Aquatic Gardens and Marsh. Picnic areas such as Holly, 

Sweetgum, and Laurel in Greenbelt Park as well as 

campgrounds and their associated facilities all have an 

impact on the natural resources at National Capital 

Parks–East. Prohibited use in non- designated areas 

increases the area of human impact and places delicate 

ecosystems at risk for contamination and physical 

damage. 

Inventory, Monitoring, and Research Suggestions for 

Recreational Demands 

• Design wayside exhibits to encourage responsible use 

of park resources. 

• Monitor erosion rates along trails; repair and stabilize 

damage. 

• Promote programs to develop a new trail linking Fort 

Circle parks, taking into account local geologic 

features and avoiding areas prone to erosion and slope 

creep. 

• Plant stabilizing native vegetation along slopes at risk 

for slumping and erosion. Special attention is needed 

for historic earthworks and other structures. 

Erosion, Sediment Load, and Channel Storage 

Erosion of the landscape within the Anacostia watershed 

leads to increases in sediment carried by park streams as 

well as slope instability and gullying of unconsolidated 

Mesozoic and Cenozoic Atlantic Coastal Plain sediments 

(including silts and clays) (O’Connor and Withington 

1977). The likelihood of slumps and slides increases with 

undercutting of slopes by roads, trails, and other 

development in addition to natural erosion. 

Slope stability and soil loss is a problem along the 

Baltimore- Washington and Shepherd parkways as well 

as in Fort Dupont Park. Unstable slopes are also a 

management concern in the Newcomb Street area, and a 

large retaining wall was erected to combat slope creep 

along O Street SE affecting Shepherd Parkway and 

Anacostia Park, respectively. 

Soils provide an important link between geology and 

biology, they support life and are derived from 

underlying bedrock, augmented by transported 

sediments and nutrients as well as organic matter. The 

geology, or the rock types, from which the soils are 

derived, influences soil chemistry. Regional soils 

developed from a variety of basement rocks including 

limestone, greenstone, red shale, and quartzite. 

The Soil Resources Inventory (SRI) Program of the NPS 

Geologic Resources Division is working with the Natural 
 NACE Geologic Resource Evaluation Report 11

Resources Conservation Service (NRCS) to complete a 

soil survey for Greenbelt Park, Maryland. This project is 

underway and projected for completion in 2009. Other 

units of National Capital Parks–East do not have a SRI 

scheduled at this time due to lack of funding. Soil 

resource inventories equip parks with maps showing the 

locations and extent of soils; data about the physical, 

chemical, and biological properties of those soils; as well 

as information regarding potential uses and limitations of 

each kind of soil type. 

The amount of construction caused erosion and pulses 

of sediment released to waterways depends on the types 

of mitigation measures required and enforced by local 

government entities. Slump events of any type cause soil 

loss and provide a large pulse of sediment to park 

waterways. Sediment loads and distribution affect 

aquatic and riparian ecosystems, and sediment loading 

can result in changes to channel morphology and 

increase the frequency of overbank flooding. 

Uncontrolled runoff has great impact on channel 

morphology. Many local streams are in the process of 

downcutting and widening, threatening habitat and 

property. Naturally stable channel morphology is the 

result of a dynamic equilibrium between mutually 

adjusting variables such as sediment load, flow 

magnitude, frequency and duration of high stands 

(Symborski et al. 1996). 

Suspended sediment load is a resource management 

concern because it can contaminate drinking water 

sources and increase concentrations of toxic chemicals 

formerly trapped in river bottom sediments. However, 

fine- grained sediments are also vital in the overall fluvial 

transport of contaminants in a water system. Some 

pesticides can bond to soil particles that are then 

transported by erosion (Anderson et al. 2002). The 

National Park Service manages portions of the bottom of 

the Anacostia River and cooperates with the 

Environmental Protection Agency (EPA) on toxic 

substance issues through the Anacostia Watershed 

Toxics Alliance (reference http://www.chesapeake 

bay.net/awta/guide/home/awta.html). Other agencies 

such as the Washington Area Council of Governments 

and the Anacostia Watershed Coordination Committee 

are also cooperating with the National Park Service for 

work on the Anacostia River. 

The National Park Service Water Resources Division is 

monitoring sites along the river and has drilled several 

cores near the Washington Navy Yard. Information from 

these cores, in addition to local piezometer (pore 

pressure gauge) data, adds greatly to the understanding 

of sediment composition, changes, and distribution in 

the watershed. The Water Resources Division should be 

contacted with further concerns. 

Channel storage of fine sediment and the contaminants 

contained therein follow a seasonal cycle. This cycle is 

subject to hydrologic variability with increased 

availability during the high stands of spring and 

decreased availability during the low stands of autumn. 

Fine- grained sediments do not travel downstream in a 

single pulse but are often resuspended bottom material 

(Miller et al. 1984). This intermittent transport of 

contaminants and fine- grained sediment increases the 

affected area. 

Inventory, Monitoring, and Research Suggestions for 

Erosion, Sediment Load, and Channel Storage 

• Monitor erosion rates by establishing key sites for 

repeat profile measurements to document rates of 

erosion or deposition and reoccupy, if possible, 

shortly after major storms. Repeat photography may 

be useful. 

• Perform a comprehensive study of active erosion and 

weathering processes at the park, accounting for slope 

aspects, location, and likelihood of instability. 

• Assess impacts of human activity on sedimentation and 

erosion including facility placement, recreation, storm 

management systems, parking lots, etc. 

• Monitor sediment inflow originating from unstable fill 

to the Yeager Tract to determine if stability is realized 

at Greenbelt Park. 

Water Issues 

Annual precipitation in Washington, D.C., averages ~111 

cm (43.7 inches) per year with almost half of the rain 

coming in the summer months during storms of short 

duration. Water resources are under constant threat of 

contamination and overuse because of development of in 

surrounding areas. Sedimentation increases when landclearing and earth- moving for development exposes 

barren soil to erosion. Water temperature increases 

because of the insulating nature of impervious surfaces 

(Allen and Flack 2001). Runoff from a parking lot on a 

hot July day is at a much higher temperature than the 

water temperature of runoff from a grassy slope. 

Much of more than 20 waterway corridors within 

National Capital Parks–East are beyond National Park 

Service jurisdiction. Deep and Still creeks, Henson 

Creek, Oxon Run, Fort Dupont Creek, Pope and Watts 

branches, and the Anacostia River are some of the more 

prominent waterways managed in part by Greenbelt 

Park, Suitland Parkway and Harmony Hall, Oxon Run 

Park, Fort Dupont Park, Kenilworth Park, and Anacostia 

Park, respectively. The National Park Service has little 

control over water quality, flow, and sediment load. 

Groundwater in most of National Capital Parks–East 

trickles through unconsolidated Cretaceous and younger 

aged sediments. Groundwater discharges directly into 

the park’s streams and local springs from pipes and from 

those places where the water table intersects the surface. 

The strongest regional effects on water quality in the 

creeks and rivers are due to increased urban 

development and increased surface runoff, which results 

from the addition of impervious surfaces in the basin, 

such as roads, parking lots, and playgrounds among 

others (Anderson et al. 2002). Unless there is mitigation 

of run- off by storm water management systems, impacts 

from impervious surfaces, begin when they cover 10% of 
 NPS Geologic Resources Division 12 

the watershed. A 20% land cover of the watershed by 

impervious surfaces leads to severe impacts on the 

watershed (Allen and Flack 2001). 

Urban developments lead to reduced base flow as a 

result of the reduction of the infiltration of groundwater 

and the channeling of water through storm water 

management facilities, thus contributing to higher peak 

flows. Higher peak flows can result in destructive 

flooding conditions along waterways. These high flows 

destroy viable habitat. Further impacts to watershed 

health include chemical pollutants (oil, grease, brake 

fluid, coolant, etc.) leaking from vehicles along roadways, 

in parking lots, and in construction areas; litter and trash 

washed in from other areas,; and flushes of sediment 

from new construction sites. 

Increased human habitation in surrounding areas also 

leads to long term increases in pesticides, fertilizers, and 

herbicides as well as increases in mercury, arsenic, lead, 

aluminum, sewage, pharmaceuticals, and endocrine 

disrupters within the hydrologic regime. Road crossings 

and water management culverts also serve to fragment 

viable habitat for plant and animal species in the area. 

The removal of culverts from streams has been proposed 

in Anacostia and other parks, with potential for 

cooperation with the U.S. Army Corps of Engineers 

(COE). Culvert removal may promote the regrowth of 

fringe wetlands, but may impact flood- control levees. 

Several of these flood- control levees are routinely 

inspected by the COE. Many are on NPS land along the 

Anacostia River. The degree of NPS responsibility to 

maintain these structures is not well defined. 

The integrity of the watershed is directly reflected in the 

quality of water in the creeks and rivers. Streams 

integrate surface runoff and groundwater flow and thus 

provide a cumulative measure of water quality within the 

hydrologic regime. 

Differences in water quality stem from a variety of 

natural and non- natural sources. For instance, major 

geochemical differences exist among water samples from 

areas underlain by different lithologic units (Bowser and 

Jones 2002). It is important to know the mineral 

compositions for both the aqueous phase and the host 

rock. 

The movement of nutrients and contaminants through 

the hydrogeologic system can be modeled by monitoring 

the composition of system inputs, such as rainfall, and 

outputs, such as streamflow. Other input sources include 

wind, surface runoff, groundwater transport, sewage 

outfalls, landfills, and fill dirt. Consistent measurement 

of these parameters is crucial to establishing baselines for 

comparison. 

Inventory, Monitoring, and Research Suggestions for Water 

Issues 

• Work with the NPS Natural Resource Program 

Center’s Water Resources Division to address specific 

areas of concern and design effective water quality 

monitoring programs. 

• Establish and/or maintain working relationships with 

the U.S. Geological Survey, the Environmental 

Protection Agency, and the Maryland Geological 

Survey as well as local to national conservation groups 

to study and monitor park watersheds and the 

hydrology of the area for applications in 

hydrogeology, slope creep, stream bank erosion, and 

other geologic hazards. 

• Monitor morphologic changes in stream channels 

within the parks. 

General Geology 

A meeting held in August 2002 to assess geologic 

monitoring objectives for the National Capital Region 

Vital Signs Network (including Wolf Trap National Park 

for the Performing Arts) identified the following geologic 

resource components: soils and bedrock, ground water, 

bare ground and exposed rock, karst, surface water, 

coastal areas, and riparian areas and wetlands. Resource 

management could benefit from consideration of these 

components and their contributions to the entire 

ecosystem. 

Stresses to these components include nutrient and 

chemical contamination, sediment erosion and 

deposition, shoreline changes, and geo- hazards. These 

stressors are potential areas for ecosystem monitoring. 

Primary sources of stress to the natural resources at 

National Capital Parks–East that were identified are: acid 

rain, atmospheric deposition of contaminants, urban 

development, climate change, abandoned mines and 

wells, and visitor use. 

Digital geologic data facilitates science based decision 

making for resource managers by allowing integration 

with other spatial data in a GIS. Potential uses of digital 

geologic data include: 

1. identification and description of critical habitats for 

rare and endangered species; 

2. hazard assessments for events such as floods, 

rockfalls, or slumps; 

3. creation of interpretive programs to illustrate the 

evolution of the landscape and Earth history of the 

park in lay- person terms; 

4. identifying the location of sources of aggregate and 

building stone for historical reconstruction; 

5. determining environmental impacts for any new 

construction; 

6. inventory of natural features such as springs, cliffs, 

marker beds, fossil localities, and caves; 

7. characterizing land use; and 

8. defining ecological zones and implementing 

conservation plans (Southworth and Denenny 

2003). 
 NACE Geologic Resource Evaluation Report 13

Inventory, Monitoring, and Research Suggestions for 

General Geology 

• Develop a geological site bulletin or brochure, and 

collect and display geological data using GIS/GPS. 

• Investigate the surficial geologic story at the parks and 

develop an interpretive program to relate the current 

landscape, ecosystem, history, and biology to the 

geology. 

Landscape Change 

Since the earliest settlements in the Washington, D.C., 

area the landscape has been altered by cutting forests, 

removing soils, flattening hills, filling valleys, 

construction of roads and parkways, and urban 

development. Development has resulted in significant 

changes in the elevation and slope of the land surfaces at 

National Capital Parks–East. Typically, hills are flattened 

and stream valleys and marshes are filled in. According to 

a comparison between current digital elevation model 

(DEM) data and a pre- development DEM from 1889 

topographic data, Chirico and Epstein (2000) 

documented as much as 18 m (60 ft) of elevation change 

for the Philadelphia area. 

Similar data are available for this comparison for 

Washington, D.C., including U.S. Coast and Geodetic 

Survey 1:4,800 scale maps from 1878 and 1888, sewer- line 

maps from 1891 and 1892, and digital U.S. Geological 

Survey topographic map data from surveys in 1996–1999. 

Significant topographic change from urban development 

in the area has occurred affecting the rates of runoff, 

infiltration, and erosion. 

Elevation data are needed throughout National Capital 

Parks–East to monitor shoreline marshes such as 

Accokeek marsh, as well as the restored marsh at 

Kenilworth Park. Very slight changes in elevation on the 

scale of 0.3 m (1 ft) appear to significantly effect 

vegetation distribution in wetlands. Implications exist for 

assessment of regulations and methodologies for 

marshland restoration and remediation. 

Seawalls are common along the Anacostia River, 

affecting shorelines within Anacostia Park and farther 

downstream. Seawalls and reductions in woody debris 

along shores reduce protection from erosion, affecting 

coastal marshes and other areas farther downstream 

such as Piscataway Park. 

Several of the parks within National Capital Parks–East 

include reclaimed landfills, all of which were operational 

before environmental standards were enforced by 

regulations. The total area within the National Capital 

Parks–East units occupied by former landfills is close to 

300 acres. The old city dump sits beneath portions of 

Kenilworth Park and may pose a methane hazard 

(O’Connor 1980). Cooperative efforts with the EPA and 

U.S. Geological Survey monitor outflow from landfills. 

These efforts attempt to prevent toxic leachates from 

reaching the Potomac and Anacostia rivers. In addition 

to surface water quality, soil and groundwater quality are 

necessary parameters to define in landfill area impact 

studies. 

Inventory, Monitoring, and Research Suggestions for 

Landscape Change 

• Determine impacts of human landscape change 

activities on sedimentation and erosion processes. 

Focus on facility placement, culverts, parking lots, 

stream and storm sewer outfalls, roads, etc. 

• Monitor morphological changes in slopes and stream 

channels, relating them to any past developments. 
 NPS Geologic Resources Division 14 

Geologic Features and Processes 

This section describes the most prominent and distinctive geologic features and processes 

in National Capital Parks–East. 

Cretaceous Age Fossils 

Dinosaurs inhabited central Maryland during much of 

the Mesozoic Era. The regional climate ranged from a 

shallow, warm sea to tropical lowlands. At least 12 species 

of dinosaurs have been documented in the area from the 

Late Triassic (228 Ma) to the Late Cretaceous (70 Ma). 

Intermittent volcanic activity and heavy sedimentation 

from the highlands to the west during the Mesozoic 

provided ideal conditions for fossil formation and 

preservation (Reger 2005). Sediments and volcanic ash 

rapidly buried animal and plant remains. Remains not 

destroyed by scavenging or erosion were preserved as 

the sediments lithified. 

In the National Capital Parks–East area, dinosaur and 

other fossils are found in the Arundel Clay of the Lower 

Cretaceous Potomac Formation. To the east of the parks, 

other units including the Severn and Mt. Laurel 

Formations from the Upper Cretaceous also contain 

fossils. The Upper Triassic Gettysburg Shale, located in 

the Frederick Valley northwest of National Capital 

Parks–East, is fossiliferous. Jurassic age rocks are not 

exposed in Maryland (Reger 2005). 

In 1858, Philip T. Tyson discovered two dinosaur teeth in 

an open pit iron mine within the Arundel Clay (fig. 6). 

This mine was near Muirkirk in Prince George’s County 

on the property of J.D. Latchford. The species of these 

teeth was named Atrodon johnstoni by Dr. Joseph Leidy, 

making it the first sauropod dinosaur described in North 

America. Other exploration yielded a wealth of fossils in 

the area. At one time, the Arundel Clay between 

Washington and Baltimore was known as “dinosaur 

alley” (Kranz 2004; Conkwright 2005). 

Fossils from this clay now reside in many museums, 

including the Smithsonian Institution in Washington, 

D.C. Astrodon johnstoni, the official Maryland State 

Dinosaur as of October 1 1998, was a large herbivorous 

species growing to lengths of 18 m (60 ft) or more (fig. 7). 

Recent explorations in the area have revealed partial 

femurs, fragments of which are more than 1 m (3 ft) in 

length and weigh approximately 40 kg (90 lbs) (Kranz 

2004; Conkwright 2005). 

With urban development rapidly covering the land 

surface near National Capital Parks–East, the parks may 

be preserving valuable dinosaur, mollusk, plant, and 

shark fossils for future study. In December 1995, the 

Maryland–National Capital Park and Planning 

Commission acquired J.D. Latchford’s property for the 

development of a dinosaur park (Kranz 2004). 

A Paleontological Resource Inventory and Monitoring 

Report has been completed for the National Capital 

Region, which includes National Capital Parks–East. 

This literature based inventory has been prepared for 

NPS administration and resource management staff and 

is not intended for distribution to the public. NPS staff 

may contact the Geologic Resources Division to obtain 

this report. 

Geology and History at National Capital Parks–East 

The entire Potomac River valley is rich in archaeological 

resources that document the human habitation of the 

area for the past 10,000 years. The geology of the area has 

always attracted people to its vast natural resources. 

Ancient people came to use the unique stones found 

there for toolmaking, including chert and metarhyolite, 

establishing base camps and processing sites in several 

locations. The river provided Algonquin Native 

Americans and other competing tribes with a 

concentration of fish, game, and numerous plant species 

as well as wood, stone, shell, and bones necessary for 

tools and trade. 

Geology played a vital role in early European settlement 

success. In the area around Washington, D.C., rivers 

supported local trade and provided resources such as 

fertile floodplains for the inhabitants. Forests were 

cleared for settlements and agriculture. For over 150 

years corn, tobacco, and other crops provided a 

livelihood for thousands of early Americans. However, 

poor land use practices led to erosion and stripped the 

soils of nutrients. Many areas were left barren and 

exposed to intense erosion. Reforestation since the early 

1900s has reintroduced stable mixed pine and deciduous 

forests to the area. 

The geology influenced placement of the local river 

crossings and fords. Early railroads and roads often 

followed the trends of natural geologic features. 

Interpretation of the impacts of geologic controls during 

settlement and development of the area provides an 

opportunity to educate the public about the 

interconnectedness between history and geology. This 

information yields a deeper understanding of the 

landscape. 

One of the major goals of the National Park Service is to 

preserve the historical context of the area. Several 

management challenges occur in maintaining this 

landscape because it often means resisting natural 

geologic changes. Geologic slope processes such as 

landslides, slumps, slope creep, and chemical weathering, 

are constantly changing the landscape at the parks and 

threatening historic features. Runoff erodes sediments 

from any open areas and carries them down streams and 

gullies. Erosion naturally diminishes higher areas and fills 
 NACE Geologic Resource Evaluation Report 15

in the lower areas, distorting the historical context of the 

landscape. 

The following sections highlight geology- history 

connections at specific units within National Capital 

Parks–East. 

Fort Circle Parks 

The Fort Circle Parks are a group of defenses active 

during the Civil War (begun in 1861) in defense of the 

Union Capital of Washington, D.C. (fig. 8). In 1861, the 

capital was considered an island amidst Confederate 

Virginia and Maryland whose loyalty to the Union was 

divided. Today these parks are largely earthworks, 

managed in part by three separate National Park Service 

units: Rock Creek Park, George Washington Memorial 

Parkway, and National Capital Parks–East. The latter 

unit contains Fort Washington (not among the Fort 

Circle Parks, see below), Fort Dupont, Fort Foote, Fort 

Stanton, Fort Mahan, Fort Carroll, Fort Davis, Fort 

Chaplin, and Fort Greble. 

Strategic placement of these forts was designed to take 

defensive advantage of any geologic features such as 

ridges, hills, shorelines, river crossings, natural ports, etc. 

By the end of the war, 68 forts and 93 gun batteries 

dotted the high ground, forming a defensive ring around 

the city. Fort Dupont’s siege guns defended the Eleventh 

Street Bridge over the Anacostia River (reference 

http://www.nps.gov/nace/ftdupont.htm). 

Like Fort Dupont, many of the Circle Forts had sides 

made of earth, protected by a deep moat with felled trees 

pointing outward (fig. 9). Most of these forts are now low 

earthworks, on the brink of disappearing due to erosion. 

Other historic factors considered by the National Park 

Service include the activities of the Civilian Conservation 

Corps at various Circle Fort sites during the 1930s, and 

communities and historic neighborhoods that developed 

around the fort sites (see http://parkplanning.nps.gov for 

latest projects). 

These historic structures are all vulnerable to change due 

to the geologic processes of weathering and erosion. 

Finding a balance between the need to let nature take its 

course and the need to preserve historic features is a 

constant struggle because the goal of the parks is to 

preserve both the natural and historical context of the 

area. This aim is under constant pressure from both the 

continuous natural processes of erosion and weathering 

and the demands of increasing local population and 

urban development. 

Issues also arise from the sometimes opposing values 

between cultural and natural resource management. For 

example, a proposal for restoration of a historic fort may 

consist of removing surrounding natural resources or 

planting exotics. The streams in the parks are also 

sometimes changed to protect trails, buildings, and 

stream banks from being undercut. These efforts attempt 

to reverse many natural geologic changes. 

Piscataway Park 

The earliest inhabitants of the Piscataway area were 

members of the Piscataway (Conoy) Tribe. These Native 

Americans spoke Algonquian and lived in permanent 

villages (Marshall 1997). About 30 dwellings were present 

prior to the first English landing in Maryland in 1634. The 

tendency of European settlement in the area was to 

follow the shores of the Potomac River (Marshall 1997). 

This settlement pattern allowed easy access to the trade 

routes and vast resources of the riverways, but also left 

settlements vulnerable to flooding and with increased 

development, shoreline erosion increased as well. 

The Piscataway Tribe was a friendly ally of the European 

settlers in struggles with the Susquehannock and Seneca 

tribes. At one point in 1680, the Piscataways were forced 

to seek shelter from Seneca- Susquehannocks raids in the 

many surrounding wetlands of Zachia Swamp in 

southern Charles County (Marshall 1997). 

Early plantation owners, including Thomas Marshall of 

nearby Marshall Hall, contributed to the development of 

the landscape by clearing forests and fields, reshaping 

topographic highs and filling in lows. 

In addition to archaeological potential, Piscataway Park 

also has significant paleontological resources that have 

yet to be formally catalogued as well as local seeps that 

provide direct access to groundwater. 

Fort Washington Park 

Fort Washington’s masonry walls stand as one of the few 

U.S. seacoast fortifications still in original form. The fort 

sits on a relatively flat upland plateau of high ground 

(highly graded in the 19th century) overlooking the 

Potomac River, bounded to the northwest, west, and 

south by moderate to steep slopes that drain to the 

Potomac. This fort once guarded the water approach to 

Washington, D.C., against wooden ocean- going 

warships. 

Current plans are being made to stabilize the historic fort 

(see http://www.nps.gov/archive/fowa/ea/). The fort has 

been weakened by years of moisture (both meteoric and 

from natural seeps and springs) and vegetation intrusion 

into the masonry walls. Stabilization plans involve 

developing a drainage system, remediating vegetation 

encroachment, and supporting earthen terraces, slopes, 

buildings, and other historic features. Prominent 

outcrops of Marlboro clays create landslide hazards at 

Fort Washington Park (O’Connor 1980). These loose 

clays have played a role in undermining the historic 

structures. 

This park is a stratigraphic locality for lower Tertiary 

marine units and associated fossils. Additionally, Fort 

Washington Park contains gypsum crystals in the 

substrate. Because these geologic resources might attract 

illegal collectors, they raise resource protection 

concerns. 
 NPS Geologic Resources Division 16 

Anacostia Park 

Early settlement in this area organized around a natural 

deep- water port on the Anacostia River. The 

Bladensburg settlement was founded in the area in 1742. 

By 1800 the depth of the channel at Bladensburg was 

dramatically reduced from 14 m to 8 m (46 to 26 ft) by 

silting. Sediment eventually filled in much of the tidal 

estuary and subsequently the deep- water port at 

Bladensburg. 

Erosion induced by agriculture and urbanization silted 

the river further and caused severe flood hazards. In 

response to flooding, dikes were built in the 1950s and 

the Anacostia River Flood- Control Project was started 

by the Army Corps of Engineers to control flooding and 

improve navigation along the Anacostia River (O’Connor 

and Withington 1977). 

Figure 6: Drawings of Astrodon johnstoni tooth after Leidy (1865). Graphic is courtesy of the Maryland Geological Survey: 

http://www.mgs.md.gov/esic/fs/fs12.html (accessed April 11, 2008). 

Figure 7: Drawing of the Maryland State Dinosaur, Astrodon johnstoni by Gregory Paul, 1979, 1988. Graphic is courtesy of the 

Maryland Geological Survey: http://www.mgs.md.gov/esic/fs/fs12.html (accessed April 11, 2008). 
 NACE Geologic Resource Evaluation Report 17

Figure 8: Drawing showing the location of the series of forts belonging to the Fort Circle Parks of National Capital Parks–East. Drawing 

is courtesy of the National Park Service: http://www.nps.gov/nace/ftdupont.htm (accessed July 11, 2005). 
 NPS Geologic Resources Division 18 

Figure 9: Drawing of Fort Dupont showing six-sided shape and surrounding moat. Image is courtesy of Fort Ward Museum. 
 NACE Geologic Resource Evaluation Report 19

Map Unit Properties 

This section identifies characteristics of map units that appear on the Geologic Resource 

Evaluation digital geologic map of National Capital Parks–East. The accompanying 

table is highly generalized and is provided for background purposes only. Grounddisturbing activities should not be permitted or denied on the basis of information in this 

table. More detailed map unit descriptions can be found in the help files that accompany 

the digital geologic map or by contacting the NPS Geologic Resources Division. 

The map units that are exposed west of National Capital 

Parks–East and underlie the entire area at depth include 

those of the Potomac Terrane of the Piedmont 

physiographic province. The Potomac terrane is bound 

on the west by the Pleasant Grove fault and is covered to 

the east by Atlantic Coastal Plain sediments (Kunk et al. 

2004). These ancient sedimentary and volcanic rocks 

were thrust along faults during deposition in a 

Neoproterozoic–Early Cambrian oceanic trench setting 

mixed with unconsolidated sediments to form a mélange, 

or mixture, of rocks. 

This mélange then metamorphosed into deformed 

crystalline rocks. Late Proterozoic–Early Cambrian 

amphibolites, metagabbros, and actinolite schists are 

present in pods throughout the area (Fleming et al. 1994). 

The units commonly associated with this mélange of 

rocks west of the parks include the Mather Gorge, 

Sykesville, and Laurel formations as well as the various 

igneous intrusive rocks. 

This metamorphic bedrock underlies much of 

northwestern Washington, D.C., and Maryland. Locally, 

the bedrock is thick- bedded to massive, bearing 

boulders and pebbles. The overall composition is 

arenaceous (consisting wholly or in part of sand- size 

fragments) to pelitic (derived from mixed mudstones) 

metamorphic rock that in outcrop typically appears as a 

medium- grained gneiss or schist with garnet- oligoclase 

(a sodium feldspar)- mica- quartz. The apparent 

thickness of this unit is 4,600 m (15,000 ft) (Maryland 

Geological Survey 1968). Debate over formation 

designations continues today among geologists. 

A very thick mantle of rock debris, regolith, soils, and 

transported alluvium and colluvium covers most of the 

bedrock in the Greenbelt Park area forming a wedge that 

thickens to the east. Within National Capital Parks–East, 

the Cretaceous Potomac Formation dominates the map 

units (Diecchio and Gottfried 2004). These deposits 

include interbedded, unconsolidated protoquartzitic to 

orthoquartzitic (well- sorted subrounded to rounded 

quartz grains, respectively) argillaceous (clay- rich) 

sands, gravels, white to dark gray silts, and clays. 

Local thickness of the Potomac Formation is 240 m (800 

ft) (Maryland Geological Survey 1968). Blue quartz grains 

from Grenville rocks of the Blue Ridge province to the 

west, are present in this formation (Diecchio and 

Gottfried 2004). Fleming et al. (1994) divided the 

Potomac Formation into a coarse- grained and a finegrained unit. The Maryland Geological Survey’s 1968 

map divides the Potomac into the Raritan and Patapsco 

formations (containing crossbedded sands, silts, and 

clays), the Arundel Clay (with lignitic or organic- rich 

clay and siderite or iron- enriched carbonate 

concretions, including dinosaur fossils), and the 

Patuxent Formation of coarser sands and gravels. 

Atop the Cretaceous sediments in the National Capital 

Parks–East area are Tertiary deposits from Paleocene 

thru Pliocene. Marine clays of the Brightseat Formation 

record a high- stand of sea level, whereas the Aquia 

Formation and Marlboro Clay record a later sea 

transgression following a period of erosion. Eocene units 

include the Nanjemoy, Piney Point, and Chickahominy 

formations. Oligocene sediments are missing from this 

part of Maryland. Miocene beds include the Calvert, 

Choptank, St. Mary’s, and Eastover formations (Ward 

and Powars 2004). 

Gravels, sands, silts, and clays of Pleistocene and 

Holocene age alluvium line the creek valleys in National 

Capital Parks–East. The sands are commonly orange to 

brown, locally cemented with limonite, with some 

interbedded red, white, or gray clay (Maryland 

Geological Survey 1968). Flood deposits are also present 

locally. Elsewhere, artificial fill is associated with the 

anthropogenic development of the area (Maryland 

Geological Survey 1968; Southworth et al. 2001). 

The geologic units in the following table and their 

geologic features and properties correspond to the units 

found in the accompanying digital geologic data. Source 

data for the GRE digital geologic map are from: 

Scott Southworth and Danielle Denenny, 2006, Geologic 

Map of the National Parks in the National Capital 

Region, Washington D.C., Virginia, Maryland and 

West Virginia, USGS, OF 2005- 1331, 1:24,000 scale 

The following pages present a table view of the 

stratigraphic column and an itemized list of features per 

rock unit. This table includes several properties specific 

to each unit present in the stratigraphic column 

including age, name and map symbol, unit description, 

resistance to erosion, suitability for development, 

hazards, paleontologic resources, cultural resources, 

mineral occurrence , habitat, recreational use, and 

geologic significance. 

 NACE Geologic Resource Evaluation Report 25

Geologic History 

This section describes the rocks and unconsolidated deposits that appear on the digital 

geologic map of National Capital Parks–East, the environment in which those units were 

deposited, and the timing of geologic events that created the present landscape. 

National Capital Parks–East is located at the western 

edge of the Atlantic Coastal Plain physiographic province 

near the Fall Line, which divides the Coastal Plain from 

the Piedmont to the west. The parks contain features that 

are associated with the long geologic history of the 

eastern United States. A regional perspective is presented 

here to connect the landscape and geology of the parks 

to their surroundings. 

The recorded history of the Appalachian Mountains 

begins in the Proterozoic (figs. 10 and 11). In the midProterozoic, over 1 billion years ago during the Grenville 

Orogeny (fig. 12A), a supercontinent (Rodinia) had 

formed comprising most of the continental crust in 

existence at that time (Diecchio and Gottfried 2004) 

including North America and Africa. The sedimentation, 

deformation, plutonism (the intrusion of igneous rocks), 

and volcanism are manifested in the granites and gneisses 

exposed through intense erosion in the core of the 

modern Blue Ridge Mountains (Harris et al. 1997). 

These Grenville age rocks were deposited over a period 

of 100 million years and are more than a billion years old, 

making them among the oldest rocks known from this 

region. Following uplift, the rocks were exposed to 

erosion for hundreds of millions of years. Their subdued 

surface forms a platform upon which all other rocks of 

the Appalachians were deposited (Southworth et al. 

2001). 

The late Proterozoic, roughly 800–600 million years ago, 

brought a tensional, rifting tectonic setting to the area 

perhaps resulting from mantle convection changes (fig. 

12B) (Diecchio and Gottfried 2004). The crustal 

extension created fissures through which massive 

volumes of basaltic magma extruded. This volcanic 

activity lasted tens of millions of years and alternated 

between flood basalt flows and ash falls. The 

metamorphosed remnants of these igneous rocks form 

the Catoctin Greenstones of Shenandoah National Park 

and Catoctin Mountain Park west of National Capital 

Parks–East. 

Because of tensional tectonic forces, the supercontinent 

broke up into islands formed from crust of the Grenville 

Orogeny and a sea basin began to open that eventually 

became the Iapetus Ocean. This basin subsided and 

collected many of the sediments that would eventually 

form the Appalachian Mountains. Thick layers of sand, 

silt, and mud deposited in the Iapetus Ocean underwent 

regional deformation and extensive metamorphism that 

became the Sykesville and Mather Gorge formations. 

Large blocks of eroded fragments from the Grenville 

highlands mixed with these sediments (Southworth et al. 

2000b). 

Massive deposits of sands, silts, and muds in near shore, 

deltaic, barrier island, and tidal flat areas were associated 

with a passive margin, shallow marine setting along the 

eastern continental margin of the Iapetus Ocean (fig. 

12C). Some of these deposits are preserved today in the 

Chilhowee Group in Central Maryland (Schwab 1970; 

Kauffman and Frey 1979; Simpson 1991). Portions of the 

sediments were deposited as alluvial fans, large 

submarine landslides, and turbidity flows, which today 

preserve the dramatic features of their emplacement. 

These early sediments are exposed on Catoctin 

Mountain, Short Hill–South Mountain, Blue Ridge–Elk 

Ridge, and in areas to the west of the parks as the 

Chilhowee Group (Loudoun Formation, Weverton 

Formation, Harpers Formation, and Antietam 

Formation) (Southworth et al. 2001). 

As the source of clastic sediment diminished from the 

eroded Grenville Mountains, huge masses of carbonate 

sediment were deposited over the Chilhowee Group 

forming the Cambrian age Tomstown Dolomite and 

Frederick Limestone as well as the Upper Cambrian to 

Lower Ordovician Grove Limestone (Means 1995; 

Diecchio and Gottfried 2004). They formed a grand 

platform, thickening to the east, that persisted during the 

Cambrian and Ordovician periods (545–480 Ma) and 

form the floors of Frederick and Hagerstown valleys (fig. 

13A) (Means 1995). 

Somewhat later (540, 470, and 360 million years ago) 

pulses of igneous granodiorite, pegmatite, and 

lamprophyre, respectively, intruded the sedimentary 

rocks including those of the Mather Gorge Formation. 

The entire pile of sediments, intrusives, and basalts were 

deformed and metamorphosed into schists, gneisses, 

marbles, slates, and migmatites during several episodes of 

mountain building and continental collision (described 

below) (Southworth et al. 2000a). 

Taconic Orogeny 

From Early Cambrian through Early Ordovician time, 

orogenic activity along the eastern margin of the 

continent began again. The Taconic orogeny (~440–420 

Ma in the central Appalachians) was a volcanic arc–

continent convergence. Oceanic crust, Grenville 

remnant islands, and the volcanic arc, developed from a 

subduction zone in the Iapetus basin, were thrust onto 

the eastern edge of the North American continent as the 

composite continent Gondwana pushed westward 

(Diecchio and Gottfried 2004). These additions to the 
 NPS Geologic Resources Division 26 

continent now form the Piedmont physiographic 

province. Gondwana consisted of the existing crust of 

South America, Africa, Antarctica, India, Australia, 

portions of southwest Europe and even at one time 

included Florida (Kazlev 2002). 

The Taconic orogeny involved the closing of the ocean, 

the subduction of oceanic crust, the creation of volcanic 

arcs, and the uplift of continental crust (fig. 13B) (Means 

1995). Initial metamorphism of the igneous and 

sedimentary rocks of the Sykesville and Mather Gorge 

formations into schists, gneisses, migmatites, and 

phyllites occurred during this orogenic event. 

The crust bowed downwards in front of the rising 

Taconic Mountains creating a deep basin that filled with 

mud and sand, which had eroded from the highlands to 

the east in response to the overriding plate thrusting 

westward onto the continental margin of North America 

(Harris et al. 1997). This so- called Appalachian basin was 

centered on what is now West Virginia (fig. 13C). These 

infilling sediments covered the grand carbonate platform 

and are today represented by the shale of the Ordovician 

Martinsburg Formation (Southworth et al. 2001). 

The oceanic sediments of the shrinking Iapetus Ocean 

were thrust westward onto other deepwater sediments of 

the western Piedmont during the Late Ordovician. This 

deformation occurred along the Pleasant Grove fault and 

other local faults, such as the Plummers Island fault and 

the Rock Creek shear zone. Sandstones, shales, 

siltstones, quartzites, and limestones continued to be 

deposited in the shallow marine to deltaic environment 

of the Appalachian basin. These rocks, now 

metamorphosed, currently underlie the Valley and Ridge 

province to the west of National Capital Parks–East 

(Fisher 1976). 

This shallow marine to fluvial sedimentation continued 

for a period of about 200 My from the Ordovician into 

the Permian, resulting in thick piles of sediments. Their 

source was the highlands that were rising to the east 

during the Taconic orogeny (Ordovician) and the 

Acadian orogeny (Devonian). 

Acadian Orogeny 

The Acadian orogeny (~360 Ma) continued the mountain 

building of the Taconic orogeny as the African continent 

approached North America (Harris et al. 1997). Similar to 

the preceding Taconic orogeny, the Acadian event 

involved land mass collision, mountain building, and 

regional metamorphism (Means 1995). This event 

focused farther north than central Maryland. 

Alleghenian Orogeny 

Following the Acadian orogenic event, the protoAtlantic Iapetus Ocean was completely destroyed during 

the Late Paleozoic as the North American and African 

continents collided. This collision formed the Pangaea 

supercontinent and the Appalachian mountain belt we 

see today. This mountain building episode, termed the 

Alleghanian orogeny (~325–265 Ma), is the last major 

orogeny of the Appalachian evolution (fig. 14A) (Means 

1995). 

The rocks deformed by folding and faulting to produce 

the Sugarloaf Mountain anticlinorium and the Frederick 

Valley synclinorium in the western Piedmont, the Blue 

Ridge–South Mountain anticlinorium, and the numerous 

folds of the Valley and Ridge province (Southworth et al. 

2001). During this orogeny, rocks of the Great Valley, 

Blue Ridge, and Piedmont provinces were transported as 

a massive block (Blue Ridge– Piedmont thrust sheet) 

westward onto younger rocks of the Valley and Ridge 

along the North Mountain fault. The amount of 

compression was extreme. Estimates were of 20–50 % 

shortening which translates into 125–350 km (75–125 

miles) of movement (Harris et al. 1997). 

Deformed rocks in the eastern Piedmont were also 

folded and faulted, and existing thrust faults were 

reactivated as both strike slip and thrust faults during the 

Alleghanian orogenic events (Southworth et al. 2001). 

Paleoelevations of the Alleghenian Mountains are 

estimated at approximately 6,000 m (20,000 ft), 

analogous to the modern day Himalaya Range in Asia. 

These mountains have been beveled by erosion to 

elevations less than 1,234 m (4,051 ft) west of National 

Capital Parks–East in Shenandoah National Park (Means 

1995). 

Triassic Extension to Cenozoic Deposition 

A period of rifting began during the late Triassic and 

following the Alleghenian orogeny as the deformed rocks 

of the joined continents began to break apart about 230–

200 Ma (fig. 14B). The supercontinent Pangaea was 

segmented into roughly the continents that persist today. 

This episode of rifting or crustal fracturing initiated the 

formation of the current Atlantic Ocean and caused 

many block- fault basins to develop within the continent. 

Pervasive volcanism accompanied these rifts (Harris et 

al. 1997; Southworth et al. 2001; Diecchio and Gottfried 

2004). 

The Newark Basin system is a large component of this 

tectonic event. Large alluvial fans and streams carried 

debris shed from the uplifted Blue Ridge and Piedmont 

provinces. This debris was deposited as nonmarine 

shales and sandstones in fault- created troughs such as 

the Frederick valley in central Maryland and the 

Culpeper basin in the western Piedmont of central 

Virginia. Many of these rifted openings became 

lacustrine basins for thick deposits of siltstones and 

sandstones. 

Large faults formed the western boundaries of the basins 

and provided escarpments that were quickly covered 

with eroded debris. Igneous rocks intruded into the new 

sandstone and shale strata as sub- horizontal sheets, or 

sills, and near- vertical dikes that extend beyond the 

basins into adjacent rocks. After these molten igneous 

rocks were emplaced approximately 200 Ma, the region 

underwent a period of slow uplift and erosion. The uplift 

was in response to isostatic adjustments within the crust, 
 NACE Geologic Resource Evaluation Report 27

which forced the continental crust upwards and exposed 

it to erosion (fig. 14C). Erosion preferentially removed 

the less resistant sedimentary rocks, leaving the igneous 

intrusions present as topographic highs on the landscape 

(Diecchio and Gottfried 2004). 

Thick deposits of unconsolidated gravel, sand, and silt 

were shed from the eroded Alleghenian mountains. 

These sediments were deposited at the base of the 

mountains as alluvial fans and spread eastward to be part 

of the Atlantic Coastal Plain (Duffy and Whittecar 1991; 

Whittecar and Duffy 2000; Southworth et al. 2001). The 

amount of erosion inferred from sediment thickness and 

from the now exposed metamorphic rocks is immense. 

Many of the rocks exposed at the surface must have been 

at least 20 km (~10 miles) below the surface prior to 

regional uplift and erosion. 

Units exposed in the Chesapeake Bay area of Mesozoic 

(Cretaceous Potomac Formation) and Cenozoic age 

were deposited in a tectonic downwarp known as the 

Salisbury embayment. This low area stretches from 

southern New Jersey to southern Virginia, bounded by 

the New Jersey and Norfolk arches to the north and 

south, respectively (Ward and Powars 2004). 

The arches are characterized by thinning or truncation of 

the sedimentary layers over crystalline basement rocks at 

depth. Within the Salisbury embayment, the underlying 

basement complex is a structural low. Various tectonic 

models attempt to explain these structural differences 

including block faulting and transverse movement of 

portions of the Coastal Plain as well as sediment loading 

and subsidence (Ward and Powars 2004). The best 

explanation incorporates several of these mechanisms 

working in concert to create the Salisbury embayment. 

Lower to Middle Tertiary sediments in the embayment 

record periodic marine transgressions (rises in sea level). 

These sediments are rich in marine shelf deposits and 

indicate a temperate to sub- tropical climate for the area 

throughout the Tertiary (Ward and Powards 2004). 

Significant pulses of marine transgression during the 

Tertiary are the result of both tectonic shifts beneath the 

embayment and global climate changes. Major 

transgressions occurred during the Paleocene, the 

Eocene (the greatest during the Middle Eocene resulting 

in the Piney Point Formation deposition), the Late 

Oligocene, and the Middle and Late Miocene (Ward and 

Powars 2004). 

Quaternary Landscape Evolution 

Since the breakup of Pangaea and the uplift of the 

Appalachian Mountains, the North American plate has 

continued to drift toward the west. The isostatic 

adjustments that uplifted the continent after the 

Alleghenian orogeny continued at a subdued rate 

throughout the Cenozoic Period (Harris et al. 1997). This 

adjustment influences the erosion that continues today 

with the Potomac, Rappahannock, Rapidan, Monocacy, 

and Shenandoah rivers and tributaries such as the 

Anacostia River stripping the Piedmont and Atlantic 

Coastal Plain sediments, lowering the mountains, and 

depositing alluvial terraces to create the present 

landscape (fig. 14D). 

The landscape and geomorphology of the greater 

Potomac River valley are the result of erosion and 

deposition from about the mid- part of the Cenozoic 

Period to the present, or at least the last 5 million years. 

The distribution of flood plain alluvium and ancient 

fluvial terraces of the rivers and adjacent tributaries 

record the historical development of the drainage 

system. There is little to no evidence that the rivers and 

tributaries migrated laterally across a broad, relatively 

flat region. It seems that the rivers have cut downward 

through very old, resistant rocks, overprinting their early 

courses (Southworth et al. 2001). The rolling landscape 

present at National Capital Parks–East attests to this 

downward cutting and overprinting. 

The position, distribution, thickness, and elevation of 

terraces and the sediments deposited on them along the 

rivers vary by province and rock type. The elevations of 

terraces along the rivers show that the slope values of the 

ancient and modern river valleys are similar, which 

suggests that the terraces formed as the result of either 

eustatic sea level drop or uplift (Zen 1997a, b). 

There are at least six different terrace levels in the 

Washington, D.C., area. The oldest of these terraces is 

located on the crest of Glade Hill in Great Falls Park. 

Here the river cut though bedrock and left deposits of 

large quartzite and diabase boulders. In creating these 

terraces, the erosional features left behind as islands, 

islets, pinnacles, oxbows, shoestring canals, potholes, 

and plungepools dot the landscape along the Potomac 

River today (Southworth et al. 2001). 

Although glaciers from the Pleistocene ice ages never 

reached the central Maryland area (the southern 

terminus was in northeastern Pennsylvania), the colder 

climates of the ice ages played a role in the formation of 

the landscape at National Capital Parks–East. The 

periglacial conditions that must have existed near the 

glaciers intensified weathering and other erosional 

processes (Harris et al. 1997). The landforms and 

deposits are probably late Tertiary to Quaternary in age 

when a wetter climate, sparse vegetation, and frozen 

ground caused increased precipitation to run into the 

ancestral river channels, enhancing downcutting and 

erosion by waterways (Means 1995; Zen 1997a, b). 

Given the erodability of the unconsolidated deposits 

throughout the area, dating of recent tectonic and 

climatic regimes is problematic. Most of the sediments 

have eroded away. However, loess deposits (wind blown 

silt- sized particles, frequently associated with glaciation) 

found on stable landforms in surrounding areas indicate 

that the local transition from a colluvial- dominated 

(slope processes) to a fluvial- dominated (river 

processes) geomorphic regime did not occur in the midAtlantic region until the end of the early Holocene 

(Feldman et al. 2000). Similarly, geologists measure the 
 NPS Geologic Resources Division 28 

oxygen isotope ratios in pedogenic clays such as kaolinite 

(formed from the weathering of muscovite and 

microcline) to determine the climatic conditions during 

weathering. In the Piedmont province (and by extension 

the Atlantic Coastal Plain), a cooler climate persisted 

beyond the Pleistocene glacial stage in North America 

(Elliott et al. 1997). 
 NACE Geologic Resource Evaluation Report 29

Figure 10: Geologic time scale; adapted from the U.S. Geological Survey. Red lines indicate major unconformities between eras. 

Included are major events in the history of life on Earth and tectonic events occurring on the North American continent. Absolute ages 

shown are in millions of years (Ma, or mega-annum). 
 NPS Geologic Resources Division 30 

Figure 11: Geologic time scale specific to Virginia-Maryland. Dates are approximate. Modified from Bailey and Roberts 1997–2003. 
 NACE Geologic Resource Evaluation Report 31

Figure 12: Geologic evolution of the Appalachian Mountains in the National Capital area. West to east cross sectional view. A) First, 

intrusions of granitic gneiss, metamorphism, and deformation related to the Grenville orogeny lasted 60 million years from 1.1 billion 

to 950 million years ago. These rocks are found in the Blue Ridge province. B) Then, continental rifting and volcanic activity in the 

Grenville terrane (current Blue Ridge province), and turbidites deposited in deep water basin to the east (current Piedmont province), 

lasted about 200 million years, from about 770 to 575 million years ago. C) Next, the margin of the continent became stable with 

carbonate rocks deposited in quiet water (rocks of the current Great valley and Frederick valley). Fossil shells appeared about 545 

million years ago. Then, deep-water rocks were deposited into a basin east of the shelf margin for about 65 million years. Adapted from 

Southworth et al., (2001). 
 NPS Geologic Resources Division 32 

Figure 13: A) Following deposition, the stable shelf was destroyed as the Taconic orogeny, (B) (480–460 Million years ago) elevated the 

rocks to the east and provided a source for the clastic material that make up the shale of the Martinsburg Formation. Plutonic rocks 

intruded rocks in the Piedmont province. C) Then, a thick sequence of sedimentary rocks was deposited in a deepening Appalachian 

Basin for 120 Million years. Most of these rocks are now found in the Valley and Ridge province. Igneous rocks were intruded in rocks 

near Great Falls about 370 million years ago. Adapted from Southworth et al. (2001). 
 NACE Geologic Resource Evaluation Report 33

Figure 14: A) About 240 Ma, the continental tectonic plates of North America and Africa collided, resulting in the Alleghanian orogeny. 

Many of the folds and faults in rocks west of the Piedmont province are related to this event. B) About 20 million years later,

continental rifting began and lasted for about 20 million years (220 to 200 Ma). C) Thick sequences of sedimentary rock were deposited 

in fault-bounded basins, there was volcanic activity, and the result was the opening of the Atlantic Ocean. The Culpeper and 

Gettysburg basins in the western Piedmont are the result of this event. D) For the last 200 million years, the landscape has eroded and 

rivers have carried the sediment eastward to deposit the thick strata of the Atlantic Coastal Plain. Diagrams are not to scale and are 

broadly representative of the tectonic settings. Adapted from Southworth et al. (2001). 
 NPS Geologic Resources Division 34 

Glossary 

This glossary contains brief definitions of technical geologic terms used in this report. 

Not all geologic terms used are referenced. For more detailed definitions or to find terms 

not listed here please visit: http://wrgis.wr.usgs.gov/docs/parks/misc/glossarya.html. 

alluvial fan. A fan- shaped deposit of sediment that 

accumulates where a high- gradient stream flows out 

of a mountain front into an area of lesser gradient such 

as a valley. 

alluvium. Stream- deposited sediment that is generally 

rounded, sorted, and stratified. 

anticlinorium. A regional anticlinal (convex up) structure 

composed of lesser folds.

aquifer. Body of rock or sediment that is sufficiently 

porous, permeable, and saturated to be useful as a 

source of water. 

arenite. A sedimentary rock composed of sand- sized 

particles, regardless of composition, e.g. sandstone. 

ash (volcanic). Fine pyroclastic material ejected from a 

volcano (also see tuff). 

barrier island. A long, low, narrow island formed by a 

ridge of sand that parallels the coast. 

base flow. Streamflow supported by groundwater flow 

from adjacent rock, sediment, or soil. 

basement. The undifferentiated rocks, commonly 

igneous and metamorphic, that underlie identified 

rock units. 

basin (structural). A doubly plunging syncline in which 

rocks dip inward from all sides (also see dome). 

basin (sedimentary). Any depression, from continental 

to local scale, into which sediments are deposited. 

bed. The smallest sedimentary strata unit, commonly 

ranging in thickness from 1 centimeter to a meter or 

two and distinguishable from beds above and below. 

bedding. Depositional layering or stratification of 

sediments. 

bedrock geology. The geology of underlying solid rock 

as it would appear with the sediment, soil, and 

vegetative cover stripped away. 

bioturbation. The churning, stirring, and mixing of 

sediment by organisms. 

block (fault). A crustal unit bounded by faults, either 

completely or in part. 

calcareous. A rock or sediment containing calcium 

carbonate. 

chemical sediment. A sediment precipitated directly 

from solution (also called nonclastic). 

chemical weathering. The dissolution or chemical 

breakdown of minerals at Earth’s surface via reaction 

with water, air, or dissolved substances. 

clastic. Rock or sediment made of fragments of 

preexisting rocks. 

clay. Clay minerals or sedimentary fragments the size of 

clay minerals (grain size <0.002 mm). 

continental crust. The type of crustal rocks underlying 

the continents and continental shelves; having a 

thickness of 25–60 km (16–37 mi) and a density of 

approximately 2.7 grams per cubic centimeter. 

cross section. A graphical interpretation of geology, 

structure, and (or) stratigraphy in the third (vertical) 

dimension based on mapped and measured geological 

extents and attitudes depicted in an oriented vertical 

plane. 

crust. The outermost compositional shell of Earth, 10–40 

km (6–25 mi) thick, consisting predominantly of 

relatively low density silicate minerals (also see 

oceanic crust and continental crust). 

crystalline. Describes the structure of a regular, orderly, 

repeating geometric arrangement of atoms. 

deformation. A general term for the process of faulting, 

folding, shearing, extension, or compression of rocks 

as a result of various Earth forces. 

delta. A sediment wedge deposited at a stream’s mouth 

where it flows into a lake or sea. 

dike. A tabular, discordant igneous intrusion. 

dinocyst. A spore of dinoflagellate, abundant in the fossil 

record 

dip. The angle between a structural surface and a 

horizontal reference plane measured normal to their 

line of intersection. 

drainage basin. The total area from which a stream 

system (or watershed) receives or drains precipitation 

runoff. 

estuary. The seaward end or tidal mouth of a river where 

fresh and sea water mix; many estuaries are drowned 

river valleys caused by sea- level rise (transgression) or 

coastal subsidence. 

eustatic. Relates to simultaneous worldwide rise or fall 

of sea level in Earth’s oceans. 

fan delta. An alluvial fan that builds into a standing body 

of water. The landform differs from a delta in that a fan 

delta is next to a highland and typically forms at an 

active margin. 

fault. A subplanar break in rock along which relative 

movement occurs between the two sides. 

felsic. Pertaining to a fine- grained igneous rock 

composed of light colored- minerals, e.g. quartz, 

feldspar. 

formation. Fundamental rock- stratigraphic unit that is 

mappable and lithologically distinct from adjoining 

strata and has definable upper and lower contacts. 

graben. A down- dropped structural block bounded by 

steeply dipping normal faults (also see horst). 

igneous. Refers to a rock or mineral that originated from 

molten material; one of the three main classes or rocks: 

igneous, metamorphic, and sedimentary. 

intrusion. A body of igneous rock that invades older 

rock. The invading rock may be a plastic solid or 

magma that pushes its way into the older rock. 
 NACE Geologic Resource Evaluation Report 35

isostatic. The condition of equilibrium; the weight of 

glaciers, water, or sediment load causes isostatic 

depression or downwarping, and removal of the load 

results in isostatic uplift (rebound) or upwarping. 

karst topography. Topography characterized by 

abundant sinkholes and caverns formed by the 

dissolution of calcareous rocks. 

lacustrine. Pertaining to, produced by, or inhabiting a 

lake or lakes. 

lamprophyre. A porphyritic igneous rock with 

phenocrysts of mafic minerals (esp. biotite, 

hornblende, and pyroxene) and a fine- grained 

groundmass of the same mafic minerals plus feldspar. 

landslide. Any process or landform resulting from rapid 

mass movement. 

lava. Magma that has been extruded out onto Earth’s 

surface, both molten and solidified. 

leucosome. The light- colored part of a migmatite 

composed mainly of quartz and feldspar. 

levees. Raised ridges lining the banks of a stream; may be 

natural or artificial. 

lithification. The conversion of sediment into solid rock. 

lithology. The description of a rock or rock unit, 

especially the texture, composition, and structure of 

sedimentary rocks. 

lithosphere. The relatively rigid outmost shell of Earth’s 

structure, 50–100 km (31–62 mi) thick, that 

encompasses the crust and uppermost mantle. 

loess. Silt- sized sediment deposited by wind, generally 

of glacial origin. 

mafic. Pertaining to an igneous rock composed of dark 

colored- minerals containing iron and magnesium, e.g. 

olivine, diopside (pyroxene), hornblende (amphibole). 

magma. Molten rock generated within Earth that is the 

parent of igneous rocks. 

mantle. The zone of Earth’s interior between crust and 

core. 

mechanical weathering. The physical breakup of rocks 

without change in composition (syn: physical 

weathering). 

meta-. A prefix used before the name of an igneous or 

sedimentary rock to indicate metamorphism, e.g. 

metagabbro and metapyroxenite 

metamorphic. Pertaining to the process of 

metamorphism or to its results. 

metamorphism. Literally, “change in form.” 

Metamorphism occurs in rocks with mineral 

alteration, genesis, and (or) recrystallization from 

increased heat and pressure. 

migmatite. Literally, “mixed rock” with both igneous and 

metamorphic characteristics due to partial melting 

during metamorphism. 

mineral. A naturally occurring, inorganic crystalline solid 

with a definite chemical composition or compositional 

range. 

monzogranite. A variety of granite having Ca- feldspar 

and plagioclase in equal amounts. 

normal fault. A dip- slip fault in which the hanging wall 

moves down relative to the footwall. 

oceanic crust. Earth’s crust formed at spreading ridges 

that underlies the ocean basins. Oceanic crust is 6–7 

km (3–4 mi) thick and generally of basaltic 

composition. 

orogeny. A mountain- building event, particularly a wellrecognized event in the geologic past. (The Laramide 

orogeny is one well- recognized example.) 

outcrop. Any part of a rock mass or formation that is 

exposed or “crops out” at Earth’s surface. 

overbank deposits. Alluvium deposited outside a stream 

channel during flooding. 

paleontology. The study of the life and chronology of 

Earth’s geologic past based on the phylogeny of fossil 

organisms. 

Pangaea. A theoretical, single supercontinent that 

existed during the Permian and Triassic. 

passive margin. A tectonically quiet continental margin 

indicated by little volcanic or seismic activity. 

pebble. Generally, small, rounded rock particles from 4 

to 64 mm in diameter. 

pegmatite. A very coarse- grained intrusive igneous rock, 

usually occurring as dikes, lenses or veins; composition 

is similar to granite but often with rare minerals rich in 

lithium, boron, fluorine, niobium, etc. 

phyllite. A metamorphic rock intermediate in grade 

between slate (low) and mica schist; has a silky sheen 

from presence of chlorite, sericite, and graphite. 

plateau. A broad, flat- topped topographic high of great 

extent and elevation above the surrounding plains, 

canyons, or valleys (both land and marine landforms). 

plate tectonics. The theory that the lithosphere is broken 

up into a series of rigid plates that move over Earth’s 

surface above a more fluid asthenosphere.(Compare 

lithosphere and asthenosphere.) 

pluton. A body of intrusive igneous rock. 

plutonic. Describes igneous rock intruded and 

crystallized at some depth in Earth. 

porosity. The proportion of void space (cracks, 

interstices) in a volume of a rock or sediment. 

pyroxenite. An ultramafic intrusive igneous rock 

composed mainly of pyroxene (e.g., diopside, augite, 

hypersthene) with hornblende, biotite, or olivine. 

recharge. Infiltration processes that replenish ground 

water. 

regression. A long- term seaward retreat of the shoreline 

or relative fall of sea level. 

sandstone. Clastic sedimentary rock of predominantly 

sand sized grains. 

scarp. A steep cliff or topographic step resulting from 

vertical displacement on a fault or by mass movement. 

seafloor spreading. The process in which tectonic plates 

diverge and new lithosphere is created at oceanic 

ridges. 

sediment. An eroded and deposited, unconsolidated 

accumulation of lithic and mineral fragments. 

sedimentary rock. A consolidated and lithified rock 

consisting of detrital and (or) chemical sediment(s). 

shale. A clastic sedimentary rock made of clay- sized 

particles that exhibit parallel splitting properties. 

sill. A tabular, igneous intrusion that is concordant with 

the country rock. 
 NPS Geologic Resources Division 36 

silt. Clastic sedimentary material intermediate in size 

between very fine sand and coarse clay (1/256- 1/16 

mm). 

siltstone. A variably lithified sedimentary rock with siltsized grains. 

slope. The inclined surface of any geomorphic feature or 

rational measurement thereof (syn: gradient). 

slump. A generally large, coherent mass movement with 

a concave- up failure surface and subsequent 

backward rotation relative to the slope. 

soil. Surface accumulation of weathered rock and 

organic matter capable of supporting plant growth and 

often overlying the parent rock from which it formed. 

spring. A site where water flows out at the surface due to 

the water table intersecting the ground surface. 

strata. Tabular or sheetlike masses or distinct layers (as, 

of rock). 

stratigraphy. The geologic study of the origin, 

occurrence, distribution, classification, correlation, 

and age of rock layers, especially sedimentary rocks. 

strike. The compass direction of the line of intersection 

that an inclined surface makes with a horizontal plane. 

strike-slip fault. A fault with measurable offset where the 

relative movement is parallel to the strike of the fault. 

subduction zone. A convergent plate boundary where 

oceanic crust descends beneath a continental or 

oceanic plate and is carried down into the mantle. 

subsidence. The gradual sinking or depression of part of 

Earth’s surface. 

synclinorium. A regional synclinal (concave) structure 

composed of lesser folds. 

taeniodont. A member of an extinct order (Taeniodonta) 

of mammals that lived in North America throughout 

the Paleocene and into the middle Eocene Epoch. 

Taeniodonts may have been related to early insecteating mammals; varied in size from a rat to a bear 

tectonic. Relating to large- scale movement and 

deformation of Earth’s crust. 

terraces (stream). Step- like benches surrounding the 

present flood plain of a stream due to dissection of 

previous flood plain(s), stream bed(s), and (or) valley 

floor(s). 

terrane. A region or group of rocks similar in age, often 

fault- bounded with complex metamorphic, igneous, 

and/or structural geology. 

terrestrial. Relating to Earth or Earth’s dry land. 

thrust fault. A contractional, dip- slip fault with a 

shallowly dipping fault surface (<45o) where the 

hanging wall moves up and over relative to the 

footwall. 

topography. The general morphology of Earth’s surface 

including relief and location of natural and 

anthropogenic features. 

transgression. Landward migration of the sea due to a 

relative rise in sea level. 

trend. The direction or azimuth of elongation of a linear 

geologic feature. 

trondhjemite. A light- colored intrusive igneous rock 

composed mainly of Na- plagioclase (oligoclase), 

quartz, with sparse biotite and little or no Ca- feldspar; 

plagiogranite, leucocratic tonalite. 

tuff. Generally fine grained igneous rock formed of 

consolidated volcanic ash. 

uplift. A structurally high area in Earth’s crust, produced 

by movement that raises the rocks. 

volcanic. Related to volcanoes; describes igneous rock, 

such as lava, crystallized at or near Earth’s surface. 

water table. The upper surface of the saturated (phreatic) 

zone. 

weathering. The set of physical, chemical, and biological 

processes by which rock is broken down in place. 
 NACE Geologic Resource Evaluation Report 37

References 

This section provides a listing of references cited in this report. It also contains general 

references that may be of use to resource managers. A more complete geologic 

bibliography is available through the NPS Geologic Resources Division. 

Allen, O., and S. Flack. 2001. Potomac Gorge site 

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Nature Conservancy (version for internal use). 

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and stream- channel classification of Rock Creek, 

Washington, D.C., 1999–2000: U. S. Geological Survey 

Water- Resources Investigations 02- 4067. 

Bailey, C. M., and C. Roberts, 1997–2003, The Geology of 

Virginia. Williamsburg, Virginia: College of William 

and Mary. http://www.wm.edu/geology/virginia/ 

(accessed July 10, 2005). 

Bowser, C. J., and B. F. Jones. 2002. Mineralogic controls 

on the composition of natural waters dominated by 

silicate hydrolysis. American Journal of Science

302(7):582–662. 

Cecil, C. B.; D. K. Brezinski; and F. T. Dulong. 2004. The 

Paleozoic record of changes in global climate and sea 

level; Central Appalachian Basin. In Geology of the 

National Capital Region; field trip guidebook. Edited by 

S. Southworth and W. Burton. U. S. Geological Survey 

Circular 1264: 77–135 

Chirico, P., and J. Epstein. 2000. Geographic information 

system analysis of topographic change in Philadelphia, 

Pennsylvania during the last century. U. S. Geological 

Survey Open- File Report 00- 224. 

Conkwright, R. D. 2005. Fact Sheet 12: Astrodon johnstoni, 

the Maryland State Dinosaur. Division of Coastal and 

Estuarine Geology, Maryland Geological Survey 

website. http:// www.mgs.md.gov/esic/fs/fs12.html 

(accessed July 29, 2005). 

Diecchio, R., and R. Gottfried. 2004. Regional tectonic 

history of northern Virginia. In Geology of the National 

Capital Region; field trip guidebook. Edited by S. 

Southworth and W. Burton. U. S. Geological Survey 

Circular, pp. 1–14. 

Duffy, D. F., and G. R. Whittecar. 1991, Geomorphic 

development of segmented alluvial fans in the 

Shenandoah Valley, Stuarts Draft, Virginia. Abstracts 

with Programs (GSA) 23(1):24. 

Elliott, W. C.; S. M. Savin; H. Dong; and D. R. Peacor. 

1997. A paleoclimate interpretation derived from 

pedogenic clay minerals from the Piedmont Province, 

Virginia. Chemical Geology 142(3–4):201–211. 

Feldman, S. B.; L. W. Zelazny; M. J. Pavich; and H. T. 

Millard, Jr. 2000. Late Pleistocene eolian activity and 

post- depositional alteration on the Piedmont of 

northern Virginia. In Regolith in the Central and 

Southern Appalachians. Edited by G. M. Clark; H. H. 

Mills; and J. S. Kite. Southeastern Geology 39(3–4):183–

198. 

Fisher, G. W. 1976. The geologic evolution of the 

northeastern Piedmont of the Appalachians, Abstracts 

with Programs—Geological Society of America, v. 8, 

no. 2, p. 172–173. 

Fleming, A. H.; Drake, A. A., Jr.; and McCartan, L., 1992, 

The Rock Creek shear zone, a major tectonic 

boundary in the central Appalachian Piedmont. 

Abstracts with Programs (GSA) 24(3):21. 

Fleming, A. H.; A. A. Drake, Jr.; and L. McCartan. 1994. 

Geologic map of the Washington West Quadrangle, 

District of Columbia, Montgomery and Prince 

George’s Counties, Maryland, and Arlington and 

Fairfax Counties, Virginia. U. S. Geological Survey 

Geologic Quadrangle Map, GQ- 1748, 1 sheet, 1:24,000 

scale. 

Harris, A. G.; E. Tuttle; and S. D. Tuttle. 1997. Geology of 

national parks. Kendall/Hunt Publishing Company, 

759 p. 

Kauffman, M. E, and E. P. Frey. 1979. Antietam 

sandstone ridges; exhumed barrier islands or faultbounded blocks? Abstracts with Programs (GSA) 

11(1):18. 

Kazlev, M. A. 2002. The supercontinent of Gondwana. 

http://www.palaeos.com/Earth/Geography/Gondwan

a.htm (accessed July 12, 2005). 

Kranz, P. M. 2004. Astrodon rediscovered; America's 

first sauropod. Mosasaur, Delaware Valley 

Paleontological Society (Philadelphia, PA) 7:95–103. 

Kunk, M. J.; R. P. Wintsch; C. S. Southworth; B. K. 

Mulvey; C. W. Naeser; and N. D. Naeser. 2004. 

Multiple Paleozoic metamorphic histories, fabrics, and 

faulting in the Westminster and Potomac Terranes, 

Central Appalachian Piedmont, northern Virginia and 

southern Maryland. In Geology of the National Capital 

Region; field trip guidebook. Edited by S. Southworth 

and W. Burton. U. S. Geological Survey Circular, pp. 

163–188. 
 NPS Geologic Resources Division 38 

Leidy, J. 1865. Memoir on the extinct reptiles of the 

Cretaceous formations of the United States. 

Smithsonian Contributions to Knowledge XIV (VI): 1-

135. 

Marshall, M. E. 1997. Marshall Hall on the Potomac. 

http://www.marshallhall.org/history.html (accessed 

July 15, 2005). 

Maryland Geological Survey. 1968. Geologic map of 

Maryland, scale 1:250,000. 

http://www.mgs.md.gov/esic/geo/index.html 

(accessed July 1, 2005). 

Maryland Geological Survey. 2001. Physiographic 

Provinces and Their Subdivisions in Maryland. 

www.mgs.md.gov (accessed January 31, 2008). 

Means, J. 1995. Maryland's Catoctin Mountain parks; an 

interpretive guide to Catoctin Mountain Park and 

Cunningham Falls State Park. Blacksburg, VA: 

McDonald & Woodward Publishing Company, 168 p. 

Southworth, S., and W. Burton, eds. 2004. Geology of the 

National Capital Region; field trip guidebook. U. S. 

Geological Survey Circular 1264. 

Miller, A. J.; J. A. Smith; and L. L. Shoemaker. 1984. 

Channel storage of fine- grained sediment in the 

Monocacy River basin. Eos, Transactions (AGU) 

65(45):888. 

Muller, P. D. 1990. Geologic map of the Delta 7.5- minute 

Quadrangle, Maryland and Pennsylvania. Maryland 

Geological Survey, unpublished file map, scale 

1:24,000. 

National Park Service. 2003. Environmental assessment: 

2003 Gypsy moth suppression project. Greenbelt Park 

and Baltimore- Washington Parkway, National Capital 

Parks–East. U.S. Department of the Interior, National 

Park Service. 

http://data2.itc.nps.gov/parks/gree/ppdocuments/Gre

enbelt%20Environmental%20Doc.doc (accessed July 

1, 2005). 

Nickelsen, R. P. 1956. Geology of the Blue Ridge near 

Harpers Ferry, West Virginia. Geological Society of 

America Bulletin 67(3):239–269. 

O’Connor, J. V. 1980. The National Capital and earth 

science education. Abstracts with Programs (GSA) 

12(7):493. 

O'Connor, J. V., and C. F. Withington, leaders. 1977. 

Urban geology of the Nation's Capital. In Guidebook 

for field trips in Maryland and the National Capital 

area. Edited by R. W. Ridky. National Association of 

Geology Teachers, Eastern Section, pp. 16–44 

Reed, J. C. Jr.; R. S. Sigafoos; and G. W. Fisher. 1980. The 

river and the rocks; The geologic story of Great Falls and 

the Potomac River Gorge. U. S. Geological Survey 

Bulletin 1471, 75 p. 

Reger, J. 2005. Dinosaurs! Maryland’s Geological 

Features. Maryland Geological Survey website. 

http://www.mgs.md.gov/esic/features/mddino.html 

(accessed July 11, 2006). 

Schwab, F.L. 1970. Origin of the Antietam Formation 

(late Precambrian?; lower Cambrian), central Virginia. 

Journal of Sedimentary Petrology 40(1):354–366. 

Simpson, E. L. 1991. An exhumed Lower Cambrian tidalflat; the Antietam Formation, central Virginia, U.S.A. 

In Clastic tidal sedimentology. Edited by D. G. Smith; B. 

A. Zaitlin; G. E. Reinson; and R. A. Rahmani. 

Memoir—Canadian Society of Petroleum Geologists

16:123–133. 

Southworth, S., and D. K. Brezinski. 1996. Geology of the 

Harpers Ferry Quadrangle, Virginia, Maryland, and 

West Virginia. U. S. Geological Survey Bulletin, Report: 

B 2123, 33 p., 1 sheet. 

Southworth, S.; D. K. Brezinski; R. C. Orndorff; P. G. 

Chirico; and K. M. Lagueux. 2001. Geology of the 

Chesapeake and Ohio Canal National Historical Park 

and Potomac River Corridor, District of Columbia, 

Maryland, West Virginia, and Virginia. 2 discs. A, 

Geologic map and GIS files; B, Geologic report and 

figures. U. S. Geological Survey Open- File Report OF 

01- 0188. 

Southworth, S.; P. Chirico; D. Denenny; and J. Triplett. 

2002. Geology and GIS in the parks of the National 

Capital Region. Abstracts with Programs (GSA) 

34(6):456. 

Southworth, S., and D. Denenny. 2003. Geologic maps 

support land resource management in the national 

parks in the Eastern U.S. Abstracts with Programs

(GSA) 35(6):331. 

Southworth, S.; D. K. Brezinski; R. C. Orndorff; K. M. 

Lagueux; and P. G. Chirico. 2000a. Digital geologic map 

of the Harpers Ferry National Historical Park. U. S. 

Geological Survey Open- File Report OF 00- 0297, 1 

disc. 

Southworth, S.; C. Fingeret; and T. Weik. 2000b. 

Geologic map of the Potomac River Gorge: Great Falls 

Park, Virginia, and part of the C & O Canal National 

Historical Park, Maryland. U. S. Geological Survey 

Open- File Report 00- 264. 
 NACE Geologic Resource Evaluation Report 39

Symborski, M. A.; M.- S. Cheng; J. W. Gracie; and M. 

Lahlou. 1996. Brinkley Manor run; a case study in 

geomorphologically- based stream restoration design 

in Prince George's County, Maryland. Proceedings of 

Watershed '96; A national conference on watershed 

management. Washington, D. C.: U. S. Environmental 

Protection Agency. Fairfax, VA: Tetra Tech. pp. 815–

818. 

Tollo, R. P.; C. M. Bailey; E. A. Borduas; and J. N. 

Aleinikoff. 2004. Mesoproterozoic geology of the Blue 

Ridge Province in north- central Virginia; petrologic 

and structural perspectives on Grenvillian orogenesis 

and Paleozoic tectonic processes. In Geology of the 

National Capital Region; field trip guidebook. Edited by 

S. Southworth and W. Burton. U. S. Geological Survey 

Circular, pp. 17–75 

Ward, L. W., and D. S. Powars. 2004. Tertiary lithology 

and paleontology, Chesapeake Bay region. In Geology 

of the National Capital Region; field trip guidebook. 

Edited by S. Southworth and W. Burton. U. S. 

Geological Survey Circular, pp. 263–297 

Whittecar, G. R., and D. F. Duffy. 2000. Geomorphology 

and stratigraphy of late Cenozoic alluvial fans, Augusta 

County, Virginia, U.S.A. In Regolith in the Central and 

Southern Appalachians. Edited by G. M. Clark; H. H. 

Mills; and J. S. Kite. Southeastern Geology 39(3–4):259–

279. 

Widatalla, N. A., and F. A. Wilson. 1988. Field and zircon 

study of Wissahickon Fm. and Georgetown Complex 

granitic rocks, Rock Creek Pk., Washington, D.C. 

Abstracts with Programs (GSA) 20(4):323. 

Withington, C. F., and H. W. Coulter. 1964. Geology in 

the National Capital. Geotimes 8(5.1):12–14. 

Zen, E- an. 1997a. The Seven- Storey River: 

Geomorphology of the Potomac River channel 

between Blockhouse Point, Maryland, and 

Georgetown, District of Columbia, with emphasis on 

the Gorge Complex Below Great Falls. U. S. 

Geological Survey Open- File Report 97- 60, 96 p. 

Zen, E- an. 1997b. Channel geometry and strath levels of 

the Potomac River between Great Falls, Maryland and 

Hampshire, West Virginia. U. S. Geological Survey 

Open- File Report 97- 480, 93 p. 
 NPS Geologic Resources Division 40 

Appendix A: Geologic Map Graphic 

The following page is a preview or snapshot of the geologic map for National Capital 

Parks–East. For a poster size PDF of this map or for digital geologic map data, please see 

the included CD or visit the GRE publications webpage: 

http://www2.nature.nps.gov/geology/inventory/gre_publications.cfm 
 NACE Geologic Resource Evaluation Report 43

Appendix B: Scoping Summary 

The following excerpts are from the GRE scoping summary for National Capital Parks–

East. The scoping meeting was held on April 30–May 2, 2001; therefore, the contact 

information and Web addresses referred to in this appendix may be outdated. Please 

contact the Geologic Resources Division for current information. 

Summary and Overview 

Geologic Resource Evaluation (GRE) workshops were 

held for National Park Service (NPS) Units in the 

National Capital Region (NCR) April 30–May 2, 2001. 

The purpose was to view and discuss the park’s geologic 

resources, to address the status of geologic mapping for 

compiling both paper and digital maps, and to assess 

resource management issues and needs. Cooperators 

from the NPS Geologic Resources Division (GRD), 

Natural Resources Information Division (NRID), 

individual NPS units in the region, and the United States 

Geological Survey (USGS) were present for the 

workshop. 

This workshop involved half- day field trips to view the 

geology of Catoctin Mountain Park, Harpers Ferry NHP, 

Prince William Forest Park and Great Falls Park, as well 

as another full- day scoping session to present overviews 

of the NPS Inventory and Monitoring (I&M) program, 

the GRD, and the on- going GRE. Round table 

discussions involving geologic issues for all parks in the 

National Capital Region included the status of geologic 

mapping efforts, interpretation, paleontologic resources, 

sources of available data, and action items generated 

from this meeting. 

It is stressed that the emphasis of the inventory is not to 

routinely initiate new geologic mapping projects, but to 

aggregate existing "baseline" information and identify 

where serious geologic data needs and issues exist in the 

National Park System. In cases where map coverage is 

nearly complete (ex., having only 4 of 5 quadrangles for 

Park “X”) or maps simply do not exist, then funding may 

be available for geologic mapping. 

After introductions by the participants, Tim Connors 

presented overviews of the Geologic Resources Division, 

the NPS I&M Program, the status of the natural resource 

inventories, and the GRE in particular. 

Pete Chirico (USGS–Reston, VA) demonstrated the 

digital geology of Harpers Ferry and also showed the 

group potential uses of a digital geologic coverage with 

his examples for Anacostia and Cumberland Island. The 

USGS also showed various digital products that they 

have developed already for Chesapeake and Ohio Canal 

NHP and Great Falls. 

Geologic Mapping 

Existing Geologic Maps and Publications 

After bibliographies were assembled, a separate search 

was made for any existing surficial and bedrock geologic 

maps for the National Capital Region parks. The 

bounding coordinates for each map were noted and 

entered into a GIS to assemble an index geologic map. 

Separate coverages were developed based on scales 

(1:24,000, 1:100,000, etc.) available for the specific park. 

Numerous geologic maps at varying scales and vintages 

cover the area. Index maps were distributed to each 

workshop participant during the scoping session. 

Status 

The index of published geologic maps is a useful 

reference for the NCR. However, some of these maps are 

dated and are in need of refinement, and in other places 

there is no existing large- scale coverage available. The 

USGS began a project to map the Baltimore–Washington, 

D.C., area at 1:100,000 scale and as a result it was brought 

to their attention that modern, large- scale geologic 

mapping for the NCR–NPS areas would be beneficial to 

NPS resource management. 

Because of this, the USGS developed a proposal to remap the NCR at large scale (1:24,000 or greater) and to 

supply digital geologic databases to accompany this 

mapping. Scott Southworth (USGS–Reston, VA) is the 

project leader and main contact. 

The original PMIS (Project Management Information 

Systems) statement is available in Appendix C and on the 

NPS intranet (PMIS number 60900); of note is that 

portions of it need to be changed to reflect that the 

source of funding will be Inventory and Monitoring 

funds and not NRPP. 

Desired Enhancements in the Geologic Maps for NCR Parks 

To better facilitate the geologic mapping, Scott 

Southworth would like to obtain better topographic 

coverage for each of the NCR units. Tammy Stidham 

knows that some of these coverages are already available 

and will supply them to Scott and the USGS. In general, 

anything in Washington, D.C., proper has 1 meter 

topographic coverage and Prince George's county has 

1:24,000 coverage.
 NPS Geologic Resources Division 44 

Notes on National Capital Parks–East (NACE) 

Prioritize the parks 1–12: 

• Ft. Washington (gypsum crystals, Paleontology, seeps) 

• Piscataway (significant paleontology, seeps); located in 

Prince George's and Charles counties 

• Greenbelt Park 

• Oxon Run Parkway in D.C. 

• Fort Circle Parks in D.C. with the exception of Forts 

Foote, Stanton, and Mayhan 

• Oxon Cove Park 

• Anacostia and Kenilworth parks; separate but 

contiguous 

• Baltimore- Washington Parkway 

• Suitland Parkway 

• Shepherd Parkway 

• Harmony Hall 

• Frederick Douglass NHS 

Digital Geologic Map Coverage 

The USGS will supply digital geology in ArcInfo format 

for all of the NCR parks. GRE staff will take these data, 

add the Windows help file and NPS theme manager 

capability to the digital geology and will supply to the 

region to distribute to each park in NCR. 

Other Desired Data Sets for NCR 

Soils 

In, 2001, Pete Biggam (GRD Soil Scientist) supplied the 

following information in reference to soils for parks: 

National Capital Parks–East is covered by portions of 

three soil survey areas; "District of Columbia" (MD099), 

"Charles County, Maryland" (MD017), and "Prince 

George's County, Maryland" (MD033). Both Charles 

County and Prince George's County are currently being 

updated, with Charles County scheduled to be available 

sometime in calendar year 2002, and Prince George's 

County sometime within calendar year 2003. 

Paleontology 

Greg McDonald (GRD Paleontologist) would like to see 

an encompassing, systematic Paleontological inventory 

for the NCR describing the known resources in all parks 

with suggestions on how to best manage these resources. 

In addition to the parks containing paleo resources in 

NACE, according to his current database, the following 

are considered "paleo parks" in the NCR: 

• Chesapeake & Ohio Canal NHP 

• George Washington Memorial Parkway 

• Manassas NBP 

• Prince William Forest Park 

• Harpers Ferry NHP 

Geologic Report 

A "stand- alone" encompassing report on each park’s 

geology is a major focus of the GRE. As part of the USGS 

proposal to map the NCR, they will be summarizing the 

major geologic features of each park in a report to 

accompany their database. 

It was suggested that after the individual reports are 

finished that a regional physiographic report will be 

completed for the entire NCR. 
 NACE Geologic Resource Evaluation Report 45

List of Attendees for NPS National Capital Region GRE Scoping Meeting 

NAME AFFILIATION PHONE E- MAIL 

Joe Gregson NPS, I & M Program 970- 225- 3559 Joe_Gregson@nps.gov 

Tim Connors NPS, GRD 303- 969- 2093 Tim_Connors@nps.gov 

Bruce Heise NPS, GRD 303- 969- 2017 Bruce_Heise@nps.gov 

Lindsay 

McClelland NPS, GRD 202- 513- 7185 Lindsay_mcclelland@nps.gov 

Scott Southworth USGS 703- 648- 6385 Ssouthwo@usgs.gov 

Pete Chirico USGS 703- 648- 6950 Pchirico@usgs.gov 

Pat Toops NPS, NCR 202- 342- 1443, ext. 212 Pat_toops@nps.gov 

James Voigt NPS, CATO 301- 416- 0536 Cato_resource_management@nps.

gov 

Marcus Koenen NPS, NCR 202- 342- 1443, ext. 

216 

Marcus_koenen@nps.gov 

Ellen Gray NPS, NCR 202- 342- 1443, ext. 

223 

Ellen_gray@nps.gov 

Dale Nisbet NPS, HAFE 304- 535- 6770 Dale_nisbet@nps.gov 

Suzy Alberts NPS, CHOH 301- 714- 2211 Susan_alberts@nps.gov 

Dianne Ingram NPS, CHOH 301- 714- 2225 Dianne_ingram@nps.gov 

Bill Spinrad NPS, CHOH 301- 714- 2221 William_spinrad@nps.gov 

Debbie Cohen NPS, ANTI 301- 432- 2243 Debbie_cohen@nps.gov 

Ed Wenschhof NPS, ANTI/MONO 301- 432- 2243 Ed_wenschhof@nps.gov 

Ann Brazinski NPS, GWMP 703- 289- 2541 Ann_brazinski@nps.gov 

Melissa Kangas NPS, GWMP 703- 289- 2542 Melissa_Kangas@nps.gov 

Barbara Perdew NPS, GWMP 703- 285- 2964 Barbara_Perdew@nps.gov 

Barry Wood NPS, GWMP 703- 289- 2543 Barry_wood@nps.gov 

Marie Sauter NPS, CHOH 301- 714- 2224 Marie_frias@nps.gov 

Carol Pollio NPS, PRWI 703- 221- 2176 Carol_pollio@nps.gov 

Duane DonnellyMorrison NPS, PRWI 703- 221- 6921 Duane_donnellymorrison@nps.gov 

Diane Pavek NPS–NRS 202- 342- 1443, ext. 

209 

Diane_Pavek@nps.gov 

Chris Jones NPS–WOTR 703- 255- 1822 Christopher_Jones@nps.gov 

Doug Curtis NPS–NCR–NRS 202- 342- 1443, ext. 

228 

Doug_Curtis@nps.gov 

Brent Steury NPS–NACE 202- 690- 5167 Brent_Steury@nps.gov 

Dave Russ USGS 703- 648- 6660 Druss@usgs.gov 

Tammy Stidham NPS–RTSC 202- 619- 7474 Tammy_stidham@nps.gov 

Dan Sealy NPS–GWMP 703- 289- 2531 Dan_Sealy@nps.gov 

Sue Salmons NPS–ROCR 202- 426- 6834, ext. 33 Sue_salmons@nps.gov 
 NPS Geologic Resources Division 46 

Appendix C: Report of the NPS Monitoring Workshop – 

Planning for the Future in the National Capital Network 

The following excerpts are from the National Capital Network monitoring workshop 

held on July 9–11, 2002 in Shepherdstown, West Virginia. Pages 29–43 are included in 

this appendix as they have direct relevancy to the geologic resource evaluation of 

National Capital Parks–East. 

B. Geology Workgroup 

Purpose: 

Continue the development of vital signs indicators for 

geologic resources in the National Capital Region of the 

National Park Service to provide essential information 

needed to preserve and enhance the region’s most 

important geologic resources. 

Outcomes: 

1. Complete the geology table from previous meetings, 

allowing time to clarify items already in the table and 

identify additional information gaps 

2. Prioritize items in the geology table for future 

monitoring efforts 

3. Develop monitoring objectives for high priority threats 

in the geology table. 

4. Develop a list of potential protocols that would meet 

the above monitoring objectives from the geology 

table. 

Overview 

This breakout session began by reviewing the conceptual 

model describing the geologic resources developed by 

the geology workgroup of the SAC including (1) resource 

components, (2) stressors to those resources, (3) sources 

of stressors, (4) ecological effects, and (5) potential vital 

signs monitoring indicators. Terminology was clarified, 

existing information was edited, and new information 

was added. The results of this discussion are captured in 

Table 4 below. 

One point that was not captured in Table 4 (but which 

should be noted) is that the geology workgroup 

examined soil from an agricultural perspective, rather 

than from an engineering perspective. In addition, 

several people in the group commented that geology is 

an integrative, long- term perspective for monitoring, 

although there are both short- and long- term indicators 

that may be used to examine threats to the geological 

resources in the NCN. 

Other topics of discussion during the morning session 

were urban soils and "engineered or created landscapes". 

Urban soils are generally horticultural in context, some 

of which may be "engineered" but, by far, most urban 

soils are not. Urban soils tend to be non- agricultural or 

non- forest situations where man has, to one degree or 

another, manipulated the landscape such that the natural 

soil regime no longer exists. In most cases, soil structure 

has been lost or redeveloped. In many cases, urban soils 

were composed from subsurface soils and, therefore, 

nothing resembling an "A" horizon exists. 

Urban soils are often compacted, resulting in high bulk 

densities, and, as a result, have reduced oxygen content 

(e.g. trails, campsites, etc.). In addition, these soils are 

poorly drained, low in organic matter, retain little 

moisture, may be disconnected from the water table or 

capillary water, could be contaminated or have 

considerable "artifacts" (ash, glass, etc.), and are often 

depauperate in microfauna (bacteria, fungi) and 

macrofauna such as worms (even if most worms are 

non- native). Thus, many of the highly important 

landscape areas of National Capital Region, including the 

National Mall, battlefield cemeteries, visitor centers, 

picnic areas, trails, tow paths, etc., are places where 

manipulated soils need to be understood from their 

creation, through use and then management. 

In addition, created landscapes were identified as one of 

the more unique, geological components of the National 

Capital Network (and especially, Washington DC), and 

for which the group felt that very little information 

currently was available. On one hand, these changed 

environments could lead to increased diversity — due to 

the potentially more- complex mosaic of soils and 

resulting vegetation communities. On the other hand, 

these landscapes are commonly affected by human 

manipulation, horticultural and agricultural practices, 

and urban landscaping efforts, all of which tend to lower 

biodiversity and lead to an increased occurrence of 

exotic species. 

Several potential research topics were discussed: 

historical records of floods, sedimentation, and land use 

in the region. Historical records of floods should be 

relatively easy to find for the National Capital Region. 

For example, Metro records and historical documents 

may provide an indication of historic structures affected 

by flooding on a sequential basis. In addition, Jim 

Patterson (NPS–retired) may have a lot of background 

information on NCR parks. 

Sediment coring may also be used to provide a historical 

perspective on sediment "cycling" throughout the 

history of this region. The use of aerial photos, as 

available, may provide the necessary data to examine 

land use change over time, changes in stream 

morphology over time, and shoreline change over time. 
 NACE Geologic Resource Evaluation Report 47

Finally, through the use of newer technologies such as 

LIDAR and GPS, it is possible to examine changes in 

topography and geomorphology, at a fine scale, which is 

especially important in the Piedmont and Coastal Plain 

areas of the National Capital Region that have little or no 

topographic relief (e.g. Dyke Marsh). 

In the afternoon session, the workgroup focused upon 

ways to condense the list of 30 threats to geological 

resources into a more manageable size (Table 5). This 

proved to be a difficult task due to the varied nature of 

some of the components in Table 4. The first two 

categories, (1) nutrients and contaminants and (2) 

erosion and sedimentation, were natural groupings of 

many of the entries in Table 4. The remaining 

components of Table 4 were more difficult to categorize 

because they did not fit nicely into a single group 

heading. However, the workgroup was finally able to 

group the components into the following subject 

headings: nutrient and contaminant cycling, sediment 

cycling, engineered lands and urban soils, shoreline 

change, geo- hazards, human influences within the park 

boundary, and human influences outside the park 

boundary. The group next began to prioritize these 

subject areas, but decided that some of these categories 

were too contrived, or overlapped too much, to be 

separated out in this way. 

The final geology working group session was held on 

Thursday morning. The group decided to continue 

through the prioritization process by beginning with the 

categories that they were satisfied with nutrient and 

contaminant cycling, and sediment cycling. For these 

two groupings, the group suggested established 

protocols for monitoring, wrote monitoring goals and 

objectives and identified potential collaborators. Once 

this analysis was completed for nutrient/contaminant 

and sediment cycling, the discussion continued for 

engineered lands and urban soils, shoreline change and 

geo- hazards. 

The categories of human influences within the park 

boundary and human influences outside the park 

boundary were decided to be too broad and thus were 

eliminated from Table 4. 

Categories were then ranked by considering the 

significance of the threat to the parks in the NCN, which 

included the following factors: amount of area affected 

by the threat, intensity of the threat to the resource, 

urgency of the threat to the resource, monitoring 

feasibility, and cost of monitoring. 

By the end of the morning session, the group had 

decided upon the following categories, in priority order: 

nutrient and contaminant cycling, sedimentation and 

erosion, lack of understanding of engineered lands, 

shoreline change and geo- hazards. The workgroup then 

went back through Table 4 to assign all 30 elements to 

one (or more) of these specific groupings. 

In addition to the work above, the workgroup noted 

information needs and studies of interest throughout the 

discussion. They are summarized below. 

Information Needs: 

A more recent and complete soils map for the region is 

needed. 

Inventory information regarding land changes and the 

creation of lands for baseline data as well as how these 

lands change towards equilibrium is needed. 

Are locations of air quality monitoring stations that also 

capture atmospheric deposition known? They need to be 

checked at the National Atmospheric Deposition 

Program (http://nadp.sws.uiuc.edu) or discussed with 

the air workgroup. 

What about non- point source pollution monitoring in 

the region? 

Is anyone considering the effects of acid rain on 

monuments in the region? There was, at one time, a 

long- term monitoring project regarding this process (in 

DC)? 

Has anyone examined the flood and floodplain history of 

this area? 

Previous studies of interest in NCR: 

There were studies at 4- Mile Run beginning in the 1950's 

(pre- urbanization) to look at or capture the effects of 

urbanization. 

Jeff Houser (Oak Ridge) has looked at the effects of 

sedimentation on streams and stream biota. 

Personnel Involved: 

Facilitator: Christina Wright, NPS–NCN I & M Program: 

and Dale Nisbet, NPS–HAFE 

Participants: Joe Calzarette, Michelle Clements, Sid 

Covington, Dick Hammerschlag, Bob Higgins, Wright 

Horton, Lindsay McClelland, Wayne Newell, Scott 

Southworth, L. K. Thomas, and Ed Wenschhof. 
 NPS Geologic Resources Division 48 

Table 4. Revised conceptual model for geological resources in the NCN. 

Resource 

Component Stressor Sources Ecological 

Effects 

Priority of 

Threat to 

Resource 

Grouping 

used in 

priority 

table 

Indicator/ Vital 

Sign Protocol Monitoring 

Goal 

Potential 

contacts or 

collaborators 

Soil Pesticide 

loading 

Agricultural, 

residential, and 

commercial 

use 

Accumulation of 

pesticides that 

adhere to soil 

particles, causing 

changes to or the 

elimination of 

non- target soil 

fauna populations

High 1 

Test soils and 

sediment for suite 

of pesticides 

commonly used 

in local area 

Lithogeochem

ical studies 

(USGS), mass 

balance or 

input/output 

approach 

Use an 

input/output 

approach to 

understand 

nutrient and 

contaminant 

cycling in the 

ecosystem. 

Owen Bricker, 

Nancy Simon, 

Wayne Newell, 

Wright Horton, 

David Russ 

(USGS–Reston), 

Mark Nellis 

(USGS–Denver), 

USDA, EPA, 

USGS–NAWQA 

Soil/Bedrock Nutrient 

loading 

Agricultural, 

residential and 

commercial 

use 

Acidification of 

the soil, reduction 

of soil organic 

matter, change in 

soil fertility status

High 1 

Soil pH, soil N 

and P status, soil 

organic matter 

levels 

Lithogeochem

ical studies 

(USGS), mass 

balance or 

input/output 

approach 

Use an 

input/output 

approach to 

understand 

nutrient and 

contaminant 

cycling in the 

ecosystem. 

Owen Bricker, 

Nancy Simon, 

Wayne Newell, 

Wright Horton, 

David Russ 

(USGS–Reston), 

Mark Nellis 

(USGS–Denver), 

USDA, EPA, 

USGS–NAWQA 

Soil/Bedrock 

Change in pH, 

loss of 

buffering 

capacity 

Acid rain, 

atmospheric 

deposition 

Change in 

vegetation types, 

mycorrhiza and 

other soil flora, 

fauna 

Unknown 1 

Soil pH, acid 

neutralizing 

capacity (ANC) 

Lithogeochem

ical studies 

(USGS), mass 

balance or 

input/output 

approach. 

Mass 

flow/hydrologi

c modeling. 

Use an 

input/output 

approach to 

understand 

nutrient and 

contaminant 

cycling in the 

ecosystem. 

Owen Bricker, 

Nancy Simon, 

Wayne Newell, 

Wright Horton, 

David Russ 

(USGS–Reston), 

Mark Nellis 

(USGS–Denver), 

USDA, EPA, 

USGS–NAWQA 

Soil Temperature 

change Climate change Changes in soil micro- climate Unknown, locally high 

Soil temperature/ 

moisture regime, 

changes in soil 

flora, fauna and 

mycorrhiza suite 

Soil temperature and moisture monitoring. Soil 

organism analysis. 

Soil/Surficial 

Factors 

Clearing of 

land 

Soil surface 

exposure, 

development, 

agriculture, 

zoning laws 

(local and 

county 

governments) 

Loss of soil 

surface cover, 

increased soil 

surface and 

groundwater 

temperatures 

High 2 and 3 

Soil and 

groundwater 

temperature/ 

moisture regime. 

Change in 

vegetation 

community. Land 

use change. 

Measurement 

of soil surface 

and 

groundwater 

temperature, 

monitoring of 

bare soils in 

region. Land 

use change 

analysis, 

vegetation 

community 

analysis. 

Use survey 

and analysis 

methods to 

evaluate 

changes in 

topography, 

sediment 

loading and 

water flow 

rates. 

Rebecca Beavers 

(NPS–GRD), 

Wayne Newell, 

Nancy Simon, Pete 

Chirico (USGS–

Reston), EPA–

Office of Water 

and ORD, USGS–

NAWQA, Loren 

Setlaw (?), Doug 

Curtis (NPS–

CUE), Don Weeks 

(NPS–Denver) 
 NACE Geologic Resource Evaluation Report 49

Resource 

Component Stressor Sources Ecological 

Effects 

Priority of 

Threat to 

Resource 

Grouping 

used in 

priority 

table 

Indicator/ Vital 

Sign Protocol Monitoring 

Goal 

Potential 

contacts or 

collaborators 

Soil Erosion 

Development, 

land clearing, 

increasing 

impervious 

surface 

Increased 

siltation, reduced 

productivity/ 

health/abundance 

of soil, plants, and 

aquatic organisms

High 2 and 4 

Sediment loading, 

increased 

sedimentation 

and changes in 

sedimentation 

patterns, land use 

change, change in 

topography, 

shoreline change, 

change in wetland 

extent and 

condition. 

Shoreline 

change/Wetla

nd extent - 

aerial photo 

analysis. 

Change in 

topography - 

LIDAR, GPS. 

Changes in 

sedimentation 

- bedload 

analysis, storm 

water event 

sampling, total 

suspended 

solids, light 

penetration in 

water column. 

Condition of 

wetland - 

changes in 

wetland plant 

species, 

multiband 

aerial 

photography. 

Use survey 

and analysis 

methods to 

evaluate 

changes in 

topography, 

sediment 

loading and 

water flow 

rates. 

Rebecca Beavers 

(NPS–GRD), 

Wayne Newell, 

Nancy Simon, Pete 

Chirico (USGS–

Reston), EPA–

Office of Water 

and ORD, USGS–

NAWQA, Loren 

Setlaw (?), Doug 

Curtis (NPS–

CUE), Don Weeks 

(NPS–Denver) 

Soil/Surficial 

Factors Erosion Development 

Change in 

“normal” 

sedimentation 

sequence and 

composition 

Unknown, 

low 2 and 4 

Increased 

deposition, 

change in 

scouring and 

deposition 

patterns, change 

in hydrologic 

flow regimes. 

See above 

protocols. 

Also, analysis 

of sediment 

cores, 

including an 

analysis of 

historical 

sediment 

records. 

Use survey 

and analysis 

methods to 

evaluate 

changes in 

topography, 

sediment 

loading and 

water flow 

rates. 

Rebecca Beavers 

(NPS–GRD), 

Wayne Newell, 

Nancy Simon, Pete 

Chirico (USGS–

Reston), EPA–

Office of Water 

and ORD, USGS–

NAWQA, Loren 

Setlaw (?), Doug 

Curtis (NPS–

CUE), Don Weeks 

(NPS–Denver) 

Soil 

Change in 

vegetation/ 

exotics 

Development, 

nursery use of 

exotics 

Change in soil 

organic matter 

composition, 

changes in soil 

flora and fauna, 

pH, nitrification 

rates 

Unknown Exotic species monitoring and control measures, soil chemistry, soil 

organic matter levels, soil pH, soil nitrification rates 

Soil, creation 

of new soils 

Fill dirt: 

complete 

changes in soil 

physical and 

chemical 

composition 

resulting from 

filling in land 

areas with soil 

from another 

location (esp. 

DC) 

Landfills, 

abandoned 

mines, land 

engineering 

Changed, 

destroyed, or new 

soil profile, 

change in 

chemical 

composition of 

soil, introduction 

of toxics, 

introduction of 

impervious 

structures into 

soil profile, 

compaction. 

Resultant changes 

to biodiversity 

and vegetation 

communities. 

Changes to 

hydrologic cycle. 

High – esp. 

urban 1 and 3 

Assessment and 

description of soil 

profile, change in 

subsurface 

temperatures, 

change in land 

surface elevation 

profile, 

movement of 

physical debris 

from land, soil 

compaction, 

change in 

biodiversity of 

flora and fauna 

Assessment 

and 

description of 

soil profile, 

surface and 

ground water 

monitoring 

(lithogeochem

ical studies), 

bulk density, 

porosity or 

other soil 

compaction 

measures. 

To 

understand 

the 

functioning 

and 

components 

of 

engineered 

landscapes 

(components 

– landfills, 

engineered 

soils, etc.) 

USDA–NRCS, 

Dick 

Hammerschlag 

(USGS–

Patauxent), Wright 

Horton (USGS–

Reston). Also see 

contacts for 

nutrient and 

sediment cycling. 
 NPS Geologic Resources Division 50 

Resource 

Component Stressor Sources Ecological 

Effects 

Priority of 

Threat to 

Resource 

Grouping 

used in 

priority 

table 

Indicator/ Vital 

Sign Protocol Monitoring 

Goal 

Potential 

contacts or 

collaborators 

Soil Compaction Visitor Use 

Changes in 

vegetation 

survival, changes 

in soil physical 

properties, 

creation of soil 

crusts (an 

impervious 

surface). 

Urban, 

locally – high 1 and 3 

Monitor soil 

compaction, bulk 

density, porosity, 

or other soil 

compaction 

measures. 

Formation of soil 

crusts. 

Soil coring, 

bulk density, 

porosity or 

other soil 

compaction 

measures. 

To understand the effects of 

visitor use upon the soil profile – 

includes social and official trails. 

Soil Impervious 

surfaces 

Paving, walls, 

armored banks 

Scouring, 

cutting/changing 

shoreline, 

flooding, 

High 1 and 3 

Increased velocity 

of storm water 

flow, land use 

change 

Storm water 

event 

sampling, 

aerial photos 

to examine 

land use 

change. 

To 

understand 

the effects of 

increasing 

impervious 

surfaces in 

the 

watershed 

upon 

hydrology. 

Pat Bradley–EPA, 

USGS–NAWQA, 

EPA–Office of 

Water 

Unique soils: 

calcareous 

and 

serpentine 

soils 

Lack of 

information 

for these soils 

and soil in 

general 

Lack of 

information for 

these soils and 

soil in general 

Potential for 

damage to 

unknown/ 

unmapped 

resource 

Unknown 1 Soils inventory 

work necessary. 

Complete, upto- date, high 

resolution soil 

maps 

N/A Pete Biggam–NPS, 

USDA–NRCS 

Groundwater 

Consumption 

of 

groundwater 

in excess of 

replenishment 

Human, 

agricultural, 

residential, 

commercial 

use and 

domestic 

animal use 

Reduced 

groundwater 

quantity, and 

quality. Loss of 

springs and seeps, 

wetland loss, 

changed of soil 

saturation zones. 

Change in 

drinking water 

quality and 

quantity. 

High 1 and 2 

Changes in 

groundwater 

table, Changes or 

loss of springs 

and seeps, change 

in extent of 

wetlands, changes 

in soil moisture 

profile. 

Survey of groundwater table and groundwater 

chemistry. Groundwater flow monitoring wells 

Groundwater 

Introduction 

of toxics, acid 

drainage 

(natural and 

mining) 

Landfills, 

abandoned 

mines, land 

engineering, 

bedrock. 

Reduced 

groundwater 

quality 

High 1 

Change in 

groundwater 

quality, quantity, 

and temperature. 

Increased toxics 

in groundwater. 

Groundwater 

monitoring 

wells in 

conjunction 

with 

lithogeochemi

cal studies 

(USGS), Mass 

balance or 

input/output 

approach 

Use an 

input/output 

approach to 

understand 

nutrient and 

contaminant 

cycling in the 

ecosystem. 

Owen Bricker, 

Nancy Simon, 

Wayne Newell, 

Wright Horton, 

David Russ 

(USGS–Reston), 

Mark Nellis 

(USGS–Denver), 

USDA, EPA, 

USGS–NAWQA 

Groundwater Physical 

Failure 

Landfills, 

abandoned 

mines, land 

engineering 

Change in 

subsurface water 

flow patterns, 

change in 

subsurface 

temperatures, 

introduction of 

contaminants 

High 5 

Groundwater 

monitoring wells 

(flow and 

mapping), 

subsurface 

temperature 

changes 

Aerial photo 

mapping of 

areas with 

potential 

physical 

failures. Park 

staff 

observations 

of potential 

geo- hazard 

sites. Expert 

analysis of 

geo- hazard 

sites on a 

periodic basis. 

To use 

observation 

and 

assessment 

to provide an 

early 

warning of 

physical 

failure in 

order to 

protect the 

resource, 

visitors, and 

park 

infrastructur

e. 

John Pallister, Bula 

Gori, Gerry 

Wieczoff–USGS 
 NACE Geologic Resource Evaluation Report 51

Resource 

Component Stressor Sources Ecological 

Effects 

Priority of 

Threat to 

Resource 

Grouping 

used in 

priority 

table 

Indicator/ Vital 

Sign Protocol Monitoring 

Goal 

Potential 

contacts or 

collaborators 

Groundwater 

Water 

bypasses the 

soil profile 

Old – 

abandoned 

wells (farms) 

Increased 

groundwater 

contamination 

with nutrients, 

pesticides and 

other chemicals 

Unknown 1 

Change in 

groundwater 

quality, increased 

toxics in 

groundwater. 

Groundwater 

monitoring 

and 

monitoring of 

abandoned 

wells in 

conjunction 

with 

lithogeochemi

cal studies 

(USGS), Mass 

balance or 

input/output 

approach. 

Abandoned 

wells need to 

be found and 

sealed to 

minimize 

contamination

. 

Use an 

input/output 

approach to 

understand 

nutrient and 

contaminant 

cycling in the 

ecosystem. 

Owen Bricker, 

Nancy Simon, 

Wayne Newell, 

Wright Horton, 

David Russ 

(USGS–Reston), 

Mark Nellis 

(USGS–Denver), 

USDA, EPA, 

USGS–NAWQA 

Groundwater Impervious 

Surfaces 

Roads, 

buildings, 

infrastructure 

Reduced water 

infiltration 

leading to 

reduced 

groundwater 

recharge, 

movement of 

water between 

watersheds 

Medium 1 and 2 Map and monitor groundwater recharge areas, monitor groundwater 

table levels and chemistry, subsurface temperature monitoring. 

Exposed rock 

Cutting the toe 

of slopes, 

oversteepened 

slopes, 

dipslopes 

Development, 

roads, 

structures, 

trails, flooding, 

vegetation 

death 

(hemlock etc.), 

logging 

Reduced slope 

stability Low 5 

Slope failure, 

reduced slope 

stability, 

movement of 

materials 

downslope, 

erosion, gully 

formation 

Aerial photo 

mapping of 

areas with 

potential 

physical 

failures. Park 

staff 

observations 

of potential 

geo- hazard 

sites. Expert 

analysis of 

geo- hazard 

sites on a 

periodic basis. 

Monitoring 

for gulley 

formation or 

increasing 

erosion. 

To use 

observation 

and 

assessment 

to provide an 

early 

warning of 

physical 

failure in 

order to 

protect the 

resource, 

visitors, and 

park 

infrastructur

e. 

John Pallister, Bula 

Gori, Gerry 

Wieczoff–USGS. 

Also see personnel 

under erosion 

categories. 

Karst 

Toxics: 

pesticides, 

dumping, spills 

Agriculture, 

septic systems, 

sewage, 

dumping, 

industry, spills 

Rapid movement 

of contaminants 

to ground water, 

change in ground 

water chemistry 

and resulting in 

change in biology 

High – locally 1 

Subterranean 

invertebrates, 

ground water 

chemistry/ quality

Analysis of 

subterranean 

invertebrates. 

Lithogeochem

ical studies 

(USGS), Mass 

balance or 

input/output 

approach 

Use an 

input/output 

approach to 

understand 

nutrient and 

contaminant 

cycling in the 

ecosystem. 

Smithsonian 

Institute 

Invertebrate 

specialists. Owen 

Bricker, Nancy 

Simon, Wayne 

Newell, Wright 

Horton, David 

Russ (USGS–

Reston), Mark 

Nellis (USGS–

Denver), USDA, 

EPA, USGS–

NAWQA 
 NPS Geologic Resources Division 52 

Resource 

Component Stressor Sources Ecological 

Effects 

Priority of 

Threat to 

Resource 

Grouping 

used in 

priority 

table 

Indicator/ Vital 

Sign Protocol Monitoring 

Goal 

Potential 

contacts or 

collaborators 

Karst Nutrient 

loading 

Agriculture, 

septic systems, 

sewage, 

dumping, 

industry, spills 

Rapid movement 

of nutrients to 

ground water 

resulting in 

change to ground 

water quality and 

change in biology 

High – locally 1 

Subterranean 

invertebrates, 

ground water 

nutrient content 

Analysis of 

subterranean 

invertebrates. 

Lithogeochem

ical studies 

(USGS), Mass 

balance or 

input/output 

approach 

Use an 

input/output 

approach to 

understand 

nutrient and 

contaminant 

cycling in the 

ecosystem. 

Smithsonian 

Institute 

Invertebrate 

specialists. Owen 

Bricker, Nancy 

Simon, Wayne 

Newell, Wright 

Horton, David 

Russ (USGS–

Reston), Mark 

Nellis (USGS–

Denver), USDA, 

EPA, USGS–

NAWQA 

Karst 

Structural 

collapse, 

sinkholes 

Inappropriate 

construction 

practices, 

dissolution in 

karst areas 

Change in biology 

due to changes in 

air flow and 

temperature, 

volume and flow 

of water increased 

in areas 

dissolution of 

bedrock 

High – locally 5 

Change in 

sinkhole size, 

aerial photos to 

capture surface 

changes, 

subsurface 

temperature 

monitoring 

Aerial photo 

mapping of 

areas with 

sinkholes. 

Park staff 

observations 

of potential 

geo- hazard 

sites. Expert 

analysis of 

geo- hazard 

sites on a 

periodic basis. 

To use 

observation 

and 

assessment 

to provide an 

early 

warning of 

physical 

failure in 

order to 

protect the 

resource, 

visitors, and 

park 

infrastructur

e. 

John Pallister, Bula 

Gori, Gerry 

Wieczoff–USGS 

Surface water Impervious 

surfaces 

Infrastructure, 

development, 

residential and 

agricultural 

use, rip rap, 

armoring etc. 

Increased storm 

water flow, 

increased erosion, 

changes in 

sedimentation, 

changes in stream 

morphology, 

increased 

exposure to 

nutrients/ 

pesticides, change 

in hydrologic 

cycle effecting 

floodplains, and 

floodplain/riparia

n buffer capacity, 

change in base 

flow 

High 1 and 2 

Stream storm 

water flow, flood 

frequency, 

sedimentation 

load, stream 

morphology. 

Photo points. 

Storm event 

sampling, Mass 

flow/hydrologic 

modeling 

Lithogeochem

ical studies 

(mass balance 

approach). 

Shoreline 

change/Wetla

nd extent - 

aerial photo 

analysis. 

Change in 

topography - 

LIDAR, GPS. 

Changes in 

sedimentation 

- bedload 

analysis, storm 

water event 

sampling, total 

suspended 

solids, light 

penetration in 

water column. 

Condition of 

wetland - 

changes in 

wetland plant 

species, 

multiband 

aerial 

photography. 

Use an 

input/output 

approach to 

understand 

nutrient and 

contaminant 

cycling in the 

ecosystem. 

Use survey 

and analysis 

methods to 

evaluate 

changes in 

topography, 

sediment 

loading and 

flow rates. 

Rebecca Beavers 

(NPS–GRD), 

Owen Bricker, 

Nancy Simon, 

Wayne Newell, 

Pete Chirico, 

Wright Horton, 

David Russ 

(USGS–Reston), 

Mark Nellis 

(USGS–Denver), 

USDA, EPA–Office 

of Water, USGS–

NAWQA 
 NACE Geologic Resource Evaluation Report 53

Resource 

Component Stressor Sources Ecological 

Effects 

Priority of 

Threat to 

Resource 

Grouping 

used in 

priority 

table 

Indicator/ Vital 

Sign Protocol Monitoring 

Goal 

Potential 

contacts or 

collaborators 

Surface water Pesticide 

loading 

Agricultural, 

residential, and 

commercial 

use 

Reduced water 

quality, fishery 

health, and 

aquatic 

invertebrate 

communities and 

populations 

High 1 

Test for suite of 

pesticides 

commonly used 

in local area. 

Lithogeochem

ical studies 

(USGS), Mass 

balance or 

input/output 

approach 

Use an 

input/output 

approach to 

understand 

nutrient and 

contaminant 

cycling in the 

ecosystem. 

Owen Bricker, 

Nancy Simon, 

Wayne Newell, 

Wright Horton, 

David Russ 

(USGS–Reston), 

Mark Nellis 

(USGS–Denver), 

USDA, EPA, 

USGS–NAWQA 

Surface water Nutrient 

loading 

Agricultural, 

residential and 

commercial 

use 

Reduced water 

quality, fishery 

health, and 

aquatic 

invertebrate 

communities and 

populations. Algal 

blooms, 

eutrophication 

High 1 

Soil water and 

stream levels of N 

and P. High algal 

growth, low light 

penetration 

Lithogeochem

ical studies 

(USGS), Mass 

balance or 

input/output 

approach 

Use an 

input/output 

approach to 

understand 

nutrient and 

contaminant 

cycling in the 

ecosystem. 

Owen Bricker, 

Nancy Simon, 

Wayne Newell, 

Wright Horton, 

David Russ 

(USGS–Reston), 

Mark Nellis 

(USGS–Denver), 

USDA, EPA, 

USGS–NAWQA 

Coastal areas Impervious 

surfaces 

rip rap, 

armoring, 

coastal walls, 

dredging 

Changes in water 

flow rates, 

unnatural erosion 

and deposition, 

changes in natural 

shoreline, 

changes in 

sedimentation, 

wetland flooding, 

changes in 

wetland extent. 

High – locally 1 and 2 

Sedimentation 

coring (deep 

cores – research, 

shallow cores – 

monitoring), 

mapping of 

shoreline change, 

use of Pope's 

Creek as a 

reference area 

Using aerial 

photos or 

survey 

methods to 

map shoreline 

and shoreline 

change over 

time. 

Use mapping 

or survey 

methods to 

track 

changes in 

shoreline 

and 

depositional 

patterns, 

over time. 

NOAA (?) 

Lakes, ponds, 

seeps, vernal 

pools 

Nutrient 

loading 

Agriculture, 

residential 

lawn care, 

vegetation 

change 

Eutrophication, 

change in fauna 

(esp. herps), effect 

upon T&E species

Unknown 1 

Size/volume, 

chemistry, and 

temperature of 

surface water 

component 

Lithogeochem

ical studies 

(USGS), Mass 

balance or 

input/output 

approach 

Use an 

input/output 

approach to 

understand 

nutrient and 

contaminant 

cycling in the 

ecosystem. 

Owen Bricker, 

Nancy Simon, 

Wayne Newell, 

Wright Horton, 

David Russ 

(USGS–Reston), 

Mark Nellis 

(USGS–Denver), 

USDA, EPA, 

USGS–NAWQA 

Lakes, ponds, 

seeps, vernal 

pools 

Pesticide 

loading 

Agriculture, 

residential, and 

commercial 

use 

Addition of 

herbicides and 

pesticides to 

surface water, 

change in fauna, 

effect upon T&E 

species 

Unknown 1 

Pesticide, 

herbicide content 

of surface water 

component 

Lithogeochem

ical studies 

(USGS), Mass 

balance or 

input/output 

approach 

Use an 

input/output 

approach to 

understand 

nutrient and 

contaminant 

cycling in the 

ecosystem. 

Owen Bricker, 

Nancy Simon, 

Wayne Newell, 

Wright Horton, 

David Russ 

(USGS–Reston), 

Mark Nellis 

(USGS–Denver), 

USDA, EPA, 

USGS–NAWQA 
 NPS Geologic Resources Division 54 

Resource 

Component Stressor Sources Ecological 

Effects 

Priority of 

Threat to 

Resource 

Grouping 

used in 

priority 

table 

Indicator/ Vital 

Sign Protocol Monitoring 

Goal 

Potential 

contacts or 

collaborators 

Riparian 

areas, 

Wetlands 

Change in soil 

surface 

elevation and 

horizontal 

dimensions 

Land 

engineering 

resulting in 

changes to 

deposition and 

erosion, 

dredging, 

dumping, 

creation of 

impoundments 

and dams 

Disruption to the 

wetland/riparian 

ecosystems, 

change in storm 

water flow rates, 

vegetation 

change, wildlife 

change, change in 

stream bed 

characteristics 

High 4 

High resolution 

riparian/ wetland 

elevation 

monitoring, 

vegetation 

monitoring, 

sediment budget, 

changes in size of 

wetland area 

Changes in 

wetland extent 

- aerial photo 

analysis. 

Change in 

topography - 

LIDAR, GPS. 

Changes in 

sedimentation 

- bedload 

analysis, storm 

water event 

sampling, total 

suspended 

solids, light 

penetration in 

water column. 

Condition of 

wetland - 

changes in 

wetland plant 

species, 

multiband 

aerial 

photography. 

Use survey 

and analysis 

methods to 

evaluate 

changes in 

topography, 

sediment 

loading and 

water flow 

rates. 

Rebecca Beavers 

(NPS–GRD), 

Wayne Newell, 

Nancy Simon, Pete 

Chirico (USGS–

Reston), Richard 

Lowrance 

(USDA/ARS), 

EPA–Office of 

Water and ORD, 

USGS–NAWQA, 

Loren Setlaw (?), 

Doug Curtis (NPS–

CUE), Don Weeks 

(NPS–Denver) 
 NACE Geologic Resource Evaluation Report 55

Table 5. Priority threats, vital signs, and monitoring goals and objectives for geological resources in the NCN. 

Threats 

(in priority order) Vital Sign Monitoring Goal Monitoring Objectives 

Nutrient and chemical 

contamination 

Changes in soil and 

ground water chemistry. 

Use an input/output 

approach to understand 

nutrient and contaminant 

cycling in the ecosystem. 

(1) Measuring nutrient inputs from 

sources pertinent to each park unit. (2) 

Measuring contaminant inputs from 

sources pertinent to each park unit. (3) 

Tie information from numbers 1 and 2 

to the hydrologic cycle, flood history, 

flood effects, and flood impacts. 

Erosion and 

sedimentation 

Changes in topography, 

sediment loading and 

deposition, shoreline 

change, wetland extent 

and condition. 

Use survey and analysis 

methods to evaluate changes 

in topography, sediment 

loading, and flow rates. 

(1) Measure loss of soil, growth of 

gulleys, changes in streambanks.... (2) 

Track sedimentation history, effects, 

and impacts (including streams and 

ponds, hillslopes and gulleys). 

Lack of understanding 

of urban soils and 

engineered lands 

Compaction, runoff, 

chemical composition, 

soil profile and 

structure, biodiversity. 

To understand the 

functioning and components 

of urban soils engineered 

landscapes and their effects 

upon resident biota. 

Components include: highly 

impacted soil (compaction in 

and around trails, visitor 

centers), landfills, engineered 

soil, etc. 

(1) Measure changes to physical 

components of urban soils and 

engineered lands and correlate with 

changes in resident biota (and exotic 

species). (2) Measure contaminant 

outflow from landfills, abandoned 

mines, etc. 

Shoreline change 

Inundation of wetlands, 

erosion and 

sedimentation 

processes. 

Use mapping or survey 

methods to track shoreline 

change and depositional 

patterns. 

(1) Measure shoreline change using 

aerial photos, LIDAR and survey 

methodologies and correlate changes 

to development, when possible. (2) Use 

sediment coring and historical data to 

understand long- term flood histories. 

Geo- hazard 

Physical failure, rock 

falls, landslides, 

sinkhole collapse. 

Use observation and 

assessment to provide an 

early warning of physical 

failure to protect the 

resource, visitors, and park 

infrastructure. 

(1) Monitor areas of potential hazard 

due to unstable slopes, rockfalls, etc. (2) 

Monitor for changes in unstable 

engineered sites or areas that are 

geologically active (e.g. Potomac 

Gorge). (3) Document and monitor 

areas underlain by swelling clays. 
 NPS Geologic Resources Division 56 

Appendix D: Geoindicators Report 

National Capital Parks East Geoindicators Meeting 

Introduction 

National Capital Parks–East (NACE) comprises more than 10,000 acres of the Atlantic Coastal Plain from Anne 

Arundel County, Maryland, through the eastern part of Washington, D.C., to Prince George’s and Charles 

counties, Maryland. The Coastal Plain is composed of a wedge- shaped sequence of soft sediments, deposited 

intermittently during periods of higher sea level over the past 100 million years. Thicknesses of coastal plain 

sediments reach 10,000 feet near the Maryland coast (Reed, Sigafoos, and Fisher 1980). Significant habitats 

include tidal and non- tidal wetlands and upland forests. Legislative purposes for some National Capital Parks–

East units include preventing pollution and ensuring flow into the Potomac and Anacostia rivers. [See the 

National Capital Planning Commission Act of 1924. Parks established under the Act were later given to the NPS. 

Steve Syphax can provide language. Other NACE parks were established under the George Washington 

Memorial Parkway's legislation.] [Check NRBib and with Doug Curtis for information on current monitoring in 

NACE.] 

Tributary Streams 

The NACE generally owns only a small portion of its approximately 20 streams, many of which emerge from 

pipes into the watershed. Major streams include Henson Creek (Suitland Parkway and Harmony Hall), Fort 

Dupont Creek (Fort Dupont Park), Deep and Still creeks (Greenbelt Park), Oxon Run (Oxon Cove Park) and 

Pope and Watts branches (Kenilworth Park). Park staff exerts considerable effort in working with surrounding 

jurisdictions to protect stream corridors. 

Research is needed on sediments, including coring and N- alkanes. 

Streams in effect integrate the surface runoff and groundwater flow of their watersheds, so provide a cumulative 

measure of watershed hydrologic health. NACE generally manages only the downstream portions of its streams, 

so has little control over water quality, quantity, or sediment load. Erosion and aggradation data for NACE 

streams are scarce. 

The most severe threats to park streams are from impacts of existing and future development in the surrounding 

region. Allen and Flack (2001) cite a number of specific threats, excerpted below. Their assessment of each threat 

severity (severe/major/moderate/minor) is given in brackets. 

• Habitat fragmentation from road crossings, primarily culverts (see below for details of culvert impacts). 

[severe] 

• Habitat destruction from high storm water flows and construction of storm water management facilities. 

[severe] 

• Hydrologic changes from increased runoff from impervious surfaces. [severe] 

• Sedimentation from land clearing activities. [major] 

• Water temperature increases from runoff from heated impervious surfaces. [moderate] 

• Pollution from runoff of petroleum products from impervious surfaces, and pesticides, herbicides, and 

fertilizers from developed land. [minor] 

Allen and Flack (2001) report that impacts from impervious surfaces begin when they cover more than 10% of the 

watershed, and become severe above 20%, unless there is mitigation from storm water management systems. 

Development impacts include increased “flashiness,” a combination of reduced base flow because impervious 

surfaces reduce infiltration of groundwater and higher peak flow because of higher storm water runoff from 

impervious surfaces. Chemical pollutants such as leakage from vehicles and litter and trash that wash in from 

developed sites are additional impacts from impervious surfaces. Construction activities bring flushes of 

sediment and other debris, with volumes dependent on types of mitigation measures required and enforced by 

local governments. Development may also bring long- term increases in pollutants such as pesticides, herbicides, 

and fertilizers; organic and inorganic chemicals; metals such as mercury, arsenic, lead, and aluminum; sewage 

from humans and domestic animals; pharmaceuticals; and endocrine disruptors. 

Development has also resulted in significant changes in elevation and slope. To create suitable building sites, hills 

have historically been flattened and marshes and stream valleys filled. By developing a pre- development digital 
 NACE Geologic Resource Evaluation Report 57

elevation model (DEM) from 1889 topographic data and comparing it to current DEM data, Chirico and Epstein 

(2000) have documented as much as 60 feet of elevation change associated with development in parts of 

Philadelphia. Data for a similar project are available for Washington, D.C. U.S. Coast and Geodetic Survey 

1:4,800- scale maps from 1878 and 1888 can be digitally compared to USGS topographic map data from 1996–1999. 

District of Columbia sewer- line maps from 1891 and 1892 are also available to show evidence of topographic 

modification of stream valleys. Initial work has documented significant topographic change. The District of 

Columbia government has tentatively funded the project, but administrative issues unrelated to this project have 

delayed, and may threaten, the eventual transfer of funds. 

Daylighting of streams (removal from culverts) has been proposed in Anacostia Park, with the potential for 

significant funding from the U.S. Army Corps of Engineers (COE). A number of flood- control levees that are 

routinely inspected by the COE are on NPS land along the Anacostia River, in the same area that stream 

daylighting is being proposed. The degree of NPS responsibility to maintain these structures is uncertain. 

[Charles Karpowitz may be the best contact.] Daylighting might help to establish fringe wetlands, but might also 

impact flood control levees. 

Potential monitoring targets: 

• Changes in development in park tributary watersheds—incorporate detailed data from appropriate city and 

county maps into a GIS database, focusing on changes in impervious surfaces, road crossings, buffering 

vegetation, and storm water management systems. 

• Streamflow, including seasonal mean flows, lowest flow rates, and timing and magnitude of storm events—

develop comparative data between tributaries affected by varying degrees of development, and contrast with 

reference streams with watersheds dominantly or entirely within protected land if available. 

• Sedimentation rates and compositions, including contributions of litter and pollution from surrounding 

developed areas—establish sites for repeat stream profile measurements, and reoccupy if possible shortly after 

major runoff events. 

• Water quality data, such as pollutants, dissolved oxygen, fecal coliform, and temperature—if pollution is 

significant, collect data needed to identify sources within the watershed, such as malfunctioning sewer outfalls 

or excessive application of landscape chemicals by landowners. 

• Morphologic change in stream channels—reliable measurements generally require 3–5 cross sections over 

several hundred meters of channel. 

• Stream deltas—as surrogates for erosion and sedimentation within an entire watershed. 

Existing data, with sources if available: 

• Regional coordination for water quality data — Doug Curtis. 

• Impacts of water quality on plants — Nancy Rybicki, USGS. 

• Chesapeake Bay studies of sediment transport — Scott Phillips, 410- 238- 4200, is project coordinator; Angelica 

Gutierrez heads the modeling effort. 

The numerous seawalls also found along the Anacostia River are an obvious effect of human engineering, but the 

shoreline has also been affected by a reduction in the amount of large woody debris along the shore, thus 

reducing its protection from erosion in some areas. Changes in shoreline position may impact coastal marshes 

such as those at Piscataway Park. 

The NPS manages the bottom of the Anacostia River and works with the EPA on toxics issues through the 

Anacostia Watershed Toxics Alliance. Some toxics sites are being monitored. The NPS Water Resources Division 

has drilled 4–5 cores in the Anacostia River near the Washington Navy Yard, and also has piezometer data. 

Sediment movement may also be studied. Work on the Anacostia River is coordinated through the Metropolitan 

Washington Council of Governments (COG) and the Anacostia Watershed Coordination Committee. [John 

Galli, COG, is a good contact.] 

Henson Creek is biologically valuable and has been the focus of flood studies. Accretion occurs in areas of lower 

gradients. The flood management plan for Henson Creek depends on active management, as advocated by Prince 

George’s County. 

Several of the parks include reclaimed sanitary landfills, all of which were operated before modern 

environmental standards were established for landfills. Total area covered by former landfills is about 300 acres. 

NACE has been working with EPA and others to monitor outflow from the landfills, to prevent leachate from 

reaching the Potomac and Anacostia rivers. [USGS strengths in monitoring provide the potential for valuable 
 NPS Geologic Resources Division 58 

cooperation – Bill Banks.] In addition to water quality, groundwater level and soil quality data are important in 

assessing the impact of landfills. Heat is generated by chemical reactions in landfills, but there is no obvious visual 

or ecosystem evidence that heating is occurring above the park landfills. 

The Washington Metropolitan Area Transit Authority has numerous wells at a variety of transportation sites, 

including near the Anacostia Metro station. 

Elevation data are needed to monitor marshes such as Accokeek and the restored marsh at Kenilworth Park. 

Changes in elevation at the scale of one foot appear to have significant effects on vegetation type in wetlands, 

including the potential for invasive species to become established. Exploration of the relationship between 

elevation and wetland ecology are a high priority for wetland management and for assessments of methodologies 

and standards for restoring marshland. Chemistry of wetland soil and water should also be monitored, and 

ecosystem effects of chemical constituents assessed. Evolution of hydric soils on created wetlands is a potentially 

important factor in their evolution. [Pete Biggam will have information on soil evolution in other artificial 

wetlands.] The Natural Resource Conservation Service is developing new definitions of artificial soils. 

Impacts on soils, sedimentation, and erosion of human activity and engineering, including facility placement, 

culverts, stream and storm sewer outfalls, parking lots, etc., should be assessed. Slope stability is an issue along 

the Shepherd and Baltimore- Washington parkways, which occasionally have landslides, as does Fort Dupont. 

Unstable slopes are found in the Newcomb St. area and a large wall has been required to retain a slope along O St. 

SE. At Greenbelt Park, monitoring of sediment inflow (originating from unstable fill) to the Yeager Tract is 

needed to assess whether it has stabilized. 

References: 

Allen, O., and S. Flack. 2001. Potomac Gorge site conservation plan. National Park Service and The Nature 

Conservancy (version for internal use). 

Chirico, P. and Epstein, J., 2000, Geographic information system analysis of topographic change in Philadelphia, 

Pennsylvania during the last century. U. S. Geological Survey Open- File Report 00- 224. 

Reed, J.C. Jr.; R. S. Sigafoos; and G. W. Fisher. 1980. The river and the rocks; The geologic story of Great Falls and 

the Potomac River Gorge. U. S. Geological Survey Bulletin 1471, 75 p. 
The Department of the Interior protects and manages the nation’s natural resources and cultural heritage; provides scientific and other 

information about those resources; and honors its special responsibilities to American Indians, Alaska Natives, and affiliated Island 

Communities. 

National Capital Parks–East 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2008/039 

NPS D-28, June 2008 

National Park Service 

Director • Mary A. Bomar 

Natural Resource Stewardship and Science 

Acting Associate Director • Mary Foley, Chief Scientist of the Northeast Region 

Natural Resource Program Center 

The Natural Resource Program Center (NRPC) is the core of the NPS Natural Resource Stewardship and 

Science Directorate. The Center Director is located in Fort Collins, with staff located principally in 

Lakewood and Fort Collins, Colorado and in Washington, D.C. The NRPC has five divisions: Air 

Resources Division, Biological Resource Management Division, Environmental Quality Division, Geologic 

Resources Division, and Water Resources Division. NRPC also includes three offices: The Office of 

Education and Outreach, the Office of Inventory, Monitoring and Evaluation, and the Office of Natural 

Resource Information Systems. In addition, Natural Resource Web Management and Partnership 

Coordination are cross- cutting disciplines under the Center Director. The multidisciplinary staff of NRPC 

is dedicated to resolving park resource management challenges originating in and outside units of the 

national park system. 

Geologic Resources Division 

Chief • Dave Steensen 

Planning Evaluation and Permits Branch Chief • Carol McCoy 

Credits 

Author • Trista Thornberry- Ehrlich

Review • Lindsay McClelland 

Editing • Melanie Parker, Sid Covington, and Melanie Ransmeier 

Digital Map Production • Stephanie O'Meara 

Map Layout Design • Georgia Hybels
Geologic Resources Division 

Natural Resource Program Center 

P.O. Box 25287 

Denver, CO 80225 

http://www.nature.nps.gov/geology/inventory/ 

(303) 969-2090 

EXPERIENCE YOUR AMERICATM 

National Park Service 

U.S. Department of the Interior