U.S. Department of the Interior

U.S. Geological Survey

USGS Fact Sheet 020-99

April 1999

Maine

Coastal Wetland Issues

The information in this fact sheet

describes some of the ongoing U.S.

Geological Survey (USGS) activities

in Maine. The USGS provides

reliable and impartial scientific

information to partners and to the

public. Policy makers and partners

use USGS information to make

informed decisions and to effectively

manage natural resources.

Wetlands border 20 percent of

Maine’s shoreline and contribute vital

functions to its coastal zone, including buffering adjacent uplands from

erosion and supporting fish and

wildlife. These same coastal marshes

have been altered by man’s use of the

land from historical to present times.

These alterations include historical

ditching of marshes for salt hay

farming and more recent development

of adjacent uplands. Consequences

include lowered water tables, degradation of fish and wildlife habitat,

nutrient-laden runoff from surrounding areas, and potential changes in

water chemistry. The USGS is

studying wetland responses to various

impacts and is evaluating techniques

to restore the values and functions of

these systems.

At Rachel Carson National Wildlife

Refuge in southern Maine, the USGS

is cooperating with the U.S. Fish and

Wildlife Service to evaluate the

technique of plugging drainage

ditches to re-establish natural hydrology and enhance fish and wildlife

habitat. By measuring the effects of

ditch plugging on the physical,

chemical, and biological aspects of

marshes, this study will help determine the broad applicability of this

habitat restoration method.

The USGS also is cooperating with

the National Park Service on several

investigations at Acadia National

Park (fig. 1). At the Northeast Creek

wetland complex on Mount Desert

Island, the USGS is quantifying

nutrient inputs from streams, groundwater, atmospheric, and oceanic

sources to evaluate potential effects

of surrounding land-use changes.

Habitat maps are planned as a

baseline for continuing studies of

wetland ecological functions.

As part of its statewide survey of

mercury contamination in aquatic

systems, the USGS evaluated mercury contamination in fish collected

from lakes and ponds at Acadia

National Park. Atmospheric deposition was found to be sufficient to

account for mercury levels in the fish.

Examination of lake and bog sediment cores showed that mercury

levels began to increase about the

year 1900 and reached a peak about

1970. This contamination probably

was related to human activity. The

accumulation and transfer of mercury

through aquatic insects to tree swallows are being studied.

The USGS also is cooperating with

the National Park Service and the

University of Maine to monitor

nutrient concentrations in small

streams of Acadia National Park.

Large forest fires in the early 1900’s

altered the landscape of Mount Desert

Island. More recently, areas adjacent

to the Park have experienced substantial development pressures. Results of

this monitoring will be used to

evaluate the effects of land use and

historical burning on nutrient loads to

coastal environments.

Figure 1. Bass Harbor Marsh at Acadia National Park, Maine
science for a changing world

Restoring Upriver Access for

Maine’s Fish

The 162-year-old Edwards Dam on

the Kennebec River in Augusta,

Maine, is a significant barrier to fish

migration. In 1997, the Federal

Energy Regulatory Commission

ordered the future removal of the

917-foot-long, 24-foot-high structure.

Removal of the dam will restore the

river’s natural channel from

Waterville to the sea, benefitting searun fish species native to the

Kennebec. One concern with removal

of the dam, however, is the character

of the sediment in its impoundment.

The USGS, in cooperation with the

State Planning Office and Maine

Geological Survey, collected geophysical data to describe the character

and distribution of sediments upstream from the dam. The data were

used to map the areal extents of all

river-channel sediment types (fig. 2)

and to quantify the volume of mud

and silt behind the dam. This information will aid in the development of

an engineering plan for dam removal.

Removal of the Edwards Dam will

enhance restoration of fish that

migrate from marine to fresh waters

to spawn. The USGS is examining

the habitat requirements of these fish

species native to the river. Atlantic

salmon normally spend 2 years in

fresh water before migrating to sea as

smolts. The USGS is studying the

effects of temperature and flow on

migration and survival of Atlantic

salmon smolts. Juvenile Atlantic

sturgeon also have an extended

residency in fresh water, and their

habitat requirements are being

investigated.

Bald Mountain Mineral Deposit

The USGS, in cooperation with NNM

Resources, Inc. (a subsidiary of Black

Hawk Mining, Inc. of Toronto),

Maine Geological Survey, and other

partners, is conducting a study on the

Bald Mountain deposit in northern

Maine. This unmined deposit of

copper, zinc, gold, and silver was

formed in association with volcanic

processes. Because this deposit is

relatively undeformed, it provides a

rare opportunity to address questions

about its formation. The USGS also is

characterizing the natural chemical

signatures associated with this type of

deposit, and determining what

conditions and processes affect the

long-term mobility of heavy metals in

the weathering environment. This

information will help refine models

for the formation and weathering of

this type of mineral deposit in the

Eastern United States, and thus aid

mineral exploration and also mineralresource and environmental assessments.

Flooding

Near realtime hydrologic data from

the USGS streamflow gages (http://

me.water.usgs.gov) are used by the

National Weather Service to help

predict the size and timing of floods

for certain rivers in Maine. For latewinter and spring flooding, it also is

important to know how much water is

contained in the snowpack. The

Maine Cooperative Snow Survey

(http://www.state.me.us/mema/snow/

snow.htm), jointly run by the USGS

and the Maine Geological Survey

with the help of many cooperators,

measures the amount of water in the

snowpack in late winter and early

spring on a weekly basis (fig. 3). The

National Weather Service computer

model used for flood predictions is

more accurate with use of the streamflow and snow data.

The USGS, in cooperation with the

Maine Department of Transportation

(MDOT), is developing better ways

of estimating peak flows, such as the

100-year peak flow. This will allow

A B C D

Sidney Boat 

Launch

Sidney 

Boat 

Launch

Edwards

Dam

Edwards Dam

Study Area

MAINE

A

B

C

D

Kennebec 

River 

Geophysical 

Survey

0 1 2 MILES

PREDOMINATE SEDIMENT TYPE

Rock—contains other material

Gravel—contains other material

Sand—contains other material

Figure 2. Map of riverbed sediment in the Edwards Dam impoundment on the

Kennebec River, Maine
Maine

improved designs for bridges and

other hydraulic structures.

Another project with MDOT addresses the problem of pier scour at

bridges. During floods, the streambed

around bridge piers can erode. In

extreme cases, this erosion can cause

a bridge to collapse. The standard

methods to predict how much pier

scour is likely to occur at a bridge are

based primarily on laboratory research. The USGS is measuring the

actual pier scour at Maine bridges

during floods to assess the accuracy

of these methods.

Black Duck Studies

The continental population of the

American black duck (fig. 4), after a

30-year decline, stabilized in the early

1980’s when more restrictive harvest

regulations were initiated. Some still

speculated, however, that mallards

were competitively excluding black

ducks from fertile wetlands, thereby

reducing the numbers of young that

black ducks were able to produce.

Working with the Maine Department

of Inland Fisheries and Wildlife,

USGS scientists determined that

mallards were not excluding black

ducks from fertile wetlands. Furthermore, no difference was detected

between black ducks and mallards in

average brood size (4–5) on a range

of wetland types in northern Maine.

These data refute the hypothesis that

competitive exclusion of black ducks

from fertile wetlands caused the longterm population decline. Based on

these data and other information, an

International Black Duck Harvest

Management Strategy Committee,

recommended by the Black Duck

Joint Venture (North American

Waterfowl Management Plan) and the

Atlantic and Mississippi Flyway

Councils, is now debating a continental harvest strategy to protect black

ducks on primary breeding and

staging areas to achieve population

goals.

MTBE in a Maine Aquifer

Some areas of the United States that

use MTBE (methyl tert-butyl ether)

in reformulated gasoline have low

(<2 ppb) levels of MTBE in shallow

aquifers that do not seem to be

attributable to point-source contamination. Atmospheric deposition,

through rainfall, may be responsible

for this low-level contamination. The

USGS, in cooperation with the Maine

Department of Environmental Protection and the Town of Windham, is

studying whether these levels of

MTBE are found in a shallow sand

and gravel aquifer in Windham, and

whether air and precipitation in the

area contains MTBE in sufficient

amounts to account for any low-level

contamination.

Gulf of Maine “Red Tide” Blooms

The USGS is cooperating with

Bigelow Laboratory for Ocean

Sciences, University of Maine, and

other partners to understand the

ecology and oceanography associated

with toxic “red tide” blooms in the

Gulf of Maine. The toxic blooms

affect primarily shellfish, which if

ingested by humans or other mammals can result in paralytic shellfish

poisoning. The blooms are associated

with numerous economic and public

health issues along the Maine coast.

During 1 year of high toxicity, $8-10

million in shellfish revenues are lost.

USGS scientists are providing

measurements of water properties and

currents from moorings in the ocean

and is codeveloping a coupled

Trace—less than 0.2 inches 

 averaged over an area

0 – 1 inch

1 – 2 inches

2 – 3 inches

3 – 4 inches

4 – 5 inches

5 – 6 inches

6 – 7 inches

7 – 8 inches

8 – 9 inches

9 – 10 inches

10 – 11 inches

11 – 12 inches

Greater than 12 inches

Snow measurement site

Contributors:

U.S. Geological Survey

Maine Geological Survey

National Weather Service

New Hampshire Department

 of Environmental Services

Maine Public Service Co.

Bangor Hydro-Electric Co.

Kennebec Water Power Co.

Union Water Power Co.

Bowater/Great Northern Paper Co.

Georgia Pacific Corp.

S.D. Warren Co.

AT L A N T I C

Mount

O C E A N

Desert

Island

Presque Isle

Houlton

Eastport

Bangor

Augusta

Portland

Rumford

Fort Kent

Fryeburg

N

0 20 40 60 80 100 MILES

Figure 3. Maine Cooperative Snow Survey Program, Equivalent water content in

snowpack (in inches)—March 2–4, 1998
Printed on recycled paper

USGS office locations USGS State Representative

26 Ganneston Drive

Augusta, ME 04330

(207) 622-8201

FAX (207) 622-8204

USGS Home Page:

http://www.usgs.gov

Reports and products:

1-888-ASK-USGS

biological/physical model with

Woods Hole Oceanographic Institution to study processes controlling the

initiation and evolution of red tides.

Field data collected during April–July

1998 suggest that shellfish-toxicity

events in the western Gulf of Maine

may originate offshore. This has

prompted Maine to consider future

shellfish-toxicity monitoring stations

offshore and on islands to act as an

“early warning system.”

Habitat Map of Maine Completed

The USGS and the University of

Maine have completed a map of

Maine’s vegetation and land cover.

The map was made as part of the

Maine Gap Analysis and is accessible

on the internet at http://wlm13.

umenfa.maine.edu/progs/unit/gap.

The map shows 19 types of upland

vegetation and land cover, and 18

types of water and wetlands. It was

created as a basis for predicting and

assessing the distribution of non-fish

vertebrates that regularly breed in

Maine, but the map has many other

uses. For example, scientists at the

Maine Department of Inland Fisheries

and Wildlife and USGS are using the

map as a basis for jointly conducting

detailed habitat assessments for

selected wildlife species.

USGS Mapping

In 1998, the Maine Office of Geographic Information Systems (OGIS)

provided the USGS with elevationcontour-line data in digital format.

The USGS used these data to produce

digital elevation models (DEM),

which are digital files of terrain

elevations for ground positions at

regularly spaced horizontal intervals.

DEM’s can be used to generate threedimensional graphics displaying the

topography of an area. This datasharing partnership with OGIS

enabled the USGS to use previously

produced State data to significantly

reduce DEM production costs.

Statewide DEM coverage is now

complete and available to the public

for use in geospatial modeling and

analysis.

The USGS collected new black-andwhite aerial photographic coverage of

Maine between 1996 and 1998. In

cooperation with the U.S. Department

of Agriculture, the USGS is using

these photographs as image sources

for digital orthophoto quadrangles

(DOQ) of central and eastern Maine.

The DOQ’s are digital images of

aerial photographs that have the

geometric qualities of a map. The

USGS is planning to work with its

partners to update many of the Maine

1:24,000-scale topographic maps

using the new DOQ’s.

The USGS, in cooperation with State

agencies and universities, distributes

state-specific natural science products. The Maine Department of

Conservation’s Maine Geological

Survey provides information about

Maine’s geology from its office in

Augusta. This office sells USGS

topographic maps in addition to their

own publications (web site address:

http://www.state.me.us/doc/nrimc/

nrimc.htm). The Maine Office of GIS

provides digital geospatial data on its

web site at http://apollo.ogis.

state.me.us, including USGS coverages for the State of Maine.

Figure 4. American black duck

The USGS has 25

employees in Maine

Augusta

Orono