Section 319
NONPOINT SOORCE PROGRAM SUCCESS STORY
Local Groups Key to Mousam Lake Restoration
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Decades, Maine's Mousam Lake received increased stormwater
runoff from shoreland development, lawns, roads and aging septic
systems. Phosphorus in the stormwater led to increased algal growth and subsequent impairments to
water quality, including decreased water clarity and dissolved oxygen. Following 10 years of intensive
nonpoint source (NPS) pollution control projects, water clarity in Mousam is three feet deeper, and the
lake now attains water quality standards. The Maine Department of Environmental Protection (MDEP)
removed Mousam Lake from its section 303(d) impaired waters list in 2006.
Problem
Mousam Lake, a three-mile-long lake in southern
Maine, attracts boaters, anglers, and vacation-
ers with its sandy shores and excellent cold and
warm water fisheries. One of the largest lakes (863
acres) in Maine's southernmost county, Mousam's
watershed encompasses 21 square miles, and its
shoreline is heavily developed with 700 seasonal and
year-round homes. In addition, the lake features a
frequently used public boat ramp.
Lake residents and local activists first noticed
problems with the lake's water quality in the late
1970s. Changes in the watershed, especially the
gradual conversion of forested land into developed
land and septic systems, resulted in increased
stormwater runoff from residential areas, lawns and
roads. Phosphorus in the stormwater led to exces-
sive algal growth, which, in turn, caused increases
in chlorophyll a levels and decreases in water clarity
and dissolved oxygen. From 1980 to 1992, the lake
experienced a steady decline in trophic state. In 1998
MDEP designated Mousam Lake as impaired for
aquatic life support and added the lake to the state's
section 303(d) list.
The Total Maximum Daily Load (TMDL) assessment
developed for Mousam Lake in 2003 identified shore-
land development as the largest source (51 percent)
of phosphorus to the lake. Relatively high-density
development in shoreland areas (i.e., numerous
houses and gravel roads) increased stormwater
runoff and erosion. In addition, aging septic systems
in the sandy soils around the lake increased phos-
phorus in ground water that enters the lake. The
TMDL estimated that the annual external phospho-
rus loading (556 kg/year) would need to be reduced
by 27 percent (150 kg/year).
Foot of lake gets a facelift
Project Highlights
Since 1997, the York County Soil and Water
Conservation District (SWCD), Mousam Lake
Figure 1. Vegetated buffer planting at the foot of Mousam Lake.
Region Association (MLRA), the towns of Acton and
Shapleigh, and MDEP collaborated to identify and
mitigate NPS pollution sources and foster long-
term watershed stewardship. In 1997 a watershed
survey documented key NPS pollution sites including
erosion at residential sites, private camp roads and
driveways. In 1999 a U.S. Environmental Protection
Agency (EPA) section 319 grant was used to install
and demonstrate conservation practices at six proj-
ect sites and to initiate watershed stewardship and
education programs (see Figure 1).
From 2001 to 2006, EPA, Maine Department of
Agriculture and MDEP funded additional erosion
control practices. Cost share agreements with
public and private landowners resulted in best
management practices being installed at 45 priority
NPS sites and an associated reduction in pollutant
loading to the lake by more than 150 tons of sedi-
ment and 130 pounds of phosphorus peryear. Work
included stabilizing erosion at developed shoreland
properties and improving gravel road surfaces and
roadside drainage. In addition, more than 250 other
landowners received technical assistance to reduce
erosion on their properties. The Mousam Lake Youth
Conservation Corps (YCC) program was established
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with section 319 funds in 2001 to install practices,
raise local awareness and commitment to lake pro-
tection, and involve local youth in stewardship. The
program was so effective and popular that the towns
and MLRA fully funded the YCC from 2002 through
2007, enabling the YCC to complete 115 projects in
the watershed.
In addition, more than 200 residents attended work-
shops known as Septic Socials to learn about septic
system function, proper maintenance and water con-
servation. These socials, modeled after a successful
Washington State Sea Grant program, were led by
project staff and local septic system professionals,
and hosted by local residents in their homes.
The high-profile work around Mousam Lake inspired
lake protection efforts on several neighboring lakes.
Most notably, the Acton Wakefield Watersheds
Alliance (in Maine and New Hampshire) formed in
2004 and started its own YCC program.
Results
Following a decade of local watershed management
and restoration efforts, Mousam Lake now meets
water quality standards. As seen in Figure 2, water
clarity in recent years (2002-2006) was one meter
deeper than the lows experienced in the early 1990s
(1989-1992). The water quality data trend from 1997
through 2006 indicates that Mousam Lake has a
stable or improving trophic state and meets Maine's
water quality standards for lakes. MDEP removed
Mousam Lake from its 303(d) list in 2006 because all
trophic parameters indicated a persistent improve-
ment or stabilization of water quality/trophic state.
Partners and Funding
York County SWCD provided sustained leader-
ship, technical services and grants management.
Other key partners include Pat Baldwin (a longtime
watershed resident and advocate for lake protec-
tion programs), the towns of Acton and Shapleigh,
MLRA, MDEP, Maine Department of Transportation
(MOOT), and EPA.
Since 1997, federal- and state-funded projects
helped prompt widespread implementation of
erosion control practices. EPA provided $230,000
in section 319 and 604(b) grants, and the Maine
Department of Agriculture provided $40,000 toward
these efforts. In addition, MOOT fixed three major
erosion problems associated with state roads.
The local match for the restoration work exceeded
$400,000. Each year since 2002, the towns of Acton
and Shapleigh have provided approximately $39,000
per year, fora total of $234,000, to fund the YCC
program. In addition, MRLA provided a $17,500 cash
match, and local residents, road associations and
towns provided $151,000 of in-kind matches.
Mousam Lake Mean Secchi Disk Transparencies (SDT): 1 980 to 2006
1980 1985 1990 1995 2000 2005
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1 "
3 "
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SDT Trendline (1 980 -1 992) SDT Trendline (1 997-2006)
Figure 2. Mousam
Lake Mean Secchi Disk
Transparencies (SDT)
from 1980 to 2006.
Annual mean Secchi
depth readings from
1980 to 1992 indicate a
trend (red line) toward
reduced water clarity.
Secchi readings from
1997 to 2006 indicate a
trend (green line) toward
stable and improved
water clarity. (Note: no
data were collected
between 1993 and 1996.'
I
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-08-001A
February 2008
For additional information contact:
Wendy Garland, Maine DEP
207-822-6300 • wendy.garland@maine.gov
Joe Anderson, York County Soil and Water
Conservation District
207-324-0888 • janderson@yorkswcd.org
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