Section 319
NDNPDINT SOURCE PROGRAM SOGGESS STORY
Stakeholders Cooperate to Control Sediment Inputs and Restore Navigability
A / t h H imnr^/pH By the late 1990s navigation in Middle Brook canal was
vvdiei uuuy n i ipi uvwu extreme|y difficu|t and the upper end Of the cana| was
impassable due to sediment deposition and resulting shallow water depths. The sediments in
the canal were largely attributed to runoff from eroding unpaved roadways, flooding caused
by an undersized culvert, and erosion from a nearby boat ramp and beach. The canal was
listed as impaired for secondary contact recreation on New Hampshire's 2004 303(d) list. To
reduce erosion and sedimentation throughout the sub-watershed, the Balmoral Improvement
Association (BIA) partnered with state and local agencies on stormwater management projects.
BIA and the New Hampshire Department of Environmental Services (DES) also partnered on a
successful dredging project to restore the canal to navigable depths. As a result. Middle Brook
Canal is no longer impaired for secondary contact recreation, and DES removed the impairment
from New Hampshire's 2006 303(d) list of impaired waters.
Problem
Middle Brook is a tributary that enters Lake
Winnipesaukee's Moultonborough Bay in the
town of Moultonborough. Situated in a 75-acre
sub-watershed, the canal is a 2,000-foot-long
by 50-foot-wide man-made inlet at the mouth
of Middle Brook (Figure 1). The canal provides
access to boat docks for 39 canal-front residents.
There is a boat ramp and a beach located on the
southeast corner of the canal's confluence with
Moultonborough Bay. The canal is within the
Balmoral homeowner's association neighborhood.
Balmoral consists of approximately 400 homes,
about half of which are seasonal homes, and the
other half are primary residences.
Historically the canal's approximately 10-foot
depth allowed for the safe passage of boats into
Lake Winnipesaukee. Residents who routinely
used the canal began noticing sediment accu-
mulation and reduced canal depth as early as the
1980s. By 2003, sediments from unpaved roads,
undersized culverts, and an eroding boat ramp
and beach resulted in drastically reduced water
depths and visible sediment deltas. In addition
to causing navigation difficulties, the sediments
reduced water depths and exacerbated the growth
of invasive species and other aquatic plants. By
2004, Middle Brook Canal was listed as impaired on
New Hampshire's 303(d) list for secondary contact
recreation due to sedimentation/siltation.
Figure 1. Summer 2008 photograph showing boats in
the restored Middle Brook Canal.
Project Highlights
BIA undertook several projects in the sub-
watershed to reduce sediment inputs to the canal.
Beginning in 2000, BIA hired contractors to install
a concrete boat ramp and "no wake" buoys to
mitigate boat-related erosion and sediment trans-
port. To reduce erosion caused by flooding and
high flow velocities, BIA worked with engineers and
consultants to increase the size of the canal's inlet
culvert. BIA also hired crews to crown roads, pave
critical sections of dirt roads, stabilize roadside
swales, and implement a street sweeping program.
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BIA worked with the DES Invasive Species Program
to identify invasive species, and then collaborated
on an agreement with a contractor who chemically
treated milfoil growing in the canal.
After addressing the major erosion problems in
the watershed, BIA received a U.S. Environmental
Protection Agency (EPA) section 319 grant to
restore the canal to navigable depths. An engineer-
ing firm hired by BIA completed a dredging plan,
submitted permit applications for approval, and
collected sediments for laboratory analysis. A local
dredging company then removed tons of accumu-
lated sediment from the canal (Figure 2) and created
a 5.5-foot deep trapezoidal channel to allow for safe
boat passage.
Results
Figure 2: Dredge removing accumulated sediment
from the mouth of Middle Brook Canal (Fall 2004).
To protect the canal from future sedimentation, BIA
continues to operate a street sweeping program. In
addition, BIA conducted a public education cam-
paign to help reduce erosion and halt the spread
of invasive species. Through project signs and key
chains, boaters were asked to refrain from power-
loading boats onto trailers, warned against spread-
ing milfoil, and reminded of the no wake zone in and
around the canal. Information was also provided to
residents on best management practices, such as
proper yard waste disposal, that should be followed
around the home.
After several years of BMP installations, dredg-
ing, street sweeping, and public education
efforts, Middle Brook Canal has been returned to
a navigable channel which is no longer impaired
by sedimentation/siltation. The dredging removed
approximately 3,780 tons of sediment from the
canal. Post-implementation surveys indicated that
boaters could navigate the canal without difficulty.
Secondary contact recreation was restored in the
canal and the impairment was removed from NH's
2006 303(d) list; however, Middle Brook Canal
remains listed for mercury.
Partners and Funding
The work to restore recreational uses at Middle
Brook Canal involved the cooperation of BIA, local
residents, the town of Moultonborough, DES, and
EPA. BIA funded and managed all of the erosion
and sediment control projects, and also provided
the required non-federal cash match through a
coordinated fundraising effort with all 39 canal-front
residents. DES provided technical assistance and
administered the EPA section 319 grant that funded
a portion of this project. The town continues to
provide street sweeping for some of the area roads.
In 2003 EPA provided a $51,126 section 319 grant to
dredge and restore the canal to navigable depths.
BIA provided $51,057 in cash and in-kind match and
completed the project in 2005. In 2001 BIA provided
$23,000 for roadway runoff improvements, and
$10,160 for the new boat ramp and no-wake signs.
Funding and in-kind services continue to be pro-
vided by BIA and the town for ongoing road runoff
maintenance activities. In addition, between 2000
and 2003 BIA provided $7,500 for milfoil treatment.
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U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-09-001EE
September 2009
For additional information contact:
Barbara McMillan
Watershed Outreach Coordinator
New Hampshire Department of Environmental
Services
603-271-7889 • Barbara.mcmillan@des.nh.gov
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