Little River Salt Marsh Restoration Project
Little River Salt Marsh Restoration Project
The Little River Salt Marsh Restoration Project in North Hampton and
Hampton, New Hampshire has been a huge success from many
perspectives. The great saga of restoring Little River Salt Marsh goes
back over 100 years, and is worth reviewing in detail here as a success for
ecosystem restoration, locally-led conservation, partnership efforts, and for
protecting private property.
The following are included here on the Little River Salt Marsh
Restoration Project web site:
Quick Links to other Little River Salt Marsh Resources
The Little River Salt Marsh Restoration Plan and
Environmental Assessment is available for download. This document requires
River Salt Marsh Restoration Plan and Environmental Assessment (2.0 MB)
The Little River Salt Marsh is a back barrier marsh lying between
Little Boars Head in North Hampton and a rocky headland just south of North Shore
Road in Hampton. The original marsh was approximately 193 acres in size,
and had deteriorated over many years due to reduced tidal flow to the marsh. Phragmites,
cattails, and purple loosestrife had invaded due to the lack of adequate salt
water, and flooding of nearby homes was problematic during heavy rains.
Over many many years, residents and agency partners have nearly completed
the restoration of the marsh. The first culvert to restore tidal flow to
the marsh was installed in 1999 under Appledore Road, and the second culvert
at the north end of the marsh was installed under Route 1A in 2000. Only
one small portion remains.
Soil Survey of New Hampshire Tidal Marshes (1974) indicated that originally the marsh was approximately
193 acres in size. Most of the original marsh had seriously deteriorated and the
extent of viable salt marsh greatly reduced. The marsh had deteriorated because it
lacks a connection to the ocean of sufficient size to allow adequate tidal flow to the
marsh. Tidal flow is the life blood of a salt marsh. Without tidal flow the overall health
of the marsh ecosystem is reduced.
The characteristic salt marsh plants such as salt meadow cord grass
and spike grass, are replaced by the invasive plants Phragmites (see
photo to right), narrow leaf cattail, and
purple loosestrife. The lack of an adequate connection with the ocean
caused serious flooding problems because storm flows from the Little River do not have
stable a outlet from the marsh.
View the complete
plan and environmental assessment (pdf) for the Little River Salt
For many years, the Little River has had two connections
with the ocean. The southern connection is at the Hampton - North
Hampton town line. This connection, long known locally as the
breach, has been the outlet of the river since at least 1742.
In that year it was used to fix one end of the line separating the towns
of Hampton and North Hampton. At the present time the breach is
partially filled with sand which blocks tidal flow to the marsh. The
other connection is a 48 inch concrete culvert which runs through the gap
between the second and third (from the north) fish houses at Little
Boar�s Head. This culvert carries twice daily tidal flow to
the marsh but its capacity is far below that necessary to support the
marsh. The north culvert is also inadequate for carrying storm flows
from the Little River. See 1992 aerial photo to the right. (click
here for the higher quality version of this aerial photo)
Even under natural conditions, the flow of the Little River
is sometimes inadequate to maintain an open connection with the ocean.
During times of low flow, the river silts in, disconnecting the marsh from
tidal flow. Under natural conditions, however, the river eventually
ponds enough water in the marsh to break through the dunes again,
reconnecting the marsh to the ocean. This phenomenon is probably the
origin of the name breach. Early on, settlers helped this process
along by physically cleaning out the breach. They recognized the
importance of tidal flow for salt marsh hay production which began as
early as the 17th century and continued until early this century. The
first recorded attempt to clear sediment from the breach was in 1780 when
residents received permission from the New Hampshire Legislature to open
the mouth of the river for the purpose of restoring tidal flow.
Below are aerial photographs from 1942 and
1992 showing land use changes in and around the marsh. These changes have
further degraded the marsh. In particular the culverts at Appledore
Road and Huckleberry Lane have severely restricted tidal flow to the
southern portions of the marsh.
a higher quality version of this image, click here.
help maintain tidal flow, residents also attempted at various times to
create a northern opening (known locally as the trunk,) to the marsh.
In 1890, the forerunner of the present culvert was installed.
This was replaced by a 30 inch culvert in 1929. This, in turn, was
replaced with the present 48" culvert in 1948 (see photos to the
Unfortunately, the creation and subsequent enlargement
of the trunk reduced flow through the breach, probably increasing its
tendency to silt in. Up until about 1950, the breach was
regularly cleaned out. For most of the time since, it has been
completely blocked with sand and has only been cleaned out during
times of high water in the marsh. The increase in the number of
buildings around the mouth of the river over the years has made that task
Because the breach is essentially an erosive
channel through a sand dune, it is very unstable under flood flows.
Once it begins to flow it is subject to rapid erosion and meander.
High flows through the breach during a storm in October 1996 combined
with wave action damaged adjacent property and buildings. The breach
has since been partially refilled with sand but the potential for future
flooding remains. During major storms, runoff is forced to pond in
the marsh. Ultimately the river breaks through the barrier dune at
some point. Historically it has broken through at the breach but it
could break through at other points. The only thing that is known
with any certainty is that it will break through somewhere.
has also been a concern to local residents, as an inadequate outlet from
the marsh creates flooding during high rainfall events. The photos
to the right show flooding across a local road (top right), and
the backup of water to the edge of a residents steps (bottom right).
Residents in Hampton and North Hampton expressed a
strong interest in restoring the marsh and solving their flooding
problems. Preliminary studies indicate that it may be possible to solve
both problems simultaneously. Properly restoring the salt marsh not
only saved this rare and valuable ecosystem, but will also reduce
In 1998, the U.S. Army Corps of Engineers and the USDA
Natural Resources Conservation Service conducted surveys and prepared a
computer model of the marsh under various conditions of tides and storm
water runoff. This led to the development of a restoration
plan and environmental assessment (pdf) prepared by the NRCS.
On August 19, 1999, a public hearing (part of the
wetland permit process) was held at which time the entire project was
explained and comments taken from those present. In September 1999
the project received state and federal wetland permits for the majority of
the project which is located in the town of North Hampton. The
remainder of the project in the town of Hampton is still in the planning
In January 2000, the first of two planned culverts in the
The photos to the left show the original culvert under
Appledore Road (top left) and the installation of the new
5' x 7' box culvert (bottom left). The photo below shows the new
culvert under Appledore Road.
On July 23, 1998 a public informational meeting was held
in the North Hampton Town Hall. The North Hampton Conservation
Commission had invited 150 people, primarily abutters to the marsh.
In attendance at the meeting were 125 local residents and agency
personnel. The plan proposed by NRCS and COE was to install twin 12'
concrete box culverts at the location of the present north outlet to
the marsh. Based on hydrologic and hydraulic modeling of the marsh
under various conditions of tides and storm flows, these culverts will
allow adequate tidal flow to restore the marsh while at the same time
solve the current flooding problem. In straw vote, those present
unanimously supported the installation of the proposed culverts.
the right, the photo shows members of the the North Hampton Conservation
Commission dedicating a sign proclaming the Little River Marsh Restoration
Project. The local citizens have been working on the restoration and
of this marsh for more than 200 years! The Natural Resources
Conservation Service and the other state, Federal, and private partners
were proud to join their efforts.
Technical and financial
assistance: The funding for this project will come from a number of
sources including, the Natural Resources Conservation Service, the Towns
of North Hampton and Hampton, the Audubon Society of New Hampshire, the
U.S. Fish and Wildlife Service, the New Hampshire Coastal Program,
Ducks Unlimited, the Fuller Foundation, and private donations. The
Selectmen and Conservation Commissions of these towns are actively
involved in the restoration effort.
Local residents have volunteered their time to help this
project. Also cooperating in the restoration effort are the New Hampshire
Department of Transportation, the U.S. Fish and Wildlife Service, the U.S.
Environmental Protection Agency, the Rockingham County Conservation
District, the New Hampshire Office of State Planning, and the New
Hampshire Wetlands Bureau.
The Selectmen and Conservation Commissions of these towns
are actively involved in the restoration effort.