Awcomin Salt Marsh
Rye, New Hampshire
Alan P. Ammann, Ph.D., Biologist
Natural Resources Conservation Service
Durham, New Hampshire
Salt marsh is one of the rarest native ecosystems in New Hampshire. Ammann et al.
(1994) estimated that there are only 6,200 acres of salt marsh remaining in the state.
Of those 6,200 acres, current estimates indicate that approximately 700 acres have
been severely impacted by restrictions to tidal flow. Since the 1994 - study,
approximately 530 of these 700 acres have been restored through a multi-agency
The Awcomin Salt Marsh Restoration Project proposes to restore an additional 24.7
acres of salt marsh across route 1A from the Rye Harbor State Park boat launch
parking lot. Project measures include the excavation and removal of approximately
95,000 cubic yards of dredge spoil from Rye Harbor. This material was placed on the
marsh in the 1940’s and again in the early 1960’s during two harbor dredging
operations. Included in this project are the installation of approximately 6,000 feet of
reconstructed tidal creeks, three pannes, and two small wildlife islands to replace
features of the marsh lost when it was filled.
There has been an ongoing restoration effort on the Awcomin marsh since the early
1990’s. This has included breaching the 1940’s and 1960’s dikes with new tidal
ditches and the removal of dredge spoil down to an elevation averaging around 4.3
feet NGVD (National Geodetic Vertical Datum of 1929) in several areas. NGVD is
a standard reference elevation taken from Boston Harbor which roughly approximates
mean sea level. In the last two years several meetings have been held to solicit input
from local experts for a plan to complete the restoration. From these discussions, a
conceptual restoration framework was adopted.
During the spring of 2001, NRCS personnel, under the direction of an NRCS
engineer, conducted a detailed t