Project Description
Brown's River Marsh is a named portion of the Hampton-Seabrook Estuary, the largest salt marsh complex in New Hampshire. It is bisected by the abandoned Boston and Maine Railroad Embankment, which was built upon the marsh in the 1800s and restricts tidal flow. Seabrook Station, the only nuclear power plant in New Hampshire, manages the salt marsh. Prior to restoration, all tidal flow to the 41-acre portion of the marsh upstream of the causeway had to pass through a round, 48-inch culvert. The tidal restrictions led to the proliferation of invasive species such as Phragmites, and insects such as mosquitoes.
In cooperation with Seabrook Station, the U.S. Fish and Wildlife Service (USFWS), the Natural Resource Conservation Service (NRCS), and New Hampshire Coastal Program worked to restore greater tidal flow into this section of marsh by installing a new 4 x 6-foot box culvert during the winter of 2006. This almost doubled the cross-sectional area under the railroad causeway. Following the installation of the new box culvert, spring tides completely inundate the upstream marsh and tidal reduction is minor. The University of New Hampshire (UNH) worked with USFWS to monitor conditions of the Brown's River Marsh prior to and following the restoration activities, including photo documentation, surveying plant communities in the impacted and non-impacted areas, assessing fish use of the marsh, and measuring tidal range and soil salinity upstream and downstream of the culvert.
Parties Implementing Restoration
Natural Resource Conservation Service; New Hampshire Department of Environmental Service
DOI Project Representatives
Fish and Wildlife Service