The Hampton-Seabrook Estuary is a shallow, tidally dominated, barrier beach system, The watershed encompasses 47 square miles, and includes the towns of Hampton, Hampton Falls, North Hampton, Stratham, Seabrook, Exeter, and Kensington, NH, and Salisbury, MA. The Estuary receives freshwater inputs from Tide Mill Creek to the north, the Taylor and Hampton Falls Rivers from the northwest, Brown’s River and Cain’s Brook from the west, and the Blackwater and Little Rivers from the south. Unlike the Great Bay Estuary, the Hampton Seabrook Estuary is dominated by salt marsh habitat. In fact, the Estuary contains over 1,800 hectares (4,000 acres) of tidal marsh. In addition, the Estuary supports many other important coastal habitats including the most productive softshell clam beds in the state; important roosting, feeding and nesting grounds for shorebirds and saltmarsh sparrows; as well as remnant sand dunes. As a result of the important ecological services provided by the Hampton-Seabrook Estuary, it was listed as a conservation focus area in The Nature Conservancy’s Land Conservation Plan for New Hampshire’s Coastal Watersheds (Zankel et al. 2006). The Hampton Salt Marsh was registered as a Prime Wetland, with approval of the Town’s voters, in 2009.
The history of land use in the Hampton-Seabrook Estuary dates back at least 4,000 year to native American settlements. From the few remnants of these settlements that remain, it is clear that Native Americans relied on the Estuary for its rich finfish and shellfish resources. In the early 17th century, European settlers were attracted to the Hampton-Seabrook Estuary by the large expanse of saltwater marsh. Salt marsh hay (Spartina patens) was considered a valuable food source for livestock. Salt hay could be harvested relatively easily and at a low cost due to the fact that expensive manure and fencing was not needed. In fact, it was considered so valuable that each of the settlers of Hampton received an expanse of salt marsh in their land grant so that they could take advantage of the salt hay. In addition to nourishing livestock, the extensive marshlands provided abundant food resources for
colonial settlers including shellfish, finfish and waterfowl.
Although the European settlers valued the salt marsh, their use of it was not without impacts. heavy pasture use resulted in the high density of ditching that is still seen in the marsh today. By cutting ditches to drain the marsh, it was thought to sustain the abundance and improve the quality of the salt hay as well as increase the abundance of black grass (Juncus geradii), another valuable marsh grass used as feed. Salt pannes were reduced in these systems not only by cutting ditches to connect them to the drainage network, but also because the dredge spoil from ditching was deposited in the salt pannes to reclaim them as high marsh.
Along with exploiting the marshlands for food, the early settlers constructed sawmills, windmills, grist and fulling mills along the rivers and creeks of the Hampton-Seabrook Estuary, the first of which was built as early as 1640. Dams were erected to harness the energy needed to drive these mills, and in so doing, resident and migratory fish movement throughout the stream network became impeded.
Overtime, salt hay farming declined as uplands were cleared of forests and farming methods became more efficient and cost-effective. By the early 1900s, salt hay farming ceased in the Hampton-Seabrook Estuary and the marsh was no longer perceived as valuable. Development of salt marsh for commercial and residential interests quickly followed. By 1930, the majority of Hampton Beach was developed, resulting in the destruction of both marsh and dune habitats. As the area developed into a popular summer resort, the abundance of mosquitoes produced in the marshes became a problem that needed to be addressed. In the late 1930s, additional ditches were cut into the marsh to drain it of potential mosquito breeding habitat, further altering the marsh drainage patterns, vegetation and density of pannes. Unfortunately, the small fish that preyed on the mosquitoes lost their habitat as well.
Historically, the shoreline of the Hampton-Seabrook Estuary was quite dynamic. The rapid development of the dunes and marshes, as well as the construction of the mile-long bridge at the turn of the 19th century, served to harden and decrease the dynamic nature of the shoreline. The jetties along either side of the inlet, installed in 1930, further decreased shoreline movement. As the narrow channel connecting the Estuary to the ocean filled with sediment, it required dredging, first conducted in 1965, to maintain a navigable inlet. The inlet is currently maintained by the U.S. Army Corps of Engineers and due to the high rates of sediment transport and deposition within and around the channel, maintenance dredging is required approximately every 5 years.
Source: Hampton-Seabrook Estuary Habitat Restoration Compendium, 2009, Alyson L. Eberhardt and David M. Burdick, UNH