Historical development of the saltmarsh at Wells, Maine

Abstract

Comparisons of maps and aerial photographs dating from the late 1700s to the present document the recent development of an 8 km2 saltmarsh that is situated behind a barrier spit in southern Maine. Tidal channels that were relatively narrow in 1794 became wider by 1872. The reduction of marsh bordering tidal channels is interpreted as evidence that marsh accretion could not keep pace with rising sea-level. This suggests that the rate of sea-level rise had increased, although a change in discharge or sediment load caused by extensive settlement and land clearance may also have been involved.Meander patterns of the tidal streams changed considerably throughout the time period covered by the maps, demonstrating that the streams of this marsh are more dynamic than some others that have been widely reported in the literature. These differences in stream dynamics are probably related to the differences in sedimentological structure of the marshes.Between 1872 and 1956 the barrier spit eroded on its inside (shoreward) edge, probably in response to the construction of riprapping and houses along the spit, and the subsequent reduction of overwash and aeolian transport of sediment.Modification of the tidal inlet and adjacent marsh during the 1960s, including jetty construction, dredging, and filling of portions of the marsh surface, affected the marsh only locally. One tidal stream has been migrating rapidly apparently in response to compaction of peat by dredge spoils and consequent local disruption of the marsh hydrology. Except for this migration, erosion of the marsh edge occurred immediately after the inlet modifications; planimetric changes in the marsh and its streams have been minor since then.

Vegetation Change on a Northeast Tidal Marsh: Interaction of Sea‐Level Rise and Marsh Accretion

“…We propose that at Barn Island the shifts in species dominance have resulted from a deficiency in sediment accretion and vertical marsh growth relative to sea-level rise. Jacobson ( 1988) interpreted the reduction in marsh bordering tidal channels in Wells, Maine, as an imbalance between marsh accretion and sea-level rise. The apparent influence of accelerating RSL rise on much of the Barn Island complex reported here is probably related at least in part to a reduction in available sediments as a result of the 1938 hurricane.…”

A 17-yr record of sediment accretion in the salt marshes of Maine (USA)

“…In 2003, marsh plot arrangements were relocated using a metal detector aided by detailed location maps that were constructed during the original investigation (Wood, 1991). Sites had also been visited in 1987in , 1988in (Wood, 1990in , 1991 and in this paper we make comparisons with these earlier measurements.…”

“…Back-barrier marshes are generally large and open, occurring behind barrier beaches (Jacobson, 1988). They occur most commonly in southwestern Maine and began forming 4000-5000 yr BP, when the rate of RSLR slowed (Kelley et al, 1988).…”

Study of the Influence of the Deep-Water Channel Project in the Yangtze River Estuary on Ecological Landscape and Fractal Dimensions of Jiuduan Shoal Tidal Channels

“…Tidal channels with differences in width and depth through lateral migration and swing constantly change the spatial patterns of the tidal flat system. Using fractal dimension to study the differences in the spatial structure of tidal channels system can provide an important basis for analyzing tidal flat space-time evolution (Garofalo, 1980;Jacobson, 1988;Knighton, Woodroff, and Mills, 1992;Shi, Lamb, and Collin, 1995). We took tidal channels in the Jiuduan Shoal of the Yangtze River estuary as a research object using information which was extracted from 1997 to 2013 by remote sensing data.…”