Hydrologic and Chemical Impacts of Diking and Drainage of a Small Estuary (Cape Cod National Seashore): Effects on Wildlife and Fisheries

Portnoy JW, Roman CT, Soukup MA. 1987. Hydrologic and Chemical Impacts of Diking and Drainage of a Small Estuary (Cape Cod National Seashore): Effects on Wildlife and Fisheries. National Park Service

Ecological studies in the 400 ha Herring River estuary have documented impacts from the nearly 80 years of diking and drainage for mosquito control. These impacts include lowered wetland water levels and the invasion of upland vegetation, sulfur mobilization, and stream acidification, summertime oxygen depletion, and consequent fish kills and pest insect outbreaks. Habitat changes have been dramatic with salt marsh generally replaced by brackish-freshwater wetlands and seasonally flooded herbaceous marsh invaded by woody species. The acidification of surface water, from the oxidation of pyrite, together with annual summertime stream anoxia, serve to exclude native predatory fish and invertebrates, while favoring the production of mosquitoes. Current efforts to restore this degraded wetland-estuarine system center on experimentation and modeling with increased tidal flow through the unobstructed river mouth. Implications of restoration to wildlife, fisheries and other ecological aspects are discussed.

Type
Unpublished Report
Authors
Portnoy, John; Roman, Charles; Soukup, Michael
Date of Issue
1987
Publisher
National Park Service
Units
CACO
Keywords
CACO, Cape Cod National Seashore, Dike, Estuary, Fisheries, Herring River, Hydrology, Restoration, River, Salt Marsh, Wildlife

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