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Channelized stream with spoil piles |
- Delaware's Wetlands Status and Trends report was based largely on the results of a wetland trends analysis performed by the U.S. Fish and Wildlife Service's National Wetlands Inventory (NWI) Program. The work was funded by DNREC's Division of Water Resources. The study involved a comparison of aerial photographs from the early 1980's to the early 1990's. Wetland trends were identified as going to (loss) or coming from (gain) a specific land use or land cover type. Tiner, R.W. Delaware’s Wetlands: Status and Recent Trends
Facts Presented by the Status and Trends Report
Thirty percent of Delaware is covered by wetlands, with over 350,000 acres inventoried. Tidal wetlands represent about one third of the State's wetlands while non-tidal wetlands comprise the remainder. Delaware may have lost as much as 54% of its wetlands since the 1780’s.
Human impacts:
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Filling of wetlands |
Filling for commercial, industrial, and residential development
Disposal of dredged material and garbage (e.g., sanitary landfills)
Dredging for navigation and marinas
Conversion to cropland or pasture
Conversion of natural wetland forests to pine plantations
Creation of diked impoundments for water supply and wildlife management
Pond construction
Alteration of hydrology (e.g., drainage and channelization projects)
Direct or indirect discharge of pollutants (e.g., oil, pesticides, herbicides, and other chemicals, sediment, domestic sewage, and agricultural wastes)
Spreading invasive and/or exotic species (e.g., Phragmites and Japanese honeysuckle)
Cause of Loss:
From the early 1980’s through the early 1990’s, 1,900 acres of wetlands were lost. The losses were primarily comprised of non-tidal wetlands, mostly forested. The main causes of loss were identified as residential development and agriculture.
What wetlands are currently at risk?
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Wetland Stressors
Additional potential wetlands stressors:
Sea Level Rise Research - Conducted by DNREC's Delaware National Estuarine Research Reserve
Climate Change and Delaware
Wetland Loss and Sea Level Rise
View maps of the Inland Bays watershed representing impacts to wetlands including:
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Channelized Streams - Excavated streams cause the water to move quickly downstream preventing the water from receiving the benefits of a slow meandering stream. Such benefits include the cleansing the water receives as it floods over the stream bank into adjacent wetlands during storm events.
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Wetlands Lost - Indicates wetlands that have been lost since Delaware was settled in the 1700's.
DNREC's Watershed Assessment Section was recently awarded a grant to fund an updated Status and Trends Report based on 2007 aerial photography to determine the most recent causes of wetland loss. The results are expected in 2009.
