Deer Lagoon, the most extensive estuarine marsh on Whidbey Island, is located near the island's south end, on the north shore of Useless Bay. The site includes an open lagoon with dikes on both east and west, and an open channel to salt water. The substrate is sand, silt, and mud. Most of the lagoon and surrounding uplands are privately owned, and public access is prohibited.
The Washington State Department of Ecology will acquired 379 acres of estuarine lagoon and freshwater wetland in Useless Bay on Whidbey Island in Island County (ca. 2001). The acquisition protected existing intertidal habitat and provided water control to restore the freshwater wetlands to intertidal habitat.
NOAA's Coastal and Estuarine Land Conservation Program has helped to protect nearly 400 acres of mixed freshwater and estuarine habitat, including approximately 1,200 feet of shoreline at Deer Lagoon. Restoration and enhancement is also planned for the property, which provides important habitat for salmon and other intertidal fish species, as well as several species of birds, mammals, amphibians, and plants.
A 55 acre site adjacent to these lands was placed in an agricultural conservation easement, funded in 2008.
The wetlands in Deer Lagoon provide an unusually favorable combination of fresh water and salt water habitats in an array that includes bay and tidal marshlands, an extensive brackish water pond, small islands, grass, and brushy uplands. Major wetland plants include cattail, bulrush, and invasive reed canarygrass in fresh water; and, in the estuary, pickleweed, spearscale, and saltgrass, along with invasive Spartina, a non-native cordgrass.