Wetland habitat development and long-term monitoring at Windmill Point, Virginia

Abstract

Windmill Point (WP) is an 8-ha dredged material island site in the intertidal reach of the James River. This fine-textured, freshwater site was one of the first habitat development projects built by the U. S. Army Corps of Engineers (CE). Long-term physical, chemical, and biological monitoring has been conducted since 1974. Three nearby natural wetlands have been used for comparison purposes in order to document site success or failure and the speed of wetland development. With the exception of some herbaceous plantings on the WP containment dikes, vegetation has colonized naturally. Over time, predominant species have beenPeltandra virginica, Pontederia cordata, andSagittaria latifolia. Wild-life and fish populations and species diversity have been consistently greater at WP than at the 3 reference wetlands. Benthos regained pre-disposal levels within 6 months. Five heavy metals and 14 PCBs were examined in soil and plant samples. Only DDE was found to translocate to wetland plant shoots, and kepone was found to be relatively stable. WP was broken into 2 smaller islands by flooding in 1983 and now consists of as much shallow aquatic habitat as emergent wetlands. The CE recognizes that active site management of such riverine wetlands through placement of additional dredged material and dike repair is needed to ensure long-term site integrity.