From 1953 to 1961, the Atlantic Intercoastal Waterway was created by dredging a 12ft deep channel in the Indian River Lagoon. The spoil from the dredging created 137 spoil islands throughout the 156 miles and 4 counties of the Indian River Lagoon. Indian River County has the most islands (55), followed by Brevard (41), St. Lucie (34), and Martin (7) counties.
Of the 137 islands, the State of Florida owns 124. Four of the islands have since been dedicated to Martin County. The other 13 islands are owned by private interests, the United States Government, or the Florida Inland Navigation District (FIND).
The management of the 124 islands has been granted to the Florida Department of Environmental Protection (FDEP), Office of Coastal and Aquatic Managed Areas, with oversight from FIND.
The islands are designated by use categories determined by accessibility, presence of native plants and animals, and historical human use. After creation, the islands were quickly populated by both native and exotic plants and animals. Conservation islands typically have the highest percentage of native resources both on and around the island. These sensitive islands are not to be used for public recreation. Education islands are those islands that possess diverse (mainly native) habitats and thus are of high value in environmental education programs. Recreation islands are those islands where sensitive resources are minimal. They have a history of human use, one or more deep water access points, small or non-existing seagrass beds, no threatened or endangered species, and no breeding bird populations. Passive recreation islands are small or densely vegetated islands that cannot support development of structures. They are typically used for daytime recreation only. Active recreation islands are larger islands with open areas that could support construction of permanent facilities (campsites, sanitary facilities, barbecue pits, docks, etc.) Currently, there are 47 conservation, 9 education, 56 passive, and 12 active recreation islands. (Source: Spoil Islands Management Plan, 1990).