Designing an Island Habitat for the Interior Least Tern
Mary Crawford, Matthew Simpson, Scoot Schneider
The purpose of this project was to develop a design that will create an island environment for the nesting and habitation of the Interior Least Tern. The creation of this island is expected to facilitate the recovery of this endangered species. The 2002-2003 Oklahoma State University Biosystems Engineering Senior Design Team was selected by the U.S. Army Corps of Engineers (USACE) Tulsa District to analyze and propose a solution to the problem. The Interior Least Tern was listed as an endangered species in 1985, with a total population estimated at 5000. Channelization, irrigation, and construction of reservoirs and pools have drastically depleted the nesting habitats used by the Least Terns. The U.S. Army Corp of Engineers has done various studies on the habitation and breeding styles of the least tern species in the Arkansas River area in order to devise a plan to stabilize the species in that area. Analysis into the possibility of implementing a structure or structures in the river to divert and manipulate flow to promote sediment deposition within the center of the channel was conducted by the team. The analysis was accomplished through several testing methods to determine a possible design structure that creates an island habitat for the birds. The structures that best served in the manipulation of the river mechanics for island creation are discussed in detail herein.
A solution to problem must conform to a variety of specifications determined both by the habitation preferences of the Least Tern and by the U.S. Army Corps of Engineers. These criterion include location, flow conditions, island design specifications, and cost limitations.
Scope of Work
The design of the island habitat should conform to the following criteria. The surface area of the island should be 0.8 to1.2 ha (2 to 3 acres) and should be concentrated in the center of the channel. The island should have gently sloping sandy beaches, less than ten percent vegetation, and should withstand high flow conditions.No specified cost limitation was provided by the USACE as a guideline for the project. However, the proposed solution should fall within reasonable limits, resulting in a feasible and practical design for implementation.