Book Description

The report presents the results of a feasibility study to determine if widening and/or deepening the existing Federal deep-draft navigation project would be economically justified and environmentally feasible. The plan recommended provides for deepening the existing entrance channel to 44 feet at a width of 550 feet from the gulf to the southern end of Horn Island Pass, then continuing the 44-foot depth through Horn Island Pass at a width of 600 feet. Within Mississippi Sound and into the Pascagoula River, the channel would be deepened to 42 feet at the present width of 350 feet. The existing Bayou Casotte channel would be deepened to 42 feet and widened to 350 feet and would include a new 1150-foot diameter turning basin just inside the mouth of Bayou Casotte. Mitigation for the unavoidable loss of 4 acres of emergent wetlands from the construction of the Bayou Casotte turning basin would be provided by restoring 6 acres of disturbed wetland habitat to a natural emergent nature. Construction is estimated to cost $57.3 million. Interest and amortization and future maintenance of the channel modifications amount to an annual charge of $5.4 million. Average annual equivalent benefits amount to $22.3 million, yielding a benefit-cost ratio of 4.1 to 1. Contents: Geotechnical Conditions; Design and Cost Estimates; Benefit Evaluation; Environmental Documentation; Public Involvement and Comments.