FINAL ENVIRONMENTAL IMPACT STATEMENT SAN JUAN HARBOR, PUERTO RICO 1.00 Project description. 1.01 General. The proposed project, shown on plate 1, is located within San Juan Harbor on the north coast of the island of Puerto Rico. The proposal under consideration consists of a plan for deepening, widening, and possibly realigning and extending channels; deepening of turning basins, and easing of channel connecting angles within the authorized existing project. Additionally, consideration is being given to incorporation of Sabana approach channel, a Puerto Rico Ports Authority project, into the authorized Federal harbor project. Excavation volume is estimated at 12,795,000 cubic yards of soft material and rock with work to be accomplished by bargemounted clamshell or dragline and dredged material barged to an offshore disposal area (see plate 2). Accomplishment of the project would require an estimated 41 months from the letting of the initial contract. Maintenance would be scheduled at 2-year intervals and would involve an increase of an estimated 185,000 cubic yards per year over previous maintenance. 1.02 Authorization. The project plan was developed in response to the following resolution adopted 3 September 1964: 1.03 "Resolved by the Committee on Public Works of the Goals and purposes. The proposed plan was formulated after an extended study of the existing harbor project in cooperation with local officials, including the project sponsor, the Puerto Rico Ports Authority, and after a public meeting to solicit comments from interested parties. The resulting plan is designed to permit larger vessels to utilize the harbor and to secure safer navigation conditions in the harbor entrance and inner channels. 1.04 Proposed works. The following proposals, shown on plate 3, currently are under study: 75-259 0-76-9 a. Modifying the Bar Channel to a maximum width of 800 feet, deepening to a depth of 48 feet, and shifting the centerline 350 feet west, and a minor easing of the bend at the intersection with Anegado Channel. b. Deepening Anegado Channel in steps to 40 feet, 43 feet, and 46 feet, and reducing its width to 800 feet, and easing the bend at the junction with Army Terminal Channel. C. Deepening Army Terminal Channel and turning basin to 40 feet, widening it to 450 feet, and easing the bend at the junction of Army Terminal and Puerto Nuevo Channels. d. Deepening Puerto Nuevo Channel to 40 feet, widening it to 400 feet, easing the bend at the intersection of Puerto Nuevo and Graving Dock Channels, and providing 44 feet of advanced maintenance depth at the mouth of Cano de Martin Pena over a length of 1,200 feet and a width of 500 feet due to rapid shoaling in that area. e. Deepening Graving Dock Channel to 40 feet and easing the bend at the junction with Anegado Channel. f. Deepening San Antonio Channel to 40 feet at varying widths, with a minimum of 500 feet. g. Deepening the cruise ship basin to 36 feet at an irregular width between San Antonio Channel and the cruise ship piers on the south side of Old San Juan. h. Maintaining Sabana Approach Channel at a depth of 30 feet and a width of 250 feet. i. Providing a 38-foot depth at Anchorage Area E and mooring dolphins for vessels using the area. 1.05 Costs and benefits. Initial cost of the proposed work is estimated at $46,800,000. Annual costs for maintenance are estimated at $3,310,000. Annual benefits to the public interest are estimated at $6,168,000 for a benefit-to-cost ratio of 1.9. 1.06 Excavation quantities, methods, and disposal area. Types of material and respective quantities to be excavated were estimated by standardized methods from extensive data gathered from published sources and from analyses of 49 core borings and numerous jet probes and soundings. 1.07 An estimated 12,795,000 cubic yards of material would be excavated over a 41-month period with soft material accounting for 11,950,000 cubic yards and rock for 845,000 cubic yards. Amounts, broken down in channel reaches and basins, would be as follows: |