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Title: Preliminary Assessment, Environmental Assessment and Finding of No Significant Impact : Dillingham Small Boat Harbor, Dillingham, Alaska
Authors: United States. Army. Corps of Engineers. Alaska District
Keywords: Dillingham (Alaska)
Dredging spoil
Environmental management
Environmental protection
Publisher: United States. Army. Corps of Engineers. Alaska District.
Abstract: The Dillingham Small Boat Harbor was authorized by the River and Harbor Act of 3 July 1958 (House Doc. 390, 84th Congress, 2nd Session), which initially provided for a small boat basin of 230,000 square feet (ft²) dredged to a depth of +2 feet mean lower low water (MLLW). The harbor and 1,100-foot-long entrance was dredged at the mouth of Scandinavian Creek where it enters Nushagak Bay. A sheet-pile sill with elevation of 7 feet MLLW was authorized for placement at the basin outlet, but design modification replaced the sheet-pile sill with a rock sill. An embankment was constructed on three sides of the basin to protect moored vessels from waves. The project depth was reduced in 1963 from +2 feet to +7 feet MLLW due to excessive siltation. Maintenance was suspended in 1964 pending restudy of the project. In 1968 a supplemental design memorandum was approved authorizing re-excavation to the project depth of +2 feet MLLW and the purchase of a dredge owned by the Corps of Engineers. The harbor was dredged with the Corps dredge, "Dillingham" from 1969 through 1988. The Corps dredge was sold in 1988 and the harbor dredged by contract beginning in 1989. The rock sill was removed to the depth of the existing bottom in 1999. The harbor currently provides moorage for about 320 commercial fishing and recreational craft. At conclusion of the 2004 dredging season, controlling depth of the basin was +2 feet MLLW and entrance channel was +2.6 feet MLLW. The project is subject to rapid siltation due to sediment from the turbid Nushagak Bay settling out in the harbor basin.
Description: Preliminary Assessment, Environmental Assessment and Finding of No Significant Impact
Rights: Approved for Public Release; Distribution is Unlimited
Appears in Collections:Environmental Documents

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