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Title: Distribution and abundance of fish above Hartwell Dam during a period of entrainment
Authors: Kasul, Richard L. (Richard Lawrence)
Conley, Kenneth E.
Keywords: Fishes--Effect of dams on
Dams--Environmental aspects
Hartwell Dam (Ga.)--Environmental aspects
Publisher: Environmental Laboratory (U.S.)
U.S. Army Engineer Waterways Experiment Station.
Series/Report no.: Technical Report;EL-92-20
Abstract: Following the entrainment of approximately 295,000 blueback herring (Alosa aestivalis) at Hartwell Dam, hydroacoustic surveys were performed in the dam forebay and in the lower portion of the corresponding reservoir to document the occurrence of fish in relation to the 34-m-deep water intakes of the dam's five hydroelectric generators. During the period 3-5 September 1990, a set of 15 acoustic surveys was performed in the dam forebay to monitor the abundance, distribution, and movement of fish during scheduled periods of power generation. A one-time acoustic survey to obtain similar information was also performed in the lower 7 km of Hartwell Reservoir. Variable numbers of fish were detected in acoustic surveys of the dam forebay. Numbers of fish generally were low to moderate from 3 September through the afternoon of 4 September. Then, a large school of fish 28 to 40 m deep appeared near the dam, just west of the intake area. Over a 3-hr period, this school of fish grew in size and moved eastward to fill the area immediately in front of the water intakes. Echo integration results indicated that this school contained approximately 2.1 million fish at its largest size. The fish persisted in front of the water intakes from approximately 1745 hr on 4 September through the last forebay survey at approximately 1100 hr on 5 September. Echo integration estimates from the reservoir survey indicated that approximately 3.1 million fish were present in the 28- to 40-m depth stratum of the lower 7 km of the reservoir. Outside the forebay region, densities of fish in the lower reservoir were greatest approximately 2 km above the dam, then gradually decreased until fish nearly disappeared at distances greater than 5 km from the dam. The gradual disappearance of fish in the 28- to 40-m depth zone generally paralleled the deteriorating dissolved oxygen concentrations that occurred within this depth stratum at increasing distances from the dam.
Appears in Collections:Technical Report

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