Modification of Fish Ladders at John Day Dam Columbia River, Oregon and Washington. Hydraulic Model Investigation
Modification of Fish Ladders at John Day Dam Columbia River, Oregon and Washington. Hydraulic Model Investigation

Author: P. M. Smith

Publisher:

Published: 1984

Total Pages: 119

ISBN-13:

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Prototype operation of the originally constructed fish ladders at John Day Dam revealed the need for ladder modifications to improve fish passage. A 1:10-scale model was used to evaluate the design modifications for both the north-and south-shore ladders. Improvements were desired in the flow-regulating sections and at the fish counting station for both fish ladders. The model was instrumental in developing a successful modification to the Hell's Gate slot-orifice type regulating section. The modification consisted of a slot-only design having a maximum head drop of approximately 6 inches. A vertical counting station was developed for the north-shore ladder. Successful operation in the prototype has verified the effectiveness of the design.

Fish Ladders for John Day Dam, Columbia River, Oregon and Washington; Hydraulic Model Investigations
Fish Ladders for John Day Dam, Columbia River, Oregon and Washington; Hydraulic Model Investigations

Author:

Publisher:

Published: 1968

Total Pages: 108

ISBN-13:

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Facilities for passing fish upstream over John Day Dam include a powerhouse collection system with fishway entrances at each end and along the downstream face of the powerhouse, and a 24-ft-wide fish ladder with 1-on-10 slope on both sides of the river. The north fish ladder (except entrance section) and a portion of ladder adjacent to the south fish counting station were studied in a 1:10-scale model. A group of four typical diffusion chambers in each ladder was reproduced in a 1:8-scale model. Fishway weirs with 6-ft-long overflow crests at each end of a 12-ft-long nonoverflow section, upstream fins, and 18- by 18-in. orifices at the floor were adopted. Orifice sizes in the regulating sections were adjusted to control discharge and head drops between 19 nonoverflow bulkheads for an 11-ft range in forebay levels. Sloping floors, baffle beams at a constant elevation, and metering orifices sized to provide 60 cfs each were selected for diffusers in sloping portions of the fish ladders. (Modified author abstract).