RECOVERY--Y--PROJECT NUMBER 122744, John Day Lock and Dam Avian Predation Deterrent Array Phase II

RECOVERY--Avian predation of migrating juvenile salmonids, particularly from gulls, is a common occurrence downstream of hydropower projects. In general terms, juvenile fish passing the dam may become disoriented due to a number of factors (acceleration, change in pressure, etc.) thereby becoming increasingly vulnerable to avian predation downstream of the dam.

An Avian Predation Deterrent Array (APDA) in the tailrace areas have been shown to significantly reduce avian predation rates on passing juvenile salmonids. The goal of the APDA is to provide a passive physical deterrent (wire coverage) over the entire tailrace area, from the face of the project downstream to the boat restricted zone (BRZ) to provide protection from avian predation, providing the juvenile salmonids time to recover before moving downstream.

Six array support structures (anchor poles) will be required. Three 40 ft anchor poles on the Oregon shore and three 90 ft anchor poles on navlock guidewall islands. Carrier lines will be installed between the anchor poles, to provide intermediate anchor points for the avian lines. Anchor pole and foundation design work will be required as part of the solicitation.

The typical span for a single wire will be approximately 2800 ft, while the longest span will approach 3100 ft. The avian lines will drape across the BRZ within 40 ft above normal high tailwater (minimal sag).

This will require in-water work with construction starting no earlier than 1 December 2009 and work completion no later than 15 March 2010.

Avian predation on migrating juvenile salmonids, particularly by gulls, is a common occurrence downstream of Columbia River Basin hydropower projects. Juvenile fish passing dams may become disoriented due to a number of factors (acceleration, change in pressure, etc.), making them vulnerable to avian predation subsequent to passage.

Avian Predation Deterrent Arrays (APDA) have been shown to significantly reduce gull predation on juvenile salmonids below dams. The proposed John Day Lock and Dam APDA is designed to provide a passive physical deterrent (wire coverage) effect over the entire tailrace area, from the face of the project downstream to the boat restricted zone (BRZ). This coverage is intended to give disoriented juvenile salmonids time to recover before they move downstream.

The array support structures (anchor poles) will be anchored on the Oregon shore and navigation lock guidewall, with an anticipated pole height of 90 ft. Carrier lines will be installed between the anchor poles to provide intermediate anchor points for the avian lines. Anchor pole and foundation design work will be required as part of the solicitation.

The typical span for a single wire will be approximately 2800 ft, while the longest span will approach 3100 ft. Minimizing line height is an important component of an effective APDA design. The avian lines will drape across the BRZ within 40 ft above normal high tailwater (providing minimal sag), with 20 ft above normal high tailwater being the minimum allowable line height.

This will require in-water work with construction starting no earlier than 1 December 2009 and work completion no later than 15 March 2010.