9380

• UCREFRP Catalog Number: 9380
• Author: U.S. Bureau of Reclamation.
• Title: Grand Valley Irrigation Company Fish Screens ‎(Predesign)‎.
• USFW Year: 2000.
• USFW - Doc Type: Boise.
• Copyright Material: NO

flow of3,000 cfs. From Figure 4.3a of the Concept Development Report, 3,000 cfs corresponds

to a water surface of about El. 4682.0 (gates fully closed). The top of the cofferdam will be

assumed to be at El. 4683.0. The cofferdam will be constructed of clean inert fill material. It

will be placed on the diversion dam and extend from the sluice gates upstream on the diversion

dam to a location upstream of the trashrack and then extend to the right bank at the sheet pile

wall. The portion of the cofferdam on the existing diversion dam will be about 2 feet tall, and

the remaining portion will be about 5 feet tall. An extensive pump system will be required to de-

water the construction area.

The layout and placement of this screen in the river is not a typical application of a vertical flat

plate fishscreen. There are uncertainties as to the flow distribution along the face of the screen

under all river flow scenarios with this option. If this option is selected for final design,

consideration should be given to evaluating the hydraulics of the site with a physical model in
the laboratory.

Estimated Cost

The estimated cost of this structure was determined by a preliminary sizing of the structure and

then preparing a quantity and cost estimate. Because of the unique nature of this design, the cost

curves were not believed to be valid. The Estimate Worksheet for this option is shown in

Appendix E and it shows an estimated total cost of $4,740,000.00.

22

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I