9593

• UCREFRP Catalog Number: 9593
• Author: Tetra Tech Inc.
• Title: Concept Development Report Hartland Diversion Dam Fish Passage Structure Delta, Colorado.
• USFW Year: 2000.
• USFW - Doc Type: Grand Junction, CO.
• Copyright Material: NO

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Calculations indicate that this alternative lowers the water surface elevations at the
Hartland headgate by less than 0.1 feet when the river flows are 350 cfs. For flows that equal
or exceed 3,000 cfs, the change in water surface elevations, at the headgate, are negligible
(0.03 feet or less).
6.1.1 Baffles
Two different baffle designs are being considered; the chevron baffle and the Redlands
style baffle. The Redlands style baffle is based on the baffle design in use at the Redlands fish
passageway (Burdick 2000a). The baffle includes an orifice opening on the bottom plus one
slotted opening from bottom to top. Redlands has documented success in fish passage,
however, it is not known which fish are using which opening. Chevron ladders have two slots
extending from bottom to top and have a slight bend in the center of the baffle to form a v-
shape in plan view. Chevron ladders are being used for Cui-ui sucker fish passage structures
in Nevada. The Cui-ui are believed to be weak swimmers (weaker than the razorback suckers)
because they are ordinarily lake dwellers that swim in rivers only for spawning. The chevron
style baffles appear to be working well for the Cui-ui, providing streamlined flows and less
eddies on the upstream side of the baffle than the Redlands style baffle. Eddies may cause
fish disorientation in the ladders, especially when turbidity is high and the fish rely on flow for
swimming direction. (Mefford 2000a) The chevron slots allow for fish passage anywhere in the
water column between the floor and the surface.
6.1.2 Alignment
The upstream end of the fish ladder is approximately 60 feet upstream of the dam and
50 feet from the attractive flow pipe intake. This distance is set to maintain a minimum of 50
feet between the ladder exit and the intake for the attractive flow pipe to reduce the possibility
of fish floating downstream into the inlet. The downstream end of the fish ladder is 30 feet
from the face of the dam.

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