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

VI. FISH PASSAGE ALTERNATIVES
The following section presents and evaluates three fish passage alternatives. The three
include: a concrete fish ladder with baffles on the left bank, a fish ladder with boulder drops on
the left bank, and an in-channel boulder drop structure which provides passage for both fish
and boats. These alternatives are formulated to provide a set of options, which span the
potential range of costs and functionality. Since the HIC headgate and ditch are located on the
right bank, to avoid interference with the HIC operations all three alternatives utilize either the
left floodplain (Alternatives I and II) or the center of the channel (Alternative III).
6.1 Alternative I
Fish passage for Alternative I is depicted on Drawing 2 in Appendix A. This alternative
includes a concrete fish ladder located opposite the Hartland Ditch headgate on the east (left)
bank of the river. The fish entrance is located approximately 35 feet downstream of the dam,
below the white water being created at the dam toe. The fish ladder is a concrete structure
open on top to allow for natural lighting. The top of the fish ladder is set flush with the ground
elevations along the left bank and is therefore inundated for flows equal to or greater than
11,600 cfs or the 5-year event. To prevent the entrainment of trash and debris in the ladder
during a flood event, the top of the concrete structure includes a horizontal grate. The
maximum slope for the concrete fish ladder is 1.3% based on velocity and flow limitations in the
ladder.
One optional feature for Alternative I being considered is constructing the fish ladder
bottom with grouted river rock to create a roughened bed as shown on the typical details. The
purpose of the roughened bottom is to provide diversity in flow velocities, including pockets of
low velocities to serve as resting areas. To date there are no known roughened bottom
concrete fish ladders in use for the species of concern, so it is experimental. However, flume
tests have demonstrated the potential for success (Mefford 2000b).

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