9371

• UCREFRP Catalog Number: 9371
• Author: Levee Removal Evaluation Group.
• Title: Green River levee Removal and Floodplain Connectivity Evaluation.
• USFW Year: 1998.
• USFW - Doc Type: CAP-6 LR,
• Copyright Material: NO

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INTRODUCTION I
Goals and Objectives
The goal of the levee removal project is to restore and enhance floodplain habitats and
functions that support recovery of native fishes in the Upper Colorado River Basin (UCRB)
through selected floodplain restoration via levee removal. The first year of the project, 1996,
served as a pre-restoration base-line monitoring year in which naturally flooding sites were
monitored for invertebrate and nutrient productivity and fish utilization. Monitoring was
continued in 1997 with the restoration of two sites plus an additional restored site. Utah State
University (USU) worked in conjunction with Utah Division of Wildlife Resources (UDWR),
and the U.S. Fish and Wildlife Service (USFWS) collecting data in the monitoring process. USU
was responsible for data collection associated with invertebrate (fish food) and water quality
(nutrients) at three sites in the main channel of the Green River, at four floodplain sites on the
Ouray National Wildlife Refuge, and at four floodplain sites on Bureau of Land Management
(BLM) administered land. The UDWR and USFWS were jointly responsible for the collection
of data on fish population (native and nonnative) densities, composition, and habitat utilization at 1
the same sites.
The specific objectives of this portion of the study were to: monitor fish food organisms
including, macroinvertebrate density, distribution, species composition, and size composition;
and, to monitor physical parameters including, temperature, and dissolved nutrients (nitrogen,
phosphorous, and carbon). These goals were identified so that we could determine if. 1) '
invertebrate (fish food) production is the same between floodplain terraces and depressions; 2)
invertebrate densities are higher in the floodplain compared to the main channel of the river; 3)
invertebrate densities in the main channel of the river are increased as a consequence of
floodplain connection; and 4) inundation of floodplain habitats effects levels of available
nutrients and therefore, production potential.
METHODS
Sampling Design
In 1996, six flooding sites were selected for sampling on the Green River. The sites were
defined as terraces (T) and depressions (D) according to hydrologic functional characteristics.
We selected three of each type. These sites were Bonanza Bridge (D), Baser/Chew (T), above
Brennan (D), Johnson 4 (D), Leota 10 (T), and below Shepard (T). In 1997, below Shepard was
removed and three additional sites, the Stirrup (D), Old Charlie Diked (T), and Old Charlie Wash
(T), were added to the sampling regime. In 1998, Horseshoe Bend (T), Baesar Bend (D), and
Leota 7 (D) were added to the sampling regime.
In each of the three years, nine to ten sampling trips were conducted, one before high e
fy
spring flows, four to five weekly trips during floodplain connection, and four to five month
trips after flood recession. The first trip took place before peak flows and floodplam inutio
ng hid
to establish base line data on pre-flood invertebrate communities and water quality.. 1P
flows, five sampling trips were conducted to monitor the influence of floodplain ir?at' ti
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