Wetland Improvement Project
at the Audubon Nature Preserve The Grand Valley sits on the eastern edge of the Pacific Flyway, a major migratory corridor for the continent’s waterfowl and other migratory birds. Historically, wetlands and backwaters along the Colorado River in the valley provided important stopover habitat for these migrating birds as well as critical habitat for the river’s endemic fish species, the razorback sucker, bonytail, humpback chub and Colorado pikeminnow which use these areas as nursery habitat. But for the last century, dams and diversions along the river have reduced the extent of natural wetlands and backwaters.
Since irrigated agriculture began in the valley, flood irrigated fields and unlined irrigation canals have provided some substitute wetland habitat for migrating waterfowl and shorebirds, but the endemic fish species have lost significant habitat. The humpback chub is now listed as threatened, while the other three species are listed as endangered. Population growth in the Grand Valley is leading to the conversion of agricultural land to residential development. In addition, more efficient irrigation practices necessitated by water shortages in the Colorado River will decrease the amount of these substitute wetlands in the Grand Valley. The goal of this project is to enhance and increase the wetland habitat available to migrating waterfowl, shorebirds, as well as endangered fish species on the Grand Valley Audubon Nature Preserve in Grand Junction. This project is a partnership between Grand Valley Audubon Society, Ducks Unlimited, RiversEdge West and others to improve wetland habitat on the Audubon Nature Preserve property in the heart of Grand Junction. The property is a former gravel mine that includes several former gravel pit ponds. Two of the ponds south of Dike Road, Osprey Pond and Traylor Pond, had/have steep and deep profiles and supported some populations of waterfowl, shorebirds and other wetland species. However, GVAS had no means by which to manage water levels in the ponds to maximize use by wildlife. Water quality is poor and anoxic and levels are driven by groundwater fluctuations, out of phase with habitat needs of wetland birds during their annual migrations. Waterfowl use the habitat but only in small numbers. Phase 1 of this project- completed in 2020- recontoured Osprey Pond and a portion of the smaller Avocet Pond- partially filling them in to create a shallower, more level depth profile. In addition, a headgate was installed to allow us to bring water onto the property from the Redlands Tailrace Canal under a Cooperative Use Agreement with the City of Grand Junction. Currently water can only be added to Osprey Pond and initial additions of water to the pond in the fall and spring have already resulted in the recruitment of beneficial emergent aquatic vegetation. Phase 2 of this project will recontour the northern portion of Traylor Pond to create a shallower, more level depth profile as in Osprey and Avocet ponds. Water management and conveyance infrastructure will be installed to allow us to add water to Osprey, Avocet and the recontoured portion of Traylor Pond seasonally. Fill for the recontouring of the northern section of Traylor Pond will be harvested from the property in the area designated as the Irrigated Wetland #1. Excavation of fill will lower the elevation of this area and bring it closer to the water table. An |
irrigation turn out will also be included that will allow us the irrigate this area seasonally and create wet meadow habitat. Following construction we will revegetate with native plant species.
The water conveyance (pipe) will be extended north under Dike Road and into the North Pond to set the stage for Phase 3 of the project- construction on the North Pond to convert it to a grow out pond for endangered native fish. This section of water conveyance will allow USFWS to add water to the North Pond when necessary to ensure fish survival. In Phase 3 of the project, we will construct nursery habitat for native fish in the North Pond, which sits north of Dike Road and alongside the Colorado River. This will involve relocating the cut in the riverbank that allows water to flow into the pond to a more advantageous location approximately 150 yards downstream. This new cut will require the removal of a few large cottonwoods (see Fig. 1.) The North Pond will also be recontoured to provide a more favorable profile for fish. This recontouring will not require borrowing fill from other portions of the property, earth-moving activities will be confined to within the existing perimeter of the pond. A water control structure will be installed in the new cut that will allow USFWS managers to open it, allowing water in and close it to prevent water from draining out. This water control structure will also be fitted with a screening device to prevent large, non-native predatory fish from entering the pond. A fish “kettle” will be constructed on the pond-side of the water control structure to allow USFWS to collect and process native fish before they are released back to the river. |
