Wheel Gulch was the first of the “Phase Two” suite of sites. The Wheel Gulch Rehabilitation Project, approximately three miles downstream of Junction City, increased and enhanced salmon and steelhead habitat via construction of slow water refuges, placement of structures (e.g. large woody debris, trees and root balls), and introduction of gravel into the river’s floodplain.
The project area is approximately one half of a mile long. Wheel Gulch, a small intermittent tributary, enters the project area from the north and crosses under Highway 299 through a box culvert, giving the project site its name. The Wheel Gulch Overview Map shows the areas of construction activities. Below is a description of those activities (download the Site Design map for reference):
- Activity R-1 created an approximate, 60-40 flow split in the mainstem Trinity River channel when combined with Activity IC-1. The new channel, approximately one half of the width of the existing mainstem channel, was excavated through and behind the existing riparian berm and vegetation.
- Activity R-2 was the construction of a low-flow side channel behind the riparian berm that connected activity areas R-1 and R-3. This side channel was designed to flow year-round and carry approximately 10 percent of the total Trinity River flow.
- Activity R-3 was the construction of an alcove to connect the side channel (R-2) and the Wheel Gulch connection (R-4) to the Trinity River. This alcove is not a true alcove in that water from the low-flow side channel will be flowing through it, but with a width three times wider than the side channel, the water velocity was one-third of what it is in the side channel. The addition of large wood in the alcove also provided cover and velocity breaks, which is beneficial to salmonid rearing habitat. Wheel Gulch is ephemeral; therefore, it will only be adding water to the system during periods of rainfall or snow melt.
- Activity R-4 was the construction of a channel to connect Wheel Gulch to the alcove in Activity R-3. This improved the flow of water and sediment through Wheel Gulch and provided off-channel habitat for a variety of plant and animal species. This activity also created a backwater area specifically designed to provide rearing habitat for fish and herpetiles. Small wood structures and cover elements were be added to the sides of the channel.
- Activity R-5 was the construction of a dual-purpose revegetation area and high-flow channel. This channel was be designed to flow at 6,000 cfs. The main purpose was to excavate the channel deep enough, so the margins of the channel would be close enough to groundwater to be suitable for planting appropriate native riparian species.
- Activity IC-1. When combined with Activity R-1, Activity IC-1 created an approximate, 60-40 flow split in the mainstem Trinity River channel, with 60 percent of the low-flow river flowing through the R-1 channel. Material excavated from Activity R-1 was be placed to form Activity IC-1. The larger size fraction of the material excavated during Activity R-1 formed the core of the island; the fish spawning size class of material formed the middle layer; and finer material formed the upper layer. Portions of the new island were replanted.
- Activity U-1 was the construction of an upland terrace with excavated material not put to beneficial use elsewhere within the Wheel Gulch Project area. This terrace was planted with upland tree species.
Wheel Gulch construction in 2011: