The following project description and back ground are described in full in the draft Conceptual Restoration Plan, River Mile 20 to 50 Project area Descriptions Tucannon River Phase II prepaired for the Columbia Conservation District in Dayton Washington.

5.5 Project Area 5 (River Mile 46.4 to 45.95)
Project Area 5 (PA-5) is located within the active channel from the downstream end of the Camp Wooten Environmental Learning Center (46.4) to the Tucannon Campground Bridge at RM 45.95.
Restoration actions include: Protect and maintain existing conditions, reconect isolatied habitats, address roads levees, and other anthropogenic infrastructure, restore riparian process, and improve instream habitat conditions.

Throughout the project area, the river is characterized by multiple channels separated by unvegetated gravel bars or forested islands. This portion of the channel is located downstream of a tightly confined section (PA-4). The active channel area is wider and wood and sediment is more likely to deposit resulting in a relatively dynamic reach with a greater volume of LWD, temporary sediment storage, and channel migration than has been observed in upstream reaches (Photograph 5-5). Steady migration of meander bends was observed in many of the outside meander bends, most notably at RM 46 along the left bank. Side channels ranging from perennial to high-flow were observed with variable depths and presence of LWD. Many side channels, however, were relatively wide, shallow, and lacking complexity. The variety of hydraulic conditions created by the channel processes, wood, and sediment in this project area create relatively good instream habitat conditions. Overall, however, the reach is lacking in sufficient volume and size of LWD and the log jams observed did not appear substantial enough to persist and retain additional LWD over time.

5.5.2 Conceptual Project Actions

Restoration actions in PA-5 involve re-connecting the low floodplain via road removal, enhancing instream habitat by LWD placement, and developing a surface water connection to the spring flow near RM 46.3 (Figure B-5). These actions are independent from each other and may be implemented in phases. Road removal would occur from the intersection of the Camp Wooten loop (RM 46.4) to the intersection of the campground loop (RM 46.0). A new bridge crossing to Camp Wooten will be required. The location of the bridge may be affected by project actions associated with PA-4 (see Section 5.4).


5.5.2.1 Geomorphic Implications
Widening the floodplain corridor by removing the roadway would double the accessible floodplain through the project area and allow natural floodplain and channel processes to occur. During high flows, dispersion of floodwaters over this area would decrease velocities in the main channel and allow for dispersion of overbank sediments and mobile debris. Over
time, channel, floodplain, and riparian function will be increased, in turn leading to ecosystem benefits. Addition of LWD will initiate additional pool scour and sediment retention, developing pools with cover and maintaining existing side channels. In the long term, large wood structures will maintain a complex channel network by maintaining and creating additional islands and promoting channel migration. Connecting the side channel to the river is not expected to have significant geomorphic implications.