On Oct. 29, River Group members examined geomorphology and management problems in the lower Long Tom River (LLT). The LLT, a tributary of the Willamette River, is below the U.S. Army Corp of Engineers Fern Ridge Dam, about 15 miles west of Eugene. The LLT below the dam was channelized in 1947 to reduce flooding of farmland. The historic LLT channel (pre-channelization) was highly sinuous and many of the cutoff meanders are still evident in the landscape. The constructed channel is trapezoidal, low sinuosity, and contains several concrete weirs that function as grade control structures.
Current management problem include bank erosion, reduced flood conveyance due to bar development and vegetation within the channel, and fish passage blockage at grade control structures. The Long Tom Watershed Council is working with the Corps to develop potential solutions that will enhance water quality and ecological conditions in the LLT. One idea is to open up some of the old meander bends to increase conveyance and provide more complex habitat. There are a variety of geomorphic, hydraulic, ecological, social and financial issues to consider in finding solutions.
Jed Kaul of the watershed council came along and provided a lot of information and insight into the council’s plans. We had the pleasure of meeting with one of the farmers on the LLT, Tony Stroda, who showed us bank erosion and historic meanders on his property, and described events in the history of the river that he has witnessed.