For those of you who follow my blog, you know that I wrote a series of somewhat contentious posts last spring concerning bank stabilization work that was done downstream from Tucker Crossing. This series of blogs elicited everything from praises to threats against me and my business. My biggest concern regarding this project was not just the timing, but also the siltation it created, the loss of aquatic life and the lasting effect of the work itself.
I believe that the biggest threat to the Bitterroot watershed is rip-rapping the stream side banks for stabilization. Not only does this channelize the river, it creates erosion downstream (See previous posts). However, when Wildland Hydrology took on the project below Tucker Crossing, they had a completely different approach to bank stabilization. Instead of placing large rocks along the bank, they proposed a more natural bank by driving logs (toe wood) deep into the bank, folding large areas of sand and soil over the top of the logs and planting willow and alder in the sod mats. This is a very simplified explanation of their complex project. To my knowledge, this project was the first of it's kind on the Bitterroot River and everyone in the fishing community was eager to see the results.
Recently, I have attended some Bitterroot Conservation District (BCD) meetings. The BCD is the agency responsible for issuing 310 permits. The BCD is comprised of local citizens, most of whom have been born and raised in the Bitterroot and from varied backgrounds. Chris Clancy, Fisheries Biologist for Montana Fish Wildlife & Parks, is not on the board but acts as an advisor to the board. Also, Jack Mauer, a longtime fly fishing outfitter in the Bitterroot, attends almost every meeting and provides input to the board concerning anglers and outfitters. In order to do ANY type of work in the floodplain a 310 permit must be issued first. When I say floodplain, I mean all the area on the streambed that is below the high water line. Typically, that mark is defined as where terrestrial vegetation begins. 310 permits are not required for any work above the high water line. This requires a county floodplain permit, which is issued by Ravalli County. The first meeting I attended was akin to walking into the lions den. In previous posts, I have had some choice words regarding Mr. Clancy and the BCD. However, I have been treated with respect by not only Mr. Clancy, but all the members of the BCD. I plan to attend as many meetings as possible because they are very informative with regards to any projects occurring or set to occur on the Bitterroot River.
It was at the latest meeting (January 25, 2011) that the Annual Maintenance Report was released on the bank stabilization work done downstream of Tucker Crossing. Wildland Hydrology is contracted to maintain their work for five years after the date of completion. If any of their work is damaged by the natural process of the river, they are required to fix the damage. The spring of 2010 was a large runoff event and was a great first test for their work. According to Wildland Hydrology's report, the total loss of "toe wood" for the entire project was 3%. The entire project is comprised of three separate sites; Site #1 The Bucholz Project consisted of 1500 lineal feet of work; Site #2 The Hanson Project consisted of 1,700 lineal feet; Site #3 The Double Fork consisted of 250 lineal feet. The Hanson project lost 80 feet of toe wood after runoff (the largest amount of the three) and the Double Fork lost just 30 feet. There was no loss of toe wood on the Bucholz project. Wildland Hydrology credited the zero loss on the Bucholz project to the fact that the homeowner used sprinklers in the summer months; thereby increasing the growth rate of the willow and alder. Furthermore, the photo evidence seems to suggest that the toe wood structure, on all the projects, created lower velocity of flows of the river near the banks. Instead of the river slamming into the bank, a seam was created a few feet off the bank. According to the report, this aided in the deposition of sand and sediment behind the toe wood structures. The photos further indicated that after the flood water receded, there were cottonwood seedlings sprouting behind the structures. In all the projects, there was no further terrace bank erosion; also credited to the toe wood structures.
Wildland Hydrology has painted a rather positive picture of their own project and it seems to have been successful, after the first year. However, my concern is how well it will stand the test of time. The true test will come in the next 3-6 years and if we continue to have large runoff events. This years snow pack is currently well over 100% and we are slated for a large runoff. It will be interesting to see how this project performs. I hope that it will be successful. If so, it should only encourage other landowners to do this type of bank stabilization instead of traditional and harmful rip-rap.
