Rip-rap on the Bitterroot River
The four projects viewed by this group are in various stages. The first two are in progress and fairly new in design and construction. The third is similar to the first two but was done last summer and there were no structures threatened. The fourth project is of old design and has been completed for about a year and a half. All of the stabilization projects are being done to protect the landowners’ assets.
The purpose of the first two projects is to protect the landowners’ houses along the banks of the ever changing Bitterroot River. The houses were built on very high banks-- you might call them cliffs – and are in danger of falling into the river. The loose gravels and soils that make up much of these banks are being rapidly eroded causing severe slough-off of rock and gravels and all kinds of plant material including large trees. The scope of these projects is quite large and requires a significant amount of rock, wood debris and gravel to be displaced from one area of the flood plain and then replaced at the bottom of the erosion (toe of the stream bank) in an effort to prevent water from eating away these unstable banks. A backhoe is used to move the material, reduce the steepness of the bank and build up a “flood plain” area that will include vegetation. Small dikes are built just inside the waters’ edge to “break or brake” the energy of the river as it moves down the bank. Both projects are pro-active in reestablishing native, healthy vegetation along the waters’ edge. There is a natural fabric-like material securing live plant material/cuttings such as trimmed cottonwood, willow, aspen and grasses. Stout stakes and some rock help hold the fabric in place. The hope is that the roots will grow deep and securely hold the bank thereby reducing erosion. The test of whether or not these projects will be successful, only time will tell.
The second project was issued a 310 Permit from BCD last fall. The project was also permitted by the Army Corps of Engineers, the US Fish and Wildlife Service and the County Floodplain Administrator.
The third project was a bank stabilization using rock and wood as fill, topping with finer material, adding riparian plant stock and grasses, laying the fabric-like material and securing with stakes. The bank is along a fairly flat field or flood plain. No buildings were threatened.
The fourth project looked and was “old-time” bank stabilization. In an attempt to protect their real estate, they used massive amounts of very large rock. There was no fine material added and no native vegetation had been planted or encouraged. The most significant vegetation was an invasive weed, mullein http://en.wikipedia.org/wiki/Mullein which does not have enough of a root system to keep soil in place when erosion takes place. This project was permitted for less than 100 feet of bank stabilization and the final project resulted in at least 500 feet of “rock armored bank.”
Read MoreThe purpose of the first two projects is to protect the landowners’ houses along the banks of the ever changing Bitterroot River. The houses were built on very high banks-- you might call them cliffs – and are in danger of falling into the river. The loose gravels and soils that make up much of these banks are being rapidly eroded causing severe slough-off of rock and gravels and all kinds of plant material including large trees. The scope of these projects is quite large and requires a significant amount of rock, wood debris and gravel to be displaced from one area of the flood plain and then replaced at the bottom of the erosion (toe of the stream bank) in an effort to prevent water from eating away these unstable banks. A backhoe is used to move the material, reduce the steepness of the bank and build up a “flood plain” area that will include vegetation. Small dikes are built just inside the waters’ edge to “break or brake” the energy of the river as it moves down the bank. Both projects are pro-active in reestablishing native, healthy vegetation along the waters’ edge. There is a natural fabric-like material securing live plant material/cuttings such as trimmed cottonwood, willow, aspen and grasses. Stout stakes and some rock help hold the fabric in place. The hope is that the roots will grow deep and securely hold the bank thereby reducing erosion. The test of whether or not these projects will be successful, only time will tell.
The second project was issued a 310 Permit from BCD last fall. The project was also permitted by the Army Corps of Engineers, the US Fish and Wildlife Service and the County Floodplain Administrator.
The third project was a bank stabilization using rock and wood as fill, topping with finer material, adding riparian plant stock and grasses, laying the fabric-like material and securing with stakes. The bank is along a fairly flat field or flood plain. No buildings were threatened.
The fourth project looked and was “old-time” bank stabilization. In an attempt to protect their real estate, they used massive amounts of very large rock. There was no fine material added and no native vegetation had been planted or encouraged. The most significant vegetation was an invasive weed, mullein http://en.wikipedia.org/wiki/Mullein which does not have enough of a root system to keep soil in place when erosion takes place. This project was permitted for less than 100 feet of bank stabilization and the final project resulted in at least 500 feet of “rock armored bank.”
Project #1
