The eroding bank prior to construction, looking downstream. The force of the river moves along river left, eroding the bank 12 to 16 feet from Fall 2008 to Summer 2009. The erosion over this time period is estimated at 850 tons.
Above eroding bank, April 2009. MF LRR USGS stream gage near Shirely AR was at about 7.3 feet on this day.
Topographic Survey of the site.
Stream restoration design. The rock vane at the top of the page is designed to steer the channel away from the stream bank. The second structure, called a j-hook, is designed to focus the energy of the river downward into a scour pool.
Channel structure detail.
Typical cross-sections. The proposed design would include excavating a deep scour pool in the middle of the channel. The excavated material would be used to fill the deepest part of the existing channel. This would reduce shear stress along the eroding bank (right part of existing cross section).
Reviewing the design.
Double-checking the numbers before construction.
Our fleet of rental equipment from Riggs CAT. From lest to right: CAT 924 and 928 wheel loaders, CAT 315 and 320 hydraulic excavators. Deere 650 bulldozer belongs to our contractor.
Improving acess prior to construction.
Transporting three 15" x 20' smooth bore, double-walled plastic pipes.
Constructing temporary crossing prior to construction.
Rocks were harvested on the property from as far as one mile from the construction site. We used wheel loaders and a dump truck to move rock.
Harvesting rock. We used excavators to secure and load the rock.
That is a very large rock!
Dumping rock near the construction site.
Transporting rock using wheel loaders.
Staged rock (this is not a completed structure).
Staged rock, ready for build.
Applying water drainage features (water bars with stable outlets) straw, and grass seed to minimize impacts of rock harvest activities.
Excavating the scour pool.
excavating the top of the j-hook.
excavation and transfer of fill toward the eroding bank.
Checking the eventual location of the j-hook structure using differential GPS with 1-meter horizontal accuracy.
Checking the depth of the scour pool using a laser level. Elevations needed to be within 1/10 of a foot of the design.
Placing the first footer stone of the j-hook.
Checking the elevation of the first footer stone.
Adjusting the first stone.
Placing a flat rock over the first footer.
Building the j-hook out on both ends.
Constructing the rock vane.
The completed j-hook.
The long arm of the j-hook.
The completed rock vane.
The first test. This photo was taken on September 16th at about 4pm. The USGS stream gage was at about 14 feet at this time. That evening, the gage peaked at about 18.5 feet. We are all anxious to see the structures after the flood waters recede.