The combination of Gabion Mattresses, gravel and MacTex geotextiles provided the optimal solution for channel linings
The Muddy River to Cooper Street Bridge rehabilitation project was part of a larger plan for river widening to mitigate the flooding along the Muddy River in Nevada. A pinch-point existed at the Cooper Street Muddy River crossing where the river went under the roadway through concrete box culverts, which were insufficient to contain higher flows following heavy rain. To avoid flooding over the roadway, a new bridge and a channel lining solution was designed using Maccaferri’s Gabion Mattresses and MacTex non-woven geotextiles.
Clark County Regional Flood Control District and Clark County Public Works undertook a flood control plan to avoid the ongoing flooding causing damages to rail road structures, roadways and urban infrastructure in Moapa Valley, Nevada.
Project engineering firm, GC Wallace Inc. (GCW), designed the Muddy River to Cooper Street Bridge rehabilitation project. A pinch-point existed at the Cooper Street Muddy River crossing, a low water crossing with the river going under the roadway through concrete box culverts. During higher flows following heavy rain, the river flowed over the roadway, causing disruption. At this point, a new bridge was constructed and a new armoured channel was installed. The channel lining was selected depending on the shear resistance required.
Upstream of the bridge, a 360ft long Gabion Mattress lined channel was installed, which connected to a concrete lined channel to take the flow under the new bridge. Gabion Mattresses continued the protection downstream, until traditional rip-rap took over the protection in the low-shear zones.
The Gabion Mattresses were placed over a layer of Type II gravel, which in turn was placed over a MacTex® N47.1A geotextile. The combination of the mattresses, gravel layer and the geotextile provide the overall protection system to the channel banks and bed. The gravel filtration layer is used in high-flow conditions and further reduces the interface velocities underneath the mattress protection.
The Gabion Mattresses used were engineered from 8×10 type double twist steel wire mesh. This mesh type is ideal for use in channeling and hydraulic works as the double twist mesh is flexible. It easily conforms to the channel profile and if there is any settlement or unexpected erosion beneath the mattress, it can settle into the new channel profile without cracking or rupturing, unlike other more rigid protection systems. The Gabion Mattress units are heavily galvanised with an additional polymer coating suitable for use in these high-flow physically aggressive environments.
For more information, please download our Case History.