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Flexamat Erosion Control Gallery
American River Armoring
This was a residential project that involved two homeowners. The homes back up to the American River, outside of Sacramento, CA. The two properties sit atop the right bank of the American River, near USACE river mile 13.4. Gunite slope protection had been installed in the 1960s, but it had become severely undermined. Large cracks and voids had developed. Equipment access was limited. The only access point for equipment and material via a small boat launch that connected to one of the residential driveways. In order to utilize small equipment that would not damage the driveway, small customed-sized Flexamat Plus rolls were ordered. The rolls varied in length, but each were 7.5' wide and included geogrid and underlayment extensions. The installation began at the downstream end of the properties, with the next subsequent mat being installed over the previous mats extensions, thus creating a continuous armor. The slope had steep sections that varied up to .75:1. Percussion anchors were incorporated throughout the slope in a diamond patten. The percussion anchors were also installed at the mat seams, through the top Flexamat Plus layer and through the extension underneath. This project had a site specific planting plan. Prior to the Flexamat Plus installation, the slope was seeded with a grass seed blend. After the installation of the Flexamat and anchors was complete, the contractor planted plugs, live cuttings, and container plans. This residential slope is now fully protected. The performance life of the new Flexamat Plus system exceeds the lifespan of the gunite that had been installed in the 1960s. The new slope protection will perform better and is also much more aesthetic.
Reservoir Spillway Protection
The spillway at this reservoir experienced significant damage in 2019 that impacted the integrity of the dam. FEMA funds were approved but the 2020 pandemic put off the project for two years. After Federal Regulations for design, permits and making sure no Native American Cultural sites or native species would be disrupted, the repair was commenced and completed in 2023. Flexamat Plus was specified by the engineer to armor the spillway and protect it from future erosion. The Flexamat team worked closely with the engineer and contractor to provide a comprehensive mat layout, showing where each mat would be installed, along the anchoring layout. Having a clear mat layout helped the contractor install the mats efficiently. Flexamat Plus rolls were stockpiled onsite, keeping the installation steadily moving as the grading was completed. The specifications directed the contractor to seed prior to installing the Flexamat. This locks the seed within the armor and ensure the root growth penetrates through the layers of the Flexamat Plus system. 365,000 square feet of Flexamat Plus was specified on this project. The first Flexamat deliveries were made in mid July, 2023 and all of the mats were installed by the first week of September, 2023. Vegetation was already growing through the mats installed in August as the project was completed.
Flexamat Levee Protection
This project was performed in conjunction with the US Army Corps of Engineers along with several state agencies. The armoring was required to be environmentally friendly, without any plastic components, and safe for wildlife, including endangered snakes inhabiting the site. Nearly 7 miles or 36,000 linear feet of the water side of levee was armored with Flexamat. Mats were unrolled from the the top of the levee to the toe, in continuous sections. The each mat had an overlapping extension for the next adjacent mat to be installed over, tying the entire system together. The contractor had 4, 4-person crews operating at the same time. Each crew installed 50,000 square feet per day, for a total of 200,000 square feet installed per workday. The vegetation seen in the video is all native growth, the site has not yet been seeded with the site specific seed mix. Flexamat will protect the levee during flood events, when it will be exposed to wave action and water flow.
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