Galerie de contrôle de l'érosion Flexamat

The US Army Corps of Engineers had Flexamat Plus articulated concrete vegetative mats installed to protect against erosion on the steep backslope of the dam at Lake Harsha in East Fork State Park. This state park is located outside of Cincinnati, in Southwest Ohio. East Fork Lake, also known as William H. Harsha Lake, was built in the 1970s by the U.S. Army Corps of Engineers. A partial pool was impounded in 1978, and the lake reached its normal pool of 1,971 acres in the spring of 1979. The lake is primarily used for flood control, recreation, and as a water source. The original concrete gutter installed in the late 1970s had severely deteriorated. There were many cracks and the gutter had undermined in multiple areas from erosion. This created not only a performance issue, but a safety concern as well. In 2020, Cornerstone Engineering, Inc. was awarded the contract to designed a new and improved gutter system. The work consisted of the removal of the existing concrete drainage ditch that ran down back side on the east side of the dam. The slope was regraded and Flexamat Plus articulated concrete vegetative mats were installed to help alleviate the erosion along the ditch line. The Flexamat armored channel discharges into the tail water at the end of the slope. Learn more at Flexamat.com.

Revitalizing a community green space: A case study in innovative erosion protection - Discover how an innovative erosion control system revitalized a residential park in Toronto. In 2015, significant erosion issues in a residential park in Toronto, Ontario, were first documented by the Toronto and Region Conservation Authority (TRCA) through its Erosion Hazard Monitoring Program. The park, located within the Etobicoke Creek watershed and covering an area of approximately 215,000 square feet (20,000 sqm), features a grassed swale intended to convey stormwater runoff along the length of the park. At the end of the swale, the runoff was funneled beneath a pedestrian footpath via an 18- inch (450 mm) diameter culvert and discharged at the top of the slope. Over time, erosion at various sections of the slope had developed, including outflanking of a mid-slope catch basin and gully formation, some as deep as 3 meters, further downslope. The progression of the gully crest posed a direct risk to adjacent residential backyard boundaries. Given the rapidly degrading conditions, TRCA’s Restoration and Infrastructure Division consulted Terrafix Geosynthetic Inc. (a division of Hanes Geosynthetics) to explore erosion control solutions. A major factor to consider was site constraint, including restricted access due to residential proximity and varied terrain. After a thorough evaluation of the site, Terrafix proposed Flexamat Plus, a tied concrete block mat system designed to control erosion and promote vegetation growth. The primary objective of the project was to reconstruct and stabilize the eroded channel from the culvert to the base of the slope. Flexamat Plus, composed of 5,000 psi (34.5 MPa) strength concrete blocks interconnected with a high tenacity polypropylene bi-axial geogrid and underlaid with a wood excelsior erosion control blanket and polypropylene turf-reinforcement mat (TRM), offered the strength and flexibility necessary for this restoration. The 1.5 inch (38mm) spacing between the blocks allowed for both flexibility and vegetative integration, enabling roots to grow below the mat and establish a green, reinforced surface over time. Prior to installation of the mats, the contractor filled the gully areas with granular ‘B’ Type II followed by compaction to 95% Standard Proctor Maximum Dry Density (SPMDD). They then prepared the subgrade, ensuring it was smooth and free of rocks, stumps, roots and other protrusions of any kind. The subgrade was graded into a trapezoidal shape to concentrate the flow to the middle of the mat and then covered with 2 feet of (50 mm) terraseeding. The steepest section of the work was between a mid-slope catch basin to 100 feet (~30 m) uphill, measuring 39.6% in grade. The bedding was then seeded with a riparian mix consisting of wild rye, evening primrose fox sedge and other varieties at a rate of 22.3 lbs/acre (25 kg/ha). Using an excavator, the contractor unrolled the mat over the prepared bedding at their assigned locations. Each mat was spray painted with their individual number and mat dimensions. At the top of the slope, the initial leading edge of the mat was embedded 18 inches (450 mm) vertically into the subgrade, serving as an anchor trench. The trench would then be filled and compacted. Eighteen-inch (450 mm) u-shaped #3 rebar anchors were then installed in increments of 610 millimeters behind the first exposed blocks. Further downslope, downstream mats were shingled 18 inches (450 mm) under the upstream mats and secured every 2 feet (610 mm) with the U-anchors. Flexamat facilitates and supports long-term vegetation growth. Its open design allows plants to root directly through the mat, anchoring it to the soil and creating a biologically reinforced system. This enables phytoremediation – a natural process in which perennial vegetation absorbs and filters pollutants like heavy metals, oils, and sediments often present in road and parking lot runoff. As vegetation establishes, it also shades the concrete surface, reducing thermal loading of runoff and mitigating urban heat island effects. Within a few weeks of installation, vegetation began to establish between the blocks, visually softening the hard armor erosion protection and blending the restored channel with the surrounding park. As the root system matured, it further stabilized the underlying soils, enhancing the long-term-resilience of the restoration. From an environmental standpoint, the project delivered multiple benefits. First, it minimized sediment transport and downstream degradation. Second, it promoted native plant restoration and biodiversity. Third, by integrating erosion control with revegetation, the project aligned with TRCA’s broader goals of sustainable watershed management. By integrating engineering innovation with ecological restoration, the project revitalized a green space at risk – transforming it into a stable, functional, and attractive community asset. www.Flexamat.com

The Clear Creek Wetlands provide flood control for growing area development. Native vegetation cleanses rainwater while providing a home for wildlife. Trails winding through the wetlands offer the opportunity for a quiet walk among turtles, frogs, and water birds. The concrete erosion control mat Flexamat Plus FR was specified to armor the spillway structures. This product was selected for its permanent erosion control while also being flame resistant to allow for controlled burn vegetation management. www.Flexamat.com

The City Engineer needed to rehab and stabilize an eroded section of Heath Creek behind a medical facility. The eroding banks were encroaching on the parking lot of the medical facility. The erosion had become so severe that the parking lot was at risk of falling into the Heath Creek. The site was originally designed with eight tiers of gabion baskets stacked on top of each other with passive and active tieback anchors to stabilize the streambank. The engineer's cost estimates were nearly $800,000 and this amount exceeded the City's budget. The City Engineer sought a permanent solution that was within the City's budget. The engineer developed a solution that incorporated vegetated armoring. In order to reduce the slope ratio from a 1:1 to a 1.5:1, the engineer incorporated a Scourlok toe wall. To armor the 1.5:1 slope above the toe wall, the engineer specified Flexamat Plus. Flexamat Plus is a concrete erosion mat that allows vegetation growth to establish within the armor. The concrete mat is packaged in roll, making installing the material simple and efficient. The solution was 1/3rd the initial cost estimates for the gabion wall and was a solution the City could afford. Along with saving the City considerable funds, the streambank was stabilized with a more environmentally friendly solution. More information is available at Flexamat.com.

Installation included specific cuts of 16'x31' Flexamat 10NW with grid extension, and 175 Gripple percussion anchors. The Chattahoochee River flows between Alabama and Georgia and eventually down into the tributary of Apalachicola.

Un banco de arroyo detrás de una estación de bombeo está blindado con rollos Flexamat Plus de 10' x 35' que incluyen extensiones. Las extensiones constan de una geomalla y un contrapiso que se extiende desde la estera en el lado aguas arriba de la estera. La instalación comienza en el extremo aguas abajo del proyecto. Los tapetes posteriores se instalan superponiendo las extensiones de los tapetes adyacentes aguas abajo. Aunque este sitio tenía un acceso extremadamente estrecho, los rollos Flexamat Plus se instalaron rápidamente. Esta ribera fue blindada en menos de un día de trabajo. Durante la primera temporada de crecimiento, la vegetación pronto prosperará dentro de la armadura Flexamat Plus. Flexamat.com

A streambank behind a pump station is armored with Flexamat Plus 10' x 35' rolls that included extensions. The extensions consists of geogrid and the underlayment extending from the matting on the upstream side of the mat. Installation begins on the downstream end of the project. Subsequent mats are installed by overlapping the adjacent downstream mat's extensions. Although this site had extremely tight access, the Flexamat Plus rolls were quickly installed. This streambank was armored in less than one work day. Within the first growing season, vegetation will soon be thriving within the Flexamat Plus armor. Flexamat.com

This video shows how to quickly remove the lifting straps from a roll of Flexamat erosion control matting. More info available at Flexamat.com