C+S April 2023 Vol. 9 Issue 4

Moreover, using a permeable access road instead of a paved road provided the added advantage of decreasing the overall imperme- able surface area at the site, in turn reducing runoff and associated stormwater management requirements, and bringing even more savings in terms of both up-front and long-term operations and maintenenance costs. GEOWEB Slope Protection System: Protecting Solar Develop- ments Against Major Storm Events The Spotsylvania Solar Farm, a massive 617 megawatt utility scale solar farm covering 6,350 acres, posed unique erosion protection challenges that required a permanent stabilization solution. A sloped area leading into one of the larger detention ponds on the site was experiencing severe erosion due to concentrated stormwa- ter flows. Following multiple unsuccessful attempts to stabilize the surface

using conventional erosion and sediment control practices (including hydroseeding, sod/staples, turf reinforcement mats (TRMs), etc.), the contractor opted for the GEOWEB Slope Protection System, citing cost and performance as the major determining factors. The GEOWEB system cell walls allow water to flow throughout the system while holding the soil in place, preventing soil loss and gullies. The GEOWEB system (mid-size cells, 6-inch depth) was successfully secured over the 2:1 slope utilizing TP-225 tendons (woven polyester, 5100 lb. break strength) anchored to a buried deadman pipe and fastened to the cell walls using the patented ATRA® Tendon Clips - which provide twice the pull-through strength of any other tendon-based load transfer device. The ATRA Tendon Clips lock into the GEOWEB cell wall for the most secure connection on the market, and together with the tendons, can be preassembled at the top of slope prior to expanding for fast and easy installation. After installation, the slope was hydroseeded and covered with a straw-coconut erosion control blanket. The GEOWEB® 3D Slope Protection System provides a structurally stable environment for topsoil and sustainable vegetation through a structured network of interconnected cells. The 3D GEOWEB system confines and reinforces the vegetated upper soil layer, and over time, will facilitate root mat entanglement with cell wall perforations, even further increasing system resistance to erosive and sliding forces. The 3D GEOWEB system at the Spotsylvania Solar farm has held up to multiple high-intensity rain events, including the remnants of Hurricane Ian, which impacted the region with heavy rain and storms in September of 2022. The system will continue to provide robust erosion protection against similar major storm events in the future, allowing

the Spotsylvania Solar Farm to generate reliable power for the local community. Design Support & Resources for the GEOWEB System Applications The engineering team at Presto Geosys- tems works closely with engineers and project planners, offering free project evaluation services and on-site support. Our recommendations will deliver a technically sound, cost-effective solu- tion based on four decades of accredited research and testing data. Please contact our knowledgeable staff and network of qualified distributors and representa- tives to discuss your project needs today.

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April 2023 csengineermag.com

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