In 2017, a severe landslide slid thousands of tons of soil off a mountain and onto the road below near Elk City, Idaho. The slide blocked Idaho State Highway 1, cutting off Elk City from surrounding areas. Emergency stabilization and repairs of the mountainside were critically important to the residents and Idaho Department of Transportation (DOT). Idaho DOT needed a solution that quickly and effectively stabilized the soil.
The steep grade of the mountain proved to be challenging. Several areas of the 1:1 slope were inaccessible to traditional hydroseeding equipment, and traditional erosion control products would not adhere to or protect the soil. In addition to the steep slope, the weather was a challenge and a durable, fast-acting product was needed.
Apex Erosion Control and Hamilton Mfg. Inc. NaturesOwn X9000 FRM, a high-strength fiber-reinforced matrix, was selected for the challenge. The product is a 70/30 blend of high-strength flax and cellulose fibers, combined with organic polymer tackifiers. The product meets and exceeds the requirements of bonded fiber matrix and flexible growth medium.
The fiber-reinforced matrix specifically was suited for the project because it excels in steep slope applications, and its formulation has advantages in yield per load, adhesion and bio-compatibility. Since the fiber-reinforced matrix does not include any non-organic ingredients and is USDA certified, Idaho DOT was confident in its use within the existing ecosystem.
Given the challenging slopes, the product’s ability to blend smoothly and distribute evenly was an asset. Apex was able to engineer methods to spray the fiber-reinforced matrix from nearly 500 ft away. This allowed the product to reach hard-to-access places. The Apex team sprayed a network of fibers from several angles to fully cover the soil surface. The cross-linked bast and cellulose fibers, in conjunction with the strength of the triple tac, created an immediate bond with the soil. The fiber-reinforced matrix stuck to the extreme slopes without an issue. Water usage and loading efficiency also were considerations for this project. By using X9000 FRM, the project used 30% to 40% less water than competitive products.
Immediately after application, the fiber-reinforced matrix was able to withstand rain and help secure the slope against additional slides. One year later, the mountainside has been fully reclaimed by vegetation.