Perennials are planted above and/or below the dam, whose roots will soak up and slow the rain and nutrients as they rush down the hill. In this method, logs and brush are laid across the hillside like a beaver dam and held in place with wooden stakes.
I had no idea what check logs were, but I found more information in Edible Forest Gardens as well as in Rainwater Harvesting for Drylands and Beyond, where they are referred to as check dams. I sought council from local permaculture practitioners, who suggested that I look into the concept of check logs. Oh, and the solution needed to be cheap and low tech, because after all, we’re just a volunteer group operating on a small budget. We were looking for a garden terrace solution that not only helped stabilize the hillside, but also helped increase fertility (to make up for all that had washed away). Any topsoil and nutrients that may have been there at one time had since washed away. The hillside was prone to land-sliding and erosion.
In 2011, I started Hillside Community Garden, and as the name implies, we had a steep challenge. Oh, and don’t forget to grab your FREE DOWNLOAD: Building a Check Log Terrace Quick Start Guide at the end of the article. A typical application is a rock-lined chute (EM 1601 section 3.7 (e)).Are you challenged with sloping land? Here’s a solution to stop erosion on a hillside and create an easily-navigable terrace garden. For steep slopes ranging from 2 to 20 percent where unit discharge is low, EM 1601 presents a separate design process that is not included in the riprap calculator. As the Froude number approaches 1.0 (critical depth), the user should strongly consider alternative methods. For installations immediately downstream of concrete channels, a vertical velocity distribution coefficient of 1.25 (an option in the calculator) should be used due to the difference in velocity profile over the two surfaces.īoth the EM 1601 riprap computation and HEC-RAS model application are suitable for shallow slopes with gradually varied flow. In expanding transitions, flow can concentrate on one side of the expansion and design velocities should be increased. In areas where flow changes from tranquil to rapid and then back to tranquil, riprap sizing methods applicable to hydraulic structures (HDC 712-1) should be used.
The procedures in this calculator are applicable to gradual transitions where flow remains tranquil. Transitions in size or shape may also require riprap protection. The EM 1601 design guidance applies to riprap design for open channels not immediately downstream of stilling basins or other highly turbulent areas (for stilling basin riprap, use HDC 712-1, EM 1601 Plates 29 and 30).
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