Failed slopes lose their value in a habitat and can increase siltation in many streams and tributaries. Successful slope restoration and slope reclamation require a basic understanding of regional geology, geotechnical engineering, vegetation conditions, and proper water management. Overall, an understanding in slope stabilization and knowing which dynamic, analytical, and empirical methods to utilize to successfully obtain slope stability is key to the slope restoration process.
In order to conduct slope restoration, you must juxtapose construction and bioengineering methods. Natural causes to movement of slopes mostly consist of water infiltration and appearance of erosion—whether that be due to stormwater, an increase in hydrostatic pressure in cracks and fractures, physical and chemical weathering or absence of vegetative structure. Adding vegetation to the restoration and reclamation plan can be favorable for two reasons: vegetation slows down the rate of water flow, and their roots hold soil which can prevent soil erosion from occurring. Vegetation cover also intercept rain and direct the impact of rainwater to the ground surface, protecting the slope from surface runoff.
Common methods used for slope failure and mitigation include drainage, terracing and benching, retaining walls, friction piling, sheet piling, geogrids and biotechnical slope stabilization. Drainage used to increase the weight of soil that makes up the entirety of the slope, allowing the slope to become more vulnerable to mass movement while exerting the pressures that the supporting structures cannot handle. Terracing and benching make the slope more manageable by dividing it up in to smaller and less steep slopes that are reinforced by retaining walls and friction piles. Retaining walls are designed to hold in a substantial amount of soil. Geogrids are made up of heavy gauge plastic mesh that is installed in layers perpendicular to retaining walls. Lastly, biotechnical slope stabilization allows vegetation to do all of the work, letting the nature of the plants stabilize the slopes.