Rolled erosion control systems for hillslope surface protection: a critical review, synthesis and analysis of available data. I. Background and formative years

Landscapes disturbed by human activities commonly have erosion rates accelerated by several orders of magnitude over pre-disturbance conditions. New approaches to effectively decrease soil erosion rates from disturbed lands are urgently required to decrease non-point source pollution. One such best management practice (BMP) combines the application of rolled erosion control systems (RECSs), composed of either natural or synthetic fibers, with seeding of hillslopes to enhance biomass production. This synergistic approach is thought to be one of the most appropriate for mitigating excessive soil erosion on disturbed non-agricultural hillslopes. Over the past decade an active erosion control industry (ECI) has developed, and a variety of different RECSs have been brought to market. However, limited scientific data are available to the land manager, specifier, or design engineer to assess the relative effectiveness of these products in reducing sediment yield and in enhancing the development of vegetation. Few studies exist that have rigorously compared RECSs using a well-developed experimental design. Most studies lack sufficient replication and/or randomization. Additionally, in many studies there is a failure to control variables between cycles, runs, or events, including antecedent moisture content and sediment availability. The result is a mass of information that can be potentially misused to justify the selection of a given product that may be less effective than a competing product. The objectives of this two-part paper are: (i) to synthesize all available erosion-related literature dealing with RECSs applied to hillslopes during two periods: up to 1990 and post-1990; (ii) to highlight important scientific contributions to the literature on RECSs; (iii) to assess the scientific rigor of various studies, and re-analyze and re-interpret data when available; and (iv) to make constructive suggestions to improve future studies to develop a quantitative linkage between the physical characteristics of RECSs, soil erosion processes, and vegetation cover.