Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
SUMMARY COST-EFFECTIVE AND SUSTAINABLE ROAD SLOPE STABILIZATION AND EROSION CONTROL In the United States and internationally, most roads are located in rural areas and have low traffic volumes. Worldwide, it is estimated that 88% of miles of road are low volume. In the United States it is estimated that 75% of miles of road are low volume, maintained by some 35,000 federal, state, and local agencies. Because low-volume roads often omit surface slope protection, they may be vulnerable to slope failure; erosion; and maintenance, safety, and ecological issues. This report presents information on cost-effective and sustainable road slope stabilization techniques, with a focus on shallow or near-surface slope stabiliza- tion and related erosion control methods used on low-volume roads. To fully address this topic, planning and site investigation are discussed along with erosion control techniques, soil bioengineering and biotechnical techniques, and mechanical stabilization and earth- work techniques. The information presented in this report was obtained through an extensive literature review, and from survey and interview responses. Information gained from the literature review was used to develop a survey that gathered additional information from practi- tioners, scientists, contractors, and vendors on the current practices, effective practices, and emerging solutions being used regionally, nationally, or internationally. The survey was distributed by e-mail. Eighty-one survey responses were received. From the survey responses, 30 individuals were asked to be interviewed based on the information they made available in the survey. A total of 25 interviews were conducted over the phone, and in two cases written responses were received. Information gained from the literature review and the survey and interview responses was incorporated into this report as the body of the text, additional resources, references, erosion control and slope stabilization techniques and tools, current and effective management practices, useful points, photographs, and knowledge and research gaps. Many techniques can be used to stabilize slopes, including several cost-effective and sus- tainable options. Every worksite is unique, and it is critical to understand the site-water, soil, and topography, as well as the user needs, before selecting an appropriate slope stabilization technique. To accomplish this, a full site assessment should be completed, one that provides information on the soil types and characteristics and surface and subsurface water condi- tions, and also takes into consideration short- and long-term planning. Developers should consider using a multidisciplinary team with a diverse knowledge and experience base. Tech- niques that are used frequently in planning for cost-effective roadway erosion control and soil stabilization include studying flora and fauna issues in the planning phase, considering the use of specific products, and clearly marking areas where the soil can be disturbed. Appropriate water management through the development of a water management plan may be the key to preventing slope failures. Vegetation and mechanical structures can be used alone or in conjunction to stabilize slopes. When using vegetation to stabilize slopes, mulch and soil amendments can aid in on-site vegetation establishment. Saving and reusing topsoil and mulching with on-site materials are cost-effective and sustainable practices. Erosion control products could be considered for use at every site on any disturbed soil surface, as it is much easier to prevent erosion than to fix an already eroded slope. Methods
2 used to control surface erosion or stabilize slopes can be used alone or as components of a system. Mechanical slope stabilization methods can also be used alone or in conjunction with plants (biotechnical stabilization). Earthwork techniques can be used to make slope surface less likely to erode and more stable. (The conclusion provides tabular summaries of soil bioengineering and biotechnical, erosion control, mechanical, and earthworks stabiliza- tion techniques.) The literature review, survey, and interviews identified the following knowledge and research gaps: ⢠A better understanding of erosion control and slope stabilization productsâ purpose and capabilities, and ⢠Cost-benefit analyses of products and techniques.
