scope:

The authors of this report do not attempt to assume that bioengineering for streambank protection is a cure unto itself. First, bed stability, another whole subject area, must be achieved before banks are addressed. If streambeds are not stable, it does little good to attempt bank stabilization. This report does not attempt to address the details of fluvial geomorphology, but the authors recognize that bioengineering must be done in consonance with good riverbed and planform stability design; there are several texts and engineer manuals that address these subjects. Consequently, good bioengineering takes an interdisciplinary team approach with expertise representing engineering, physical, and biological fields, as well as others, a point reemphasized throughout this report. The authors also recognize that causes of streambank erosion are complex and can often be related to land-use practices being conducted in the watershed and/or in the immediate vicinity of the erosion problem on the streambank. Therefore, careful study should be made of the causes of erosion before bioengineering is contemplated. Again, an interdisciplinary team is often required to develop an optimum plan. Bioengineering must be done within the context of a landscape approach, but erosion control must be addressed by reaches, from a practical standpoint. The report provides a planning sequence, or bioengineering design model, that is tailored to a zonal approach within reaches.

Vegetation, per se, is not a panacea for controlling erosion and must be considered in light of site-specific characteristics. When vegetation is combined with low-cost building materials or engineered structures, numerous techniques can be created for streambank erosion control. This report summarizes a number of techniques that utilize vegetation. For understanding how vegetation can be used in bioengineering and as a basis for conceptualizing a bioengineering design model, it is important to understand both the assets and limitations of using planted vegetation.

Purpose

This report synthesizes information related to bioengineering applications and provides preliminary planning and design guidelines for use of bioengineering treatments on eroded streambanks. It can be used by both planning and design elements, not as a cookbook, but as a guide with tools to accomplish bioengineering projects. It presents a bioengineering design model with examples in the text that describe specific case studies where certain stream conditions, such as velocities, have been provided. It also describes appropriate plants to use, their acquisition, and their handling requirements.

This study is divided into two reports. The main report, Report 1, provides bioengineering guidelines for streambank erosion control. Report 2 presents several case studies of bioengineering treatments applied to one or more streams in various geographic locations around the continental United States.