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1 CHAPTER 1 INTRODUCTION Each year, more discoveries are made regarding the impact information, selects the techniques most suited to the project. that human activity and infrastructure have on the surrounding Appendix A provides descriptions and illustrations of environ- environment. For many years, project designers have included mentally sensitive channel- and bank-protection techniques. structures that perform well for stabilizing streambanks and Appendix B is a user's manual for Greenbank. decreasing pollution of our nation's waters by reducing ero- sion. However, many of these structures are missing key com- ponents critical to complete environmental restoration. What It Means to Be Environmentally Sensitive There is an ever-growing number of streambank stabiliza- tion practices, and many were considered for inclusion in this CHANGING REQUIREMENTS report and CD. Most were not included because they offered little in the way of environmental benefit beyond simply In response to increased knowledge and public concern, reducing bank erosion or channel incision. To be included in regulations and other requirements have been placed on these guidelines, techniques had to enhance or protect aquatic agencies and organizations to implement environmentally or terrestrial habitats, provide aesthetic value, or both. friendly and beneficial practices. This requires projects to Although aesthetic values vary from person to person, mea- incorporate components into erosion and sediment control sures were avoided that appeared visually incompatible with programs that provide improved habitat for the flora and naturally occurring riparian features. We generally included fauna of our waters, produce aesthetic value for roadsides measures that facilitated natural revegetation of eroding and waterways, and advance the sustainability of stable banks either directly (by planting) or indirectly (for example, streambanks and riverine systems. Under many conditions, by slope stabilization) but were visually unobtrusive. The these "soft" practices are more successful for erosion control appearance of banks treated with such measures should even- than structural "hard" systems and provide the additional tually be compatible with naturally occurring riparian features benefit of restoring ecological value to streams and rivers. and demonstrate a properly functioning stream system. Often These environmentally sensitive "soft" practices combine these measures lead to green, verdant, inviting banks that are with traditional structures to provide engineers with the abil- accessible for recreational use. The techniques included in ity to restore ecological health and stability within the infra- this report and CD have varying environmental benefits, and structures so critical to human society. those benefits are identified in this report. To answer the need for specifications and guidance regard- ing environmentally sensitive channel- and bank-protection measures, NCHRP funded the development of Environmen- Interdisciplinary Effort tally Sensitive Channel- and Bank-Protection Measures to aid highway engineers, restoration ecologists, watershed hydrolo- Due to the dynamic nature of any projects within or adja- gists, biologists, and soil conservationists in designing projects cent to a stream and the current awareness on the part of that restore stream and river systems, while protecting property designers, the public, and the regulatory community, it is crit- and structures. This report and the accompanying CD are the ical that interdisciplinary teams be developed. Members of dif- result of that project. The CD includes typical design drawings, ferent disciplines provide insight and guidance into specific construction and installation specifications, a comprehensive concerns surrounding a project and can provide the necessary bibliography with numerous links to the documents listed, and input for project success. Examples of specialists include an extensive photo gallery of project examples, all based on riparian ecologists, aquatic biologists, geomorphologists, extensive research and experience. Also included is a software hydraulic engineers, structural engineers, geologists, botanists, program, entitled Greenbank, that provides users with a reli- biologists, and erosion control specialists. Specialists should able, straightforward approach to selecting these innovative be involved early in project development to identify the envi- techniques for streambank protection. The program allows ronmental benefits desired, to promote communication, and to users to enter site characteristics and restraints and, using that facilitate the adjustment of project plans and designs.