Erosion Control During Highway Construction: Volume 1

Summary: Highway constuction as we know it today is a high-risk activity with respect to engendering soil erosion. In earlier days of road building, when rights-of-way were generally narrow and excavations mostly shollow, erosion was rarely a serious problem. Only occasionally was it considered necessary to design and apply specific measures for erosion control. With the advent of the superhighway involving far greater widths of right-of-way, and much deeper disturbance of the natural ground to affort the horizontal and vertical highway geometry necessary for high-speed travel, came a several fold increase in erosion potential and a direct need for specific action aimed at its control. Highway engineers have reacted by revising contruction specifications to include many protective measures. In creaseing public awareness of the desireability of protecting the environment has been a source of both support and pressure in the application of erosion control in highway construction. Although improvement has been significant, unwanted soil erosion and accompanying sedimentation resulting from highway construction activity continue to be problems. A lack of knowledge within the highway industry of improved erosion control measures developed outside the industry, perhaps some resistance to change because of a lack of familiarity with erosion control measures, and in some instances a need for information not now available anywhere, are probably the major contributors to continuation of the problem. The present project was directed at improving erosion control practice in highway construction by providing assistance in all three of the foregoing areas contributory to the problem. The principal output of the study is a MANUAL of erosion control principles and practices. The MANUAL focuses on techniques for predicting the erosion potential of highway construction sites, and for estimating the effectiveness of various erosion control measures. A wide variety of control measures are listed and described, and information that will aid in selecting measures to meet specific site requirements is presented. Design standards for control measures, and information on such matters as size selection for mechanical control measures, are not included in the MANUAL because these are already widely available in highway engineering offices. To develop the erosion control MANUAL on which the project effort was centered, means had to be established for estimating the water and wind soil erosion potentials on highway construction sites and the effectiveness of various measures that might be considered for controlling the erosion. The universal soil loss equation