Damage caused by erosion is often difficult to repair because the impacted area is usually subject to repeated episodes of erosive flows of water. Simply replacing eroded materials generally is not sufficient to stabilize the eroded area. In most cases it is necessary to excavate the eroded channel in the fashion shown in Fig. 7.27, and to tamp into place new material. For areas with velocities that exceed the ability of the soil to resist shearing it is necessary to provide at least temporary geotextile protection. Some places may require permanent protection. Similar steps are required for eroded slopes. It may also be necessary in some cases to divert the runoff from the impacted area during construction and even for a short time afterward.

Figure 7.27: Eroded channel repair detail.