Estimating Flood Damage to Vegetated Deep Soil Spillways

Although design guides are available, there is presently no procedure available for predicting damage and/or failure of a vegetated earth spillway subjected to flood flow conditions. The limited data available for vegetated spillways constructed in deep soil deposits are examined and shown to have sufficient consistency to allow calibration of simplified relations for use in damage estimation for spillways having similar geologic and hydraulic conditions. The nature of the data and the assumptions underlying these simplifications are discussed. Application of the relations with appropriate engineering judgment provides a means of damage and/or failure prediction until more analytic procedures become available.