Impact of animal burrows on earthen levee body vulnerability to seepage

A novel procedure for estimation of the vulnerability to seepage inducing piping pro-cesses in earthen levees affected by animal burrows is presented. The proposed meth-odology combines an available procedure of seepage vulnerability assessment forundamaged levees with the result of a finite element analysis software, which is usedfor identifying the seepage path and hydraulics head profile of both damaged andundamaged levees. The main steps of the procedure for estimating the impact of bur-rows in increasing the vulnerability of levees are presented. Twenty-one levees alongthe Tanaro River (north-western Italy) are used as a case study, and the results showthat the critical conditions for the onset of inner erosion are achieved for shorter flooddurations in damaged levees. If burrows occur, the probability of inner erosion (seep-age probability) increases resulting in a potential increase of forming longer tunnels.This approach is a first attempt to quantify the seepage probability of extended leveesystems affected by burrows and is applied for simplified geometrical and two-dimensional representation of the cavities. This procedure can be applied by thehydraulic authorities to set the priorities in levees maintenance. Future researchwould focus on the analysis of more realistic burrows conditions.