Flooding Along the Fence

Abstract

In the summers of 2010, 2013 and 2014, Eagle Pass, Texas along the U.S.-Mexico border experienced three large flood events that inundated the border fence along the Rio Grande floodplain. The initial construction of the border fence is thought to have impacted lower socio-economic residents given its location and exacerbated flooding along the Rio Grande. I examine inundation using Nays2DFlood to model flooding extents in fence and non-fence conditions Results are then subtracted from each other to determine the impact of the border fence. I found that water depths do not differ between fence and non-fence conditions, but the fence plays a significant role in decreasing water velocities at the fence line and increasing water velocities at fence gaps and flood margins. Given on-the-ground observations by residents during flood events, this decrease in velocity can pick up debris and trap it against the fence, prolonging flood inundation times and thus delaying flood recessional flows. In addition, these conditions may lead to dangerous water velocity conditions near populated areas.