Using subsurface geophysical methods in flood control: A resistivity survey to define underground storage capacity of a sand body in Ciudad Juárez, Mexico

Abstract

A DC resistivity survey was conducted over a flood prone area (playa lake) in the southern urbanized area of Ciudad Juárez, Chihuahua, Mexico to locate and evaluate the water storage capacity of a subsurface permeable sand stratum to prevent flooding "El Barreal", a large urban area of housing developments and industrial compounds. Recent major floods in July 2008 record were caused by precipitation levels of 68 mm in 24 hours, and a monthly accumulation of 146 mm. Hundreds of homes and industrial enterprises were flooded. Nine vertical electrical soundings (VES) were conducted utilizing a Schlumberger array to generate a geologic model. Two trenches were excavated to calibrated the method and perform permeability tests. The method successfully discriminated between fine grained clay and silt and coarse sand. The subsurface sand body will be used as a temporary storage facility for flood control during summer storms amounting to up to half the total annual rainfall.