Investigation of Longitudinal Cracks Along Kickapoo Dam, Bronte, Tx Using Resistivity Surveys

Bronte, Texas has an earthen flood protection dam, known as the Kickapoo Dam, with extensive structural damage. Along the crest of the dam there is systematic cracking with some cracks reaching depths of 7+ feet. Bronte officials contracted government personnel to determine the causation of cracking along the dam. In March and May of 2017 students and faculty from Angelo State University assisted these government personnel to conduct resistivity surveys along the structure. Resistivity profiles were conducted using the Super Sting system from Advanced Geosciences Incorporated (AGI). Five lines were ran parallel to the dam along with two perpendicular lines. The total depth of penetration was 64 feet.

Two dimensional models were conducted using EarthImager 2D, through the courtesy of AGI, to identify structural abnormalities present. The results show areas of high resistivity, some in the shape of channels, believed to coincide with local bedrock. Thin areas of low resistivity stretch vertically into the dam, reaching depths of 32-64+ feet. Most of these areas coincide with visible cracking along the dam. However, these low resistivity areas do not coincide with every location of cracking found at the surface of the dam.

Test pits were also dug along the dam where soil samples were collected and sent for analysis. These tests revealed collapsible compressible soils are present within the structure. Overall, it appears that the cracking in the dam is a direct correlation to the presence of these aforementioned soils.