Geophysical Mapping of Lost Historical Sites: Brenham, TX

Abstract

Brenham, Texas has an interesting past that may surprise some of its residents. This past is discoverable through the use of geophysical methods. The site in question is owned by Blue Bell Creameries and is located on South Chappell Hill Street. An old distillery is believed to have been built on this site and may be the first of its kind in Texas. To accurately identify the location of the historic building, multiple geophysical methods were used. The Magnetometer (MAG) measured any magnetic objects in the soil. Electromagnetic Induction (EMI) measured the apparent conductivity of the soil and sub-surface objects. Ground Penetrating Radar (GPR) recorded any relative dielectric permeability contrasts in the subsurface. Each of these techniques has drawbacks when used separately, but when combined these three methods provided a more complete picture of the sub-surface. MAG, EMI, and GPR all showed significant anomalies throughout the survey area. To combine the three methods, each technique’s results were both qualitatively and quantitatively analyzed together. EMI and GPR were seen to correlate the best, showing significant sub-surface structures warranting further examination. Findings from future studies could be significant as the community’s economy thrives on historical tourism.