Frederick Farm Well Contamination: Borehole Camera Analysis of Bedrock Structure

Abstract

A borehole camera analysis was conducted at the Frederick Farm to characterize bedrock structure, quantify fractures, and establish the condition of the well casing. Through the use of a GeoVISION Jr.™ and recording equipment, footage of the camera decent was recorded for data analysis. The 5 ft well casing appeared intact and was properly constructed within bedrock. The well above the water table contained few fractures and appeared to be weathered. Flowing water was visible in the two main fractures, located on the south (5.5 ft depth) and south-western (13.5 ft depth) walls of the well respectively. The water table interface was observed at 31.125 ft depth. Below the water table the well was laden with many fractures. The size of the fractures appear to increase in size with depth, with the larger fractures approaching ~1 ft in thickness. Also noted in this interval were areas of enhanced chemical weathering, particularly below 62.5 ft. The bedrock fracture profile is indicative of a well built within heavily fractured karstic limestone.