INFILTRATION STUDIES OF MECHANICALLY ALTERED BRINE SPILL IMPACTED SOILS

Brine water contamination alters soil chemistry, soil structure and infiltration rate of many locations in West Texas. Brine contamination results in lower soil infiltration rates due to destruction of soil structure. This study was conducted at a 14-acre brine spill historic “kill zone” site on a ranch located approximately 14 km south of San Angelo, Texas. Ripping and furrowing was conducted of the site in the spring of 2016. Rips to a depth of approximately depth of 50 cm were obtained by using a single 5 cm wide chisel point and furrows were constructed to a depth of 15 cm with a single furrow drop behind a small farm tractor. The rips and furrow were implemented on the brine affected site in an attempt to loosen the soil structure, increase infiltration rates and potentially allow for remediation of the site through in-situ bioremediation. Infiltration measurements were obtained using a double-ring inflitrometer to determine if implementing rips and/or furrows allowed for higher infiltration. Preliminary infiltration tests were conducted on rips, furrows and at randomly chosen unworked locations. From this data, average infiltration rates for the rips were 4.7 cm/hr, the furrows were 2.4 cm/hr and the control sites were 5.6 cm/hr. Ripping the soil appears to increase infiltration rates in comparison to furrowing. However, the locations that had not been ripped or furrowed showed a higher infiltration rate than either the rip or the furrow. Further tests will be conducted to determine if this is a consistent result or if ripping of the soil is an ideal method of remediation. In conjunction with the use of the double-ring infiltrometer a Hobo U23 temperature sensor was used to monitor temperature fluctuations vertically in the ground during each infiltration test by driving the sensor in the annular spacing between the two rings of the infiltrometer. As water infiltrated, the upper and lower temperature sensors had about a 2.7ºC difference in temperature at a spacing of 2.5 cm and 10 cm from the surface. Temperature data was recorded in combination with infiltration data to study if there is a relationship between heat flux and infiltration rates. The goal of the temperature studies is to obtain an understanding of heat flux in the soils over time during infiltration.