Dr. Brad Wilcox from the Department of Ecology and Conservation Biology at Texas A&M University gave a presentation on the potential for enhancing recharge in the Carrizo Wilcox Aquifer at the Board’s monthly meeting May 11, 2020. The presentation entitled “Potential for Increasing Recharge in the Post Oak Savannah Ecoregion” outlined a study Dr. Wilcox and PhD student Shishir Basant have been working on in Milam County over the recharge area of the Carrizo Wilcox aqufer. They were studying the effects of brush clearing to increase the potential for recharge into the aquifers by restoring the land to true savannahs.
The Board of Directors funded a grant of $30,000 to study the contrasts in recharge amounts in the different types of land cover. The study took place on property south of Cameron in the central Milam County which is in the outcrop of the Carrizo Wilcox aquifer. Studies have shown there has been an intensive change in the landscape of this area of Texas from rangelands to forested areas and shrub lands. This change aligns exactly with the recharge area of the Carrizo Wilcox. This change is due to several factors including new farming practices, fewer fires that would reduce the brush, and other factors that have caused the landcover to change from a true savannah with rangelands to thicketized woodland with post oak, yaupon and eastern red cedar.
By managing vegetation landowners can increase groundwater recharge. Trees and woody areas reduce recharge because of transpiration by the plants keeping that water from reaching the aquifer.
Dr. Wilcox’s team used specialized moisture measuring tools along with taking core samples to measure the recharge rates. Another method used to estimate the amount of water moving through the soil is to determine the amount of chloride at different depths. The chloride in the atmosphere gets absorbed into the soil. By measuring the variation of chloride at different depths from the pasture’s areas and the woodlands, we can estimate the recharge rates. These studies show that the amount of recharge is greater in the pastures than in the woodlands.
These studies could lead to grants awarded to local landowners to reduce the woodlands and restore the area back to true savannahs to increase the recharge to our aquifers. To see the entire program, go to www.vimeo.com/5484736929 or our website www.posgcd.org/agendas-minutes/posgcd-agendas-minutes/