Water runoff from highways carries pollutants which can cause serious damage to the local environment. The Texas Department of Transportation (TxDOT) formulated a plan in 2003 that would use different best managing practices (BMP) to counteract the effects of runoff. However, this plan did not involve bioretention, a BMP that uses plant fibers and engineered soil to absorb pollutants and requires minimum maintenance. Bioretention is a proven method in the removal of pollutants, but bioretention tests have only been performed in the northern states or in Australia, where the climate and soil types are different than those found in Texas. Texas A&M Transportation Institute (TTI) researchers performed a bioretention study to develop a plan for use in TxDOT districts, running tests on the effectiveness of bioretention both in a laboratory and in a real-world scenario. Along with testing different soil and plant types, researchers looked at how internal water storage (IWS) affects bioretention. Including IWS in the bioretention plan can provide a constant source of water during hot Texas summers and decrease the stress plant roots undergo during droughts. After the tests, researchers recommended increasing the drainage area to increase pollutant removal. Read the Featured Project Page…