Field and Laboratory Evaluation of Conjunctive Pervious Concrete and Bioretention Systems in Challenging Soil Ecosystems of Southeast Coastal Texas

In southeast coastal Texas, expansive shrink–swell vertisols limit the effectiveness of infiltration-based green infrastructures (GIs) for stormwater management. Both pervious concrete (PC) and bioretention (BR) were conjunctively deployed at Lamar University (LU) and Montrose Park (MP) to evaluate their performance. The field measurements of drawdown rates indicated that post-event evaporation enhanced the system’s effectiveness by draining the media pore spaces of PC-BR. A SWMM model was developed at LU to verify soil infiltration behavior. A total of 66 water samples have been collected in the PC-BR systems to measure levels of NH4+-N, NO2−-N, NO3−-N, TN, PO43−, and COD. The results showed that no elevated pollution was observed, and the measurements were compliant with the local river water criteria. Both systems were operated under local weather conditions, without irrigation or other human interference, and are still functioning well after 3 years. Two identical laboratory systems were fabricated to replicate the field system as zero-tension lysimeters. Laboratory testing demonstrated effective removal of nutrients, organic matter, and E. coli, with removal efficiencies generally exceeding 80% for PO43− and NH4+-N and reaching up to 95% for E. coli. These findings demonstrate that the PC-BR systems are an effective and sustainable solution for managing stormwater runoff and mitigating nutrient and bacterial pollution, particularly in regions with expansive shrink–swell vertisols and vulnerable to localized nuisance flooding.