Water Quality Analysis of Permeable and Impermeable Paver Systems

An increase in impervious surface area within a drainage basin can alter the receiving water body by increasing the quantity and velocity of runoff as well as serving as a conduit for pollutants and excess nutrients. Stormwater management options are thus often focused on improving the quality and reducing the quantity of runoff. This research compares the impact of impervious and pervious surfaces on the quality of both natural and simulated stormwater runoff, with the goal of proposing a permeable walkway system for Elon University that reduces path flooding. A 3 by 3-meter patio was built with one section of an impermeable brick design and three sections of permeable designs consisting of gravel/bricks, gravel, and grass/pavers. All sections were underlain with sand and perforated PVC piping sloping to collection vials for sampling and a concrete slab in accordance with university construction standards. Water samples were collected after natural rainfalls and simulated rainfalls via sprinkler. Simulated rainfalls were also conducted using nutrient-laden water that could represent runoff after lawn fertilization. Water quality measurements included organic carbon, nitrate, and phosphate concentrations as well as pH and turbidity. Time of concentration data reveal that permeable pavements significantly enhance runoff absorption rates. Tests with natural and simulated stormwaters will show the capacity of pervious pavements to mitigate stormwater pollution by reducing nutrient concentrations. It is essential to analyze the impact pervious pavements can have on surrounding water sources to decrease pollutants and result in healthier ecosystems.