Development of a Monitoring Program for a Porous Concrete BMP

Abstract

A conventional concrete and asphalt pedestrian area in the center of Villanova University’s campus was recently voluntarily retrofitted with an infiltration BMP. The conventional materials were removed and replaced with porous concrete underlain by stormwater recharge beds. To date, infiltrated water from infiltration BMPs has not the subject of much study. The development of this monitoring program will be the focus of this paper. This site has been instrumented to measure the effectiveness of this BMP, and specifically, to track the change in water quality and quantity as the water infiltrates into the soil. A series of electronic moisture meters and suction lysimeters have been placed both under the recharge beds and along the side of the recharge beds. The information gathered from the instrumentation alongside the beds will be used as a “control” to compare to the results obtained from the instrumentation under the beds. Background Urbanization and the resulting increase in urban storm water over the past few decades have led to an increase in runoff and pollution. This increase directly affects the surrounding rivers and streams, with impacts such as increased stream bank erosion, decreased water quality, and decreased base flow as areas become less and less pervious. Studies show this increase in urban storm water is a leading contributor of non-point source pollution (Paul and Meyer 2001). Such discoveries have led to a demand for innovative practices that will discourage future stream water degradation and help deal with, and possibly reverse, some of the damage already done. This demand is becoming more recognized, and as a result, such technologies are emerging. Many of these technologies are emerging in the form of best management practices (BMP). BMPs use innovative processes to help minimize adverse effects of urbanization. One of the problems with the BMPs is the lack of documented research displaying their effectiveness, especially storm water infiltration BMPs. The National Stormwater Best Management Practice Database has taken the first steps in dealing with this issue and is pioneering the way in collecting and reviewing numerous documented uses of BMPs (http://www.bmpdatabase.org/). The database is broken into two categories, structural and non-structural. The non-structural BMP database contains a total of 28 BMPs consisting solely of maintenance practice type BMPs. The structural component totals 170 BMPs ranging from biofilters to detention basins to hydrodynamic devices. Of the 170 structural BMPs contained in the database, only five document test sites that utilized porous pavement. Furthermore, within this group of five, only one of these test sites used a concrete based porous pavement. The need