The project focuses on the impact of the permeable parking lot on an environmentally sensitive area under considerable public scrutiny. We will use the parking lot as a demonstration site for conducting research on the fate and transport of automobile derived pollutants and other compounds that impact water quality (such as nutrients). The project will further serve as a vehicle for experiential learning for URI students. The study’s principal objectives are:
Intermodal
Accidental or diffuse releases of pollutants onto transportation structures such as parking lots are often transported to surface and ground water via storm water runoff threatening water quality. A porous pavement parking lot on the University of Rhode Island campus was recently constructed in an environmentally sensitive area, i.e., in close proximity to a drinking water well field. This project will investigate the possible impact of pollutants originating from the new parking on the water quality immediately beneath it. We have already installed four nested, 1 m2 water sampling stations inside the new parking lot. The sampling stations use a nested design to capture infiltrating water at both 3 ft and 5 ft levels below the parking lot surface. This unique sampling network permits not only the collection and analysis of water samples for environmentally relevant organic and inorganic compounds and properties, but it also allows for spatial and temporal contaminant mass flux studies. Beyond the timely and important research aspects, the project includes an outreach component and involves graduate and undergraduate students.
The surface of the new parking lot is permeable and allows the passage of water into the subsurface. During the construction of the parking lot, we install four nested sampling stations to catch water infiltrating below the parking surface after a precipitation event. Each station consists of two infiltration catchment and sampling components. The catchment component is a 1 m2 stainless steel box (5 cm deep). Knowing the exact dimensions of the catchment port ensures that only water infiltration from above is being captured. This is an essential requirement for correctly quantifying the vertical mass transport of pollutants. Each box is graded towards a central outlet to prevent stagnant water from accumulating. A stainless steel outlet is welded below a central opening through which the infiltrating water is gravity-feed into an adjacent 1 gal glass sampling bottle. The glass bottle and the catchment port are connected by ¼ inch Teflon® tubing that is protected by a ½ inch HPPE tube. The bottle can be accessed from the surface through an 8” diameter PVC pipe with manhole cover. The bottle will be retrieved following a rainfall event using a metal basket attached to a metal rod. The rod can be reached from the surface and the bottle in the basket can be replaced with an empty one. Thus, there is no need for entering confined spaces. The water in the bottle will be taken immediately to our nearby research labs to measure the quantity of rainfall moving through the pervious pavement and to measure the various contaminants within the infiltrating waters. Dr. Stolt’s lab will analyze for inorganic and Dr. Boving’s lab will analyze for organic contaminants
Each nested sampling station consists of a two sample ports. The first port is placed at a shallow depth, i.e., located immediately within or at the base of the gravel layer (approximately 3 feet below surface). A second port is installed about 5 feet from the surface and about 2 yards away from the upper port. The deeper sample port is buried under 2 ft. of soil and sits below a geotextile layer that marks the boundary between fill (gravel) and soil. These nested sampling ports allow for monitoring water quality at different depth levels to assess the effectiveness of the soil on pollution abatement and contaminant removal .
A total of four nested sampling stations have been installed (i.e., 8 individual sample ports). One station is located at the edge of the parking lot in an area that serves as an overflow protection. A second station was installed near the entrance/exit of the lot, i.e., in an area that is expected to see a lot of travel. A third station is located within the central portion of the parking area. The fourth sampling station is located outside the parking lot and serves as a background monitoring station.
The chemical analysis of PAH will be based on methods described in Boving (2002). Briefly, PAH compounds are extracted from the aqueous solution (liquid-liquid extraction with methylene chloride), processed through silica gel and then analyzed using a Shimadzu GC-17A gas chromatograph with flame ionization detector. Volatile petroleum hydrocarbons (e.g., toluene) will be analyzed GC/FID, too. The volatiles will be concentrated before analysis (e.g. purge-and-trap). Heavy metal (Cr, Zn, Pb, Cu) and Na concentrations will be analyzed using atomic absorption analysis (Perkin-Elmer 3300). Nitrogen and phosphorous levels will be measured using a rapid flow analyzer (Alpkem 304)or will be determined in the field with HANNA Ionspecific field meters. Biological oxygen demand (BOD) will be measured following 5 day incubations (APHA, 1995). Chloride concentration and pH will be measured using an anion probe (Orion 720A) and a combination pH electrode (Accumet pH/ATC model), respectively. Conductivity will be measured using a conductivity meter (YSI Model 33). Total suspended solids (TSS) will be measured by weight following evaporation (APHA, 1995). Climatologically data will be obtained from the URI weather station adjacent to the parking lot.
The tentative start date is September 01, 2003. Because the sample stations are already in place, sampling can begin immediately after appropriate training of the field assistants and review of the sampling protocols by outside consultants. Simultaneously, appropriate methods and standard operating procedures will be developed. Sampling and chemical analysis will be carried out over the following months. An interim report will be submitted to URI TC 6 months after the start date. A final written and oral report to US DOT personnel and/or URITC will be submitted by the end of the funding period (August 30, 2004).
$120,174.00 ($120,174.00 Yearly)
One graduate student (Tution, salary, and fees) will be funded for one academic year. One (undergraduate) student will be hired to work part time on the project.
A literature search of the Transportation Research Board Data Base confirmed that currently no study such as the one proposed herein has been publicized. According to Cahill Environmental Associates (Dan Wible, personal communications), a research project is under way at the Penn State University's Visitor Center, where the performance of a porous pavement/recharge bed system is investigated and monitored since its completion two years ago. A second project at Villanova University is only in its early stages. At the Villanova site a porous concrete plaza with subsurface infiltration located between two dorm buildings is investigated.
Thus, the realization of this project would significantly contribute to the understanding of fate and transport of pollutants below a porous pavement parking lot – especially near a drinking-water well field. The expected results will have important implications for scientist, regulators, and professional in the area of transportation and pollution control. It will help decision makers nationwide to form an educated argument either for or against this type of BMP and should increase the public awareness about environmental efforts in the transportation community.
Over the project duration, periodic status reports will be submitted in accordance with URI TC reporting requirements. At the conclusion of the project, the major findings will be presented to US DOT and/or URITC Research & Development Advisory Committee in written (i.e., final report) and oral format. Ideally, we would like to submit a paper outlining the results of this study to a peer-reviewed journal, internationally distributed such as Journal of Environmental Engineering, and to present the results at a national or international conference.
The results of this study will contribute to the understanding of fate and transport of aqueous contaminants associated with transportation structures. This study’s’ outcome may affect or benefit ongoing research projects and efforts in the area of water quality management and pollution control. As the steward of most roadways and support structures, the Department of Transportation has an interest maintaining a transport system that has minimal impact on the environment. Therefore, this research project should be of interest to the Department of Transportation.
The proposed field experiments will be organized in close cooperation with BETA Group INC. Periodic meetings will facilitate information exchange between all groups involved in this study. These meeting will serve to communicate preliminary results and coordinate future efforts. At the conclusion of this project, the major findings of this study will be summarized in a report. Pending on the quality of the results, it is further planned to submit a paper to a peer reviewed journal, such as Environmental Science and Technology, and to present the results at a national conference.
Permeable structures, roadway runoff, BMP, water quality, contaminants