HR: 0830h
AN: H21D-05    [Abstracts]
TI: Assessment of porous asphalt pavement performance: hydraulics and water quality
AU: * Briggs, J F
EM: briggs@unh.edu
AF: Center for Stormwater Technology Evaluation and Verification, University of New Hampshire 35 Colovos Road, Durham, NH 03824 United States
AU: Ballestero, T P
EM: tom.ballestero@unh.edu
AF: Center for Stormwater Technology Evaluation and Verification, University of New Hampshire 35 Colovos Road, Durham, NH 03824 United States
AU: Roseen, R M
EM: robert.roseen@unh.edu
AF: Center for Stormwater Technology Evaluation and Verification, University of New Hampshire 35 Colovos Road, Durham, NH 03824 United States
AU: Houle, J J
EM: james.houle@unh.edu
AF: Center for Stormwater Technology Evaluation and Verification, University of New Hampshire 35 Colovos Road, Durham, NH 03824 United States
AB: The objective of this study is to focus on the water quality treatment and hydraulic performance of a porous asphalt pavement parking lot in Durham, New Hampshire. The site was constructed in October 2004 to assess the suitability of porous asphalt pavement for stormwater management in cold climates. The facility consists of a 4-inch asphalt open-graded friction course layer overlying a high porosity sand and gravel base. This base serves as a storage reservoir in-between storms that can slowly infiltrate groundwater. Details on the design, construction, and cost of the facility will be presented. The porous asphalt pavements is qualitatively monitored for signs of distress, especially those due to cold climate stresses like plowing, sanding, salting, and freeze-thaw cycles. Life cycle predictions are discussed. Surface infiltration rates are measured with a constant head device built specifically to test high infiltration capacity pavements. The test measures infiltration rates in a single 4-inch diameter column temporarily sealed to the pavement at its base. A surface inundation test, as described by Bean, is also conducted as a basis for comparison of results (Bean, 2004). These tests assess infiltration rates soon after installation, throughout the winter, during snowmelt, after a winter of salting, sanding, and plowing, and after vacuuming in the spring. Frost penetration into the subsurface reservoir is monitored with a frost gauge. Hydrologic effects of the system are evaluated. Water levels are monitored in the facility and in surrounding wells with continuously logging pressure transducers. The 6-inch underdrain pipe that conveys excess water in the subsurface reservoir to a riprap pad is also continuously monitored for flow. Since porous asphalt pavement systems infiltrate surface water into the subsurface, it is important to assess whether water quality treatment performance in the subsurface reservoir is adequate. The assumed influent water quality is derived from that which is entering the stormwater treatment system in the adjacent parking lot. Since the facility is new, parking has been less intensive here, and influent concentrations will be adjusted down accordingly. Several wells have been installed in and around the facility. Screened intervals are at two levels; in the reservoir and beneath the facility. One well in the facility is continually monitored for basic water quality parameters (temperature, specific conductivity, pH, dissolved oxygen) and level, and is also sampled with an automated refrigerated sampler. Grab samples are collected from the other wells as a basis for comparison. Water samples are collected during several storm events and during interstorm periods to assess water quality treatment performance. The samples are analyzed for nutrients, metals, petroleum hydrocarbons, and pathogens. The potential for leaching of pollutants from the asphalt binder will also be assessed during these storm events. Water quality treatment performance is compared to those of several other studies. Updates on spring 2005 data are also included in the presentation.
UR: http://www.unh.edu/erg/cstev/
DE: 1823 Frozen ground
DE: 1829 Groundwater hydrology
DE: 1863 Snow and ice (1827)
DE: 1871 Surface water quality
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2005 Joint Assembly