The project site is located on J Street between N 16th Avenue and N 20th Avenue in Yakima, Washington.
Why J Street?
Prior to construction this street was a 650-foot section of aging road surface with a roadside ditch on the south side. The average daily traffic count is relatively low at 1120. Most traffic is industrial use and the site is on a city bus route.
The project consisted of placing 3 types of pervious pavements (porous asphalt, porous concrete, permeable pavers) in the north lane of the existing road. A filter layer of crushed stone or sand was included under the pervious layer. A plastic liner and a system of underdrains were placed below the crushed stone and sand to collect runoff and direct it to collection vaults and then into infiltration trenches.
The south lane was paved with conventional impervious asphalt and curbed to provide a control for the test sections. Curb cuts provide a sampling location and direct runoff from the impervious lane to a series of bioswales with 0%, 5%, and 10% amended organic compost.
The pervious pavements and swale amendments will be duplicated to provide sampling replicates, resulting in 2-1,625-square-foot sample surfaces per pervious pavement type. Each swale is approximately 108 feet long and receive and treat runoff from 1,625 square feet of conventional asphalt.