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Rainier Blvd Street Improvements
UPDATE
The Rainier Boulevard project was constructed in 2007, with installation of pervious asphalt considered a complete success. In response to an email invitation sent to many city contracts, there were many visitors including public agency staff and private consultants that observed the paving operation.
A summary of information on this project, updated to reflect experience gained, is provided below:
The Rainier Boulevard Street Improvement Project was constructed in the summer of 2007 to upgrade a 520-foot long section of badly deteriorated roadway. The new road will include two vehicle lanes with parallel parking on both sides, 5-foot sidewalk on the west side, a 12-foot multi-purpose trail/sidewalk (Rainier Trail) on the east side, undergrounding of power lines and utilities, and decorative street lights. A diagram of the road project can be viewed by clicking on the image to the right.
Project Funding
This project is funded by the City of Issaquah and a $140,000 State Department of Ecology Stormwater Low Impact Development Grant.
Low Impact Development Features
This project is noteworthy because it incorporates Low Impact Development techniques to reduce impacts of stormwater runoff. In 2006 the State Department of Ecology awarded a $140,000 Stormater Low Impact Development Grant to the City of Issaquah to incorporate LID designs into projects that were scheduled to constructed in the near term. As part of it's proposal, the City will be incorporating two LID techniques to the construction project:
Pervious Asphalt. Pervious asphalt allows rainwater to percolate through the pavement to underlying soil. This is done using a porous asphalt mixture made of pea gravel-sized rock. Extra gravel sub-base is also used. Nearly all rainfall will infiltrate into underlying soils, which is farily sandy at this location. The pavement will be durable to last many years.
Rain Gardens. A portion of existing roadway that was constructed a few years ago as part of the Rainier Bridge project will drain to two new rain gardens. A rain garden is a depressed planted area within the parking strip, where runoff can collect and infiltrate into underlying soils. The figure at the right illustrates the two rain gardens that will be constructed in this project. The City will monitor the rate of stormwater runoff from the project area to determine the effectiveness of these LID techniques. The City is also evaluating use of pervious asphalt in other projects, given its benefit towards reducing stormwater runoff.
Project Outreach
The City will hold a workshop during construction of the project, to demonstrate the installation of pervious asphalt. Anyone interested is invited. Call Kerry Ritland, Senior Water Resources Engineer, at 837-3410 (or email to kerryr@ci.issaquah.wa.us) to be placed on a list to be called when the workshop is scheduled.
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