Ada County Highway District

Downtown Alley Paver Projects

General Description:

Starting at the end of June, crews will retrofit the alley behind 5th and 6th streets (just north of Idaho Street) in Downtown Boise with permeable pavers. The pavers will help eliminate standing water, and clean the rain and snow melt. The result is less polluted runoff going into the Boise River.

Crews have completed the alley on the north side of Idaho Mountain Touring. Check out the before and after pictures below.







The alley projects are part of ACHD's green infrastructure program. ACHD has been actively exploring green infrastructure as an effective tool for managing water drainage from Ada County’s roadways. Instead of piping and treating stormwater in a centralized storm drain pond, the water quality and volume is managed through landscape features. Green infrastructure is cost effective, mimics natural conditions, improves water quality, and provides enhanced neighborhood beauty. ACHD is experimenting with bioswales and native plants, and recently completed a project on 36th Street in Garden City with permeable pavers.

How do permeable pavers work?

  1. Rainwater drains thru the cracks between pavers and soaks into the ground.
  2. The gravel between the pavers filters silt, pollutants and debris.

This system reduces runoff and eliminates standing water.Which means less pollution into the Boise River!

What will the alleys look like when the projects are completed?


High-Albedo-Concrete-and-High-Albedo-Permeable-Concrete-Trench.gif  LID_Locations-069.gif
The two Boise alleys will look similar to this example, only with permeable pavers in the center instead of pavement. Close up of permeable pavers used on 36th Street in Garden City

Before and After Photos

Below are photos (courtesy of the City of Chicago) showing an alley before and after permeable paver installation.


DSCF4259SM.gif Permeable-Paver-Alley.gif

Learn more!


Time Frame

Start Date:
June 2015
End Date:
Fall 2015

We Drive Quality Transportation For All Ada County ~

Ada County Highway District © 2017
For Questions or problems with this Web site contact the Webmaster