ASLA Students participate in SPARKcon

Several students from the NC State Chapter of ASLA were downtown this past weekend as part of the sparkCon festivities.  The students gathered the materials to install a “mock bio-retention cell” at the corner of Davie and Fayetteville Streets on Friday and Saturday.  The genesis of the idea came from the national parking day, which is an annual worldwide event that encourages people to take up metered parking spaces and convert them into temporary parks for the public good.

In a traditional street design, water sheet flows off parking lots and road surfaces, is graded to the side of the road and downhill until it reaches a drain.  From there water continues downhill until it is release into a waterway.  In Raleigh’s case, that would be one of the tributaries of the Neuse River.

Curb extension planters are one component in the designer’s toolkit to ameliorate the impact of impervious surface on stormwater runoff in urban areas.  If a street is retrofitted, the vehicular lanes could be narrowed to allow for plantings and speed reduction, and two “curb-cuts” allow water in on the uphill side and out on the downhill side.  Soil in the planter can absorb water and chemical reactions specific plant species can bind up chemicals and particulate matter that flows off the asphalt.