The traditional approach to drainage and stormwater management along transportation corridors is to collect runoff as quickly as possible using concrete inlets that convey the water through pipes to large, costly detention basins. Additionally, if water quality was considered polluted, it required costly and ineffective structural systems like hydrodynamic separators.
Fortunately, transportation agencies are evolving beyond the traditional approaches to incorporate green stormwater management strategies.
For example, stormwater can be managed and treated at the source by incorporating vegetation and pervious soils along the transportation corridor to promote filtration and infiltration. Water quality can be addressed by lining the transportation corridor with bioswales, vegetated filter strips, planter boxes and rain gardens. Water can be conveyed in vegetated swales instead of pipes, and runoff can be reduced by using bioretention ponds.
All of this results in high water quality, greater groundwater recharge, decreased runoff and reduced flooding. As a bonus, it also provides the public with a beautiful open space to enjoy. WSP is designing green streets like these across the country to help clients revitalize the quality of life in their cities and regions. In Southern California, the firm partnered the County of San Diego to develop its Green Streets Guidelines, which establishes standard designs for over 50 stormwater capture best management practices and provides an opportunity to manage significant storm water and pollutant sources through natural treatment.
Additionally, using strips of vegetation along transportation corridors, communities are implementing “pollinator paths” by planting native flowers. Pollinator paths provide continuous habitat and food for pollinator species, allowing them to safely traverse urban landscapes.
The ability to solve infrastructure challenges with strategies that emphasize ecosystem restoration speaks to the heart of WSP’s core values of sustainability, equitable community resilience, and health and wellbeing. The utility of infrastructure and promotion of natural services need not be mutually exclusive; indeed, infrastructure development provides one of the most compelling opportunities to advance environmental stewardship.
WSP’s Jennifer Brunton, Jessica Field, Katherine Herleman, Keith Kooistra, Matthew Lunemann and Scott Thompson contributed to this article.
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