Technical Description:
(8) Filterra® - Internal Bypass Curb, Street Tree configuration.
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The North 1st Street Revitalization Project includes three phases spread out over several years. The project is intended to improve safety for drivers and pedestrians and increase economic development of the North 1st Street corridor, one of the main entrances to the City of Yakima. The project will also improve the underground infrastructure, which is over 100 years old.
Phase 1 was completed in December 2019. Construction of Phase 2 started in April 2021 and included new stormwater treatment BMPs to meet most current Washington Department Ecology Stormwater Regulations.
The City’s stormwater regulations prohibit increases in
offsite flows from site-related drainage. In addition, engineers needed a
solution to ensure compliance with water quality requirements. The limited
footprint was also a concern. Engineers specified eight 6’ x 4’ Filterra
Internal Bypass Curb, Street Tree configuration bioretention systems to meet
these requirements. The Filterra systems were the first of their kind installed
on the West Coast. The Internal Bypass Curb configuration incorporates a curb
inlet treatment chamber and internal high-flow bypass in a single structure,
eliminating the need for a separate bypass structure.
The Filterra Street Tree configuration incorporates knockouts in the containment structure to allow for the planting of trees with more extensive root systems. The Filterra’s were planted with Ruby Sunset Acer’s, a tree with a mature height of 25’ and a spread of 20’.
Filterra provided everything the City needed; regulatory compliance, a 100”/hr treatment rate, a small footprint, and the ability to blend in with the overall project.
“The Contech Filterra biofiltration unit was the perfect solution to the City of Yakima’s stormwater problem of needing stormwater treatment with a small footprint that provided a large treatment capacity,” said Terry Alapeteri, Principal of HLA Engineering. “It was a bonus for the City to choose a street tree with the Filterra unit that fit in seamlessly with the other amenities included in the downtown revitalization project.”
Total Site Services installed the Filterra systems. When the sites were stabilized, a Contech Certified Maintenance Provider activated the systems by installing the trees and conducting a final inspection. Contech also provided the City’s operations staff inspection and maintenance training of the Filterra systems to ensure they function as designed for years to come.
“It was important to the design team to maintain the street tree aesthetic along North 1st Street, using the same size of trees there were specified for typical tree grate planters,” said Aaron Luoma, Principal of HBB Landscape Architecture. “The Filterra Street Tree worked well to maintain a consistent appearance along the corridor, utilizing the openings for future root growth and unique underground straps within the units.”
Technical Description:
(8) Filterra® - Internal Bypass Curb, Street Tree configuration.
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