The phase two design provides a system of distributed storage facilities at key points in the 375 acre watershed to reduce combined sewer overflows at Outfall 069 in the Marlborough neighborhood. For phase three, the preliminary design and basis of design report provides a system of distributed storage facilities at key points in the 375 acre watershed to reduce combined sewer overflows at Outfall 069 in the Marlborough neighborhood.
The primary objective of the design is to show a reduced frequency of overflows of the combined sewer system to not more than six events in a typical year. Currently, the overflow frequency at these outfalls is more than 36 times per year. Only rainfall events in excess of the design storm are allowed to overflow the two outfalls. To accomplish the primary goal, a system of distributed storage measures was designed to store and attenuate stormwater runoff. Target Green East Marlborough Phase 2 includes a combination of larger regional green infrastructure solutions, and small distributed green infrastructure solutions. Approximately 130 acres of stormwater is being directed to green infrastructure facilities before entering the existing combined sewer system. The green infrastructure is enhancing public spaces and surrounding community.
Arleta Park is a large-scale storage facility with conveyance methods necessary to convey runoff to Arleta Park. Improvements within the park include cascading rain gardens, centralized bioretention basin, an extended detention basin and precast pretreatment chambers. The design of Arleta Park enhances the existing park aesthetics and function, incorporating cascading rain gardens, bio-swales and bioretention facilities. New walkways provide wanted improved connectivity and access to park amenities to the residents within the community.
On the north end of the neighborhood improvements to 74th Street from the Paseo to Prospect provides approximately 16 right-of-way bioretention cells, two cascading rain gardens, eight underground detention pipe storage, two underground infiltration storage cells, and two precast pretreatment chambers. The project has improved east-west connectivity for the Marlborough community. The green infrastructure improvements will be decentralized within the existing right-of-way. These improvements will supplement the volume of stormwater capture to reduce overflows at the outfall.
City of Kansas City, Missouri, Water Services Department
Kansas City, Missouri
Scope of Work
Stormwater volume detention
Green infrastructure design
Public relations outreach
The primary objective of the design is to show a reduced frequency of overflows of the combined sewer system to not more than seven events in a typical year. Approximately 70,000 square feet of green infrastructure storage was designed to provide 68,000 cubic feet of storage volume. A total of 44 green and gray structures will be built to capture almost 1.0 million gallons of wet weather runoff. As required in the consent decree, these improvements will result in 7 or fewer overflows at Outfall 069 during a typical year.
Rachel Morado Gardens is a large-scale storage facility with park-like attributes. The green infrastructure within the site includes pretreatment chambers, level spreaders, rain gardens and extended detention facilities to capture, treat and detain stormwater before entering into the combined sewer system. Green infrastructure captures stormwater runoff from streets and lawns and routes the flow to dense vegetation to encourage pollutants to settle and flow to infiltrate through the soils to reduce volume of water directed to Outfall 069.
In addition to reducing overflows, Rachel Moardo is the central node of the Marlborough neighborhood, connecting a north/south boulevard with well-trafficked east/west thoroughfare and the lower Middle Blue basin with upper basin. The Rachel Morado site is ideally located for a physical neighborhood resource asccesible to all. The Paseo Boulevard is a historic boulevard with large trees lining the street. Green infrastructure was designed along the boulevard to route flow to the Rachel Morado Gardens. Shallow sod-turfed swales were designed for ease of maintenance, and rain gardens were designed at the intersections. The rain garden design had to keep with the historic boulevard design standards, so traditional plantings along with native plantings were incorporated to tie all the amenities together.