The METRO Blue Line Extension will provide transit improvements in the highly traveled northwest area of the Twin Cities. The Blue Line Extension will operate northwest from downtown Minneapolis through north Minneapolis, Golden Valley, Robbinsdale, Crystal, and Brooklyn Park. The proposed alignment is primarily at-grade and is about 13 miles of double track. It will have up to 11 new stations in addition to Target Field Station. The line will connect to the METRO Blue Line and METRO Green Line, the future METRO Green Line Extension, BRT on the METRO Red Line, the Northstar commuter rail line, and local and express bus routes.
As part of the BLRT Design Team, SRF is leading the water resource design and permitting, structural engineering, travel demand forecasting, and trail planning and design effort for the 13.5-mile corridor in addition to assisting with the design of the LRT guideway and site civil, roadways, utility relocation and design, traffic engineering for signals, traffic simulation, and transit signal priority.
Water Resources. SRF also led water resources design, which included:
- Design of stormwater management BMPs that met regulatory requirements and fit within the limited right-of-way. BMPs including bioretention basins, tree trenches, infiltration basins, wet sedimentation ponds, and underground detention systems.
- Detailed hydrologic and hydraulic analysis of the existing stormwater systems that are impacted by or cross the LRT corridor.
- Floodplain mitigation within the Shingle Creek and Bassett Creek floodplains.
- Hydraulic design of multiple new or reconstructed bridge crossings.
We engaged stormwater regulators at the municipal, state, and watershed level to create a water resources design framework and facilitate the review and approval process. This coordination continued during design where strategies for mitigating project impacts to water resources were discussed, including floodplain and mitigation areas, the realignment of a portion of Bassett Creek to maintain adequate conveyance as demonstrated through HEC-RAS modeling, and stormwater treatment facilities.