Xcel Energy Centre Point Facility
Roseville, MN

Larson Engineering designed the reconstruction of the employee parking lot, stormwater treatment systems and drainage improvements.

Two biofiltration basins collect roof rainwater and an underground storage chamber collects parking lot runoff. The underground treatment system consists of 20 prefabricated chambers embedded in an aggregate trench, overlaying a sand section with an outlet drain. Each system provides stormwater treatment, detention and rate control. Larson Engineering also assisted facility managers with preliminary design and coordination of construction staging. Construction phasing exhibits were prepared and communicated to site staff and contractors, mitigating disruption to facility operations and providing cost savings by means of reusing on site materials.

Reconstruction of the pavement section included removing and recycling the existing degraded asphalt pavement and replacing with new bituminous over the recycled aggregate base material. After reclaiming and stockpiling the salvaged material, a new granular sub-base section was installed over a drain tile system atop soil separation fabric. The drain tile configuration was designed to efficiently collect and route water to the existing catch basins and ultimately the underground chambers.