The Kansas Star Casino development, just south of Wichita, covers 206 acres including a 162,500-square-foot casino with hotel, parking lots and equestrian facilities. Site drainage design was a challenge as a result of multiple adjacent watersheds, downstream flow restrictions and shallow groundwater that had a history of causing problems within an adjacent residential development.
We resolved the problematic drainage by using a combination of strategically located drainage swales, a 37-acre dry-bottom detention facility (120 percent of 100-year event), and an 11,200 gallons-per-minute maximum discharge pump station to drain the detention area. The detention area and swales are sealed with a clay liner to prevent stormwater from charging the aquifer and increasing the groundwater table elevation. Native plant materials were carefully selected for the ability to thrive in periods of drought or inundation creating a site amenity.
The pump station is equipped with three submersible axial flow pumps. The lead pump operates during smaller rain events, and a lag pump starts automatically based on the water level in the wetwell. Two pumps achieve maximum capacity and a third provides back-up. This overall solution allowed the project to detain more water than the pre developed site, while releasing it at a slower rate.