August 2015 to October 2015
The site of QuikTrip's new store at the southeast corner of 45 Highway and 9 Highway in Parkville, Missouri, drained to three different watersheds, including the water quality-challenged Riss Lake. Both QuikTrip and the City of Parkville wanted to divert runoff to the drainage basin west of 9 Highway through the existing PAC Detention Pond. Water Resources Solutions analyzed the hydrology for the proposed drainage scenario and made recommendations on the retrofit of existing structures and the construction of new structures so peak flow rates downstream of the PAC Detention Pond were not increased.
The proposed and existing flows were based on the SCS Curve Number method. The proposed flows from QuikTrip were routed to the existing basin using EPA SWMM. The detention basin was analyzed with the Hydraulic Engineering Centers Hydraulic Modeling System (HEC-HMS). Once proposed flows were determined and routed to the exiting basin, it was determined that minor modifications to the outlet works would be sufficient to maintain peak flow rates downstream while still containing the 100-year storm event.