
This project was a renovation and expansion adding 300 new parking stalls in a newly acquired parcel to the west of the existing dealership. The project increased their lot from 600 to 900 stalls. The new design included incorporation of stormwater management to meet the local watershed’s requirements and site design to accommodate additional parking stalls that work with the existing vehicle circulation without impact to the adjacent wetlands. In addition, the landscape design required incorporation of the City ordinance while maintaining proper circulation of the lot to maximize parking. The main design concern was integrating the requirements of the watershed district without disturbance of the wetland. To meet the volume control requirements, the lot had to be raised to get the proper infiltration basin depth above the groundwater level. Steve Johnston worked with the watershed district to come up with a solution of utilizing the wetland buffer to provide the area for pretreatment of the stormwater before it entered the stormwater BMP and ultimately the wetland. Due to raising the grade, the site had to be designed to sheet flow to the infiltration basin as there wasn’t enough depth to accommodate traditional conveyance in pipes.