The project entailed determination of the additional retention volumes required by the addition and the site improvements. The TR-20 program was utilized to determine the pre- and post-development rainfall rates for the new site work. The detention volumes were determined by through a storage / discharge program utilizing the pre- and post-development rainfall rates determined from the TR-20. It was determined that a site amenity would be constructed for the detention volumes, so a retention pond was designed to store the detention volumes above the normal water level of the pond. TERRA coordinated all work with the landscape architect to provide an aesthetically pleasing site amenity as well as providing the required storage for detention.
The project included two new parking areas, driveways, a helipad and drop-off areas. In addition to the drainage requirements, TERRA designed the site utility connections, parking lot grading and dimension control, roadway cross-sections, site details and specifications. TERRA worked closely with the City of Joliet to obtain permits for the site work.
Perkins + Will