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HomeMy WebLinkAboutDrainage Report HESIGHT E inCERmn IINVIAOMMENTAL GIMPS 6 CONSULTANTS PROJECT DRAINAGE REPORT PROPOSED PARKING LOT EXPANSION FOR 9896 MICHIGAN ROAD, LLC (ED MARTIN PONTIAC) 9896 Michigan Road Carmel, IN PROJECT NARRATIVE This project consists of adding a 0.84 -acres of parking area to the existing facility once owned by Chrysler Reality. This site was improved per design plans approved in 2001, however the site was never occupied. The existing improvements include a building with a showroom, service area and offices, parking area for employees, customers and new /used cars, drainage infrastructure including expansion of an existing pond, installation of a storm water lift station, and landscaping per the approved plans. The proposed improvement area will conform to the existing site regarding lighting, landscaping and existing features. The disturbed area of this improvement is 0.95- acres. EXISTING DRAINAGE PATTERN Existing parking area is drained by storm water infrastructure which outlets to an existing shared retention pond at the southwest corner of the site. The existing pond outlets to the east to a storm water lift station which pumps into the Michigan Road storm water infrastructure. The area of current improvement is made up of grasses and sheet drains to the pond and 99 Street. PROPOSED DRAINAGE CONFIGURATION According to the engineer of the approved 2001 plans the retention pond was sized to handle the expansion of the parking lot. Calculations were done to verify the size of the pond. The 100 year storm event was found to reach an elevation off 883.80 in the existing pond which is below the top of bank. The proposed parking lot expansion will be "bowled" with a grate inlet at the low spot. The inlet will drain to the existing pond via a 12 -inch RCP. A proposed emergency outflow pipe was placed at 885.0 along the pond and connected to the existing infrastructure along 99 Street. Said pipe will act as a relif system for the lift station should problems occur. SUMMARY The proposed development does not increase the runoff discharge beyond the capabilities of the existing pond. Therefore this development will not adversely affect any upstream or downstream properties or drainage systems. M rk A. Settlemyre Professional Land Surveyor Tel 317-859-5000 Fax 317 -881 -0885 No. LS20200044, State of Indiana 1 E -Mail Foresite @indy.net 8404 5iear Terrace, Suite 100 Indianapolis, Indiana 46227