Summary of Specifications:
INTRODUCTION: Through this Request for Bids (RFB), the Wayne County Airport Authority (Airport Authority) hereby invites businesses that meet the qualifications set forth herein to submit Bids for the construction of a Flow Control Structure to be built at Detroit Metropolitan Wayne County Airport (DTW) between Storm water Detention Ponds 3E and 4. This structure will serve to regulate flows between Storm water Detention Ponds 3E and 4. GENERAL INFORMATION: Storm water at DTW is collected in network of underground pipes that flow to a series of pump stations that lift these flows into one of four (4) large detention ponds. The ponds are discharged to surface waters near DTW in accordance with National Pollution Discharge Elimination System Permit No. MI 0036846. Two (2) of these four (4) ponds (3E and 4) are connected by underground culverts that allow water to flow between the two ponds. For the past several years, balloons have been installed in the late spring on the Pond 3E side of the culverts, to prevent water from flowing to Pond 4. This allows Pond 4 to completely drain, which discourages birds and other wildlife from congregating on and near this pond. The balloons have been effective, however, water leaks have been observed flowing around the balloons and the balloons are cumbersome to handle and difficult to deflate/inflate during intense runoff events. The Authority intends to build a permanent structure on the Pond 3E side of the culvers to improve the functionality of managing water flowing between Ponds 3E and 4. The structure will be built based on plans and construction documents provided by the Authority and included in this RFB. This structure will be composed of a concrete berm with an embedded sluicegate that can be manually opened or closed, allowing water to flow between the two ponds. With the sluicegate closed, the structure will prevent water from flowing between the two ponds when the ponds are less than approximately 50% full, but will allow water to overflow from Pond 3E to Pond 4 during intense runoff events.
