Hermitage Inflow + Infiltration Reduction

Within the Deer Creek Watershed in the City of Frontenac, stormwater enters and overloads the sanitary sewer system causing water backups in basements, yards and streets during heavy rains.  The Metropolitan St. Louis Sewer District enlisted Oates Associates to investigate / identify potential infiltration sources and prepare plans to remove this flow from the system to alleviate sanitary sewer surcharges and overflows.

Oates Associates performed private inflow and infiltration (I/I) reduction evaluations and field investigations on 74 properties – identifying improper sanitary sewer connections.  Examples of storm connections to the sanitary sewer include roof downspouts, driveway drains, area drains, sump pumps, and broken or vented clean outs.  Oates representatives met with the owners of these properties to inspect the suspected defects.  The next phase included negotiating with the 48 properties owners with confirmed defects to obtain signed releases to complete the necessary repairs.  38 releases were successfully negotiated.

Oates designed improvements to reduce storm water flow into the sanitary sewers.  The scope consists of rehabilitating or replacing over 13,000 feet of 8 to 36-inch diameter sewers and 148 manholes.