The North Detention Basin was expanded to accommodate North Airfield Improvements as part of the O’Hare Modernization Program Completion Phase. Trunk Sewer System D was constructed to convey runoff from the proposed Northeast Cargo Development. The North Detention Basin Expansion (NDBE) consists of removal of the existing concrete divider wall between Area D and the South Winter Basin (SWB), removal of the existing earthen berm separating the North Winter Basin (NWB) and the SWB, removal of existing pavement, utilities, storm sewer piping and headwalls within the impacted areas, removal of existing flow control structure, and partial demolition of existing North Airfield Stormwater Pump Station (NASPS). The total overall detention basin storage volume expanded to 736 ac-ft from the existing 492 ac-ft. NDBE improvements included an articulated concrete block revetment mat system, a spillway structure, underdrain, erosion control, guardrail, and a bituminous access roadway with concrete curb and gutter. The construction of Trunk Sewer System D consisted of the installation of 1,093 lineal feet of 108″ RCP. Approximately 87 lineal feet of RCP were open cut and the remaining 1,006 lineal feet of RCP were jack and bored.