Managing Airfield Stormwater
Airport Master Drainage Study
Crawford, Murphy & Tilly (CMT) was given the responsibility to complete the study, based on our familiarity with the airport and our talented team of drainage professionals. The comprehensive study of existing site conditions included an inventory of drainage facilities, floodplains and wetlands, extensive modeling of storm sewer and floodplain, a geotechnical investigation program and an identification of known drainage issues. The Airport Layout Plan (ALP) was evaluated to identify impacts to the existing drainage system, quantify the amount of required stormwater detention and assess the feasibility of these stormwater improvements in an aviation environment. CMT collaborated with QCIA and Rock Island County, the local stormwater permitting agency, to develop a fee-in-lieu stormwater detention agreement that allows future development to comply with the County Stormwater Ordinance without constructing detention basins that would attract wildlife.
Additional key outcomes from the study included a determination of an airport base-flood elevation that will serve as the basis for flood protection for future development, recommended projects intended to reduce open water wildlife attractants, and suggested actions for responding to future regulatory standard updates.