Model Studies - Lawrence Avenue Sewer System, City of Chicago

Abstract

The Lawrence Avenue Sewer System will incorporate a large deep tunnel for temporary storage of the surface runoff that will be fed to it by a series of drop shafts placed at intervals along the axis of the tunnel. Each drop shaft will be designed to handle a variable discharge, the peak value of which will be different for each. As the volume of runoff increases, the tailwater elevation may change from zero to a maximum which is governed by overflow facilities. The objectives of the research described in this report are (a) to investigate the nature of the flow in the drop shafts, suggest an optimum design, and describe the flow patterns in the final design; and (b) to examine the surges in the overall system when it is subjected to discharges of various magnitudes and in various sequences.