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Drop Structures across (and under) the United States of America

Author(s): Rob Ettema; Troy Lyons; Dominque Brocard; Sean Mulligan

Linked Author(s): Troy Lyons, Sean Mulligan, Robert Ettema

Keywords: IAHR; Hydrolink; Drop Structures; combined sewer overflows (CSOs); US examples; Rob Ettema; Troy Lyons; Dominque Brocard; Sean Mulligan


Across (and under) the United States of America are many examples of vortex-flow intakes to drop structures comprising drop shafts to deep tunnels used to collect and store volumes of stormwater or combined sewer overflows (CSOs) in urban areas. From such storage tunnels, the CSO water is typically stored until the storm event (responsible for creating greatly increased flowrates) has subsided. This water is then pumped to wastewater treatment facilities, where the flows are treated before being released into nearby natural water bodies (rivers, lakes and marine coasts). Although the number of examples of this type of infrastructure is increasing, especially in the past few decades, the brief examples given here for the cities of Milwaukee, Boston, St. Louis, and Indianapolis are representative of projects that feature drop shafts feeding water to large, conveyance and storage tunnels underlying many cities across the United States.


Year: 2024

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