Sediment management by jets and turbidity currents with application to a reservoir for flood and pollution control in Chicago, Illinois

Abstract

Management of fine sediments presents an important engineering and environmental problem. The active dredging of large volumes of sediments from harbors and reservoirs involves the use of expensive equipments with large operational costs. In several situations, however, passive systems can afford an efficient and low operational cost alternative. This work assesses the feasibility of eroding fine bed sediment by jet discharges and the subsequent transport in suspension by an ensuing turbidity current.A calibrated numerical model is applied to study the flow transport capacity under field conditions. Results show that large amounts of sediment can be eroded from the bed in the near-field region of the jet discharge, and that part of this eroded sediment can be transported in suspension further downstream by turbidity currents. The flow transport capacity depends strongly on the initial conditions of the jet discharge. This work has implications on sediment management by passive methods and presents a simple setting that could result in resource savings by reducing operational costs.

Keywords:

• Cohesionless sediment
• deposition
• numerical model
• scour
• sediment dredging
• sediment erosion
• submerged jet
• suspended sediment
• turbidity current