Selection of Dredging Projects for Maximizing Waterway System Performance

Abstract

Budget allocation to annual maintenance dredging projects conducted by the U.S. Army Corps of Engineers is addressed. Of the many projects requested, only a subset may be selected for funding because of budgetary constraints. The benefits of conducting maintenance dredging at one dredging project depend on other projects in the system that also are being dredged to take advantage of transportation efficiency gains derived from deeper navigable waterways. The proposed integer programming models and heuristic solution algorithms selected dredging projects for funding, while taking into account interdependent benefits. The models considered the waterway network topology, which was derived from flow data of historic waterborne cargo. The solution algorithms ensured efficient computational performance and quality of solutions. The models and algorithms were tested on example port systems from the Great Lakes region, as well as from mainline coastal ports and inland waterways. The models were shown to increase the amounts of system cargo throughput directly supported by dredging relative to traditional rank-order approaches that did not consider project interdependencies. This result was true especially for scenarios in which the overall budget was small relative to the total of all funding requests in question.

Evaluating the Underkeel Clearance of Historic Vessel Transits in the Southwest Pass of the Mississippi River

“…Annualized sediment accumulation rates and dredging operation costs are considered in the Corps Shoaling Analysis Tool (CSAT), which is part of the optimization model . The connectivity of projects is considered to prevent unnecessary dredging in situations where connected projects have differing limiting depths (Mitchell et al 2013;Loney et al 2020). The sophisticated optimization model has brought mathematical rigor to the formerly ad hoc prioritization scheme.…”

Underkeel Clearance Reliability Model for Dredged Navigation Channels

“…Efficient design, operation, and maintenance of this navigation infrastructure is vital to the nation's economy and security. In managing its portfolio, the USACE spends more than $2 billion annually to investigate, construct, and maintain projects (1,2). Of that expenditure, approximately $1 billion is spent annually on maintenance dredging to remove sediment that reduces the depth of maintained channels (3,1).…”

“…In managing its portfolio, the USACE spends more than $2 billion annually to investigate, construct, and maintain projects (1,2). Of that expenditure, approximately $1 billion is spent annually on maintenance dredging to remove sediment that reduces the depth of maintained channels (3,1). Despite this investment in channel maintenance, dredging requirements have continu-ally outpaced available maintenance funding.…”

“…Despite this investment in channel maintenance, dredging requirements have continu-ally outpaced available maintenance funding. Funding constraints result in the need to make rational resource allocation decisions (1). One approach to resource allocation is to identify and reduce overly conservative maintenance strategies where doing so does not compromise navigation safety.…”

“…Navigation managers responsible for assessing navigation channels and recommending maintenance activities have faced budget constraints for some time. This is reflected in recent literature aimed at optimizing dredging schedules to minimize cost or maximize the availability of design project depth (1). Research into the use of underkeel clearance as a measure of channel reliability is lacking, although its use in design establishes it as a rational basis for a maintenance model (5)(6)(7).…”