6 Mar 2025

Norfolk Harbor Navigation Improvements Project: Modeling of Dredged Material Placement Schemes and Long-Term Sediment Transport at the Dam Neck Ocean Disposal Site

Abstract: US Army Corps of Engineers–Norfolk District requested assistance with the development and evaluation of dredged-material-placement schemes that evenly distribute placed material and avoid or minimize unacceptable mounding in accordance with the site management and monitoring plan. A multiple placement fate and transport modeling study was conducted to determine the optimal placement plan for dredged material from Thimble Shoals Channel and Atlantic Ocean Channel at the Dam Neck Ocean Disposal Site (DNODS). Provided the large volume of dredged material to be placed at DNODS over a short duration during the construction period, a modeling study was performed using the Geophysical Scale Multi-Block (GSMB) modeling system to determine the transport and fate of placed dredged material at the DNODS that is resuspended by currents and waves over a 2-year period. Six scenarios were undertaken to determine the best path forward. Scenarios 1 and 4 were excluded due to high exceedance of the depth threshold. Scenarios 2, 3, 5, and 6 yielded an approximate 1%–2% dispersal of placed materials from the DNODS during ambient environmental conditions; Scenario 6 yielded the least. Most dispersion occurred during two simulated hurricanes. The model findings generally support the DNODS Environmental Impact Statement and site-designation documents.

20 Dec 2024

Upper Mississippi River Main Channel Sediment Placement: Purpose, Practice, Effects, and Recommendations

Abstract: Dredged-sediment management in the Upper Mississippi River and Illinois Waterway is constrained by environmental factors and regulations that limit where sediment can be placed. Regulations regarding in-water sediment placement are not consistent among states. In-water placement should be promoted because it keeps sediment in the system and reduces costs for managing sediment dredged from the river. Studies investigating the environmental effects of in-water placement generally conclude that sand-on-sand placement has minimal effect on aquatic resources in the dynamic riverine environment. This report discusses in-water sediment management techniques, including flow- and sediment-regulating structures (i.e., dikes and wing dams) and a bed-load sediment collector by-pass system.

5 Nov 2024

Improving Aquatic Placement Practices for Beneficial Use of Dredged Material in the Great Lakes

Abstract: The Great Lakes Navigation System is an economically critical waterway. To maintain safe and navigable waterways, approximately 3–5 million yd3 (2.3–3.8 million m3) of sediments are dredged annually. The US Army Corps of Engineers (USACE) and others now recognize that beneficial use of these sediments can achieve positive economic, environmental, and social outcomes. However, historically less than 25% of dredged sediments have been beneficially used in the nearshore environment. Improvements are needed in dredged material management practices in the Great Lakes to achieve the goal of using 70% of dredged sediments beneficially by 2030. Therefore, to overcome these challenges this report reviews beneficial use of dredged material projects with the goal of improving and in-creasing beneficial-use-placement practices in the Great Lakes. Identified needs to advance beneficial-use placement in the Great Lakes include the following: (1) improved modeling of sediment-placement methods; (2) better documentation regarding the cost, benefits, and drawbacks of various placement methods; (3) demonstration of some sediment-placement techniques used successfully in other coastal environments; and (4) monitoring before and after conditions, particularly for sediments that contain greater than 10% fines. Several demonstration projects should be implemented to obtain information addressing the data gaps.

27 Sep 2024

Beneficial Use of Dredged Sediment in South St. Paul, Minnesota: 100 Years of Economic, Social, and Environmental Innovation

Purpose: This technical note provides a review of beneficial use (BU) of dredged sediment in a 5-mile river reach of the Upper Mississippi River System (UMRS) that demonstrates the triple-win solutions championed by the US Army Corps of Engineers (USACE) Engineering With Nature® Program. Several case studies exemplifying the BU of dredged sediment are presented along with a more in-depth review of the Pigs Eye Lake Islands ecosystem restoration project.

18 Sep 2024

Opportunities for Upper Mississippi River System Sand to Support Coastal Beach Nourishment

Abstract: This research presents an opportunity to review the concept, status, and cost of using Upper Mississippi River (UMR) riverine dredged sand to nourish coastal beaches for increased resilience. Several dredged placement sites, transport modes, commercial and industrial uses, and end-point destinations will be identified in regional assessments and several specific UMR sediment to Great Lakes beneficial use projects will be reviewed here and assessed in greater detail during this research investigation.

16 Sep 2024

Toward Systemic Beneficial use of Dredged Sediments in San Pablo Bay: Demonstration of a Proposed Framework for Matching Sediment Needs with Dredging Requirements

Abstract: Coastal wetlands provide a suite of valuable ecosystem services, but they are rapidly disappearing due to reductions in sediment supply and rising sea levels, making them ideal candidates for restoration through beneficial use of dredged sediment. Because sediment dredged from navigation channels is a limited resource relative to the number of degraded wetlands, a framework has been developed to align coastal restoration sediment needs with dredging requirements to maximize social, environmental, and flood risk reduction benefits while also completing the navigation mission. The framework is comprised of four key steps: (1) geographic scoping and suitability considerations, (2) quantification of the dredged sediment available and restoration project sediment needs, (3) definition of cost and benefit objectives, and (4) optimization of costs and benefits to determine the most efficient solutions. This report is a demonstration of this framework on a subset of wetland sites and local federal navigation channels in San Pablo Bay, California.

22 Aug 2024

Application of Existing Tools to Systematically Identify Nearshore Placement Sites for Beneficial Use of Navigation Sediments in Lake Michigan

Purpose: The Great Lakes includes 140 federally maintained harbors with an annual dredging program of 2–4 million cubic meters (3–5 million cubic yards)[1] of sediment. Many small harbors are not dredged regularly, and there is an undredged backlog of over 9 million cubic meters (12 million cubic yards) of sediment (USACE-LRD 2021). Current policy (Spellmon 2023) is to maximize the beneficial use (BU) of sediment, with a goal of beneficially reusing 70% of the federal navigation dredging volume by 2030 (that is, the 70/30 goal). In the Great Lakes, clean sands have often been placed on beaches or in the nearshore littoral zone to beneficially nourish the shoreline, but since many harbors are not dredged regularly, no plans exist to beneficially reuse dredged sediments. This lack of existing BU plans is particularly true for harbors with finer grained or mixed sediment. To achieve the 70/30 BU goal and support navigation maintenance and coastal management requires a strategic and systematic approach to identifying BU sites. The purpose of the technical note is to (1) provide an approach to identify potential nearshore placement sites using existing information and models; (2) describe available tools for placement site identification, coastal condition information, and the long-term fate of the sediment; and (3) provide a pertinent case study to describe this approach in practice.

22 May 2024

Beneficial Use of Dredged Material in the Atlantic Intracoastal Waterway: Approaching the Regulatory Process

Purpose: Following the Chief of Engineer’s January 2023 goal to expand the beneficial use of dredged material (BUDM), the US Army Corps of Engineers (USACE) strives to apply new and creative ways to increase utilization of dredged materials from a historic 30%–40% to 70% by 2030. As USACE Savannah District (SAS) increases BUDM efforts, a critical component of this transition is understanding and navigating the regulatory requirements. This Technical Note outlines the regulatory process for placement of dredged material in Georgia, identifies challenges and institutional barriers, and offers potential solutions to streamlining the overall process. By increasing the ease of navigating the regulatory process, USACE can facilitate an increase in BUDM and Engineering with Nature® (EWN®) projects in Georgia, and potentially other projects employing nature-based solutions (NBS). While regulatory details may vary from state to state, the Georgia example presented here can serves as a road map for the general types of regulatory procedures and potential hurdles found nationwide.

17 May 2024

Rolling Prairie, Minnesota, Beneficial Use Area: A 100-Year Plan for Multiuse Land Management and Restoration Using Dredged Sediment

Purpose: Inland waterway dredged sediment management is challenged by a lack of capacity in existing dredged material confined disposal facilities (CDFs) and a lack of available land to place sediment near frequently dredged navigation channels. Navigation operation and maintenance (O&M) dredging, material management, and coordination costs are increasing, and alternative long-term solutions are required. In response, the US Army Corps of Engineers (USACE), St. Paul District has addressed the challenge by investigating regional sediment management and beneficial use of dredged material when updating navigation pool–specific dredged material management plans (DMMP). The recently completed Pool 5 DMMP planning identified a 950 acre (384 ha)[1] placement site consisting of several land parcels available from willing sellers that will accommodate a “100-year plan” for dredged material management (USACE 2019). This technical note describes the multiple-use site plan that creates sand prairie and wetland habitat, provides public access to sand stockpiles, and implements agriculture studies with the University of Minnesota to evaluate the benefits of dredged material (i.e., sand) amendments in alluvial cropland soils, which has not been widely investigated. The Rolling Prairie site will demonstrate benefits of “distributed DMMPs” in which thin-layer placement on agricultural land near dredging locations can supplement traditional disposal methods. It also shows the advantage of having a large placement site to achieve multiple objectives.

15 Apr 2024

Development and Testing of the Sediment Distribution Pipe (SDP): A Pragmatic Tool for Wetland Nourishment

Abstract: Standard dredging operations during thin layer placement (TLP) projects are labor intensive as crews are necessary to periodically move the outfall location, which can have lasting adverse effects on the marsh surface. In an effort to increase efficiency during TLP, a novel Sediment Distribution Pipe (SDP) system was investigated. This system offers multiple discharge points along the pipeline to increase the sediment distribution while reducing pipeline movements. An SDP Modeling Application (SDPMA) was developed to assist in the design of SDP field applications by quickly assessing the pressure and velocity inside the discharge pipe and approximating the slurry throw distances. An SDP field proof of concept was performed during a two-phase TLP on Sturgeon Island, New Jersey, in 2020. The SDPMA was shown to be an accurate method of predicting performance of the SDP. The SDP was successful at distributing dredge material across the placement site; however, further research is warranted to better quantify performance metrics.