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Current EWN Projects

Current EWN Projects

The multiple benefits gained through EWN applications are ideal for field demonstrations. Investments have been made to identify projects that are broadly applicable and relevent across the USACE mission and business lines. The current EWN Projects are:

FY16 - Current - Evaluation of Bioaccumulation Control in Aquatic Sites Using Activated Carbon (project details)

Mixing of dredged material
Mixing of dredged material with activated carbon in dump scow

Sediments in the urban harbors often exhibit elevated levels of PCBs bioaccumulation, limiting their suitability for beneficial use or placement in aquatic sites. Amendment of dredged material in the bioactive zone with activated carbon has the potential to provide bioaccumulation control, permitting expanded use of aquatic placement where CDF capacity is being exhausted. Prior to this study, an application of activated carbon in a conventional mechanical dredging operation has never been demonstrated in a navigation dredging project.

FY16 - Current - A Guide to Engineering with Nature for Native Plant Community Development on Dredge Material Placement Areas (project details)

Plants stabilize dyke
Plants stabilize dyke on placement area

This EWN Action Project will provide guidance highlighting the use of native plant communities as vegetative treatments providing effective, low cost solutions, to stabilize dredged material placement areas and confined disposal facilities while providing engineering and environmental benefits. Two workshops will be held to develop case studies for the purpose of demonstrating planting techniques with native plant communities that will go into natural succession in the future.

FY16 - Current - Developing Engineering Guidance for Natural and Nature-Base Features (project details)

Marsh Creation
Marsh Creation

Natural structures are resilient, adapting to changes in physical, biological, geologic, and chemical processes. Nature-based features (NNBF) created by humans to provide specific services, such as coastal risk reduction. The use of natural and nature-based features in engineering design incorporates natural processes into the structure or project design, in order to take advantage of the resilient properties of natural systems. In addition, incorporating NNBF into USACE practices would reduce maintenance costs, and also provide ecosystem services within the project footprint. Currently, there is not an accepted guidance for incorporating NNBF into engineering design.

FY17 - Current - Resilience of Nature Based Features for Protection of Constructed Wetlands (project details)

Marsh construction
Marsh construction in Galveston Bay

Wetlands support both habitat and flood risk reduction missions of the Corps. Wetlands that are managed or supported by the Corps are often near navigation infrastructure or in open-water. Therefore, protection from erosive forces is sometimes required. The Corps therefore builds berms to absorb wave energy and protect both constructed and natural wetlands from erosive forces produced by naturally occurring waves or navigation activity. These constructed berms are typically sandy. Dredged sediment is sometimes used in the construction process. However, most dredged sediment is a mixture of sand, silt and clay which limits their application to berm construction. Increased use of mixed sediment for construction of protective berms would greatly expand this sustainable, beneficial use of dredged material.

FY18 - Current - Documentation of EWN Successes: Filling the Beneficial Use Gap (18-06) (project details)

Researchers collect assessment data
Researchers collect assessment data

Dredged materials can be used to improve environmental outcomes while maximizing navigation benefits. Few studies document mid- to long-term project benefits and USACE success stories remain poorly advertised. The purpose of the work unit is to “fill the gap” between recently restored systems and their mature counterparts, providing a framework to develop restoration trajectory curves allowing for extrapolation of EWN benefits throughout a projects lifespan.

FY18 - Current - EWN Atlas Highlighting NNBF Projects (project details)

Mordecai Island Project
Mordecai Island Project

There is tremendous interest internal to USACE and elsewhere to integrate a suite of EWN case studies that highlight natural and nature-based features (NNBF) projects. In turn, this “Atlas” Report would provide an inventory, which is comprised of a diverse grouping of projects (national and international), that exemplifies the utility of EWN solutions.

FY18 - Current - Incorporating Engineering With Nature (EWN) and Landscape Architecture (LA) Designs into Existing Infrastructure Projects (project details)

SooLocks
Soo Locks (photo by Briggs)

This project is focused on the identification of USACE infrastructure that is scheduled (or anticipated to be scheduled) for repair or replacement. USACE coastal navigation assets include: 1,067 navigation projects, 19 lock chambers, 13,000 miles of channels, 929 navigation structures, and 844 bridges. USACE inland navigation assets include: 27 inland river systems, 207 lock chambers (at 171 lock sites), and 12,000 miles of inland river channels. Many of the structures associated with these assets are in need of repair or replacement. This project seeks to incorporate EWN alternatives into project designs.

FY18 - Current - Parametric Study of Belowground Biomass on Short-term Dune Evolution (project details)

Model eroded dune
Model eroded dune showing below and aboveground biomass

Dunes have, and continue to be, natural or engineered features which prevent or delay flooding of inland areas by waves and storm surge. Currently, morphological models do not consider the effect of vegetation when estimating short-term dune response to erosional events. A previous study showed that aboveground and belowground plant structure significantly reduced the erosion of coastal dunes under both collision (scarping) and overtopping regimes.

FY18 - Current - Wave Attenuation in Vegetation (project details)

Artificial Vegetation
Artificial Vegetation used in Anderson and Smith (2014)

The bottom friction dissipation in spectral wave models (SWAN, MIKE SW, STWAVE, etc.) is commonly frequency dependent, while the dissipation due to vegetation only partially accounts for the frequency of the various wave components. For the bottom friction term, the shorter waves may locally be in deep water conditions, while the longer waves are in intermediate to shallow water conditions. Consequently, there exists a cut-off frequency above which the dissipation due to bottom friction vanishes. This cut-off frequency is also applicable to dissipation from submerged vegetation canopies.