US Army Corps of Engineers BUILDING STRONG ® Tools for Assessing the Fate of Dredged Material Speaker: Joseph Gailani Research Hydraulic Engineer Research Group: Tahirih Lackey, Earl Hayter, Ray Chapman, Sung- Chan Kim, Paul Schroeder, and Jarrell Smith Engineer Research and Development Center October 25, 2012

BUILDING STRONG ® Motivation  Data related to dredged material fate for mgmt purposes are limited  Models and tools permit user to extrapolate to conditions for which data are not available  Provide framework within which to quantify fate, assess options and compare alternatives

BUILDING STRONG ® Motivation  Increasingly complex issues related to dredged material fate ► Regulatory compliance ► Environmental Resources/Risk Assessment ► Site/lifecycle management ► Dredged material as a resource ► Engineering with Nature ► Regional or multiple project management  Models are one of several tools used to address these issues (line/lines of evidence)  Models require improved process descriptions to address these issues  Users need a suite of modeling tools ► Various levels of model (screening to detailed) ► Address specific processes  Models and databases must be interconnected to provide efficient use and maximize benefit

BUILDING STRONG ® Objective  Develop/maintain a suite of tools, models and databases to address Corps issues related to dredged material fate and management ► Develop needed process descriptions for improved accuracy and range of applicability ► Increased interaction with other Corps models, databases, and tools ► Tiered models to address appropriate level of accuracy/user needs ► Demonstrate applicability  Decrease time required for model setup, application and interpretation through efficient user interfaces

BUILDING STRONG ® Transport Model Improvements  Our understanding of sediment processes is improving thanks to improved technologies  Remote sensing  Large data set storage  Ability for field measurement at fine resolution  Demonstrate applicability  Improved process descriptions incorporated into models  Bottom boundary layer processes  Model parameterization  Long-term/large-scale change  All scales of models benefit from these new data and descriptions

BUILDING STRONG ®  Provide deposition pattern and resuspension from placement  Manage placement sites  Regulatory Compliance (water column concentration) ► Section 103 of the MPRSA ► Section 404 (B)(1) of the Clean Water Act  Evaluate environmental resource issues STFATE Short-Term Fate of Dredged Material STFATE includes descent, dynamic collapse, bottom transport, and stripping phases

BUILDING STRONG ® MDFATE/ MPFATE Multiple Disposal Fate of Dredged Material Multiple Placement Fate of Dredged Material Cumulative resuspension from placement operations (multiple STFATE clouds) Generate mound configuration from placement operations Address Issues related to: –Regulatory Compliance –Minimizing hazards –Optimizing operations, long-term mgmt –Operational efficiency –Design capping operations Tool to optimize placement locations MPFATE includes multiple STFATE simulations, mound building, erosion, consolidation, and avalanching

BUILDING STRONG ® STFATE/MPFATE Improvements  Complex hydrodynamics  Complex bathymetries  Improved settling algorithms  Continuous or discrete discharge  Source term to far field fate models  Multiple plumes for water quality assessment  Complex bathymetry  Optimization routines to maximize capacity

BUILDING STRONG ® GTRAN Sediment Pathway Model Optimize Nearshore Placement Location to maximize benefit to Tybee Island and minimize rehandling

BUILDING STRONG ® PTM Particle Tracking Model A far field dredged material transport model specifically designed to simulate multiple scenarios Quantify DM transport and fate over large domains to assess impacts/risks PTM reduces computational intensity by only modeling transport of DM DM interactions with sediment bed treated through active layer dynamics Issues Addressed: –Far-field transport, deposition, and resuspension –Time-varying sediment and constituent concentration –Dose estimates at receptors Powerful post-processing tools – convert particle distribution to TSS, sedimentation, etc Quantify erosion, deposition, and dose over large domain. Map sediment and constituent pathways, can use FATE model output as DM sources

BUILDING STRONG ® PTM Improvements  Computational efficiency for year+ simulations  Improved boundary conditions  New settling algorithms with parameterization  Fish larvae behavior  Modeling of silt curtain effects and other control systems  More complex bottom boundary conditions  Improved wetting/drying transport algorithms  Improved bottom boundary layer descriptions developed by recent laboratory and field experiments

BUILDING STRONG ®  Post-Placement migration and dispersion of dredged material mounds  Quantify ► Hydrodynamic-driven mound morphology change ► Local deposition patterns and thickness ► Mass exiting local domain  Issues addressed: ► Dispersive/non-dispersive site ► Direction/fate of material removed from ODMDS ► Long-term management of dredged material mounds ► Regulatory compliance and resource issues ► Dredged material mound as resource for sediment nourishment ► Sediment rehandling LTFATE Long Term Fate of Dredged Material Current Erosion/Deposition TSS/Transport Surge Waves LTFATE: Wave/current sediment erosion, transport, and deposition. Mound morphology, mixed sediment processes, 3-D hydrodynamics, contaminant transport

BUILDING STRONG ® LTFATE Improvements  3-D Large domain hydrodynamics, α- or z-grid  Wave/current interactions  3-D, multiple grain size sediment bed and transport  Floc/aggregate transport  Parameterize transport processes using site-specific data  Wetting/drying  Multi-Block capabilities for computational efficiency  Improved bottom boundary layer descriptions developed from recent laboratory and field experiments  Fluid mud transport  Improved nearshore/shallow water processes