US Army Corps of Engineers BUILDING STRONG ® The Particle Tracking Model: Determination of constituent fate in complex hydrodynamic and wave environments Speaker: Joseph Gailani Research Hydraulic Engineer Research Group: Tahirih Lackey, Zeki Demirbilek, Sung-Chan Kim, David King, and Pearce Cheng Engineer Research and Development Center October 25, 2012

BUILDING STRONG ®  Total Suspended Solids (TSS) concentration  light attenuation  fish and larval migrations  contaminants  sediment deposition  egg burial  seagrass smothering Issues: Effects of Sediment on Habitat (Exposure)  Areas in green depict seagrass  Data collection in center of the channel pathway Dredging operation near sensitive sea- grass region (Panama City, Florida)

BUILDING STRONG ® Particle Tracking Model Input Requirements  Grid/Bathymetry Data  Hydrodynamic and/or Wave Data  ADH  ADCIRC  EFDC  CH3D  Native Sediment Data  User Defined Source Data ► Dredging ► Placement ► CSOs Time-dependent Particle Positions P(t,X,Y,Z) PTM/Surface-water Modeling System (SMS) Data Analysis Tools Deposition Concentration Dose Exposure Accumulation Pathways Turbidity PTM is a Lagrangian particle tracker that models transport processes (advection, diffusion, deposition, etc) for representative parcels to determine constituent (sediment, contaminants, biologicals, etc) fate. PTM

PTM Dredge Source Description  User defines sources generated from: ► Dredge source models ► FATE models ► Known release rates  Sources From: ► Dredging operations ► Placement operations ► ODMDS erosion ► Overflow  Source strengths vary temporally and spatially (incl. vertically)  Each particle represents a defined mass of constituent and includes constituent behavior PTM is currently linked to FATE models used by USACE Districts Source terms are extremely important to accurate modeling. This is currently the focus of ongoing research. Barge Placement Pipeline Placement

PTM/SMS Interface The interface for PTM is found in the Surface Water Modeling System (SMS). The interface has been designed to be user-friendly and ultimately allow users to create mesh, hydrodynamics, source information for input, run PTM, and visualize and analyze output data. Visualize Model Results: Particle Positions Particle Pathways Particle Count Accumulation (mm) Rate of Accumulation (mm/hr) Deposition (mm) Exposure (kg / m 3 ) * hr Concentration (kg / m 3 ) Dosage (kg / m 3 ) * hr Turbidity (PTM/SMS Interface showing data at Apra Harbor)

BUILDING STRONG ® New PTM Capabilities New features:  High Performance Computing compiling platform  Parallel processing  Accepts hydrodynamic input as: 2D, 3D sigma, and now 3D z-grid  Optimized time step option based on courant number  Enhance particle location scheme to faster tracking New capabilities have been added to PTM to allow users to track a larger number of particles, faster. These changes allow users to simulate more alternatives and bracket parameters which may have a known range but no definite value. Ultimately this leads to a better understanding of the constituent transport in the system and provides better support for decision making.

BUILDING STRONG ® PTM Project Examples ► CSO outflow sediment, constituents, and debris (multiple sites) ► Sediment transport from dredges and dredged material placement (multiple sites) ► Contaminant transport from dredges and dredged material placement (multiple sites) ► Larval fish transport at Seabrook ► Egg transport in Newark Bay ► Water borne particulates on the Gulf Coast ► In general used for exposure estimates for risk assessment in habitat

BUILDING STRONG ® Case Study: Predicting Coral Exposure Due to Dredging in Apra Harbor, Guam  The U.S. Navy is studying alternatives for the construction of a deep water wharf at Apra Harbor, Guam to provide a berthing site for nuclear powered aircraft carriers (CVN).  Development of a site would involve dredging at the wharf location and additional dredging to provide a turning basin and access fairway (dredge depth = 16 m).  This work studies the exposure due to dredging at two of the considered sites: Polaris Point and Ship Repair Facility. Apra Harbor, Guam Objective: Model dredging alternatives and determine exposure to adjacent coral reefs. Then work with coral reef experts to help determine risk. Problem : These sites are adjacent to large, diverse coral reefs, and there are concerns about the impacts of dredging.

BUILDING STRONG ® Navigation Footprint: Polaris Point

BUILDING STRONG ® Navigation Footprint: Ship Repair Facility

Dredging Protocols Clamshell Resuspension Sources:  Impact  Ascent/Descent  Slewing Chiseling Resuspension Sources:  Major Release at bottom

BUILDING STRONG ® Modeling Scenarios Cases 1 and 4 bracket the original maximum and minimum results and will be the focus of this presentation

Sedimentation Case 1: 1800 cyd - 2% loss - 90% effective silt curtain (Deposition in g/cm 2 ) The largest values are shown near Polaris Point and the Ship Repair Facility. The majority of the sediment settles and accumulates within the dredging footprint.

Data Analysis Tables (Outside of Dredging Footprint) Case Total Accumulation Area (m 2 ) greater than 0.5 g/cm 2 Polaris Point Ship Repair Facility 178,40096, ,00070,400 Case Maximum Deposition Rate Area (m 2 ) greater than 0.01 g/cm 2 /day Polaris Point Ship Repair Facility 1252,800313, ,800187,200 Case Maximum Concentration Area (m 2 ) greater than 0.01 kg/m 3 Polaris Point Ship Repair Facility 1161,600118, ,8004,800 Shown is the quantity of area outside of the dredging footprint for which the parameter (accumulation, maximum deposition rate, maximum concentration) is greater than the specified level.

BUILDING STRONG ® Summary, Conclusions and Future Work  The transport of resuspended sediment due to dredging in Apra Harbor has been simulated and analyzes is ongoing.  Scenarios were developed to bracket the range of exposure estimates using conservative assumptions.  For total accumulation and deposition rate, preliminary analysis shows that Ship Repair Facility results appear slightly higher.  For both alternatives, maximum suspended sediment concentration values are low (instantaneously < 0.02kg/m 3 ). These maximum values occur only immediately at the site being dredged and then quickly dissipate.  Next step – coordinating with our team of coral reef biologists to interpret results.  Comparison of results with monitoring data if the project goes forward.

FAQ  How can I get PTM? ► PTM is available free of charge to USACE employees. POC:  References:  Do I have to use SMS to use PTM? ► PTM does work outside of SMS, however the data analysis tools that create deposition, concentration, etc are a part of SMS. Also, source creation is much easier utilizing SMS.  How long does it take for the model to run? ► That depends primarily on the number of particles created, the length of the simulation, and the speed of your machine. For a two week simulation with 50,000 particles on the average PC, should take less than a day to run.  How can I learn to use the model? ► Personal PTM workshops are available upon request. ► Additional Information: