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Numerical Modeling |
S.E.A. offers 3D and 2D numerical modeling services for hydrologically diverse water resources of freshwater and marine environments. |
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S.E.A. maintains customized and commercial packages for numerical modeling of freshwater and shallow marine environments. Among these are customized versions of EFDC/HEM3D, and the Princeton Ocean Model (POM) and the Army Corp of Engineers Coastal Modeling System (CMS) developed at the WES Engineering Research Development Center (ERDC). The CMS includes phase averaging wave models (STWAVE and WABED), phase resolving wave models (CGWAVE and BOUSS2D), M2D, and ADCIRC for coupled wave-current modeling in coastal environments. Our company recently acquired the Delft3D™ modeling system for long-term simulation of wave-current interaction and morphologic change in nearshore wave and tide influenced environments. |
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Data post-processing custom and commercial software routines in (i.e. SMS™, Techplot ™, MatLab™) were developed to compare field data with output from 3D and 2D Models. High pass, low pass and band-pass digital filters have also been applied to process measured and modeled data in order to emphasize selected portions of the geophysical spectrum. Spectral and harmonic analysis routines are available to resolve energy peaks that occur in measured and modeled data. Software for cross-spectral analysis is also available to compare data among field and numerical data collection stations. Our company’s experience with data acquisition in marine and estuarine environments to support modeling effort includes: field surveys to measure currents, water level, directional wave spectrum, and meteorological data. |
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| Biological Characterization/Numerical Wave Model Analysis within Identified Borrow Sites Offshore the West Coast of Florida/Physical Implications of Sand Dredging on the Topography of the West Florida Shelf 2005-2008 (In Progress) |
U. S. DEPARTMENT OF INTERIOR MINERALS MANAGEMENT SERVICE (MMS) Sand and Gravel Program, Leasing Division
This study concentrated on three study sites located in Federal waters off Florida's southwest coast: Tom's Hills 1 and 2 (T1 and T2) shoal system and Siesta Shoal. Information was collected and analyzed to identify marine communities and habitats on and adjacent to these sites and to determine potential environmental impacts of dredging on the biological communities. Numerical models were used to simulate impacts of dredging different volumes of material from borrow cuts under both normal and storm conditions in order to calculate likely erosion impacts to the shoals and to the adjacent beaches. The study objectives were to (1) characterize the biological community and physical environment of the study sites and (2) assess the potential impacts of dredging on the shoal feature biological community and on the shorelines in the region. |
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| Calibration of the Environmental Fluid Dynamics Code for Sebastian Inlet and Vicinity |
SEBASTIAN INLET TAX DISTRICT, FLORIDA
The Environmental Fluid Dynamics Code (EFDC) was applied to the Sebastian Inlet area of the Indian River Lagoon in high spatial resolution to assist the Sebastian Inlet Tax District (SITD) in the evaluation of potential impacts of extending a navigation channel to the Intercoastal Waterway. The model grid extended from the Melbourne Causeway to the Vero Beach Bridge approximately 32 miles to the south. A total of 5,403 computation cells are included in the grid along with 4 layers in the vertical. The model was set up to provide hind cast predictions from 1999 through the end of 2000 that corresponded to time series of input data available to force the model. Model calibration and verification consisted of a comparison between modeled and predicted data from 1997, 1999 and 2000. Predicted salinity, temperature and water level data compared closely with measured data in terms of trend and variability. Topographic predictions were achieved using the sediment transport formulation in EFDC for non-cohesive and cohesive sediments. The sediment transport calculation when integrated over a one-year period provided good agreement between observed and predicted topographic changes over the Sebastian Inlet Flood Shoal. Predictions of suspended sediment concentration that represented inorganic sediments from the EFDC model were consistent with measured values of total suspended solids. |
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| Columbia River Jetty Restoration Study |
WES ENGINEERING and RESEARCH DEVELOPMENT CENTER
COASTAL and HYDRAULICS LABORATORY
A study was conducted to determine the potential for physical and environmental impacts of restoring the 100-year old jetty system at the mouth of the Columbia River on the Oregon Washington Border. In the study a 3D model was applied to examine the salinity regime with and without the jetty rehabilitation. The model domain is approximately 25 x 85 km containing 18,000 cells in a Cartesian coordinate system. Ocean Boundary conditions consist of tidal elevation, salinity time series and wind stress. Model boundary conditions at the head of the Columbia River Estuary consist of water elevation and river flow time series gauged by the U.S. Geologic Survey. Model results indicate that extension of the south jetty by approximately 1,500m will have a measurable impact on salinity regime by extending the freshwater influence further west toward the mouth of the river. |
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| EFDC/HEM3D Hydrodynamic and Water Quality Model of the Loxahatchee Estuary |
FLORIDA DEPARTMENT of ENVIRONMENTAL PROTECTION
The Environmental Fluid Dynamics Code (EFDC) model is applied to predict hydrodynamics, salt transport and heat exchange within the Loxahatchee River and Estuary. Water quality calculations by the hydrodynamics are supported by simulations from the GIS-based Watershed Assessment Model (WAMView) over the larger surrounding watershed to examine the possible impacts of watershed management alternatives in the Loxahatchee watershed. Calibrated results of the EFDC model verify the impacts of salinity intrusion and stratification into the upper reaches of the Loxahatchee River over a wide range of freshwater flows.
Thus, the EFDC model can be used to accurately predict the potential of increased freshwater flows for reducing salinity intrusion. The EFDC water quality model is constructed from 21 equations of state that include major forms of algae, organic carbon, nitrogen, phosphorus and silica, as well as providing predictions of dissolved oxygen and chemical oxygen demand associated with the sediment digenesis sub model. The complexity of water quality predictions in EFDC can be set according to the availability of monitoring data for driving and calibrating the model. Water quality predictions in the Loxahatchee River and Estuary included consideration of the various forms of nitrogen and phosphorus, and suspended solids. Extensive dissolved oxygen data from the Loxahatchee River were used to verify the performance of water quality predictions. |
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| Salinity Distribution and Flow Management Studies for Lake Worth Lagoon, Florida |
SOUTH FLORIDA WATER MANAGEMENT DISTRICT
The Environmental Fluid Dynamics Code (EFDC) was applied to Lake Worth Lagoon for three-dimensional predictions of the salinity regime. Four monitoring stations collected salinity and water level data from key locations at the boundaries of Lake Worth Lagoon. Two stations were situated within the interior of Lake Worth Lagoon where continuous salinity and current velocity data were collected for calibrating the EFDC Model. Additional model inputs were provided from meteorological data collected from a local weather station maintained by the National Buoy Data Center.
Freshwater inflows to the model were provided by gauged data collected from the control structures. The model calibration process consisted of adjustments to mean elevations of water level time series at the model boundaries and local and regional adjustments of roughness height at the benthos boundary. Other calibration procedures included local adjustments to wind stress coefficients, quality control of measured data and adjustments of local water depths. Statistical measures were used to quantify and verify the calibration. The calibrated model was applied to quantify the impacts on the salinity regime of existing and future variable controlled freshwater flows from canal discharge, rainfall, runoff and groundwater inflows. |
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| Brunswick Nuclear Plant Intake Canal Sedimentation Control Study |
PROGRESS ENERGY CO. (CAROLINA POWER & LIGHT)
A water quality modeling project in Southport, NC included numerical modeling of hydrodynamics and sedimentation using the Environmental Fluid Dynamics Code/HEM3D. Project tasks were data collection, model design, and model simulations for 3-D modeling of physical and anthropogenic variables to determine optimal dredging scenarios. The model was applied to predict sedimentation rate in lower Cape Fear River. Model calibration was achieved using field measurements of suspended sediment concentration, dredging records and water level observations. |
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| Hydrodynamic and Flushing Model of Lake Jesup, Florida |
ST. JOHNS RIVER WATER MANAGEMENT DISTRICT PALATKA, FL
The goal of this project was to apply a three-dimensional hydrodynamic model of Lake Jesup to predict the performance of alternatives to improve flushing of the Lake. The model application included four distinct channel configurations at the north boundary of the Lake designed to increase exchange between the Lake and the St. Johns River. Model simulations included numerical Lagrangian drifters specified in the model to track flushing rates, as well as simulations of current velocity to predict circulation patterns. Predictions of sediment transport were also conducted to evaluate the relative rates of sediment flushing among the test cases. Model simulations of the existing conditions were included in the project for comparison to proposed modifications. Results of the model simulations showed that all of the cases tested would substantially decrease the flushing time of Lake Jesup. The key element in all four test cases was the opening of an additional channel, which provided a more direct route for exchange between Lake Jesup and the St. Johns River. |
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| Application of the EFDC Three-dimensional Numerical Model to Evaluate Water Quality Improvements in the Long Slip Canal Entrance Basin Phase 4 - Sedimentation and Dissolved Oxygen Predictions - 1999 |
DAMES and MOORE, INC.
The fourth phase of this project tested the final Canal Basin configuration associated with the HBLRT System. The modeling scheme and tests were conducted to determine the dissolved oxygen (DO) conditions and sedimentation rates under both dry conditions and episodes of high runoff. The model test case was run from the end of February 1996 to mid September, 1996. Within this period five runoff events were specified to test the CSO impacts on the Long Slip Canal Basin area, as well as the impacts from conditions in the adjacent lower Hudson River. Model setup for the 7-month test run included time series of water elevation, salinity, water temperature, dissolved oxygen concentrations, and suspended sediment concentrations. Time series of these parameters were specified at the south and north boundaries of the Environmental Fluid Dynamics Code hydrodynamic/water quality model. Model setup also includes specification of meteorological parameters for the model test period. These parameters, included wind velocity, atmospheric pressure, air temperature and rain fall acquired from local weather stations and NOAA meteorological buoys in the nearby coastal ocean. Model simulations were used to predict sedimentation rates in the Long Slip Canal Basin area in comparison with sedimentation in the lower Hudson River Estuary (Fig. 1). |
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| Tidal Inlet Hydraulics and Nutrient Transport German Wadden Sea |
GKSS RESEARCH CENTER, GEESTHACHT GERMANY
Dr. Zarillo served as a visiting scientist responsible for model development, calibration and simulations of a 3-D model to investigate flushing times and patterns of the Wadden Sea. Numerical experiments were conducted to determine how flushing rates might be optimized by modifying existing methods for controlled freshwater releases from the agricultural watershed that drains to the Wadden Sea. The project determined that nutrient influx to the Wadden Sea from surrounding agricultural lands is a strong contributing factor to excess productivity and resulting low oxygen levels during the winter to early summer wet season. Results were documented in Three-Dimensional Modeling of Circulation and Flushing in the German Wadden Sea, GKSS Research Center, Geesthacht, Germany ( Zarillo, 1997). |
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| Indian River Lagoon/Sebastian River Hydrodynamic and Salinity Model 1996 |
ST. JOHNS RIVER WATER MANAGEMENT DISTRICT
A three-dimensional hydrodynamic and transport model (EFDC/HEM3D) was applied to the Sebastian River and central Indian River Lagoon (IRL) to develop a management tool for the St. Johns River Water Management District (SJRWMD). Calibration and validation of the model was based on a comparison of measured data from four fixed stations within the Sebastian River and one fixed station near the confluence of the Sebastian River and the IRL. Results of the calibration and validation indicated that the model performed well under complex estuarine conditions and is capable of simulating the salinity and flow structure as it changes either at low frequency or abruptly due to episodic freshwater inflows. The model is now utilized by the SJRWMD to set maximum allowable discharge of freshwater from the C-54 Canal into the central IRL through the control structure at the head of the Sebastian River (Fig. 1). |
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