Water Quality

Dynamic Solutions LLC is highly experienced in collecting water quality data, compiling standardized water quality databases, conducting statistical analyses, interpreting results and using water quality models to help understand, and mitigate, the causes of poor water quality conditions. We have a through understanding of the necessary requirements for conducting water quality studies and developing water quality management plans and are experienced in evaluating water quality problems on watershed and/or site-specific scales. Dr. Andrew Stoddard, a nationally recognized expert in aquatic ecosystems and surface water quality, plays an important role in each of our water quality projects to ensure the consistent application of Clean Water Act regulations and high quality deliverables. He has been recognized by the USEPA Office of Water for his outstanding ability to extract and identify statistically robust water quality “signals” from very large “noisy” national databases.

Water quality modeling integrates hydrodynamics, physical, chemical, biological and geochemical kinetic interactions and processes to aid in the understanding of the behavior of complex aquatic systems and to predict the effects of natural and man-made pollutant inputs on receiving waters. Dynamic Solutions uses many water quality models including:

• Environmental Fluid Dynamics Code (EFDC)
• WASP5, WASP6, and WASP 7x
• CE-QUAL-W2
• QUAL2E
• CORMIX
• HSPF

Selected examples of some of our water quality management studies are described in the following project descriptions:

Hydrodynamic and Water Quality Modeling of Rio Grande de Arecibo Estuary, Puerto Rico
Dynamic Solutions was contracted to develop a hydrodynamic and water quality model of Rio Grande de Arecibo Estuary in Puerto Rico to predict the impacts on total dissolved solids and dissolved oxygen from implementation of a variety of management and environmental scenarios. These included timing and quantities of water withdrawal, normal operating and environmental conditions, drought conditions, and long duration warm weather. Dynamic Solutions applied the CE-QUAL-W2 model to simulate the following conditions:

• Base Case: 1997 flow conditions with regular tide (unaltered).
  
• Constant 20 mgd flow for one month with regular tide (unaltered).
  
• Constant 20 mgd flow with constant high tide.
  
• Constant 20 mgd flow with one pulsed release during the third week of modeling of 100 MGD.
  
• Constant 10 mgd flow for one month with regular tide.

Suspended Sediment Modeling of the Cumberland Reservoir, Kentucky, USACE Nashville District, Nashville, TN. Lake Cumberland, located on the Cumberland River in south central Kentucky, experiences influxes of high concentrations of suspended sediment into the upper portions of the lake during periods of heavy rainfall and runoff into the reservoir and tributary streams. These sediments originate both from the tributary stream beds and the areas of the watershed that have been strip mined. Subsurface plumes of high concentrations of suspended sediment are formed and often move downstream where they are discharged through the hydroelectric turbines. Dynamic Solutions staff applied the USACE model CE-QUAL-W2 to the reservoir to simulate hydrodynamics and suspended sediments. The purposes of the modeling effort were two-fold: (1) evaluate the suitability of CE-QUAL-W2 for simulating suspended sediment dynamics in Lake Cumberland; and (2) improve the understanding of the suspended sediment dynamics. The model was calibrated to temperature and suspended sediment data from 1983 and 1988. The CE-QUAL-W2 suspended solids sub-model allowed only one suspended solids settling rate. In an effort to improve the agreement of the model results with field data the code was modified to enhance the model by allowing the user to define a number of spatial and temporally dependent settling rates.

National Watershed Pollution Control Model (NWPCAM), EPA Office of Water.
In support of a series of studies designed to (a) estimate the costs and benefits of water quality improvements that have been achieved over the past 25 years and (b) evaluate water pollution control policies for pending rule making, the U.S. Environmental Protection Agency (EPA) Office of Water has contracted with Research Triangle International (RTI) to develop the National Water Pollution Control Assessment Model (NWPCAM). Dynamic Solutions, LLC has collaborated with RTI as a developer of NWPCAM by incorporating the EPA-supported WASP5 eutrophication and toxic chemical models as the in-stream water quality models for the NWPCAM framework. Version 2 of the NWPCAM framework collects, integrates, and organizes vast amounts of environmental data and complex hydrologic and water quality modeling techniques into an integrated, comprehensive modeling ORACLE data base system. The national-scale model framework is based on an innovative foundation that integrates the EPA River Reach Files RF1 and RF3 with USEPA databases for streamflow (GAGE data), point source effluent characteristics (PCS, NEEDS, IFD) and ambient water quality (STORET). Other data sources, such as USGS land use and land cover data and the USGS SPARROW model are also incorporated in NWPCAM Version 2. The model framework includes an algorithm to transform water quality concentrations generated by the water quality model to measures of beneficial use attainment categories including boating, fishing, and swimming that are commonly used to characterize water quality for public policy purposes. These beneficial use attainment estimates are then linked to economic valuation instruments to estimate the water quality dependent benefits of implementing actual, or proposed, water pollution control policies. The National Water Pollution Control Assessment Model, a key policy tool developed for EPA’s Office of Water, has been used, and is continuing to be used, to assist EPA in their evaluations of numerous water pollution control policy issues.

Lake Barkley Water Quality Modeling and Post Processing, Tennessee, USACE Nashville District, Nashville, Tennessee. Dynamic Solutions LLC used CE-QUAL-W2 to develop and calibrate a hydrodynamic and water quality model of Barkley Reservoir on the Cumberland River. The model was verified and calibrated and used to predict the effects on water quality resulting from proposed changes in reservoir operations. The calibrated model was used to evaluate the impacts of a proposed alternative headwater guide curve on water quality in the reservoir and in discharges from Barkley Dam. The effects of flows into and out of the reservoir through the Barkley-Kentucky canal and the impact of the Cumberland Steam Plant at Cumberland River Mile location 103.6 have also been investigated. The results indicated that changes in canal flows caused temperature and dissolved oxygen effects much further upstream than anticipated. An additional task was the development of a post-processor to aid in interpretation of the model output. This allowed quick and accurate display and communication of model results.

Suffolk County (Long Island) Brown Tide Comprehensive Assessment Program (BTCAMP)
Dr. Andrew Stoddard, a senior water quality modeling expert on the staff of Dynamic Solutions LLC, used an EPA-supported model framework to develop a linked two-dimensional hydrodynamic (DYNHYD5) and water quality eutrophication (WASP5) model for an assessment of the effects of point and nonpoint sources of total nitrogen loading on the occurrence of the anomalous 1985-88 "Brown Tide" bloom in the Peconic estuary, Long Island. For the upgraded three-dimensional eutrophication and hydrodynamic model (EFDC) developed for the EPA Peconic Estuary Program, Dr. Stoddard incorporated an analytical sub-model to represent diurnal variability of dissolved oxygen. The results of this study have been published as a peer reviewed book chapter in Coastal and estuarine studies, Novel phytoplankton blooms: Causes and impacts of recurrent brown tides and other unusual blooms (1989).