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Modeling Resources and Guidance

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Models Commonly Used to Evaluate Nutrient-Related Impacts

  • AGNPS (Agricultural Non-Point Source Pollution Model)
    Modeling system designed to estimate the pollution loads from agricultural watersheds and to assess the effects of different management programs. Model simulates surface water runoff, nutrients, sediments, chemical oxygen demand, and pesticides from point and nonpoint sources of agricultural pollution.
    Can be used to predict ecological responses to proposed management alternatives. It may help to determine the most important of several environmental stressors, e.g. where there are both nutrients and toxic pollutants.
  • CE-QUAL-W2 from SMIC or CE-QUAL-W@ from WQRG
    A 2-D, laterally averaged, finite difference hydrodynamic and water quality model. Because the model assumes lateral homogeneity, it is best suited for relatively long and narrow water bodies exhibiting longitudinal and vertical water quality gradients. The model can be applied to rivers, lakes, reservoirs, and estuaries.
    http://smig.usgs.gov/cgi-bin/SMIC/model_home_pages/model_home?selection=cequalw2 or http://www.ce.pdx.edu/w2/
  • EFDC (Environmental Fluid Dynamics Code)
    A state-of-the-art hydrodynamic model that can be used to simulate aquatic systems in one, two, and three dimensions. The EFDC modeling system has hydrodynamic, water quality-eutrophication, sediment transport, and toxic contaminant transport components transparently linked together.
  • EPD-RIV1 (One Dimensional Riverine Hydrodynamic and Water Quality Model)
    A 1-D (cross-sectionally averaged) hydrodynamic and water quality model. It consists of two parts, a hydrodynamic code which is typically applied first, and a quality code. The hydraulic information, produced from application of the hydrodynamic model, is saved to a file which is read by, and provides transport information to, the quality code when performing quality simulations.
  • GWLF (Generalized Watershed Loading Function) Exit EPA Disclaimer
    Provides the ability to simulate runoff, sediment, and nutrient (N & P) loadings from a watershed given variable-size source areas. It also has algorithms for calculating septic system loads, and allows for the inclusion of point source discharge data. It is a continuous simulation model which uses daily time steps for weather data and water balance calculations.
  • HSPF (Hydrological Simulation Program-Fortran) Exit EPA Disclaimer
    Simulates the hydrologic and associated water quality processes on pervious and impervious land surfaces and in streams and well-mixed impoundments over an extended period of time.
  • LSPC (Loading Simulation Program in C++)
    Includes streamlined Hydrologic Simulation Program Fortran (HSPF) algorithms for simulating hydrology, sediment, and general water quality on land as well as a simplified stream transport model.
  • PHOSMOD (Phosphate Model) Exit EPA Disclaimer
    Calculates the effects of soil-phosphate and granular fertilizer phosphate on daily crop growth, phosphate concentration in the plant, and the changes in the different forms of soil phosphate for conditions when growth is not limited by deficiency of either P or K. It is mechanistic and largely based on well-known equations for key processes.
  • PRedICT Model (Pollution Reduction Impact Comparison Tool) Exit EPA Disclaimer
    Developed as a companion tool to AVGWLF, allows the user to create various "scenarios" in which current landscape conditions and pollutant loads (both point and non-point) can be compared against "future" conditions that reflect the use of different pollution reduction strategies.
  • QUAL2K (River and Stream Water Quality Model)
    Simulates flow and water quality in simple rivers and streams. It is typically used to assess the environmental impact of multiple pollution discharges along rivers. Pollutants can come from point sources and from non-point sources.
  • SPARROW Modeling of Surface-Water Quality (SPAtially Referenced Regressions On Watershed Attributes)
    Relates in-stream water-quality measurements to spatially referenced characteristics of watersheds, including contaminant sources and factors influencing terrestrial and stream transport. The model empirically estimates the origin and fate of contaminants in streams, and quantifies uncertainties in these estimates based on model coefficient error and unexplained variability in the observed data.
  • STEPL and Region 5 Model (Spreadsheet Tool for Estimating Pollutant Load) Exit EPA Disclaimer
    Employs simple algorithms to calculate nutrient and sediment loads from different land uses and the load reductions that would result from the implementation of various best management practices. STEPL provides a user-friendly Visual Basic interface to create a customized spreadsheet-based model in Microsoft Excel.
  • WAT (Soil & Water Assessment Tool) Exit EPA Disclaimer
    Predicts the effect of management decisions on water, sediment, nutrient and pesticide yields with reasonable accuracy on large, ungaged river basins.
  • SWMM (Storm Water Management Model)
    A dynamic rainfall-runoff simulation model used for single event or long-term simulation of runoff quantity and quality from primarily urban areas.
  • WASP (Water Quality Analysis Simulation Program)
    Helps users interpret and predict water quality responses to natural phenomena and manmade pollution for various pollution management decisions. WASP is a dynamic compartment-modeling program for aquatic systems, including both the water column and the underlying benthos. WASP allows the user to investigate 1, 2, and 3 dimensional systems, and a variety of pollutant types.

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