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Methods, Models, Tools, and Databases for Water Research


  • Bacteria Methods
  • Biological Methods and Manual Development
    EPA's research in stream and source monitoring indicators includes fish, macroinvertebrates, periphyton, zooplankton, functional ecosystem indicators, water and sediment toxicity, and fish tissue contaminants. EPA exposure scientists regularly prepare and update field and laboratory You will need Adobe Reader to view some of the files on this page. See EPA’s About PDF page to learn more.protocol and methods manuals. They also provide technical assistance to EPA regions, program offices and states on the implementation and interpretation of these manuals. This website lists currently available manuals and protocols.
  • Coliphage Methods
  • Design Manual: Removal of Fluoride from Drinking Water Supplies by Activated Alumina (PDF)
    This manual is an update to the 1984 version by the same title. It supports the fluoride MCL and provides an in-depth presentation of the steps required to design and operate a fluoride removal plant using activated alumina, which is a reliable and cost-effective process for treating excess fluoride from drinking water supplies. The design manual can be used for communicating novel and relevant fluoride treatment technologies, and fills a needs gap for a comprehensive manual of available fluoride removal technologies.
  • Drinking Water Methods
  • Engineering Design and Operation: Biological Treatment Process for the Removal of Ammonia from a Small Drinking Water System from Pilot- to Full-Scale (PDF)
    This yearlong pilot study at a small system in Iowa evaluated the use of an EPA patented biological drinking water treatment process to remove ammonia from their water. A full-scale treatment system was then installed based on the design and operating configurations identified during the pilot study. The treatment plant engineering design criteria and operating conditions are presented, the project from pilot- to full-scale is discussed, and lessons learned and future considerations are presented.
  • Guidelines for Water Reuse (PDF)
    This manual provides comprehensive, up-to-date national guidance on water reuse regulations and program planning in support of regulations and guidelines developed by states, tribes, and other authorities.
  • Integrating Modeling with Petroleum Vapor Site Assessment
    This approach screens potential petroleum vapor sites that includes three main factors: (1) the concentrations of hydrocarbons in soil gas at the source of the vapors, (2) the separation distance between the receptor and the source of the vapors, and (3) a presumption that aerobic biodegradation will reduce the concentrations of hydrocarbons in the unsaturated zone. Models are included in the approach as a means of adding to the weight of evidence for aerobic biodegradation. One model, PVIScreen, can be used to show how uncertainty estimates can be made and how the results can integrate with site assessment to increase confidence in decision-making.
  • Protozoan Methods

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  • Standard Test Method for Bisphenol A in Environmental Waters 
    The environmental source of BPA is predominantly from the decomposition of polycarbonate plastics and resins, which are used in a wide range of commercial products. BPA has been reported to have adverse effects in aquatic organisms and may be released into environmental waters directly at trace levels through landfill leachate and POTW effluents. This method has been investigated for use with surface water and secondary and tertiary POTW effluent samples therefore, it is applicable to these matrices only.
  • Standard Test Methods for Perflourinated Compounds (PFC)
    Standard test methods have been developed to detect PFC compounds in soils (ASTM D7968) and water, sludge, influent, effluent and wastewater (ASTM D7979). PFCs are used widely in various industrial and commercial products, and they are persistent, bioaccumulative, and ubiquitous in the environment. PFCs have been detected in soils, sludges, surface, and drinking waters, and have been reported to exhibit developmental toxicity, hepatotoxicity, immunotoxicity, and hormone disturbance. This standard test method provides a quick, easy, and robust method to determine these compounds at trace levels in water matrices for understanding of the sources and pathways of exposure.
  • Standard Test Method and Practice Screen for Nonyphenol (NP), Octalphenol (OP), Nonylphenol Monoethoxylate (NP1EO) and Nonylphenol Diethoxylate (NP2EO) in environmental waters
    NP and OP have been shown to have toxic effects in aquatic organisms. The source of NP and OP is prominently from the use of common commercial surfactants. The most widely used surfactant is nonylphenol ethoxylate (NPEO) which has an average ethoxylate chain length of nine. The ethoxylate chain is readily biodegraded to form NP1EO, NP2EO, nonylphenol carboxylate (NPEC) and, under anaerobic conditions, this standard test method allow for the detection of these substances.
  • Virus Methods
    (EPA Manual of Methods for Virology) Twelve chapters. The individual chapters were prepared as ASCII text files to be viewed/printed with a monospaced font. It is planned to make them also available in PDF format in the future. The manual (EPA 600-4-84-013) describes in detail procedures for detecting viruses in environmental samples. 


  • Better Assessment Science Integrating point & Non-point Sources (BASINS)
    BASINS is a multipurpose environmental analysis system designed to help regional, state, and local agencies perform watershed- and water quality-based studies. It was developed to assist in watershed management and TMDL development by integrating environmental data, analysis tools, and watershed and water quality models. A geographic information system (GIS) organizes spatial information so it can be displayed as maps, tables, or graphics. Through the use of GIS, BASINS has the flexibility to display and integrate a wide range of information (e.g., land use, point source discharges and water supply withdrawals) at a scale chosen by the user. 
  • Bioaccumulation in Aquatic Systems Simulator (BASS)
    BASS is a model that simulates population and bioaccumulation dynamics of age-structured fish communities. While BASS was designed to investigate bioaccumulation of chemicals within community or ecosystem contexts, it also allows EPA to evaluate various dimensions of fish health associated with non-chemical stressors. Accurate bioaccumulation estimates help predict realistic dietary exposures to humans and fish-eating wildlife.
  • BIOCHLOR, Natural Attenuation Decision Support System
    BIOCHLOR is an easy-to-use screening model that simulates remediation by natural attenuation (RNA) of dissolved solvents at chlorinated solvent release sites. The software, programmed in the Microsoft Excel spreadsheet environment and based on the Domenico analytical solute transport model, has the ability to simulate 1-D advection, 3-D dispersion, linear adsorption, and biotransformation via reductive dechlorination (the dominant biotransformation process at most chlorinated solvent sites). Reductive dechlorination is assumed to occur under anaerobic conditions and dissolved solvent degradation is assumed to follow a sequential first-order decay process. BIOCHLOR includes three different model types:
    1. Solute transport without decay,
    2. Solute transport with biotransformation modeled as a sequential first-order decay process,
    3. Solute transport with biotransformation modeled as a sequential first-order decay process with two different reaction zones (i.e., each zone has a different set of rate coefficient values).
  • BIOPLUME II, Computer Model of Two-Dimensional Contaminant Transport under the Influence of Oxygen Limited Biodegradation in Ground Water
    BIOPLUME II is a simulation that computes concentrations of dissolved hydrocarbon under the influence of oxygen-limited biodegradation in an aquifer. The model solves the solute transport equation for both hydrocarbon and oxygen, assumes an instantaneous reaction between oxygen and hydrocarbon, and combines the two plumes using the principle of superposition. Computations account for convection, dispersion, mixing, and biodegradation effects. Also, the program can simulate slow hydrocarbon plumes undergoing biodegradation and can simulate in situ biorestoration schemes such as the injection of oxygenated water. Moreover, the model can simulate re-aeration and anaerobic biodegradation as a first-order decay in hydrocarbon concentrations.
  • BIOPLUME III, Natural Attenuation Decision Support System
    The BIOPLUME III program is a two-dimensional, finite difference model for simulating the natural attenuation of organic contaminants in ground water due to the processes of advection, dispersion, sorption, and biodegradation. The model simulates the biodegradation of organic contaminants using a number of aerobic and anaerobic electron acceptors: oxygen, nitrate, iron (III), sulfate, and carbon dioxide.
  • BIOSCREEN, Natural Attenuation Decision Support System
    BIOSCREEN is an easy-to-use screening model which simulates remediation through natural attenuation (RNA) of dissolved hydrocarbons at petroleum fuel release sites. The software, programmed in the Microsoft™ Excel spreadsheet environment and based on the Domenico analytical solute transport model, has the ability to simulate advection, dispersion, adsorption, and aerobic decay as well as anaerobic reactions that have been shown to be the dominant biodegradation processes at many petroleum release sites. BIOSCREEN includes three different model types:
    1. Solute transport without decay,
    2. Solute transport with biodegradation modeled as a first-order decay process (simple, lumped-parameter approach),
    3. 3) Solute transport with biodegradation modeled as an "instantaneous" biodegradation reaction (approach used by BIOPLUME models).
  • Capture Zone Analytic Element Model (CZAEM)
    CZAEM is a single-layer model for simulating steady flow in homogeneous aquifers using the Analytic Element Method. It serves as a tool in the wellhead protection decision making process by delineating groundwater capture zones and isochrones of residence times. CZAEM supports a limited number of analytic elements that can accommodate fairly realistic boundary conditions, such as streams, lakes, and aquifer recharge due to precipitation. CZAEM generates output on groundwater capture zones and residence times. The model accurately defines capture zone boundaries by first determining all stagnation points and dividing streamlines in the flow domain.
  • Coastal Gulf Ecology Model (CGEM)
    CGEM is a state-of-the-art complex model for nutrient dynamics and eutrophication processes and hypoxia. CGEM can assist states in the assessment of how much nutrient reduction is needed to achieve Gulf Hypoxia Task Force goals to improve water quality and reduce the Gulf hypoxic zone. It may be used to model harmful algal blooms (HABs), taking into consideration phytoplankton community dynamics. Technical expertise and high level computing resources are needed to run the three-dimensional (x, y, z) versions of the model, however, a one-dimensional version is available that can be run on a desktop computer. 
  • Environmental Fluid Dynamics Code (EFDC Hydro)
    EFDC Hydro is a state-of-the-art hydrodynamic model that can be used to simulate aquatic systems in one, two, and three dimensions. It has evolved over the past two decades to become one of the most widely used and technically defensible hydrodynamic models in the world. EFDC is a surface water modeling system that includes hydrodynamic, sediment-contaminant and eutrophication components. EFDC has been used for more than 80 modeling studies of rivers, lakes, estuaries and wetlands in the United States and abroad. The public domain EFDC model is currently maintained by Tetra Tech, Inc. with support from EPA.
    EPANET is software that models water distribution piping systems. It performs extended-period simulation of the hydraulic and water quality behavior within pressurized pipe networks.
  • EPANET – Multi-Species eXtension (MSX)
    EPANET is used in homeland security research to model contamination threats to water systems. Historically, EPANET has been limited to tracking the dynamics of a single chemical transported through a network of pipes and storage tanks, such as a fluoride used in a tracer study or free chlorine used in a disinfection decay study. EPA released a new extension to EPANET called EPANET-MSX that allows for the consideration of multiple interacting species in the bulk flow and on the pipe walls. This capability has been incorporated into both a stand-alone executable program as well as a toolkit library of functions that programmers can use to build customized applications.
  • EPANET – Real-time eXtension (RTX)
    EPANET-RTX is the first open-source set of libraries to extend EPANET’s hydraulic and water quality simulation functionality to include data acquisition and predictive forecasting capabilities. 
  • Exposure Analysis Modeling System (EXAMS)
    EXAMS is an interactive software application for formulating aquatic ecosystem models and rapidly evaluating the fate, transport, and exposure concentrations of synthetic organic chemicals including pesticides, industrial materials, and leachates from disposal sites.
    FOOTPRINT simulates the length and surface area of BTEX plumes in groundwater, when the plumes are produced from a gasoline spill that contains ethanol.
  • Hydrocarbon Spill Screening Model (HSSM)
    Hydrocarbon Spill Screening Model (HSSM), simulates flow of the light nonaqueous-phase liquid (LNAPL) transport of a chemical constituent of the LNAPL from the surface to the water table, radial spreading of the LNAPL at the water table, and dissolution and aquifer transport of the chemical constituent. The HSSM model is one-dimensional in the vadose zone, radial in the capillary fringe, and two-dimensional in the vertically averaged analytical solution of the advection dispersion equation in the saturated zone. The model is based on the KOPT, OILENS and TSGPLUME models.
    1. HSSM-DOS
    2. HSSM-Windows
    3. HSSM en Español
  • Infiltration Models
    The unsaturated or vadose zone provides a complex system for the simulation of water movement and contaminant transport and fate. Numerous models are available for performing simulations related to the movement of water. There exists extensive documentation of these models. However, the practical application of these infiltration models has not been adequately addressed in the literature. In recent years, the use of vadose zone models has increased for the purpose of estimating contaminant levels in soils related to different types of remedial decision-making. The rate of infiltration of water is generally the most important parameter required in such models. Often these models use an over-simplified estimate of the infiltration rate, which has little basis in reality and actual field conditions. This site presents a compilation of simple infiltration models for quantifying the rate of water movement. A great majority of the compiled models are based on widely-accepted concepts of soil physics. These models, represented by simple mathematical expressions, can be readily implemented in a spreadsheet environment. Proper use of these models should provide a rational and scientific basis for remedial decision-making related to soil contaminant levels.
    MINTEQA2 is a equilibrium speciation model that can be used to calculate the equilibrium composition of dilute aqueous solutions in the laboratory or in natural aqueous systems. The model is useful for calculating the equilibrium mass distribution among dissolved species, adsorbed species, and multiple solid phases under a variety of conditions including a gas phase with constant partial pressures.
  • MOFAT: A Two-Dimensional Finite Element Program for Multiphase Flow and Multicomponent Transport
    MOFAT is a two-dimensional, finite element model for simulating coupled multiphase flow and multi-component transport in planar or radically symmetric vertical sections. MOFAT evaluates flow and transport for water, nonaqueous-phase liquid (NAPL), and gas. The program also can be used when gas or NAPL phases are absent in part or from all of the domain. The flow module can analyze two-phase flow of water and NAPL in a system of constant gas pressure, or explicit three phase flow of water. The transport module can accommodate up to five components, partitioning among water, NAPL, gas, and solid phases, assuming local equilibrium inter-phase mass transfer or first-order kinetically controlled mass transfer.
  • Nonaqueous Phase Liquid (NAPL) Simulator
    This model simulates the contamination of soils and aquifers that results from the release of organic liquids, commonly referred to as nonaqueous-phase liquids (NAPLs). The simulator is applicable to three interrelated zones: a vadose zone that is in contact with the atmosphere, a capillary zone, and a water-table aquifer zone. Three mobile phases are accommodated: water, NAPL, and gas. The three-phase k-S-P sub-model accommodates capillary and fluid entrapment hysteresis. NAPL dissolution and volatilization are accounted for through rate-limited mass transfer sub-models.
  • Optimal Well Locator (OWL)
    This model evaluates existing monitoring well networks and optimizes the selection of new monitoring well locations.
  • Pesticide Analytical (PESTAN) Model
    PESTAN is used to estimate the vertical migration of dissolved organic solutes through the vadose zone to groundwater. Estimates are based on a closed-form analytical solution of the advective-dispersive-reactive transport equation. The model is intended for use in conducting initial screening assessments of the potential for contamination of ground-water from currently registered pesticides and those submitted for registration.
  • Remediation Evaluation Model for Chlorinated Solvents (REMChlor)
    This model simulates the transient effects of groundwater source and plume remediation. This is a contaminant source model based on a power-function relationship between source, mass, and discharge. It can consider partial source remediation at any time after release. The source model is a time-dependent, mass-flux boundary condition to the analytical plume model (one-dimensional flow), which simulates first-order sequential decay and production of several species. This model also calculates cancer risks posed by carcinogenic species.
  • Remediation Evaluation Model for Fuel Hydrocarbons (REMFuel)
    An analytical solution for simulating the transient effects of groundwater source and plume remediation for fuel hydrocarbons. In the analytical method, the contaminant source model is based on a power function relationship between source mass and source discharge for multiple fuel constituents, and it can consider partial source remediation at any time after the initial release. The source model serves as a time-dependent mass flux boundary condition to the analytical plume model, where flow is assumed to be one dimensional. The plume model for each fuel component simulates first order sequential decay and production of one daughter species. REMFuel can also simulate zero order or Monod's kinetics for decay of fuel components in the plume. The decay rates and other reaction coefficients are variable functions of time and distance in the plume. This approach allows for flexible simulation of enhanced plume remediation that may be temporary in time, limited in space, and which may have different effects on different contaminant species in the plume.
  • Regulatory and Investigative Treatment Zone (RITZ) Model
    RITZ is a screening model for simulation of unsaturated zone flow and transport of oily wastes during land treatment. RITZ was developed to help decision makers systematically estimate the movement and fate of hazardous chemicals during land treatment of oily wastes. The model considers the downward movement of the pollutant with the soil solution, volatilization, and loss to the atmosphere and degradation. The model incorporates the influence of oil upon the transport and fate of the pollutant.
  • Storm Water Management Model (SWMM)
    This general purpose urban hydrology and conveyance system hydraulics software is a dynamic rainfall-runoff simulation model used for single event or long-term (continuous) simulation of runoff quantity and quality from primarily urban areas.
  • Two-Dimensional Subsurface Flow, Fate and Transport of Microbes and Chemicals (2DFATMIC)
    This model simulates subsurface flow, fate, and transport of contaminants that are undergoing chemical or biological transformations. This model is applicable to transient conditions in both saturated and unsaturated zones.
  • Three-Dimensional Subsurface Flow, Fate and Transport of Microbes and Chemicals (3DFATMIC)
    3DFATMIC uses a Lagrangian-Eulerian adapted zooming and peak capturing (LEZOOMPC) algorithm. This 3-dimensional model can completely eliminate peak clipping, spurious oscillation, and numerical diffusion; i.e., solve the advective transport problems exactly, within any prescribed error tolerance, using very large mesh Courant numbers. The size of mesh Courant number is limited only by the accuracy requirement of the Eulerian step. Since this model also includes diffusion zooming in solving diffusion elemental matrix, the accuracy is improved by specifying the number of local subelements in every global element. In other words, the more subelements zoomed in diffusion step, the more accuracy at Eulerian step. To sum up, a better solution with respect to advection transport can be obtained with larger time-step sizes; the time-step sizes are only limited by the accuracy requirement with respect to diffusion/dispersion transport and chemical reaction terms. However, the limitation of time-step size imposed by diffusion/dispersion transport is normally not a very severe restriction.
  • Virulo
    Virulo is a probabilistic screening model for predicting leaching of viruses in unsaturated soils. Monte Carlo is employed to generate ensemble simulations of virus attenuation. The probability of failure is generated to achieve a user-chosen degree of attenuation.
    VLEACH is a one-dimensional, finite difference model for making preliminary assessments of the effects on groundwater from the leaching of volatile, sorbed contaminants through the vadose zone. The program models four main processes: liquid-phase advection, solid-phase sorption, vapor-phase diffusion, and three-phase equilibration.
  • WhAEM2000
    WhAEM2000 is a public domain and open source general purpose ground-water flow modeling system, with strengths in representing regional flow systems, and ground water/surface water interactions.

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  • Automated Geospatial Watershed Assessment Tool (AGWA)
    The AGWA tool is a Geographic Information Systems (GIS) interface developed to automate the parameterization and execution of the Soil Water Assessment Tool (SWAT) and Kinematic Runoff and Erosion (KINEROS2) hydrologic models. The application of these two models allows AGWA to conduct hydrologic modeling and watershed assessments at multiple temporal and spatial scales. For large river basins, typically SWAT is employed. AGWA’s current outputs are runoff (volumes and peaks) and sediment yield, plus nitrogen and phosphorus with the SWAT model.
  • BASINS 4.0 Climate Assessment Tool (CAT): Supporting Documentation and User's Manual (Final Report)
    BASINS and WEPP Climate Assessment Tools (CAT): Case Study Guide to Potential Applications (Final Report)
    BASINS CAT provides flexible capabilities for creating climate change scenarios allowing users to quickly assess a wide range of what if questions about how weather and climate could affect their systems.  The report presenting a series of short case studies illustrating the capabilities of the BASINS CAT  (and a second Water Erosion Prediction Project (WEPP) Climate Assessment Tool) is for conducting scenario-based assessments of the potential effects of climate change on water resources.
    CANARY software evaluates standard water quality data (e.g., free chlorine, pH, total organic carbon) over time and uses mathematical and statistical techniques to identify the onset of anomalous water quality incidents. Before using CANARY for the first time, historical utility data must be used to determine the natural variation of these water quality parameters. This allows the water utility to adapt CANARY to work accurately at multiple locations within the water distribution system and helps utility operators to understand the expected false alarm rates associated with CANARY and contamination incident detection. 
  • Causal Analysis/Diagnosis Decision Information System (CADDIS)
    CADDIS is a web-based technical support system for implementing the stressor identification process for determining environmental causes. Biological indices are the principal monitoring tool for evaluating the biological condition of water bodies in all 50 states, many territories and tribal lands. Yet when a biological assessment indicates a problem, it may not be readily apparent what caused the problem. CADDIS provides states a causal assessment framework by which data and other information are organized and evaluated, using quantitative and logical techniques, to determine the likely cause of an observed condition needed to identify appropriate remediation or restoration actions. 
  • CHEMFLO™-2000, Interactive Software for Simulating Water and Chemical Movement in Unsaturated Soils
    CHEMFLO-2000 enables users to simulate water movement and chemical fate and transport in vadose zones. The software can be used to assist regulators, environmental managers, consultants, scientists, and students in understanding unsaturated flow and transport processes. Water movement and chemical transport are modeled using the Richards and the convection-dispersion equations, respectively. The equations are solved numerically using the finite differences approach.
  • EPA’s Estuary Data Mapper (EDM)
    EDM is a downloadable application that can help states view and access data for estuary-scale geographical regions of interest. Data types include nitrogen sources and loads for coastal watersheds and estuaries, including atmospheric deposition, point source loads and nonpoint source loads as well as response endpoints such as seagrass and chlorophyll a.  
  • EPA H2O
    EPA H2O is a desktop GIS based decision support tool for assessing the provision of ecosystem services under different land use scenarios. Users can explore the spatial arrangement of ecosystem goods and services at regional to local scales, complete spatial queries along hydrological networks, and generate customized reports for scenario comparisons, all to gain a better understanding of where ecosystem services are produced and how land use change might affect future production. The tool is simple yet powerful with a graphical user interface designed for basic or advanced users. It demonstrates a fully populated case study database with the functionality to create new databases for other communities. This tool can be used by any community as long as they can develop their local database. States can generate pdf summary reports of what is in both an area of interest and areas upstream or connected via transportation network, compare different alternative future land use scenarios for an area, and generate custom designed scenarios including changing the placement and shape of land use parcels as well as modifying the monetary value benefit functions.
    EPANET allows users to simulate hydraulics and water quality in drinking water distribution networks. It is a Windows program freely distributed in the public domain. EPANET performs extended period simulation of pressures, flows, and disinfectant concentrations within pressurized pipe networks. Using EPANET engineers can plan and design modifications to existing distribution systems. Using the model, they can gain insight into the operation of their system and can perform studies to diagnose and fix problems. EPANET is a general tool that allows utilities to better manage the operations of their distribution networks.
  • Geostatistical Environmental Assessment (GEOEAS) 
    GEOEAS is a collection of interactive software tools for performing two-dimensional geostatistical analyses of spatially distributed data. The principal function of the package is the production of grids and contour maps of interpolated (kriged) estimates from sample data. GEOEAS can produce data maps, univariate statistics, scatter plots/linear regression, and variogram computation and model fitting.
  • Geostatistical Software Package (GEOPACK)
    GEOPACK is a comprehensive geostatistical software package that allows both novice and advanced users to undertake geostatistical analyses of spatially correlated data. The program: GEOPACK allows users to incorporate additional programs at a later date without having to alter previous programs or recompile the entire system.
  1. Generates graphics (for example, linear or logarithmic line plots, and contour and block diagrams)
  2. Computes basic statistics (for example, mean, median, variance, standard deviation, skew, and kurtosis)
  3. Runs programs for linear regression, polynomial regression, and Kolomogorov-Smirnov tests
  4. Calculates linear estimations and nonlinear estimations
  5. Determines sample semivariograms and cross semivariograms
  • HSPF Toolkit for BMP Modeling Applications (FTABLE)
    The Hydrological Simulation Program - FORTRAN (HSPF) Toolkit is a comprehensive package for simulation of watershed hydrology and water quality for both conventional and toxic organic pollutants. HSPF incorporates watershed-scale agricultural runoff management models and nonpoint source models into a basin-scale analysis framework that includes fate and transport in one dimensional stream channels. It is the only comprehensive model of watershed hydrology and water quality that allows integrated simulation of land and soil contaminant runoff processes with in-stream hydraulic and sediment-chemical interactions.
  • Hydrological Simulation Program - FORTRAN (HSPF)
    HSPF is a comprehensive package for simulation of watershed hydrology and water quality for both conventional and toxic organic pollutants. The result of this simulation is a time history of the runoff flow rate, sediment load, and nutrient and pesticide concentrations, along with a time history of water quantity and quality at any point in a watershed. HSPF simulates three sediment types (sand, silt, and clay) in addition to a single organic chemical and transformation products of that chemical. HSPF allows states to understand through simulation the hydrological effects of pollutant loads, and can help states predict which BMPs predicted impacts to water quality.
  • Mercury Geospatial Assessments for the New England Region (MERGANSER)
    MERGANSER relates atmospheric mercury deposition and lake and watershed characteristics to Hg concentrations in fish and fish-eating wildlife (common loons). The tool provides predicted mercury levels in fish and loons via a web-based interactive tool for 4,404 lakes in New England. States can use MERGANSER to assess the risk of Hg contamination in fish and loons throughout New England and to help plan Hg-pollution reduction efforts. 
  • National Stormwater Calculator with Climate Scenarios (SWC)
    SWC is a desktop application designed to help support local, state, and national stormwater management objectives using GI practices. The primary focus of the SWC is to inform site developers on how well they can meet a desired stormwater retention target, but it can also be used by landscapers and homeowners. In January 2014, it was updated to include the ability to analyze different future climate change scenarios. Users can apply these different scenarios to determine how well GI increases the resiliency of stormwater management approaches to a changing climate. The SWC is now a resource for LEED Project Credit 16 (Rainwater Management) certification by the U.S. Green Building Council for projects that are designed to reduce runoff volume and improve water quality of a site.
  • Retention Curve (RETC) Computer Program
    RETC is a program for analyzing the hydraulic conductivity properties of unsaturated soils. The parametric models of Brooks-Corey and van Genuchten are used to represent the soil water retention curve. The theoretical pore-size distribution models of Mualem and Burdine predict the unsaturated hydraulic conductivity function. The simulation can be generated from observed soil water retention data, assuming that one observed conductivity value (not necessarily at saturation) is available. The program also permits users to fit analytical functions simultaneously to observed water retention and hydraulic conductivity data.
  • Stormwater Management Model - Climate Adjustment Tool (SWMM CAT)
    SWMM, first released in 1971, models hydrology and hydraulics to simulate the movement of water through the landscape and into and through sewer systems. The most recent version of this model includes a green infrastructure module to simulate the integration of green infrastructure practices, ranging from green roofs to permeable parking lots, into a community’s stormwater management plan. SWMM is  widely used throughout the world and considered the "gold standard" in the design of urban wet-weather flow pollution abatement approaches, and allows users to include any combination of low impact development/green infrastructure controls to determine their effectiveness in managing stormwater and sewer overflows. The new CAT update for SWMM is particularly useful to states, as it is a simple to use software utility that applies monthly climate adjustment factors onto historical precipitation and temperature data to consider potential impacts of future climate on stormwater.
    SUSTAIN is a decision support system to facilitate selection and placement of Best Management Practices (BMPs) and Low Impact Development (LID) techniques at strategic locations in urban watersheds. It was developed to assist stormwater management professionals in developing implementation plans for flow and pollution control to protect source waters and meet water quality goals. From an understanding of the needs of the user community, SUSTAIN was designed for use by watershed and stormwater practitioners to develop, evaluate, and select optimal BMP combinations at various watershed scales on the basis of cost and effectiveness. SUSTAIN is a tool for answering the following questions:
    • How effective are BMPs in reducing runoff and pollutant loadings?
    • What are the most cost-effective solutions for meeting water quality and quantity objectives?
    • Where, what type of, and how big should BMPs be?
    The SSOAP toolbox is a suite of computer software tools used for the quantification of RDII and help capacity analysis and condition assessment of sanitary sewer systems. This toolbox includes EPA’s Storm Water Management Model Version 5 (SWMM5) for performing dynamic routing of flows through the sanitary sewer systems.
  • Threat Ensemble Vulnerability Assessment – Sensor Placement Optimization Tool (TEVASPOT)
    TEVASPOT allows users to define a water network contamination “scenario,” simulate the spread of the contaminant or contaminants throughout the water network, analyze the consequences, and display the results in a variety of graphical and tabular forms. The ultimate aim of a simulation and its subsequent analysis is to determine the vulnerability of the distribution system to contaminant releases and determine the optimal locations to place a set of water quality sensors in the network to mitigate the impacts of contamination.
  • Toxicity Forecaster (ToxCast™) and iCSS Dashboard
    ToxCast uses high-throughput screening assays to screen cells or proteins for changes in response to chemical exposure. Changes in biological activity may suggest potential toxic effects and eventually potential adverse health effects from chemical exposure. The data from these assays is publically available in the ToxCast database and can be explored using the Chemical Safety for Sustainability (iCSS) dashboard interactive tool.
  • Virtual Beach (VB)
    Virtual Beach is a software package designed for developing site-specific statistical models for the prediction of pathogen indicator levels at recreational beaches. Virtual Beach facilitates the development of statistical models of pathogen indicator levels at recreational beaches. VB3.0.4 reads input data from a text or Excel file, assists the user in preparing the data for statistical analysis, and provides three analytical techniques for model development:  multiple linear regression (MLR), partial least squares regression (PLS), and a gradient boosting machine (GBM). With an integrated mapping component to determine the geographic orientation of the beach, the software can automatically decompose wind/current speed and direction into along-shore and onshore/offshore components. VB3.0.4 can produce new variables from sets of variables in the input file (e.g., means, minimums, maximums, differences, sums, products), and it can test an array of transformations on the independent variables to maximize the linearity of the relationship between the response and those independent variables. Virtual Beach is primarily designed for beach managers responsible for making decisions regarding beach closures due to pathogen contamination. However, Virtual Beach can be used by states to better understand the relationships between water quality indicators and ambient environmental conditions will find Virtual Beach useful.
  • Water Quality Analysis Simulation Program (WASP)
    WASP is a spatially and temporally dynamic, mechanistic modeling framework that can assist states by simulating solids and contaminants in the surface water and the underlying sediment layers, with flexibility to handle different complexities of such systems as ponds, lakes, streams, rivers and estuaries. WASP has been widely applied in the development of TMDLs. EPA’s Office of Wastewater Management routinely uses this model to address nitrogen (N) and phosphorus (P) loadings.
  • Water Quality Analysis Tool (WQAT)
    WQAT was developed jointly between EPA and NASA to overcome some of the barriers water quality analysts encounter working with remote sensing satellite imagery. This tool simplifies access to and use of remote sensing. It allows an entry-level analyst with knowledge of GIS and Excel to work with satellite data. For example, the tool can be used to develop a time-series or extract a statistical distribution for a water body to develop nutrient criteria. Since many states are moving forward with satellite data for establishing chlorophyll criteria, this tool could reproduce the satellite remote sensing work EPA did for the Florida nutrient criteria rule making.
  • Watershed Deposition Mapping Tool
  • Watershed Health Assessment Tools Investigating Fisheries (WHATIF)
    WHATIF is software that integrates a number of calculators, tools, and models for assessing the health of watersheds and streams with an emphasis on fish communities in the Mid-Atlantic Highland region.
  • Watershed Management Optimization Support Tool (WMOST)
    WMOST is a public-domain, efficient, and user-friendly tool for local water resources managers and planners to screen a wide-range of potential water resources management options across their watershed or jurisdiction for cost-effectiveness as well as environmental and economic sustainability. The tool is intended to aid in evaluating the environmental and economic costs, benefits, trade-offs, and co-benefits of various management options.

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  • Chemical and Product Categories (CPCat) Database
    CPCat catalogs the use of over 40,000 chemicals and their presence in different consumer products. The chemical use information is compiled from multiple sources while product information is gathered from publicly available Material Safety Data Sheets (MSDS). EPA researchers are evaluating the possibility of expanding the database with additional product and use information.
  • Drinking Water Treatability Database (TDB)
    TDB presents referenced information on the control of contaminants in drinking water. It allows drinking water utilities, first responders to spills or emergencies, treatment process designers, research organizations, academicians, regulators and others to access referenced information gathered from thousands of literature sources and assembled on one site. Over time, the TDB will expand to include over 200 regulated and unregulated contaminants and their contaminant properties. It includes more than 25 treatment processes used by drinking water utilities. 
    A one-dimensional, steady-state model used to predict the concentration of contaminants migrating from a waste disposal facility via the subsurface, surface water, and air pathways to receptor sites.
  • National Database Structure for Life Cycle Performance Assessment of Water and Wastewater Rehabilitation Technologies (Retrospective Evaluation) Exit (Registration required)
    This database houses performance evaluation data for rehabilitation technologies used in the water and wastewater sectors on a national basis, including additional cured-in-place pipe liner testing. The database will improve the capability of utilities to sustainably manage their aging and deteriorating water distribution, stormwater and wastewater collection systems, and will help increase acceptance of new and innovative technologies by decision makers who adopt, regulate, and design infrastructure technologies. The databases can also assist utilities to more effectively implement comprehensive asset management, provide reliable service to their customers, and meet their Clean Water Act and Safe Drinking Water Act requirements. This will accelerate the development, evaluation, and market acceptance of the developed rehabilitation technologies.
  • PPCP (Reference Databases)
    Published Literature Relevant to the Issues Surrounding PPCPs as Environmental Contaminants
    A one-dimensional, finite difference model for making preliminary assessments of the effects on ground water from the leaching of volatile, sorbed contaminants through the vadose zone. The program models four main processes: liquid-phase advection, solid-phase sorption, vapor-phase diffusion, and three-phase equilibration.
  • Water Infrastructure Database (WATERiD)
    This database is used for helping utilities choose the best pipe rehabilitation, condition assessment, and pipe-location determining technologies for both wastewater conveyance systems and drinking water distribution systems. It includes primary information about individual renewal technologies' cost and performance, case studies for their real world applications, and the list of vendors, consultants, and contractors available for a particular technology on a regional basis. The database allows utilities to input their experiences in these areas for the benefit of other utilities.
  • WHPA
    A semi-analytical ground-water flow simulation program used for delineating capture zones in a wellhead protection area. The program consists of four computational modules (RESSQC, MWCAP, GPTRAC, MONTEC).