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Model Report

EPANET VERSION 2.0

Last Revision Date: 08/31/2009 View as PDF
General Information Back to Top
Model Abbreviated Name:

EPANET VERSION 2.0
Model Extended Name:

EPANET VERSION 2.0
Model Overview/Abstract:
EPANET is a Windows program that performs extended period simulation of hydraulic and water-quality behavior within pressurized pipe networks. A network can consist of pipes, nodes (pipe junctions), pumps, valves and storage tanks or reservoirs. EPANET tracks the flow of water in each pipe, the pressure at each node, the height of water in each tank, and the concentration of a chemical species throughout the network during a simulation period comprised of multiple time steps. In addition to chemical species, water age and source tracing can also be simulated.

EPANET provides a fully equipped, extended period hydraulic analysis package, which can:

  • Handle systems of any size
  • Compute friction head loss using either Hazen-Williams, Darcy-Weisbach, or Chezy-Manning equations
  • Include minor head losses for bends, fittings, etc.
  • Model constant or variable speed pumps
  • Compute pumping energy and cost
  • Model various types of valves including shutoff, check, pressure regulating, and flow control valves
  • Allow storage tanks to have any shape (i.e., diameter can vary with height)
  • Consider multiple demand categories at nodes, each with its own pattern of time variation
  • Model pressure-dependent flow issuing from emitters (sprinkler heads)
  • Base system operation on simple tank level or timer controls as well as on complex rule-based controls.
In addition , EPANET's water quality analyzer can:
  • Model the movement of a non-reactive tracer material through the network over time
  • Model the movement and fate of a reactive material as it grows (e.g., a disinfection by-product) or decays (e.g., chlorine residual) with time
  • Model the age of water throughout a network
  • Track the percent of flow from a given node reaching all other nodes over time
  • Model reactions both in the bulk flow and at the pipe wall
  • Allow growth or decay reactions to proceed up to a limiting concentration
  • Employ global reaction rate coefficients that can be modified on a pipe-by-pipe basis
  • Allow for time-varying concentration or mass inputs at any location in the network
  • Model storage tanks as being either complete mix, plug flow, or two-compartment reactors.
EPANET's Windows user interface provides a visual network editor that simplifies the process of building piping network models and editing their properties. Various data reporting and visualization tools are used to assist in interpreting the results of a network analysis. These include graphical views (time series plots, profile plots, contour plots, etc.), tabular views, and special reports (energy usage, reaction, and calibration reports).

EPANET was specifically developed to help water utilities maintain and improve the quality of water delivered to consumers through their distribution systems. It can be used to design sampling programs, study disinfectant loss and by-product formation, and conduct consumer exposure assessments. It can assist in evaluating alternative strategies for improving water quality such as altering source utilization within multi-source systems, modifying pumping and tank filling/emptying schedules to reduce water age, utilizing booster disinfection stations at key locations to maintain target residuals, and planning a cost-effective program of targeted pipe cleaning and replacement.

Keywords:
Model Technical Contact Information:
Lewis Rossman
U.S. EPA
National Risk Management Research Laboratory (NRMRL)
(513) 569-7603
rossman.lewis@epa.gov

The model was developed and is maintained by Lewis Rossman.

Model Homepage: http://www.epa.gov/ORD/NRMRL/wswrd/epanet.html

User Information Back to Top
Technical Requirements
Computer Hardware
Personal computer running Microsoft Windows
Compatible Operating Systems
Microsoft Windows (all versions from Windows 98 to Vista)
Other Software Required to Run the Model
C and Delphi
Download Information
A single executable installation file can be downloaded from http://www.epa.gov/nrmrl/wswrd/dw/epanet.html
Using the Model
Basic Model Inputs
Pipe network topology, pipe size, length, and roughness, storage tank sizes, pump characteristics, water usage rates, chemical source concentrations, and chemical reaction coefficients
Basic Model Outputs
Pipe flow rates and velocities, system pressures, tank levels, and chemical concentrations

User Support
User's Guide Available?
The EPANET 2 Users Manual (EPA/600/R-00/057) can be downloaded.

It provides: (1) an abstract or abstract equivalent in the introduction, (2) schematic/diagram showing model structure and interaction of model components, (3) equations, equation solution methodologies, and related simplifying assumptions, (4) example input/output files, (5) input and output variable documentation including definitions, units, temporal/spatial dimensions, temporal/spatial resolution options, (6) guidance on selecting and/or estimating values and/or distributions for input variables (including guidance on calibration and selecting default values and/or distributions), and (7) extensive instructions on running the model through its graphical user interface.

Availability of User Support
EPANET Users list serve.
User Qualifications
Basic understanding of hydraulics and drinking water chemistry

Model Science Back to Top
Problem Identification
EPANET was developed to help water utilities maintain and improve the quality of water delivered to consumers through distribution systems. It can be used to design sampling programs, study disinfectant loss and by-product formation, and conduct consumer exposure assessments. It can assist in evaluating alternative strategies for improving water quality, such as altering source use within multi-source systems, modifying pumping and tank filling/emptying schedules to reduce water age, using booster disinfection stations at key locations to maintain target residuals, and planning cost-effective programs of targeted pipe cleaning and replacement.

EPANET can also be used to plan and improve a system's hydraulic performance. The software can assist with pipe, pump, and valve placement and sizing; energy minimization; fire flow analysis; vulnerability studies; and operator training

Summary of Model Structure and Methods
See the following references:

Todini, E. & Pilati, S. (1987). "A gradient method for the analysis of pipe networks." International Conference on Computer Applications for Water Supply and Distribution, Leicester Polytechnic, UK, September 8-10.

Rossman, L.A. and Boulos, P.F. (1996). "Numerical methods for modeling water quality in distribution systems: A comparison." J. Water Resour. Plng. and Mgmt, Vol. 122, No. 2, 137-146.

Model Evaluation
See the following references:

Rossman, L.A., Clark, R.M., and Grayman, W.M. (1994). "Modeling chlorine residuals in drinking-water distribution systems," Jour. Env. Eng., Vol. 120, No. 4, 803-820.

Vasconcelos et al., (1997). "Kinetics of chlorine decay," Jour. AWWA, Vol. 89, No, 7, 54-65.

Substantial model testing (validation) has been performed. EPANET has been applied to hundreds of sites and been incorporated into several commercial modeling packages.

Model has been internally peer reviewed.


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