Citation:

Description:

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.

• 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 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.

Record Details:

Model Detail:

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.

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

Model Guidance Documents :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.

Model Decision Documents :The EPANET Programmer's Toolkit is an online Help file that describes how EPANET's computational engine can be utilized from other applications.

Full source code for EPANET is available.

Model Download Information :A single executable installation file can be downloaded from http://www.epa.gov/nrmrl/wswrd/dw/epanet.html

modelcontactinfo :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 Inputs :Pipe network topology, pipe size, length, and roughness, storage tank sizes, pump characteristics, water usage rates, chemical source concentrations, and chemical reaction coefficients

Model Outputs :Pipe flow rates and velocities, system pressures, tank levels, and chemical concentrations

Model Computer Requirements: