Introduction to EPANET and Hydraulics in Pipe Network Design

What is EPANET?

EPANET is a computer program that performs extended period simulation of hydraulic and water quality behavior within pressurized pipe networks. A network consists 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 throughout the network during simulation period comprised of multiple time steps.

Hydraulic Modeling Capabilities

EPANET is very powerful software depending on its user. Here are some list of the software's capabilities:

• No size limit of the Network

• Computes Hazen-Williams, Darcy-Weisbach, or Chezy-Mannings Formulas

• Includes minor head losses for bends and fittings

• Models constant or variable speed pumps

• Computes pumping energy and cost

• Models various types of valves including shutoff, check, pressure regulating, and flow control valves

• Allows storage tanks to have any shape (i.e., diameter can vary with height)

• Considers multiple demand categories at nodes, each with its own pattern of time variation

• Models pressure-dependent flow issuing from emitters (sprinkle heads) can base system operation on both simple tank level or timer controls and on complex rule-based controls.

Physical Components

There are two main components in EPANET: nodes & links. A node can stand alone. you can add any node anywhere in the workspace. A link is dependent to the nodes. You can't add any link without starting and end node.

• Junctions - are points in the network where links join together and where water enters or leaves the network.

• Reservoirs- are nodes that represent an infinite external source to the network. They are used to model such things as lakes, rivers, groundwater aquifers and tie-ins to the system.

• Tanks - are nodes with storage capacity, where the volume of stored water can vary with time during simulation

• Pipes - are links that convey water from one point in the network to another. EPANET assumes that all pipes are full at all times.

• Pumps – are link that impart energy to a fluid thereby raising its hydraulic head.

• Valves – are links that limit the pressure or flow at a specific point in the network.

EPANET RUNTHOUGH

The EPANET looks like this:

The Main Toolbars looks like this and located at the top left of the workspace:

New: Click to Create New Project

Open: Click to Open Existing Project

Print: Click to Print the Current View

Save: Click to Save the Project or Save the changes

Copy: can copy the text and graphics of the current window being viewed to the Windows clipboard or to a file. Views that can be copied in this fashion include the Network Map, graphs, tables, and reports.

Delete: Click to delete an object on the map or from the Data Browser.

Find: Click to find a node or link on the map whose ID label is known:

Run: Click to run a hydraulic analysis.

Query: Click to identify nodes or links on the network map that meet a specific criterion (e.g., nodes with pressure less than 20 psi, links with velocity above 2 ft/sec, etc.).

Graph: Click to select a type of graph and its contents to display

Table: Click to generate tabulated report

Options: as discussed earlier, click it to change the options

network map

The Map Toolbars looks like this and located at the alongside the main toolbars

Select Object: Click to select object

Select Vertex: Click to select vertex

Select Region: useful to edit multiple nodes and links

Pan: select to pan in the map

Zoom In/Out: Click to zoom in and out the view of the map

Full Extent: Click to zoom out to full extent

Add Junction: Click to add a junction.

Add Reservoir: Click to add a water source

Add Tank: Clink to add a water tank/storage

Add Pipe: Click to add a pipe. Connect to 2 nodes, if you don’t click on the node, it becomes a vertex .

Add Pump: Click to add a pump. There must be 2 nodes

Add Valve: Clink to add a valve. There must be 2 nodes.

Add Label: click to add a text label

Knowing these tools in EPANET can help you get started in the simulations. Here are some snips in EPANET that would give you idea how useful this program is.

Sample EPANET Simulation

The Image below is showing a simple simulation in EPANET showing the pipe diameters and elevations of certain points.

This video below will show you a simulation of a system for a 24-hour period. You can monitor the flow in each pipe at any time of the day as well as its pressure.

---

Author:

RMP Jonathan "Jong" D. Dalona

Registered Master Plumber / Licensed Civil Engineer

PRC Reg. No. 13427

Proprietor - AquaVita Engineering Services