EPANET++ is a free web application for modeling water distribution networks, an extension of EPANET.

Calibration report

Compares a file of field measurements with the calculated results at the same locations and times, one file for each parameter. The file is held for the current session only and is not saved with the project.

What the report compares

Choose Water, Reports, Calibration. The Parameter list chooses what the file measures: Demand, Head, Pressure, Chlorine concentration, Flow, or Velocity. One file is held for each parameter, and the Load calibration file… button opens a file chooser. The report has three pages. Statistics gives, for each location, the number of observations, the observed mean, the computed mean, the mean error, and the RMS error, then a Network row for all locations together and the correlation between the means. Correlation plot puts each measurement at its observed value across and its computed value up, with a diagonal line where the two agree. Mean comparisons draws the observed and computed means as a pair of bars for each location.

The computed value is read from the extended period run, and a measurement between two reporting steps is compared with the value interpolated between them. A measurement outside the times the run reported is skipped and counted. With a single instant solution, every measurement is compared with that one result, whatever time the file gives. The report fills in after the network is calculated.

The calibration file

A text file with a location ID, a time, and a measured value on each line. The time is measured from the start of the simulation, in decimal hours or hours:minutes. A semicolon starts a comment. A line with only a time and a value belongs to the location above it. The values are read in the project's units, and the report says which unit. A location that is not in the network is listed and its measurements are counted as skipped, a line that cannot be read is listed by line number, and the rest of the file is used. A file is held in memory for the open project and this page load only. It is not saved with the project or on this device. When the Time series chart shows the same quantity, the measured values are drawn on it as rings.

Example on Net1

Open the Net1 example, calculate it, and choose Water, Reports, Calibration. With Pressure chosen, load a file that gives Junction 11 as 118.5 psi at 0:00 and 121.0 psi at 12:00, Junction 31 as 110.2 psi at 6:00 and 108.7 psi at 18:00, and Junction 99 as 50 psi at 0:00, followed by a line that is not data. The report says the file has 5 measurements at 3 locations, names Junction 99 as not in the network with 1 measurement skipped, and lists the unreadable line. Statistics shows Junction 11 with 2 observations, an observed mean of 119.75 psi, a computed mean of 116.53 psi, a mean error of 3.98, and an RMS error of 5.12. Junction 31 has 109.45, 118.71, 9.26, and 9.79. The Network row has 4 observations, a mean error of 6.62, and an RMS error of 7.81.