Performing Leakage Detection Using Darwin Calibrator

	Applies To
	Product(s):	WaterGEMS, WaterCAD
	Version(s):	08.11.XX.XX, 10.XX.XX.XX
	Area:	Modeling
	Original Author:	Sushma Choure, Bentley Technical Support Group

Overview

The purpose of this technote is to discuss how to use Darwin Calibrator to perform Leakage Detection.

Background

How leakage detection works?

Leak detection works by adjusting the emitter coefficient at nodes in order to get the model to match the field data.

Leakage detection is the main criteria in the water loss management.
You can perform leakage detection using tool Darwin Calibrator in Bentley WaterGEMS.
Using Darwin Calibrator you can predict the location and size of the water loss.
To know about format of the input data required for Leakage detection, please search by phrase – Importing Field Data into Darwin Calibrator Using Modelbuilder.
Once you have detected the leakage nodes, you can use Criticality tool to repair the leaks.
Or you can use Pressure Dependent Demands to minimize the leaks in the system.

Note : Along with this technote you will find attached model used to explain Leakage Detection Using Darwin Calibrator & the input data files using Excel Format.

Tips for Water Loss Management

As an introduction to water loss management, it is advisable that you read the following article before embarking on a leakage detection study: Tips for Water Loss Management and Leak Detection

Observing leakage over the time with the help of graph using the attached model for a particular element:

For this example we have field data of flow through pipe P-13, which we will compare with the model results. (See attached model)

Create graph for P-13. (Right click on P-13>Graph)
Go to observed data tab>create new.
You can directly copy/paste data from the spreadsheet/import .txt file or enter data manually.
Once entered the observed data, the graph should look like this.

The graph shows the actual flow for Pipe P-13 at various time steps & the observed flow on the field. With the help of this graph you can visualize the leakage at the determined locations, by using the actual flow in the model Vs. observed flow on the field. The difference between the actual flow and the observed flow is the leaked flow into the system.

Calibrating the model to observe the leaks in the model

Go to Analysis>Darwin Calibrator>Create new Calibration Study>Rename it as Leakage Study.

Preparing data for importing the field data snapshots

There are several ways of importing the field data into Darwin Calibrator.

Using SCADA

You need to have SCADA element present in the model for importing SCADA data.

2. Using other file formats as

Microsoft Excel
Oracle database
Microsoft access database

Example of data format required using Microsoft Excel.

You can prepare data sheets for multiple hours of the day as seen below.
You need to import two sheets, one for observed data & second to relate the snapshot labels to the Calibrator & the name of of leakage study.
The below example shows a spreadsheet with measured flow through pipes and hydraulic grades at junctions; you can prepare a similar file for other attributes of different elements.
For directed nodes such as PRVs and PSVs, there is a "to" and "from" HGL or pressure, which need to be mapped to their respective attributes (separate from "junction attribute", "junction pressure", etc)
The correct Element Type (Label) for PRVs, PSVs, FCVs, TCVs, GPVs and pumps is “Directed Node”. For pipes, it’s “Pipe” and for junctions and hydrants its “Node”.

Importing field data through Modelbuilder into Darwin Calibrator

Go to Tools>Modelbuilder>New>Excel file. Choose this option as per your input data file.
Import the attached excel file through Modelbuilder. Uncheck sheet P-13 , as it contains observed flow data which we already used for creating the graph for pipe P-13.

Click next, change the coordinate units as per your model units.
Click next until mapping table; map the filed data of hydraulic grades, flows , element labels, time , owner etc. as shown in the image below. Please select Filed data snapshot, observed target as table type for observed data & Field Data Snapshot for Snapshot Labels.

Click next once done with the mapping of Modelbuilder, go to Calibrator to check the imported field data. It should look like this.

Go to demand groups tab to create group of demands>create new>Select edit button from Element IDs column>select elements from drawing.You can create multiple demand groups as per different pressure zones/Material groups/Diameter groups in the model. ( Please see technote of Darwin Calibrator to know how to create demand groups)

Setting up calibrator study for leakage detection

Create new optimized run>Rename it as Leakage Detection.
In the Demand tab, select Detect Leakage Node in the operation column.
Enter the following settings
- Minimum Emitter Coefficient = 0
- Maximum Emitter Coefficient = 0.5
- Increment = 0.01
- Number of Leakage Nodes = 5
Note: You can change the emitter coefficient values as per the amount of leakage.
Go to field data tab, here you can select time steps you want to calibrate, we will select 0 hr for this run. Also you can run the calibration with different combinations of time steps, or all time steps in one go.
Compute the Darwin Calibrator once all set. You can increase the number of solutions by going to options>Optimized run.
Click on the solution 1 in the left side of the window, you can see the number of leakage nodes detected in the right side of the window.
To see which nodes are affected please see the Last column – Adjusted Emitter Coefficient in the Adjustment Groups. Sort the column descending by right clicking on it, to see the affected nodes. Here you can see that junctions J-4 & J-14 are detected as leak nodes having adjusted emitter coefficients of 0.07 & 0.04 , rest all junctions are free from leakage.
Now export the results in the form of scenario to visualize in the model. While exporting the results only select Export Emitter coefficients.

Viewing the results using Element Symbology

Make newly exported scenario as active> Analysis>scenario>Compute the active scenario - New Optimizes Run .
Go to Element Symbology>Junction>New color coding.
Select Emitter Coefficient as the field name>color & size the elements.
You can visualize the leakage elements in the model.

Performing Leakage Detection Using Darwin Calibrator

Overview

Background

How leakage detection works?

Tips for Water Loss Management

See Also