Water Supply Configuration and Water Losses - Nikšić Waterworks Case Study - Page 03

Development and Calibration of the Nikšić System Simulation Model

In order to provide sufficient and reliable information about the waterworks system and water consumption/demand, the following preparatory activities were conducted:

  • System database creation (GIS), using Mapinfo software,
  • Establishment of DMAs in the distribution network and selection of locations for fixed measuring points,
  • Procurement and installation of flow meters and pressure meters and their installation at selected points (fixed measuring points),
  • Procurement of mobile flow/pressure meters and other leak detection equipment (aquaphones, correlators),
  • Connection of instrumentation at the fixed measuring points to the waterworks SCADA system.

A model of the existing Nikšić water supply distribution system was created using data from the newly created database, which includes information on the physical properties of the system elements, current consumption (divided into areas and consumer types), boundary conditions and the control philosophy of the system operation. This model was calibrated by using data from fixed measuring points measured during a 24-hours period on 08/08/2015.

In addition to the flow and pressure measurements at the fixed measurement points (see Fig 1), water meter readings were conducted every hour for three of the largest commercial and residential water consumers, for calibration purposes.

Through the calibration process, which is an iterative (gradual approximation to the measured flow/pressure values and curve shapes), observed phenomena are linked to define the cause - effect relationships in the system. The calibrated water distribution system model is a powerful tool for analyses of the system's operation.

One set of conclusions derived from the analysis conducted on the calibrated model referred to the identification of areas where high levels of losses may be expected in the present conditions. For purposes of future leakage detection, based on hydraulic analysis, a detection schedule by consumption zones was defined. Ranking of zones was based on the following criteria:

  • Existence of significant differences between billed consumption and the measured value of inlet flow;
  • Less than 1,000 water meters within the zone – which allows for water meter readings during field investigations, without a significant disruption in the regular workflow of the municipal water company;
  • In addition to measuring equipment, the entrance to the zone is equipped with a pressure regulating valve, which enables measurements under variable inlet pressures (e.g. pressure step tests).

 

Fig01
Figure 1: Nikšić water supply distribution system - measurement spots for the purpose of model calibration.

 

Fig02
Figure 2: Calibration results – Duklo BPS flows.

 

Fig03
Figure 3: Calibration results - flows at the entrance to Klicevo 1 zone.

 

Fig04
Figure 4: Calibration results – pressures at the entrance to Trebjeska ulica zone.