Reducing volumes of water loss on the drinking water supply network is a significant
challenge that is entirely in line with the sustainable development policy of all countries. Indeed, an effective network management strategy reduces water loss and saves money in different areas. This proper management requires a precise network knowledge, its infrastructure, its hydraulic operation and requires regular, and network regular maintenance. Our study consisted of analysing Rabat and Sale data to minimize drinking water losses.
Key Words: Water Supply Systems, Losses, Leakage Management.
Research and leaks repair are among the direct and essential operations in action programs for improving drinking water supply networks performance. Over time, network pipelines are subject to progressive degradation mechanisms due to operating and / or environmental conditions that are manifested by a decrease in their performance and an increase in service maintenance costs. Which explains the rehabilitation requirements that are proposed to remedy observed dysfunctions or to reduce them (Alexandre O. (1998). Elnaboulsi J.). Management objectives of drinking water networks are multiple: to avoid any break of service, to ensure the quality of rendered service, by the search for control of the costs of investments, exploitation, and maintenance of the system in a under specified conditions of dependability, to perform a required function (AFNOR, 2001 ; Dell ’Orfano et al, 2013 ;
Granger et al ,2010; Charrat, 1995). Maintenance decision, which is sensitive to economic and financial, social and technical criteria, requires a good understanding of the interaction between various factors that contribute to the damage in the drinking water system or that are related to impacts that become unacceptable.
- Water loss
Water losses are a real problem for the managers and the environment, The Data is provided by REDAL (Autonomous Water and Electricity Distribution Authority), Network heritage represents a total linear of 3980 km in drinking water. The strategy adopted by REDAL is as follows:
-Sectorization of distribution networks, this method is adopted to detect and locate leaks. It allows an annual, permanent, and punctual follow-up.
|Figure 1: Hydraulic sectors of the cities Rabat and Sale|
But before the intervention, it is necessary to analyse the performance indicators adopted by REDAL: Night flow, linear loss index, linear leakage index and age of pipes.
Table1. Some performance indicators used and their calculation formula (Renaud,2010)
|Performance of the distribution network||R = (Volume consumed annually / volume distributed annually) * 100|
|Linear loss index||ILP= night flow / network Length (m3 / km / day)|
|Linear Leakage Index||ILF= Total Number of Leaks / Cumulative Swept Linear (Leak / km)|
To prioritize the indicators used the method of multicriteria analysis. Data is processed using Geographic Information System (GIS) to establish risk maps to define priority areas.
Figure 2.Water leaks risk maps in hydraulic sectors for 2018
Prioritization of sectors facilitates tasks for managers, and then comes the role of Team intervention.
– leak detection RC, this section is responsible for investigating possible leaks in the drinking water system, responding to customer complaints to repair leaks in the drinking water system. REDAL has developed a unique application called SIGID, which facilitates the management of claims and work orders that follow customer complaints.
|Figure 3:Pressure stabilizer|
– Oriented leak detection DFO, based on night flow data and leak history, leak detection teams are oriented towards increasing night-time flow zones. After the mission, the intervention report must include the information in the GIS. The search methods use the files after the mission. The intervention report must integrate the information into the GIS. The research methods use acoustic pre-localization. Regulation, pressure modulation and telemetry and meter calibration. The results obtained in the following table by the two intervention teams: with
Water price/cubic meter:2,7 DH/m3= 0,26EUR
Table2. Leak Detection for Rabat and Sale in 2018
|Centre||Leaks detected following RC||Leaks detected following DFO||Total leaks detected||Total estimated gain in m3|
|Rabat and Sale||123,00||1 959,00||2 082,00||1 189 599,00||309295,74|
After the Rabat and Sale data processing, some sectors have priority over others. This analysis facilitated the tasks to establish an action plan for leak detection and team orientation for better management of the drinking water system, as long as the regular check and anticipate an emergency program for repair immediate leaks from the network. The hierarchical prediction plan for sector pipeline renewals obtained was consistent with the distributor’s perspective. This proves the reliability of the work developed during this work and offers the opportunity to exploit this system on a larger scale thus saving the time and resources of the manager, something that is profitable for the latter.
AFNOR, 2001, Charrat, 1995, Dell ‘Orfano & al, 2013; Granger & al ,2010: AFNOR, 2001, European standard NF EN 13306: Terminology of the maintenance, French Association of Normalization, Paris.
- Renaud, 2010, Towards a global performance indicator for losses from water supply systems. Water Loss, Jun 2010, Sao Paulo, Brazil. 11 p., 2010. <hal-00593479>.
- Elnaboulsi, O. Renewal of urban drinking water networks, A cost-effective approach to optimization.Water-agriculture-territories engineering, Lavoisier; IRSTEA; CEMAGREF, 1998, p. 3 – p. 17. ffhal-00463000f.
Ziane Imane1, MOHAMMED KARIM BENHACHMI1, Rares Halbac-Cotoara-Zamfir2
1Department of Process Engineering and Environment, University Hassan II of Mohammedia, Science and Technology Faculty of Mohammedia, 20650 Morocco.
2 Department of Hydrotechnics, Faculty of Civil Engineering, Polytechnic University of Timisoara, George Enescu Street, No. 1/A 300022 – Timisοara, Romania