Enhancing the resilience of intermittent water supply systems in Khan Younis, Gaza Strip. Knowledge transfer and lessons learned from the Gaza H2.0 project

Future water security in Palestine is challenged by the compound effect of water scarcity, operational inefficiencies in water supply infrastructure, and the unstable geo-political setting. Among these factors, water losses represent a major challenge to the environmental sustainability and financial stability of water resources management in the area. The Palestinian Water Authority estimated the amount of non-revenue water (NRW) in the Gaza Strip to approximately 35.7 million cubic meters in 2018. This is equivalent to a direct loss of 37.6% of the total water supplied, further indirectly implying inefficient use of water-related energy and resources to treat and distribute water.

Water loss reduction and more sustainable water supply are key priorities in Khan Younis, the second most populated city in the Gaza Strip. Water supply and sanitation services in Khan Younis are managed by the Khan Younis Municipality (KYM). The KYM water distribution system is currently operated with an intermittent water supply scheme based on empirical and expert-based knowledge. The water loss rate in Khan Younis is rather uncertain and different estimates exist. However, the average water consumption from data provided by KYM in early 2021 was estimated to 74.7 liters per capita per day (lcd), which resides in the range recommended by the World Health Organization to meet the basic water needs, while the daily amount of water supplied via the distribution network was on average 99.5 lcd, indicating a NRW rate of approximately 25%.

In this work, we discuss lessons learned from the ongoing EU funded project “Gaza H2.0: Innovation and water efficiency” which aims at promoting efficient and sustainable water supply and demand, along with knowledge transfer to enhance resilience against water scarcity in the Gaza Strip. First, we analyse the gaps between research and practice which emerged in the project while updating the hydraulic model of the KYM water distribution. A rich body of literature highlights that building and calibrating a hydraulic model of a water distribution network is not a straightforward task that depends greatly on available data, calibration techniques, and modeler’s expertise. This was proven true for building the KYM water distribution network model, as an up-to-date inventory of network components was not available and only limited historical data were recorded. Thus, an extensive surveying campaign was run in 2021 via the installation of 51 pressure sensors logging data with a 1-min frequency throughout the 27 distribution zones in the network. As a result, sufficient measurement data was recorded to perform an initial calibration of the hydraulic model. However, some components of the network remain ungauged. We will thus discuss lesson learned and propose recommendations to enhance hydraulic model calibration for KYM and similar networks. Second, we will describe and discuss the strategies planned and invoked during the Gaza H2.0 project to foster knowledge transfer to and increase involvement from all stakeholders. These actions aim to guarantee the long-term sustainability of the technological solutions proposed in the project, such that they can serve as a starting point to address future climate and infrastructure challenges.