Losses in water distribution systems can be between several percent in well maintained systems up to more than 50 percent in developing countries. Most of the losses originate from leaks. Therefore, a fast detection and localization of leaks is crucial for effectively reducing this losses in water distribution networks. Model-based leak localization has become increasingly popular in recent years. Certainly, the performance of these methods is linked to 1) the measurement locations in the system and 2) uncertainties at these locations. This paper provides a methodology that incorporates uncertainties of different types and sources in the optimal sensor placement problem for leak localization shown by the example of the effect of demand uncertainties on potential pressure measurement points. The problem is solved for different numbers of sensors and different strengths of uncertainties are taken into account. Additionally, to describe the relation between the number of sensors and the leak localization quality, a cost-benefit function is derived based on the different sensor placement results and GoF statistics. It was found that the function follows a power law. Results show that incorporating uncertainties leads to other optimal positions than without uncertainties, but the power law behavior still stays true. Additionally, more sensors are needed than without uncertainties.

The Arab world’s environment is among the most vulnerable and harsh ones across the globe. This entails much efforts to mitigate the potential environmental risks. Analysing contributions of Arab scholars in environmental research in terms of quantity and quality can bring up insights on their endeavours in this regard. Bibliometric techniques are proposed to conduct such this analysis over publications originated from Arab world in a leading environmental journal “Science of the Total Environment”. Research productivity is being used as quantitative indicator, while citation rates and Hirsch index (h-index) are being used as qualitative indicators. The research outputs were compared with those obtained from non-Arab Middle Eastern countries (Iran, Turkey and Israel). Worldwide research productivity was 17,258 documents, while that from Arab countries, Iran, Turkey and Israel were 215, 34, 83 and 87 documents, respectively. The h-index of Arab world research was 31, and total citations were 3616 with an average of 16.8. The highest share of publications was recorded by Saudi Arabia (53 documents; 24.7%). Egypt and Saudi Arabia had highest h-index with 15 for each one. American University of Beirut in Lebanon was the highest productive institution (16; 7.4%). The most collaborated country with Arab world was France (29; 13.5%). In the conclusion, the study reveals a clear gap in terms of research productivity between Arab countries and other Middle Eastern countries, precisely Israel and Turkey. More research efforts through optimizing investments in environmental research, developing regional experiences and fostering international collaboration are required to eliminate these lags.

Detecting and locating leaks in water distribution systems is of great interest. For the localization of leaks we make use of pressure sensors alongside a calibrated hydraulic EPANET model of the investigated system. Leakage localization is solved with a Differential Evolution algorithm. For sensor placement we use a non-binarized leak sensitivity matrix with a projection-based leak isolation approach. Additionally, the effect of uncertain hydraulic model parameters on the measurement quantities is investigated by Monte Carlo simulations and was incorporated in the sensor placement algorithm. Uncertainty analysis, sensor placement and leakage location was tested on two hydraulic systems