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Water erosion is a major problem in the semi-arid environments of Algeria. In this vein, the objective of this study is to use the Revised Universal Soil Loss Equation (RUSLE) on the watershed of Medjerda which is located at the extreme of the North-Eastern part of the Algerian territory. Based on the crossing of various factors in raster mode under ArcGIS allows the production of diverse thematic maps corresponding to multiple factors: erosivity of precipitations, erodibility of soils, topography, the vegetal cover and the anti-erosive practices. Moreover, the risks’ map of water soil erosion was obtained depending on the combination of the previous thematic maps with four class risks has been made up indicating an average erosion value of 2.68 t/ha/year. However, this value is relatively reasonable in relation to the given rate by the interpretation of the bathymetric measures carried out in the Ain Dalia dam.

Water losses due to leakage are a pernicious problem for water utilities. Understanding and quantifying Non-Revenue Water (NRW) and water loss components is the first step in the management of urban water losses. Hydraulic modeling is a powerful tool to predict the impacts of different management scenarios on the hydraulics of the Water Distribution Network (WDN). The water distribution network (WDN) can be divided into a number of District Meter Areas (DMAs) with suitable sizes in order to apply pressure management. In this study, the Fixed Area Variable Area Discharge (FAVAD) concept and the number of leaks were analyzed for a number of water network pressure management areas in the city of Bendjerrah – the district of Guelma, Algeria. The analysis identified some anomalies concerning the parameters of some networks; especially those related to leakage exponent N1 values greater than 1.5. The approach used in this framework is based on the estimation of the leakage from the Minimum Night Flow (MNF) and the burst frequency of Average Zonal Pressure (AZP). After the use of this approach and the calibration procedure using the Epanet-calibrator on real District Meter Areas, the obtained results are very close to the real state of the network. In addition, this paper studies the possibility of explicitly incorporating the variation of the leakage zone in the hydraulic modeling of the water distribution systems. The results show that the power equation leakage exponent N1 estimates the total system leakage with an error of up to 20%. From the Minimum Night Flow, obtained by using the South African Night Flow (SANFLOW) practical tool, it was found that the actual losses calculated for sectors 1, 2, and 3 are respectively 25%, 45%, and 30%.