The question of water constitutes a permanent challenge for the countries of North Africa in general and Algeria in particular. For over 20 years, western Algeria region had significant rainfall deficits that resulted in severe droughts, which seriously affected the water resources in terms of quality and quantity. This research presents one of the Water Evaluation and Planning (WEAP) model applications in watersheds of western Algeria. The model is applied to evaluate and analyze the existing balance and expected future water resources management scenarios by taking into account the different operating policies and factors that may affect demand until 2030. The results showed that neither domestic demand nor agricultural demand is met for the basis year 2006. The results also showed that domestic demand can be satisfied for the considered scenarios. Demand management and development of standard of living are the necessary procedures for proper management of the available resources. However, agricultural demand cannot be satisfied for Development of Large Irrigation System scenarios. The results confirmed that WEAP software offers a solid basis to assist planners in developing recommendations for future water resource management by revealing hot spots of action.

The present paper aims at determining the status and trends in water quality at Western Algeria reservoirs. The method consists of the computation of Water Quality Index (WQI) on the basis of the physical–chemical quality parameters that were registered at the monitoring stations placed at the reservoirs. This WQI was applied to water quality data collected from 2001 to 2010. Results revealed that the overall surface water quality mainly fell into the marginal class in all reservoirs, expect Hammam Boughrara reservoir where water quality fell into the poor category. This implies that the water quality of this reservoir is almost always threatened or impaired; conditions usually depart from natural or desirable levels. The low value of the index was registered in 2005 at the following monitoring stations: Hammam Boughrara – 26.5%, Sikkak – 33.5%, and Cheurfa – 41.2%. This low level of WQI can be attributed to a number of variables and tests that exceed or are less than the objectives. This study showed that the Canadian Council of Ministers of the Environment's WQI (CCME WQI) may assist water managers to integrate and interpret the picture of overall water quality in the study area.

Water quality indices (WQIs) are necessary for resolving lengthy, multi-parameter, water analysis reports into single digit scores; different WQIs have been developed worldwide which are greatly differing in terms of mathematical structures, the numbers and types of variables included, etc. The aim of this paper is to evaluate trends of water quality in Tafna basin with a comparison of 10 WQIs perceived as the most important indices for water quality assessment. The results show that there is an appreciable difference between indices values for the same water sample. The results also show that water quality categorization for sampling stations in the Canadian Council of Ministers of the Environment WQI (CCMEWQI) and British Columbia WQI (BCWQI) was found to be ‘marginal’ for all sampling stations, except Hammam Boughrara reservoir and Mouillah wadi where it was found to be ‘poor’. For the Aquatic Toxicity Index, it was found to be ‘totally unsuitable for normal fish life’ for all stations and ‘suitable only for hardy fish species' for Mouillah wadi and Boughrara reservoir. The results show that this transboundary catchment always needs strategies for more effective pollution control management. Future use of WQIs in this way should prove a valuable tool for environmental planning decision-makers in tracking water quality change.

The present paper aims at determining the status and trends of groundwater quality of 12 aquifers situated in Northwestern Algeria, especially under conditions of last drought that has affected the region using water quality index (WQI) over a period of 4 years. Multivariate statistical methods have been used jointly with conventional graphical methods, to classify the samples according to plausible levels of groundwater evolution. The computed WQI values range from 67 to 588 and therefore can be categorized into four categories: “good water” to “water unsuitable for drinking.” Overall, 36% of groundwater sites sampled in the study area had good water quality, while 53% were poor. Unfortunately, 6% of the samples indicate “very poor water quality” and 5% represent water “unsuitable for drinking purposes.” Results show that the majority of groundwater of Tafna basin fell under good water quality. Groundwater of poor and medium quality characterizes the majority of the studied aquifers of Macta basin. The result showed that the water quality at monitoring station “Ain Skhouna” fell under good water quality (Chott Chergui aquifer). Results also show that groundwater of Coastal Oranais basin showed poor water quality, very poor at some monitoring stations of Mléta Plain aquifer. It has been demonstrated that the water of some aquifers has degraded under water scarcity conditions and will continue to degrade given the ongoing and projected development in the study area. The analysis reveals that the water of some aquifers needs treatment before it is used for human consumption. The influence of salt water on the some freshwater aquifers in the study area needs special attention in terms of monitoring and for sustainable management.

Located in the semi-arid areas of Algeria, M'zi wadi basin experienced severe floods that pose a potent threat to the present day. In order to reduce and mitigate flood damage there is a need to develop tools for effective flood hazard management at basin scale, the paper aims to mapping of flood hazard potential areas in M'zi wadi basin, using Analytic Hierarchy Process (AHP) approach coupled with Geographic Information System (GIS), based on several parameters that are relevant to flood hazard which has been weighted depending to their contributions. The Rainfall-Runoff-Inundation (RRI) model was also used in this study to understanding the hydrological behavior of M'zi wadi basin and to evaluate the efficiency of structural measures in downstream areas of basin. The results show a reasonable agreement with the inundated areas detected by Sentinel-2 imagery. The result of the flooding hazard in M'zi wadi basin reveals that 3%, 0.84%, 67%, 29%, and 0.16% of the catchment is high, very high, moderate, low, and very low flooding hazard areas respectively. The results show also that urban areas and agricultural areas surrounding of the lower portion of M'zi wadi are extremely exposed to flooding. The RRI model simulation results shows that the new dam -under construction-can reduce the magnitude of peak storm runoff only by 7%, and the widening of wadi near to outlet of basin can help to reduce the water level at this segment by 22% compared with results of simulation of naturalized conditions. Flood hazard areas assessment at M'zi wadi basin level can be used by concerned government's department as an excellent supporter of decision-makers during extreme and intense rainfall events in making floodplain management decisions.

Environmental projects need decision-making that integrates environmental, socio-political, and economic factors. Finding a suitable location for a wastewater treatment plant (WWTP) can be a complex and challenging task for the government department, as it requires consideration of numerous geographic factors and their interactions. Located in North-Central Algeria, the city of Laghouat is vulnerable to natural hazards such as unpredictable floods of M'zi wadi that pose a threat to life and property in the surrounding urban and rural areas, as well as to the current WWTP. It is worth mentioning that prior studies related to WWTP concerns and possible solutions at the local or regional level have not been carried out. The purpose of the work reported in this paper was to select an alternative WWTP site in the urban areas of Laghouat City by using the analytic hierarchy process (AHP) and geographic information systems (GIS). Various alternative sites for a WWTP are presented and evaluated; the results of the analysis reveal that 2.12%, 68.25%, 29.36%, and 0.27% of the total area are of high, moderate, low, and very low suitability, respectively, for siting a WWTP, respectively. The southeast part of the study area, which has a low elevation and flat gradients, has the most appropriate candidate sites. Three possible sites were identified: site A is the most advantageous; it would be a very good site for maximizing the WWTP’s performance and effectiveness, and there is the possibility of using treated wastewater for nearby agriculture. The final suitability map can assist local government agencies and departments in making sustainable decisions in the planning phases of engineering projects.

Located in the hyper-arid regions of Algeria, the M’zab Wadi basin has historically experienced severe flash flooding, causing severe economic damage and loss of life. Identifying potential flood hazard areas in such an arid environment, challenged by data scarcity, is necessary to forecast flood and to create early warning strategies. The paper aims to map and highlight potential flood hazard areas in the M’zab Wadi basin using geographic information system coupled with the Analytical Hierarchy Process method based on seven related flood hazard factors. The accuracy of the flood hazard map was validated using the Receiver Operating Characteristic based Area Under Curves method. The results show that 3.04% (50.35 km2) and 0.53% (8.74 km2) of the basin area are under high and very high flood vulnerability levels, respectively. The obtained results can offer significant insights to policymakers and decision-makers to make well-informed judgments regarding the effectiveness of flood protective infrastructure/measures. Furthermore, the approach adopted can be advantageous for other regions under similar conditions.

El Bayadh province, situated in southwestern Algeria, faces significant environmental challenges, including desertification, land degradation, and natural water scarcity, owing to its arid and semi-arid climate, which impedes the achievement of water-related Sustainable Development Goals. In such regions, decision-makers need methodologies that will allow them to develop a shared vision for the future of water resources, prepare for uncertainties, and adapt to ever-evolving challenges. This paper aims to assess water availability and demand under multiple scenarios that could plausibly unfold in the future, considering uncertain factors, such as climate change, policy options, technological development, and human behavior change, using the Water Evaluation and Planning System (WEAP) model. The study findings indicate a significant water supply–demand gap, resulting in substantial unmet water demand. Furthermore, the results demonstrate that water scarcity already impacts some agricultural areas. The results highlight the need to develop long-term strategies for the worst-case scenario and enhance preparedness for all response measures. Several adaptive solutions are proposed through this study, which can help water managers handle complex and interlinked water challenges.

Hamlat, A., Hamdi, K., Kissari, D. E., Kadri, C. B., Guidoum, A., & Sekkoum, M. (2024). GIS-based multi-criteria decision analysis for groundwater dam site selection in an arid and semi-arid region of Algeria. Groundwater for Sustainable Development, 26, 101231. https://doi.org/10.1016/j.gsd.2024.101231.