The Impact of Urbanization Versus the Impact of the Change in Climatic Conditions on Groundwater Recharge from Precipitations: Case Study Algiers

A comparative quantitative study on the impact of two of the most important factors threatening fresh water resources (urbanization and climate change) is presented. Using the Soil Conservation Service-Curve Number (SCS-CN) model, the individual impacts of the development of urban areas and the changes in the climatic conditions on several components of the urban hydrological cycle (runoff, initial abstraction with a focus on groundwater recharge from precipitations) are assessed with a daily time step at the scale of Algiers during the period 1987–2016. For the presented case study, it was found that the changes in the climatic conditions impacted all three components of the hydrological cycle with a higher magnitude than the development of the urban area. A strong correlation between groundwater recharge (and runoff) and the climatic conditions is observed. Moreover, it is estimated that potential natural groundwater recharge in constructed areas can be higher than that in non-constructed ones; an aspect that can shift with changes in the climatic conditions (particularly the changes in rainfall intensity and frequency).