Water balance assessment using remote sensing, Wet-Spass model, CN-SCS, and GIS for water resources management in Saïss Plain (Morocco)

Abstract

Saiss plain contains an important aquifer. This complex groundwater system plays an important socio-economic role. Managing the groundwater resources requests a good understanding of resources availability and human needs satisfaction. These two components are estimated to get annual water balance of Saiss aquifer. Resources availability depends on meteorological parameters (rainfall, wind speed, temperature, etc.), soil types, topography, water table, and land use. Previous studies do not consider all of these parameters in assessing the water resources availability in this region. In this study, we have identified the relationship between all Saiss hydro-meteorological parameters and we have organized all data in Geographic Information System (GIS) to assess inputs of the water balance. Meteorological and hydrological data and landuse/landcover maps obtained from Landsat imageries classification were used in Wet-Spass (water and energy transfer between soil, plants, and atmosphere under quasi-steady state) model and Soil Conservation Service Curve Number (CN-SCS) method to assess annual runoff, potential evapotranspiration, interception, actual evapotranspiration, and natural recharge of shallow aquifer of Saiss plain. The results of the water balance calculation indicate significant fluctuations in the aquifer recharge: 280 Mm3 (1987) and 418 Mm3 (2018). The annual direct runoff increased from 344 Mm3 (1987) to 638 Mm3 (2018).