Spatio-temporal typology of the physico-chemical parameters of a large North African river: the Moulouya and its main tributaries (Morocco)

Abstract

The physico-chemical parameters of surface water from the largest Maghrebian river flowing into the Mediterranean Sea, the Moulouya River, show a large variability in space and time, under the influence of natural and anthropogenic phenomena. This study was conducted between March and August 2014, and involved regular bimonthly monitoring of nine abiotic parameters in each of the 45 selected stations along the Moulouya River and its main tributaries: the Anzegmur, Melloulou and Za rivers. The use of inter- and intraclass analyses facilitates the interpretation and understanding of the spatio-temporal variability of these physico-chemical descriptors and highlights the evolution of their spatial structure, and supported by the statistical analyses. In this study, a dominant spatial typology marked by a reduced temporal influence is highlighted. In terms of comparisons between the four rivers studied, the results show that the water quality in the Anzegmur and Melloulou Rivers is good with little or no pollution if judged by the Moroccan standards of the quality of the surface waters. In contrast, the water quality in the Za River and the main Moulouya River is degraded. High concentrations of organics were recorded at the M6, M8, M12 and Z11 stations, which receive untreated wastewater from the rural communes of Zaïda and Missour and the urban communes of Guercif and Taourirt, respectively. Improvement of water management in North African catchments is therefore recommended and suggestions are given herein.

Keywords: Anzegmur River, inter- and intraclass analyses, Melloulou River, organic discharges, spatial typology, Za River