Analysis of integrated water resources management (IWRM) strategies in the urban sub-watersheds of Yaoundé (Cameroon): case of Odza and Nkie watersheds

Abstract

This study analyzed the integrated water resources management (IWRM) strategies in urban sub-watersheds of Yaoundé, Cameroon, focusing on the Odza and Nkie watersheds. The objective of the research was to contribute to the improvement of sustainable water resource management in urban sub-watersheds in developing countries, particularly in Cameroon. The study used a mixed approach, integrating data obtained through interviews with 21 key stakeholders involved in water management in the city of Yaoundé, hydrometeorological data and GIS data. The methodological approach included a SWOT analysis of the regulatory and institutional framework of IWRM at the local level, water resources mapping, land use classification using the Semi-automatic Classification Plugin (SCP) of QGIS 3.34 software and sentinel-2 images dating from December 2024 for the determination of spectral indices (NDWI, NDVI, SAVI) and the realization of the hydrological balance. This methodology was based on a set of considerations, such as the validity of the precipitation data from the Ekounou station for the watersheds studied, and the importance of interactions between surface water and groundwater. The SWOT analysis of IWRM implementation reveals major strengths and opportunities. Unfortunately, the political will faces numerous weaknesses and threats, such as incomplete legal frameworks, a framework law on water regime that is not yet aligned with the IWRM principles, despite being revised, and insufficient funding, which hinders its expansion. Water resource mapping revealed high urbanization, which impacts water quality, with significant pollution due to various human activities. Furthermore, hydrological analyses demonstrated considerable variability in precipitations, evapotranspiration, and infiltration over the years, highlighting the challenges posed by climate change. Overall, the results highlight the need to strengthen institutional coordination, improve the participation and engagement of local stakeholders, develop more effective management tools and mobilize sufficient financing to address existing challenges and promote sustainable water resources management in Yaoundé's urban sub-watersheds