Weaving different forms of knowledge of managed aquifer recharge in a Saharan oasis (Algeria)

This paper demonstrates the reciprocal benefits of a socio-hydrology approach that fosters fruitful exchanges between different 'knowers' of complex water dynamics in weaving different types of knowledge. For centuries, the managed aquifer recharge and use system in the Beni Isguen oasis in Algeria was diligently monitored by communal water stewards and the data meticulously recorded and stored. Throughout our research project on the origin of groundwater and its replenishment, intense dialogue between scientists and communal water stewards greatly enhanced the research protocol based on isotope tracers, while simultaneously contributing to the active knowledge base of the community. The dialogue was based on mutual respect, trust and a reciprocal desire to share knowledge. Our findings revealed increased mineralization of shallow groundwater during drought periods, which was attributed to geological processes, and emphasized the crucial role of floods. Also, contrary to the initial assumption that deep Continental Intercalaire groundwater was only used for drinking, it was identified as a vital external resource, responsible for substantial recharge of the phreatic aquifer of the oasis. This source of water explains the continued use of the phreatic aquifer for irrigation more than 10 years after the last major flood. This collaborative socio-hydrology approach between differently situated 'knowers' contributes to the grounding of socio-hydrology. While respecting the strong water conservation culture, weaving different forms of knowledge may help develop a virtuous and original development model in the Algerian Sahara and beyond.