In February 2021; 3P Renewables Switzerland SA (3PRS) was awarded a decree by the Congolese government for the delegated management of developing and operating new drinking water production for the Pointe Noire urban area in Gambouissi Lake (the Project). The project aims to reinforce drinking water production capacities; enabling LCDE to better meet the water demand of Pointe Noire.In 2023; IFC and 3PRS signed a collaboration agreement to co-develop the Project. As part of the collaboration; IFC conducted an initial technical review of the Project which noted that there was a lack of information regarding 1) hydrological data; 2) existing uses of the raw water; 3) hydraulics of the Lake; 4) raw water quality; and; most importantly; 5) available flow of raw water for the Project. Also; the variability of all these elements considering seasonality (dry/wet season) was not clearly defined. As a preliminary mitigation measure; and to discard the raw water availability risk as a deal breaker; IFC mandated a consultant to subsequently perform a pre-hydrological mission to check the flow exiting the Gambouissi Lake (over a few days during the month of September 2022 – September being the last month of the dry season and therefore potentially presenting the worst conditions of the year in terms of water availability). The measured flow appeared to be sufficient during low-water periods; but only to operate at least one compact water treatment unit (nominal capacity of 750 m3/h).Due to the nature and reduced scope of the pre-hydrological mission; there remains a need to perform a hydrological study; in particular to 1) confirm the availability of water in terms of quantity and quality; 2) characterize the origin of the water and the sustainability of the Lake as a resource; as well as 3) define the impact of the water abstraction (downstream).