The Mara River is an iconic transboundary river in Tanzania and Kenya. The Mara River Catchment (MRC) covers 13,750 km2, 35% of which flows through Tanzania, including the high conservation value Mara Wetlands, before emptying into Lake Victoria. The MRC is known globally for its unique ecosystems, biodiversity, and national parks supporting some of the most profitable economic activities in Tanzania and Kenya through tourism, agriculture, and mining (contributing 10-15% to both countries' GDP). These activities, and the growing communities in the catchment, rely on naturally functioning freshwater resources for their livelihoods and water supply.