Lake Victoria is an aquatic reservoir which fluctuates in size as climate change influences river inflows and evaporation, and as water is released from storage downstream. Apparently the lake dried entirely during the last glaciation. The shores of Lake Victoria are densely populated, and population growth has contributed to release of raw sewage to the lake. Environmental impacts due to nutrient inputs, the introduction of non-native fish species, and invasion by water hyacinth have reduced services provided by this largest tropical lake in the world. Easy access at multiple points and at all inflows from the Kenyan territory is available within a one day travel from Maseno.