Lake Urema is located in the middle of the valley, about three-quarters of the way down from the Park's northern boundary. The Muaredzi River, flowing from the Cheringoma plateau, deposits sediments near the outlet of the lake slowing its drainage. This "plug" causes the Urema to greatly expand in the rainy season. Water that makes its way past this alluvial fan flows down the Urema River to the Pungue and into the Indian Ocean. In the flooded rainy season, water backs up into the valley and out onto the plains, covering as much as 200 square kilometers in many years. During some dry seasons, the lake's waters shrink to as little as 10 square kilometers. This constant expansion and retraction of the floodplains, amidst a patchwork of savanna, woodland, and thickets, creates a complex mosaic of smaller ecosystems that support a greater abundance and diversity of wildlife than anywhere else in the Park.