Dominica is water-rich with swift-flowing highland streams, which cascade into deep gorges and form natural pools and crater lakes. The streams are not navigable, but many are sources of hydroelectric power. Trafalgar Falls, located near the national park, is one of the most spectacular sites on the island. The falls consists of twin waterfalls known as the mother and father or the Mama and the Papa. At the base of each waterfall are natural pools. Locals and tourists alike come here to enjoy the water. At the base of the Papa fall a natural hot spring can also be found which heats a portion of its pool. The principal rivers flowing westward are the Layou and the Roseau, and the major one emptying eastward is the Toulaman. The largest crater lake, called Boeri, is located in the national park. There are 83 "significant" waterways on the island out of a total of 365 with also includes rills and brooks.