 The Río Nuevo flows from Lamanai Lake in Belize northwards to Chetumal Bay.The Mopan River and the Macal River flow through Belize and join to form the Belize River, which empties into the Caribbean Sea.In the southwest of the peninsula, the San Pedro River, the Candelaría River and the Mamantel River, which all form a part of the Gulf of Mexico drainage.