What river was damned in order to form Gatun lake and madden lake?

The Chagres River was dammed to form Gatun Lake and Madden Lake in Panama. The construction of the Gatun Dam created Gatun Lake, which played a crucial role in the Panama Canal's operation by providing a navigable waterway. Madden Lake was created by damming the Madden River, and both lakes are important for water management in the region. These lakes are integral to the canal's functioning, allowing ships to traverse the isthmus.