Tonto Basin

Over six million years ago, the surrounding mountains were lifted skyward, and as they rose, the land between them sank to create the valley known as Tonto Basin. Melting snow and summer rains drain from the vast Salt River watershed toward the basin, while countless thousands of years of erosion carved numerous canyons and arroyos throughout the mountains. The Salt River enters Roosevelt Lake from the east, carrying runoff from melting snow and rain from across northeastern Arizona and at times becoming a raging torrent. Tonto Creek enters the valley from the north and merges with the Salt River where Roosevelt Dam now stands. The construction of Roosevelt Dam enabled downstream communities to manage and control downstream water delivery.

Arizona · United States