Water is a vital resource in the Greater Yellowstone Ecosystem. The headwaters of great rivers are located here, and water drives the complex geothermal activity in the region. Water resources provide recreational opportunities, plant and wildlife habitat, and scenic vistas. The quality of the nation’s waters is protected by laws and policy at local, state and federal levels. To understand and maintain or improve water quality and aquatic ecosystems, resource managers take inventory and actively monitor water resources throughout the region.