Routing the pipeline across the Missouri River near Bismarck was rejected because of the route's proximity to municipal water sources; residential areas; and road, wetland, and waterway crossings. The Bismarck route would also have been 11 miles (18 km) longer. The alternative selected by the Corps of Engineers crossed underneath the Missouri River half a mile (800 m) from the Standing Rock Indian Reservation. A spill could have major adverse effects on the waters that the Tribe and individuals in the area rely upon. Using a permit process that treated the pipeline as a series of small construction sites, the pipeline was granted an exemption from the environmental review required by the Clean Water Act and the National Environmental Policy Act.