A U.S. Marine volunteer with the Single Marine Program (SMP) throws built-up silt from a Bighorn Sheep watering hole at the Betty Lee Tank in Yuma, Ariz., Mar 20, 2021. The SMP sends volunteers to help with community efforts and build relations between the community and the Marine Corps. (U.S. Marine Corps photo by Lance Cpl. Matthew Romonoyske-Bean) - A U.S. Marine volunteer with the Single Marine Program (SMP) throws built-up silt from a Bighorn Sheep watering hole at the Betty Lee Tank in Yuma, Ariz., Mar 20, 2021.