The Santa Cruz rivershed encompasses 8,200 square miles in Southern Arizona. Agriculture has been practiced along the Santa Cruz River for thousands of year starting in 1200 B.C. The Hohokam mainly used the Santa Cruz River for their drinking water, irrigation of crops, and fishing as a food source. In 1691, Spaniards arrived and brought new crops and livestock which helped support valley residents. By the 1890s, the river started to disappear when groundwater tables dropped after settlers started using groundwater pumps. In the late 1800s, the Santa Cruz was dammed up to create Warner and Silver Lakes and many gardens and picnic areas lined its banks containing trees such as cottonwoods, willows, and walnuts. A giant mesquite forest lining the banks further south lasted until the 1940s, but by the 1950s, the river was gone, destroyed by years of urban expansion and mismanagement.