In the mid-1970s Cochiti Dam was constructed along the Rio Grande downstream from Bandelier National Monument. The dam was built to provide flood control for a portion of the Rio Grande valley and to enhance wildlife and recreation opportunities in the area. The winter and spring of 1985 brought very heavy snowpack to the watershed of the Rio Grande. During spring runoff, the floodpool of Cochiti Dam was allowed to back up much higher than its usual level. Over 200 acres of Bandelier along the river were under lake waters for a year and a half. Trees and other plants drowned as a result of the long inundation. The high lake level could be repeated in any year with heavy runoff.