@misc{indiciae6ea21f81683b,
  title = {Hydraulic map of 24.5 Mile Rapids, Grand Canyon, Arizona},
  author = {S. W. Kieffer},
  year = {1988},
  doi = {10.3133/i1897b},
  url = {https://pubs.usgs.gov/publication/i1897B},
  note = {Source identifier: i1897B}
}