Two examples are discussed that demonstrate how information derived from the annual growth rings of certain tree species can be used as a proxy source of data to extend hydrologic records back in time. In the first case, tree-ring reconstructions of the annual flow of the upper Colorado River show that the period of record used as a basis for the 1922 Colorado River Compact was anomalously wet, in fact, the wettest comparable period in the entire 450 yr of reconstructed annual discharge at Lee Ferry, Arizona. The full impact of this overestimated flow has yet to be felt. In the second example, data from 13 carefully selected sites were used to reconstruct the annual and seasonal flows of the Salt and Verde Rivers back to 1580. These two rivers, draining some 13,000 sq miles in central Arizona, furnish water for municipal, industrial, and agricultural use as well as hydroelectric power for the metropolitan Phoenix area. Future water supply and flooding potential are both critical problems due to rapid escalation of population. Results show that several periods of prolonged low flows have occurred that were more severe than any comparable period since 1890. These low-flow periods have an apparent recurrence interval of about 22 yr on the Salt River. Also, the gaged records contain an above-average number of high seasonal and annual flows when compared with the entire 400 yr of reconstruction. (Author)

Media Info

  • Media Type: Print
  • Features: Figures; Maps; References; Tables;
  • Pagination: pp 10-17
  • Monograph Title: Improving Estimates from Flood Studies
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00382948
  • Record Type: Publication
  • ISBN: 0309036119
  • Files: TRIS, TRB
  • Created Date: Apr 30 1984 12:00AM