Two catchments of diverse hydrologic character were chosen in which to test the hypothesis that tree-ring indices contain information about runoff that is of pertinent interest to the hydrologist. These two catchments, Bright Angel Creek basin in extreme north-central Arizona and Upper San Francisco River basin in extreme east-central Arizona and west-central New Mexico, are situated in different climatic regions. Although two semiannual maxima, summer and winter, occur in the annual precipitation regime, at Bright Angel Creek the winter maximum is dominant, resulting in large amounts of snow accumulation, and at Upper San Francisco River the summer maximum is dominant. These contrasting precipitation regimes in association with the annual temperature regimes create climatic conditions for which the growth response of the trees, specifically Douglas fir, the species used in the study, and the precipitation-runoff response are greatly different and comparably complex. The complexity of the climate-growth, climate-runoff relationships necessitated the use of multivariate methods in assessing their similarities and dissimilarities. The technique used here is that of principal components, with physical meaning attached to the components by comparison with the results of other statistical approaches such as autocorrelation, cross correlation, autospectra, and cross spectra, and such tree-ring statistics as the coefficient of -mean sensitivity. The orthogonality property of the principal components was used to develop prediction equations with a minimum of variables through use of multiple linear regression. The general approach was to relate ring-width indices to climate and develop a response function, to relate runoff to climatic variables and develop a response function, and finally to develop a prediction equation for predicting runoff from ring-width indices. Prediction equations and 214-year (1753-1966) synthetic runoff series were developed for both basins. The results for Bright Angel Creek basin are not impressive because the best prediction equation accounts for only 51% of the year-to-year variance in the annual runoff. However, this was not wholly unexpected, as it is shown that the nature of the annual runoff regime and the statistical nature of the ring-width index series from this basin are not conducive to maximum hydrologic information. Nevertheless, it is shown that an improved estimate of the mean annual runoff can be gained from the synthetic series. For Upper San Francisco River basin the results were more satisfactory: 72% to 79% of the annual variance in runoff can be accounted for using prediction equations based on ring-width indices, where one equation uses untransformed values of runoff (72%) and the other uses log-transformed values of runoff (79%). The synthetic series shows an improved estimate for the mean annual runoff but also offers the hydrologist a valuable tool in providing a series from which useful information can be obtained that could be valuable in decision-making processes concerning reservoir design and operation.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/190971 |
| Date | January 1971 |
| Creators | Stockton, Charles W. |
| Contributors | Fritts, H. C., Maddock, Jr., Thomas, LaMarche, V.C., Thorud, David B. |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Dissertation-Reproduction (electronic), text |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
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