Paper No. J05095 of the Journal of the American Water Resources Association (JAWRA).
Five Hundred Years of Hydrological Drought in the Upper Colorado River Basin1
Version of Record online: 23 MAY 2007
JAWRA Journal of the American Water Resources Association
Volume 43, Issue 3, pages 798–812, June 2007
How to Cite
Timilsena, J., Piechota, T. C., Hidalgo, H. and Tootle, G. (2007), Five Hundred Years of Hydrological Drought in the Upper Colorado River Basin. JAWRA Journal of the American Water Resources Association, 43: 798–812. doi: 10.1111/j.1752-1688.2007.00064.x
- Issue online: 23 MAY 2007
- Version of Record online: 23 MAY 2007
- Received July 11, 2005; accepted September 25, 2006. © 2007 American Water Resources Association.
- Palmer hydrological drought index;
- Palmer Z index;
- Upper Colorado River Basin
Abstract: This article evaluates drought scenarios of the Upper Colorado River basin (UCRB) considering multiple drought variables for the past 500 years and positions the current drought in terms of the magnitude and frequency. Drought characteristics were developed considering water-year data of UCRB’s streamflow, and basin-wide averages of the Palmer Hydrological Drought Index (PHDI) and the Palmer Z Index. Streamflow and drought indices were reconstructed for the last 500 years using a principal component regression model based on tree-ring data. The reconstructed streamflow showed higher variability as compared with reconstructed PHDI and reconstructed Palmer Z Index. The magnitude and severity of all droughts were obtained for the last 500 years for historical and reconstructed drought variables and ranked accordingly. The frequency of the current drought was obtained by considering two different drought frequency statistical approaches and three different methods of determining the beginning and end of the drought period (annual, 5-year moving, and ten year moving average). It was concluded that the current drought is the worst in the observed record period (1923-2004), but 6th to 14th largest in terms of magnitude and 1st to 12th considering severity in the past 500 years. Similarly, the current drought has a return period ranging from 37 to 103 years based on how the drought period was determined. It was concluded that if the 10-year moving average is used for defining the drought period, the current drought appears less severe in terms of magnitude and severity in the last 500 years compared with the results using 1- and 5-year averages.