Paper No. JAWRA-10-0115-P of the Journal of the American Water Resources Association (JAWRA). Discussions are open until six months from print publication.
Streamflow Response to Climate as Influenced by Geology and Elevation1
Version of Record online: 11 APR 2011
© 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA
JAWRA Journal of the American Water Resources Association
Volume 47, Issue 4, pages 724–738, August 2011
How to Cite
Mayer, T. D. and Naman, S. W. (2011), Streamflow Response to Climate as Influenced by Geology and Elevation. JAWRA Journal of the American Water Resources Association, 47: 724–738. doi: 10.1111/j.1752-1688.2011.00537.x
- Issue online: 25 JUL 2011
- Version of Record online: 11 APR 2011
- Received July 20, 2010; accepted February 17, 2011.
- climate change/variability;
- Klamath Basin;
- groundwater hydrology;
- surface water/groundwater interactions;
- base-flow index;
- Upper Klamath Lake
Mayer, Timothy D. and Seth W. Naman, 2011. Streamflow Response to Climate as Influenced by Geology and Elevation. Journal of the American Water Resources Association (JAWRA) 47(4):724-738. DOI: 10.1111/j.1752-1688.2011.00537.x
Abstract: This study examines the regional streamflow response in 25 predominately unregulated basins to warmer winter temperatures and snowpack reductions over the last half century in the Klamath Basin of California and Oregon. Geologic controls of streamflow in the region result in two general stream types: surface-dominated and groundwater-dominated basins. Surface-dominated basins were further differentiated into rain basins and snowmelt basins on the basis of elevation and timing of winter runoff. Streamflow characteristics and response to climate vary with stream type, as discussed in the study. Warmer winter temperatures and snowpack reductions have caused significantly earlier runoff peaks in both snowmelt and groundwater basins in the region. In the groundwater basins, the streamflow response to changes in snowpack is smoothed and delayed and the effects are extended longer in the summer. Our results indicate that absolute decreases in July-September base flows are significantly greater, by an order of magnitude, in groundwater basins compared to surface-dominated basins. The declines are important because groundwater basins sustain Upper Klamath Lake inflows and mainstem river flows during the typically dry summers of the area. Upper Klamath Lake April-September net inflows have decreased an estimated 16% or 84 thousand acre-feet (103.6 Mm3) since 1961, with the summer months showing proportionately more decline. These changes will exacerbate water supply problems for agriculture and natural resources in the region.