Evaluating the influence of watershed moisture storage on variations in base flow recession rates during prolonged rain-free periods in medium-sized catchments in New York and Illinois, USA
Article first published online: 23 SEP 2013
©2013. American Geophysical Union. All Rights Reserved.
Water Resources Research
Volume 49, Issue 9, pages 6022–6028, September 2013
How to Cite
2013), Evaluating the influence of watershed moisture storage on variations in base flow recession rates during prolonged rain-free periods in medium-sized catchments in New York and Illinois, USA, Water Resour. Res., 49, 6022–6028, doi:10.1002/wrcr.20507., , and (
- Issue published online: 23 OCT 2013
- Article first published online: 23 SEP 2013
- Accepted manuscript online: 30 AUG 2013 03:41AM EST
- Manuscript Accepted: 26 AUG 2013
- Manuscript Revised: 28 JUL 2013
- Manuscript Received: 20 SEP 2012
- streamflow recession;
- watershed storage
 When dQ/dt-Q plots of stream recession are constructed for individual recession events, the slopes of the dQ/dt-Q curves are near constant in log space, but the intercepts vary seasonally. Because the intercepts increase during the summer (indicating an increase in the recession rate at a given discharge), it has often been assumed that increased evapotranspiration (ET) leads to increased recession rates. To test this assumption, we related the intercepts of dQ/dt-Q curves from 72 recession events to the concurrent ET and watershed moisture storage as determined from the National Center for Environmental Prediction (NCEP) North American Regional Reanalysis (NARR) data set. The analysis suggests that at least for the nine watersheds from Illinois and New York we studied, shifts in recession rate during prolonged rain-free periods had little linkage to concurrent ET. Instead, we observe that the shifting has a moderately strong linkage to watershed moisture storage during the recession event. While this seeming lack of dependence on ET during these prolonged rain-free periods is not necessarily reflective of more normal conditions, we suggest it provides some insight into underlying subsurface controls at the watershed scale. In particular, we hypothesize that the shift in intercept in dQ/dt-Q curves results from spatial heterogeneities in watershed surficial geology; under dryer conditions near-stream subsurface zones with high hydraulic conductivities contribute most streamflow but under wetter conditions subsurface zones in upland areas with lower hydraulic conductivities also contribute.