Premium
Watershed memory at the C oweeta H ydrologic L aboratory: The effect of past precipitation and storage on hydrologic response
Author(s) -
Nippgen Fabian,
McGlynn Brian L.,
Emanuel Ryan E.,
Vose James M.
Publication year - 2016
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2015wr018196
Subject(s) - surface runoff , precipitation , watershed , streamflow , environmental science , evapotranspiration , hydrology (agriculture) , water storage , growing season , water year , water resources , drainage basin , ecology , geography , geology , meteorology , geotechnical engineering , machine learning , computer science , cartography , geomorphology , inlet , biology
Abstract The rainfall‐runoff response of watersheds is affected by the legacy of past hydroclimatic conditions. We examined how variability in precipitation affected streamflow using 21 years of daily streamflow and precipitation data from five watersheds at the Coweeta Hydrologic Laboratory in southwestern North Carolina, USA. The gauged watersheds contained both coniferous and deciduous vegetation, dominant north and south aspects, and differing precipitation magnitudes. Lag‐correlations between precipitation and runoff ratios across a range of temporal resolutions indicated strong influence of past precipitation (i.e., watershed memory). At all time‐scales, runoff ratios strongly depended on the precipitation of previous time steps. At monthly time scales, the influence of past precipitation was detectable for up to 7 months. At seasonal time scales, the previous season had a greater effect on a season's runoff ratio than the same season's precipitation. At annual time scales, the previous year was equally important for a year's runoff ratio than the same year's precipitation. Estimated watershed storage through time and specifically the previous year's storage state was strongly correlated with the residuals of a regression between annual precipitation and annual runoff, partially explaining observed variability in annual runoff in watersheds with deep soils. This effect was less pronounced in the steepest watershed that also contained shallow soils. We suggest that the location of a watershed on a nonlinear watershed‐scale storage‐release curve can explain differences in runoff during growing and dormant season between watersheds with different annual evapotranspiration.