Separating climate change and human contributions to variations in streamflow and its components using eight time‐trend methods

Abstract

Separating impacts of human activities and climate change on hydrology is essential for watershed and ecosystem management. Many previous studies have focused on the impacts on total streamflow, however, with little attentions paid to its components (i.e., baseflow and surface run‐off). This study distinguished the contributions of climate change and human activities to the variations in streamflow, baseflow, and surface run‐off in the upstream area of the Heihe River Basin, a typical inland river basin in northwest China, by using eight different forms of time‐trend methods. The isolated contributions to streamflow variation were also compared with those obtained by two Budyko‐based approaches. Our results showed that the time‐trend methods consistently estimated positive contributions of climate variability and human activities to the increases in streamflow and its components but with obviously varying magnitudes. With regard to streamflow, the time‐trend method double‐mass‐curve–Wei, with a physical basis, produced a reasonable smaller contribution of human activities than climate changes, inconsistent with the Budyko‐based approaches. However, all the other time‐trend methods led to contrary results. The contributions to baseflow variation diverged more significantly than those to streamflow and surface run‐off, ranging from 24% to 92% for human activities and from 8% to 76% for climate variability. In terms of surface run‐off, most of the time‐trend approaches produced smaller contributions of human activities (ranging from 21% to 49%) than climate change. The uncertainties associated with the various time‐trend approaches and the baseflow separation algorithm were revealed and discussed, along with some recommendations for future work.

How is Baseflow Index (BFI) impacted by water resource management practices?

“…Baseflow, defined as streamflow fed from the deep subsurface and shallow subsurface storage between precipitation and/or snowmelt events (Tallaksen, 1995;Price, 2011;Zhang et al, 2017;Singh et al, 2019;Gnann et al, 2019), is a hydrological phenomenon that represents a whole catchment response to meteorological and other environmental signals (Bloomfield et al, 2011). It is important as it sus-Published by Copernicus Publications on behalf of the European Geosciences Union.…”

Drought-induced non-stationarity in the rainfall-runoff relationship invalidates the role of control catchment at the Red Hill paired-catchment experimental site

“…This method has been applied in many paired catchments around the world to test the basic assumptions on the interactions between vegetation and climate on catchment runoff, and to provide fundamental understanding and knowledge for water resource management under vegetation changes. The time-trend analysis method is used in the study of single catchment with long-term observations (Lee, 1980;Zhang et al, 2019;Zhao et al, 2010). The sensitivity-based method is a combination of the Budyko framework (Budyko, 1974) and the elastic response of runoff to rainfall and potential evapotranspiration developed by Zhang et al (2001).…”

“…The sensitivity-based method is a combination of the Budyko framework (Budyko, 1974) and the elastic response of runoff to rainfall and potential evapotranspiration developed by Zhang et al (2001). Given that the effect of interactions between climate variability and vegetation changes are much lower than their individual effects in small catchments, their interactions can be ignored (Li et al, 2012;Zhang et al, 2019), and the effects of vegetation changes on runoff can be obtained by subtracting the effects of climate variability on runoff from total runoff change.…”

“…Zhang et al (2011) applied the last two methods in a study of 15 catchments in Australia and demonstrated that both methods yielded differences of no more than 25%. Zhang et al (2019) also used the same methods in the Heihe River Basin in China and showed that both methods yielded https://doi.org/10.5194/hess-2021-5 Preprint. Discussion started: 20 January 2021 c Author(s) 2021.…”

Projecting The Impact of Human Activities And Climate Change On Water Resources In The Transboundary Sre Pok River Basin

“…The human activities and global climate changes have inflicted extreme impacts on global hydrology and water resources which results in significant floods, drought, degradation in water quality and quantity, water scarcity and many more (Renaud et al 2015;Xu et al, 2018;Zhang et al, 2018). The impact of global climate change is visible all over the world and mostly in the Southeast Asia region (Yang et al, 2017, Pan et al, 2018Zhang et al, 2019;Poelma et al 2021).…”