Relative Contribution of Climate Change and Anthropogenic Activities to Streamflow Alterations in Illinois

Manas Khan,Momcilo Markus,Vaskar Dahal,Rabin Bhattarai,Hanseok Jeong

doi:10.3390/w13223226

Abstract

Rainfed agricultural systems have become more vulnerable to climate change due to their significant dependence on natural precipitation. Drastic changes in precipitation, superimposed with anthropogenic activities, including land use land cover change, can modify the hydrologic response, especially in agricultural watersheds. In this study, Fisher Information and cumulative sum charts (CUMSUM) methods were applied to detect the hydrologic regime shifts in six watersheds in Illinois, USA. The regime shift analysis identified shifts in streamflow regime in three agricultural watersheds, mainly around the 1970s; whereas, no significant change in streamflow was observed for forest-dominated watersheds. Furthermore, the Budyko framework was used to determine the relative contribution in streamflow alterations (i.e., regime shifts in streamflow) for the agricultural watersheds, which evidenced significant shifts in streamflow. The Budyko analysis inferred that alterations in streamflow could be primarily attributed to anthropogenic activities with a comparatively lower contribution from climate in agricultural watersheds. The relative contribution from anthropogenic activities were 71.66%, 81.46%, and 74.04%; whereas, the relative contribution from climate were 28.34%, 18.54%, and 25.96% for the Sangamon, Vermillion, and Skillet agricultural watersheds, respectively. The techniques used and the results obtained from the study would be helpful for future research in assessing the vulnerability and impact of management practices in a highly managed agricultural watershed.

Highlights

Hydrological processes are affected by various atmospheric and surface drivers
Even though the temporal pattern of the precipitation and runoff is similar, it can be observed that the pattern in the runoff amount between different watersheds is different from the pattern of corresponding precipitation amounts for the same watersheds
Exploratory statistical tools were deployed to identify the sources of changes in the hydrological regime and interpret its implications in six watersheds, which were different from each other in terms of various watershed characteristics

Summary

Introduction

Hydrological processes are affected by various atmospheric and surface drivers. While climate has been identified as the most potent atmospheric driver, land use and land cover (LULC) changes and soil types alter the surface hydrological processes [1,2,3,4,5]. The soil type and its properties are assumed to remain constant over time, while climate and LULC are evolving gradually. The climate is an inherently variable process, but its major signatures can be considered stationary for a short period of time. In recent decades, that assumption has been undermined by the anthropogenic global changes that have introduced new variability in the climate, a phenomenon expected to continue and intensify in the future. It has been established that climate change will increase the moisturecarrying capacity of the atmosphere, altering the precipitation amount and its pattern [6,7]

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