sustainability Article Variation in Runoff of the Arys River and Keles River Watersheds (Kazakhstan), as Influenced by Climate Variation and Human Activity Sanim Bissenbayeva 1,2,3,4, Jilili Abuduwaili 1,2,3,*, Dana Shokparova 4 and Asel Saparova 5 1 State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China 2 Research Center for Ecology and Environment of Central Asia, Chinese Academy of Sciences, Urumqi 830011, China 3 Research Center for Ecology and Environment of Central Asia, University of Chinese Academy of Sciences, Beijing 100049, China 4 Department of Geography, Land Management and Cadastre, Al-Farabi Kazakh National University, Almaty 050040, Kazakhstan 5 Institute of Geography, Satbayev University, Almaty 050010, Kazakhstan * Correspondence:
[email protected] Received: 27 July 2019; Accepted: 29 August 2019; Published: 2 September 2019 Abstract: Runoff formation is a complex meteorological-hydrological process impacted by many factors, especially in the inland river basin. In this study, long-term (1960–2015) river runoff and climate data in the Arys and Keles River watersheds (Kazakhstan) were gathered to analyze the impacts of climate variation and human activity on runoff. The non-parametric Kendall test and the Pettitt test were used to identify trends and change points in the time data series. It was found that both watersheds had significant upward trends in temperature and potential evapotranspiration data, and insignificant upward trends in the runoff. Change points in annual runoff were identified around the year 1973. The hydrological sensitivity method was employed to evaluate the impacts of climate variation and human activity on mean annual runoff based on precipitation and potential evapotranspiration.