Quantifying the effects of climate variability and human activities on runoff from the Laohahe basin in northern China using three different methods

Abstract

Abstract:Much attention has recently been focused on the effects that climate variability and human activities have had on runoff. In this study, these effects are quantified using three methods, namely, multi-regression, hydrologic sensitivity analysis, and hydrologic model simulation. A conceptual framework is defined to separate the effects. As an example, the change in annual runoff from the semiarid Laohahe basin (18 112 km 2 ) in northern China was investigated. Non-parametric Mann-Kendall test, Pettitt test, and precipitation-runoff double cumulative curve method were adopted to identify the trends and change-points in the annual runoff from 1964 to 2008 by first dividing the long-term runoff series into a natural period (1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974)(1975)(1976)(1977)(1978)(1979) and a human-induced period . Then the three quantifying methods were calibrated and calculated, and they provided consistent estimates of the percentage change in mean annual runoff for the human-induced period. In 1980-2008, human activities were the main factors that reduced runoff with contributions of 89-93%, while the reduction percentages due to changes in precipitation and potential evapotranspiration only ranged from 7 to 11%. For the various effects at different durations, human activities were the main reasons runoff decreased during the two drier periods of 1980-1989 and 2000-2008. Increased runoff during the wetter period of 1990-1999 is mainly attributed to climate variability. This study quantitatively separates the effects of climate variability and human activities on runoff, which can serve as a reference for regional water resources assessment and management.

Drivers of drying on the Yongding River in Beijing

“…Identification of change-points is an important statistical method in studying the effects of climate variability and human activities on runoff (Jiang et al, 2011). The Pettitt rank-based approach was used to determine the most probable change-point in the streamflow time-series (Pettitt, 1979).…”

“…Chen et al (2013) used hydrological sensitivity to quantify the effects of climate variability and human activities on runoff in the Kaidu River Basin in northwest China. Regression analysis can determine the correlation between runoff and climate variables (Jiang et al, 2011). Du et al (2011) used linear regression analysis to separate the impact of human activities and precipitation on streamflow.…”

“…Zhang et al (2012) used a runoff model driven by precipitation and evapotranspiration to establish the non-linear relationship between runoff and climate. Jiang et al (2011) compared all three methods in estimating climate and human activities on runoff from the Laohahe Basin. They found all three methods created consistent estimates of percent change in mean annual runoff from climate variability and human activities.…”

Quantification of Hydrological Responses Due to Climate Change and Human Activities over Various Time Scales in South Korea

“…An understanding of the relative impacts of climate change and human activities on hydrological responses should be integral to the creation of a water management plan [20]. The quantitative separation of the impacts of climate change and human activities has therefore drawn attention [21][22][23][24][25][26][27][28][29]. Particularly in South Korea, more attention has been paid to the identification of impacts from the two types of factors because of strong variation in regional precipitation and rapid urban development during the past few decades.…”

“…Wang et al [25] used the two-parameter monthly hydrological model proposed by Xiong and Guo [33] to estimate the impact of climate variability and human activities on the Haihe River basin in China. Jiang et al [22] used the distributed VIC-3L (Variable Infiltration Capacity-3Layer) model that has been successfully applied in China to reveal the relationship between the two types of factors. Additionally, Zeng et al [27] developed a SIMHYD physically-based model to investigate the factors impacting runoff in the Zhang River basin.…”