Climate vs. Human Impact: Quantitative and Qualitative Assessment of Streamflow Variation

Abstract

This paper presents a novel framework comprising analytical, hydrological, and remote sensing techniques to separate the impacts of climate variation and regional human activities on streamflow changes in the Karkheh River basin (KRB) of western Iran. To investigate the type of streamflow changes, the recently developed DBEST algorithm was used to provide a better view of the underlying reasons. The Budyko method and the HBV model were used to investigate the decreasing streamflow, and DBEST detected a non-abrupt change in the streamflow trend, indicating the impacts of human activity in the region. Remote sensing analysis confirmed this finding by distinguishing land-use change in the region. The algorithm found an abrupt change in precipitation, reflecting the impacts of climate variation on streamflow. The final assessment showed that the observed streamflow reduction is associated with both climate variation and human influence. The combination of increased irrigated area (from 9 to 19% of the total basin area), reduction of forests (from 11 to 3%), and decreasing annual precipitation has substantially reduced the streamflow rate in the basin. The developed framework can be implemented in other regions to thoroughly investigate human vs. climate impacts on the hydrological cycle, particularly where data availability is a challenge.

Analysis of Runoff Variation Characteristics and Influencing Factors in the Wujiang River Basin in the Past 30 Years

“…This shows that human activities have become more active after 2005, the same as the abrupt year of runoff. The increase of human activities and built-up land is also the reason for the underlying surface parameter n change [ 32 ].…”

Evaluating The hydrological response due to the changes in climate and land use on streamflow in the Karkheh basin, Iran

“…A handful of studies have investigated the current land use and its effect on monthly streamflow. For example, (Kazemi et al 2021) used satellite images to establish the human activities in the area and used them to investigate a small sub-basin hydrologic process. In this research, Iran's future policies on land and their effect on future surface runoff have been considered in the area.…”

“…Considerable research has been done in the Karkheh River basin (Ghobadi et al 2015;Solaymani & Gosain 2015, Ashrafe Vaghefi et al 2017Kazemi et al 2021). Here, compared to the prior works, climate change and land-use change are considered together, as seeing both can help to better understand the effects.…”

“…Increasing demand for water in various sectors such as agriculture, industry, and urban consumption, as well as rising standards of living, is a pressing matter (Ahiablame et al 2017). A mismatch between supply and demand for this vital resource stems from the aforementioned increasing demands along with reducing the number of water supplies for various reasons such as climate change and human activities, including changes in land use and increasing dam construction (Kazemi et al 2021). However, planning and management play integral roles in adopting required strategies to evaluate how many water resources are needed and how to preserve existing resources (Oo et al 2020).…”

Investigation of the Effects of Climate Variability, Anthropogenic Activities, and Climate Change on Streamflow Using Multi-Model Ensembles

“…The streamflow is also closely related to various anthropogenic activities. These activities include a shift in land use/land cover (LULC), construction dams, embankments, urbanization, changes in agriculture patterns, deforestation, and operational management practices, which are believed to have a direct or indirect impacts on the hydrological cycle of a watershed [11][12][13][14]. Therefore, the hydrological response to anthropogenic activities and future climate change has turned out to be a core issue among the research community in the fields of hydrology and water and environmental engineering.…”