Investigation of Annual Lake Water Levels and Water Volumes with Şen Innovation and Mann-Kendall Rank Correlation Trend Tests: Example of Lake Eğirdir, Turkey

Abstract

Lakes are the most important freshwater resources for humans. It is stated that together with population growth, unplanned urbanization, excessive water consumption, industrialization, and unconscious irrigation, global climate change causes changes in the water levels and volumes of lakes. Lake Eğirdir in Turkey, which is important in terms of drinking and irrigation water use, was chosen as the study area. Lake Eğirdir water level (LWL) and water volume (LWV) values measured between 1988–2019 were used. Dependencies in the annual LWL and LWV were examined by autocorrelation analysis, and trend changes were examined by regression analysis, the Mann-Kendall rank correlation test, and the Şen innovation trend test. The research has shown a significant decrease since 2000 in LWL and since 1990 in LWV. The LWL has decreased by −1.272 to −3.514 m and the LWV has decreased by −72.980 to −1082.134 hm3 in approximately 32 years. The actions to be taken based on the values determined in this study will help protect the water resources of lakes. As a result of the tests used in our study, it was determined that there were decreases in both the water level and the volume of the lake. The climatic changes in the lake basin and the decrease in the water resources feeding the lake are shown as the biggest factor in these reductions.

Transformative Trends in Runoff and Sediment Dynamics and Their Influential Drivers in the Wuding River Basin of the Yellow River: A Comprehensive Analysis from 1960 to 2020

“…The Mann-Kendall rank correlation trend test method (hereinafter referred to as the M-K test) is a widely used and effective nonparametric statistical method for analyzing trends in time series data. It is commonly employed in the trend analysis of hydrological, meteorological, and other time series due to its simplicity, robustness, and high level of quantification [23][24][25][26][27]. This method disregards the distribution characteristics of the sample series and is unaffected by a few extreme values, making it suitable for detecting trends in time series [28].…”

The concept for innovative Comprehensive Assessment of Lowland Rivers

“…Available water is decreasing at an alarming rate due to its increased use for economic and domestic purposes. Increased transpiration causes water loss from reservoirs, and higher temperature accelerates the processes of surface water degradation [1]. A comprehensive view of the aquatic ecosystem using integral tools is needed to effectively counteract the degradation of aquatic ecosystems, assess their condition, or plan their use or rehabilitation.…”

Analyzing groundwater level trend by hybrid approach in 37 districts of Bihar State, India

“…Several previous studies (Agbo & Ekpo, 2021; Agbo et al, 2021; Das & Banerjee, 2021; Duy et al, 2022; Gadedjisso‐Tossou et al, 2021; Gumus et al, 2022; Jiang & Wu, 2021; Vinushree et al, 2022; Wang et al, 2020; Yücel et al, 2022) used the MK test and SITA to perform trend analysis of different parameters. In addition, other studies (Agbo et al, 2022; Mallick et al, 2021) have focused on conducting trend analysis tests specifically for climate data parameters such as temperature and rainfall.…”