Trend Analysis of Annual and Seasonal River Runoff by Using Innovative Trend Analysis with Significant Test

Abstract

This study investigated the temporal patterns of annual and seasonal river runoff data at 13 hydrological stations in the Lake Issyk-Kul basin, Central Asia. The temporal trends were analyzed using the innovative trend analysis (ITA) method with significance testing. The ITA method results were compared with the Mann-Kendall (MK) trend test at a 95% confidence level. The comparison results revealed that the ITA method could effectively identify the trends detected by the MK trend test. Specifically, the MK test found that the time series percentage decreased from 46.15% in the north to 25.64% in the south, while the ITA method revealed a similar rate of decrease, from 39.2% to 29.4%. According to the temporal distribution of the MK test, significantly increasing (decreasing) trends were observed in 5 (0), 6 (2), 4 (3), 8 (0), and 8 (1) time series in annual, spring, summer, autumn, and winter river runoff data. At the same time, the ITA method detected significant trends in 7 (1), 9 (3), 6(3), 9 (3), and 8 (2) time series in the study area. As for the ITA method, the “peak” values of 24 time series (26.97%) exhibited increasing patterns, 25 time series (28.09%) displayed increasing patterns for “low” values, and 40 time series (44.94%) showed increasing patterns for “medium” values. According to the “low”, “medium”, and “peak” values, five time series (33.33%), seven time series (46.67%), and three time series (20%) manifested decreasing trends, respectively. These results detailed the patterns of annual and seasonal river runoff data series by evaluating “low”, “medium”, and “peak” values.

Modifications to Snow-Melting and Flooding Processes in the Hydrological Model—A Case Study in Issyk-Kul, Kyrgyzstan

“…The PBIAS values from verification using the modified model were better than that of the model before (Tables 4 and 5). The temperatures in Issyk-Kul's northern and southern catchments begin to rise in early April, snow begins to melt into stream flow, and the water levels in the catchments begin to rise rapidly [25], eventually leading to floods [97][98][99]. Our results showed that the participation of snowmelt from October to March was limited to the modified degree-day method, which increased from April to September.…”

“…The majority of glacial-snow-type rivers flow into Issyk-Kul [24]. River runoff's shifting properties have long been focuses of hydrological and water resource research [25]. Since Issyk-Kul's rivers affect its water level, it is important to focus on the sources of the rivers, especially the snowmelt.…”

Water-Trap Series and City Pond to Control The Destructive Power of Runoff Water from Mbay Hills

“…GIS analysis method in the form of DEM analysis using Arc-View GIS software, which is supported by the Visual Basic programming language to add rain data. Software map-objects are combined to give a better view of the map [17]. The DEM analysis consists of topographic analysis of the location from art-view map data, which can then be followed by analysis of the slope of the location and analysis of the elevation model.…”

Trend in hydrological series and land use changes in a tropical basin at Northeast Brazil

“…Recently, trend analysis in hydrological series has received attention in the scientific community (Rosin et al, 2015;Pousa et al, 2019;Salehi et al, 2020;Alifujiang et al, 2021). This concern has been largely attributed to climate change, due to its impact on the hydrological cycle such as pandemics, low food productivity, reduced availability and quality of water, imbalance in ecosystems such as loss and fragmentation of habitats inducing the loss of biodiversity (Campbell et al, 2016;Das et al, 2018;Sharma et al, 2018;Moraci et al, 2020).…”