Long Term Historic Changes in the Flow of Lesser Zab River, Iraq

Rainwater harvesting (RWH) for domestic uses is widely regarded as an economic and ecological solution in water conservation and storm management programs. This paper aims at evaluating long-term trends in 20-day cumulative rainfall periods per year in Poland, for assessing its impact on the design and operation conditions for RWH systems and resource availability. The time-series employed corresponds to a set of 50-year long time-series of rainfall (from 1970 to 2019) recorded at 19 synoptic meteorological stations scattered across Poland, one of the European countries with the lowest water availability index. The methods employed for assessing trends were the Mann–Kendall test (M–K) and the Sen’s slope estimator. Most of the datasets exhibit stationary behaviour during the 50-year long period, however, statistically significant downward trends were detected for precipitations in Wrocław and Opole. The findings of this study are valuable assets for integrated water management and sustainable planning in Poland.

Section: Methodsmentioning

confidence: 99%

Long-Term Trends in 20-Day Cumulative Precipitation for Residential Rainwater Harvesting in Poland

Canales

Gwoździej-Mazur

Jadwiszczak

et al. 2020

“…Some of the Mann-Kendall's advantages is that it adapts to missing values and is minimally affected by atypical data [40]. The procedure requires comparing data pairs, meaning that each record gets compared to every other record in the time-series [4,41].…”

Section: Mk Testmentioning

confidence: 99%

“…Some of these possible effects include: underestimating design flow rates for hydraulic structures, assigning water rights beyond the capacity of the river to supply them, and consequently, over-exploitation and insufficient water to sustain the ecosystems and other uses [2]. The importance of this research topic is supported by many recent papers on the subject, as hydrological trend assessments at different timescales (decadal, interannual, annual, seasonal, monthly) have been conducted for watersheds across the world [3][4][5][6][7][8], and they serve as evidence in the debate on climate change [9] and non-stationarity. It is worth mentioning the study by Su et al [10] is of interest in the current context, where these authors evaluated data from the year 1948 to 2004 for detecting long-term streamflow trends in 916 large rivers all over the globe.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Streamflow Variability and Trends in the Meta River, Colombia

Arrieta-Castro

Donado-Rodríguez

Acuña

et al. 2020

The aim of this research is the detection and analysis of existing trends in the Meta River, Colombia, based on the streamflow records from seven gauging stations in its main course, for the period between June 1983 to July 2019. The Meta River is one of the principal branches of the Orinoco River, and it has a high environmental and economic value for this South American country. The methods employed for the trend detection and quantification were the Mann–Kendall (MK) test, the modified MK (MMK) test, and the Sen’s slope (SS) estimator. Statistically significant trends (at a 95% level of confidence) were detected in more than 30% of the 105 evaluated datasets. The results from the MK test indicate the presence of statistically significant downward trends in the upstream stations and upward trends in the downstream stations, with the latter presenting steep positive slopes. The findings of this study are valuable assets for water resources management and sustainable planning in the Meta River Basin.

“…Recently, the sharp increase in greenhouse gases emissions has resulted in a rise in temperature over many regions around the world [1][2][3]. The increasing temperature has induced various hydro-climatological hazards with lots of socio-economic consequences [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Long-Term Trends and Seasonality Detection of the Observed Flow in Yangtze River Using Mann-Kendall and Sen’s Innovative Trend Method

Ali

Kuriqi

Abubaker³

et al. 2019

194

Trend analysis of streamflow provides practical information for better management of water resources on the eve of climate change. Thus, the objective of this study is to evaluate the presence of possible trends in the annual, seasonal, maximum, and minimum flow of Yangtze River at Cuntan and Zhutuo stations in China for the period 1980 to 2015. The assessment was carried out using the Mann–Kendall trend test, and the innovative trend analysis, while Sen’s slope is used to estimate the magnitude of the changes. The results of the study revealed that there were increasing and decreasing trends at Cuntan and Zhutuo stations in different months. The mean annual flow was found to decrease at a rate of −26.76 m3/s and −17.37 m3/s at both stations. The minimum flow was found to significantly increase at a rate of 30.57 m3/s and 16.37 m3/s, at a 95% level of confidence. Maximum annual flows showed an increasing trend in both regions of the Yangtze River. On the seasonal scale, the results showed that stations are more sensitive to seasonal flow variability suggesting a probable flooding aggravation. The winter season showed an increasing flow trend, while summer showed a decreasing trend. The spring flow was found to have an increasing trend by the Mann–Kendall test at both stations, but in the Zhutuo Station, a decreasing trend was found by way of the innovative trend analysis method. However, the autumn flow indicated a decreasing trend over the region by the Mann–Kendall (MK) test at both stations while it had an increasing trend in Cuntan by the innovative trend analysis method. The result showed nonstationary increasing and decreasing flow trends over the region. Innovative trend analysis method has the advantage of detecting the sub-trends in the flow time series because of its ability to present the results in graphical format. The results of the study indicate that decreasing trends may create water scarcity if proper adaptation measures are not taken.