TREND ANALYSIS OF PRECIPITATION DATA IN FLOOD SOURCE AREAS OF KELANTAN RIVER BASIN

2016 ◽  
Vol 78 (9-4) ◽  
Author(s):  
Jabir Haruna Abdulkareem ◽  
Wan Nor Azmin Sulaiman

Rainfall is one of the most important climatic elements that influence both the spatial and temporal water availability. Therefore, identification of its trend over years is vital for detection of extreme climatic changes. The purpose of this study is to investigate the variability of precipitation in flood source areas of Kelantan river basin by detecting precipitation flood changes in the temporal structure for the period of 1984-2014. A total of 17 rain gage stations with at least 25 years’ records in the temporal structure for the period 1984-2014 were selected. For the AMF data, 4 gauging stations were selected for the analysis. Mann-Kendall and Sen slope estimator tests were used to detect possible precipitation trend. This resulted in the detection of non-statistically significant trend in the annual maximum series of 24-hr precipitation in 12 of the 17 selected rain gauge locations and statistically significant trend in 5 locations for the period under study. Whereas, the AMF series signaled significance at 5% level in all the stations. This may be as a result of watershed characteristics such as land use changes soil, topography, of the study area which needs to be studied in detail.

Author(s):  
A. Kundu ◽  
S. Dwivedi ◽  
V. Chandra

Climate science is a complex field as climate is governed by processes that interact and operate on a vast array of time and space scales. The processes involving radiative transfer, chemistry and phase changes of water are most easily described at atomic and molecular scales; the influence of ice sheets, continents and planetary scale circulations controlling the basic energy balance of the planet operate at continental scales; even planetary orbital and solar variations operating at millennial time scales cannot be ignored. Global as well as regional climate has changed due to human activities like land use changes, production of industrial effluents and other activities due to the development of the society. The consequences of these changes have a massive impact on atmospheric events like precipitation, temperature etc. So, present and future information of precipitation is required to develop adaptation and mitigation strategies at national and international levels. Precipitation is one of the major phenomena of the atmosphere. So, its prediction and the trend are very necessary to realize the change of climate. The study attempted some model based analysis to assess prediction of rainfall trend using MK test and the Sen’s slope estimator.


Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 39 ◽  
Author(s):  
Lifeng Yuan ◽  
Kenneth J. Forshay

Soil erosion and lake sediment loading are primary concerns of watershed managers around the world. In the Xinjiang River Basin of China, severe soil erosion occurs primarily during monsoon periods, resulting in sediment flow into Poyang Lake and subsequently causing lake water quality deterioration. Here, we identified high-risk soil erosion areas and conditions that drive sediment yield in a watershed system with limited available data to guide localized soil erosion control measures intended to support reduced sediment load into Poyang Lake. We used the Soil and Water Assessment Tool (SWAT) model to simulate monthly and annual sediment yield based on a calibrated SWAT streamflow model, identified where sediment originated, and determined what geographic factors drove the loading within the watershed. We applied monthly and daily streamflow discharge (1985–2009) and monthly suspended sediment load data (1985–2001) to Meigang station to conduct parameter sensitivity analysis, calibration, validation, and uncertainty analysis of the model. The coefficient of determination (R2), Nash–Sutcliffe efficiency (NSE), percent bias (PBIAS), and RMSE -observation’s standard deviation ratio (RSR) values of the monthly sediment load were 0.63, 0.62, 3.8%, and 0.61 during calibration, respectively. Spatially, the annual sediment yield rate ranged from 3 ton ha−1year−1 on riparian lowlands of the Xinjiang main channel to 33 ton ha−1year−1 on mountain highlands, with a basin-wide mean of 19 ton ha−1year−1. The study showed that 99.9% of the total land area suffered soil loss (greater than 5 ton ha−1year−1). More sediment originated from the southern mountain highlands than from the northern mountain highlands of the Xinjiang river channel. These results suggest that specific land use types and geographic conditions can be identified as hotspots of sediment source with relatively scarce data; in this case, orchards, barren lands, and mountain highlands with slopes greater than 25° were the primary sediment source areas. This study developed a reliable, physically-based streamflow model and illustrates critical source areas and conditions that influence sediment yield.


Author(s):  
Xin Zhang ◽  
Lin Zhou ◽  
Yuqi Liu

Changes in landscape patterns in a river basin play a crucial role in the change on load of non-point source pollution. The spatial distribution of various land use types affects the transmission of non-point source pollutants on the basis of source-sink theory in landscape ecology. Jiulong River basin in southeast of China was selected as the study area in this paper. Aiming to analyze the correlation between changing landscape patterns and load of non-point source pollution in this area, traditional landscape metrics and the improved location-weighted landscape contrast index based on the minimum hydrological response unit (HRULCI) were applied in this study, in combination with remote sensing and geographic information system (GIS) technique. The results of the landscape metrics showed the enhanced fragmentation extent and the decreasing polymerization degree of the overall landscape in the watershed. High values of HRULCI were concentrated in cultivated land, while low HRULCI values mostly appeared in forestland, indicating that cultivated land substantially enhanced non-point source pollution, while forestland inhibited the pollution process.


10.5109/27370 ◽  
2013 ◽  
Vol 58 (2) ◽  
pp. 377-387
Author(s):  
Yanna Xiong ◽  
Guoqiang Wang ◽  
Yanguo Teng ◽  
Kyoichi Otsuki

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