Assessing the Impacts of Land Use and Climate Changes on River Discharge towards Lake Victoria

IF 16.4 1区 化学 Q1 CHEMISTRY, MULTIDISCIPLINARY
Renatus James Shinhu, Aloyce I. M. Amasi, M. Wynants, J. Nobert, K. Mtei, K. Njau
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引用次数: 1

Abstract

The Lake Victoria basin’s expanding population is heavily reliant on rainfall and river flow to meet their water needs, making them extremely vulnerable to changes in climate and land use. To develop adaptation and mitigation strategies to climate changes it is urgently necessary to evaluate the impacts of climate change on the quantity of water in the rivers that drain into Lake Victoria. In this study, the semi-distributed hydrological SWAT model was used to evaluate the impact of current land use and climate changes for the period of 1990–2019 and assess the probable future impacts of climate changes in the near future (2030–2060) on the Simiyu river discharge draining into Lake Victoria, Northern Tanzania. The General Circulation Model under RCPs 4.5, 6.0 and 8.5 predicted an increase in the annual average temperature of 1.4 °C in 2030 to 2 °C in 2060 and an average of 7.8% reduction in rainfall in the catchment. The simulated river discharge from the hydrological model under RCPs 4.5, 6.0 and 8.5 revealed a decreasing trend in annual average discharge by 1.6 m3/s from 5.66 m3/s in 2019 to 4.0 m3/s in 2060. The increase in evapotranspiration caused by the temperature increase is primarily responsible for the decrease in river discharge. The model also forecasts an increase in extreme discharge events, from a range between 32.1 and 232.8 m3/s in 1990–2019 to a range between 10.9 and 451.3 m3/s in the 2030–2060 period. The present combined impacts of climate and land use changes showed higher effects on peak discharge at different return periods (Q5 to Q100) with values of 213.7 m3/s (Q5), 310.2 m3/s (Q25) and 400.4 m3/s (Q100) compared to the contributions of climate-change-only scenario with peak discharges of 212.1 m3/s (Q5), 300.2 m3/s (Q25) and 390.2 m3/s (Q100), and land use change only with peak discharges of 295.5 m3/s (Q5), 207.1 m3/s Q25) and 367.3 m3/s (Q100). However, the contribution ratio of climate change was larger than for land use change. The SWAT model proved to be a useful tool for forecasting river discharge in complex semi-arid catchments draining towards Lake Victoria. These findings highlight the need for catchment-wide water management plans in the Lake Victoria Basin.
评估土地利用和气候变化对流向维多利亚湖的河流流量的影响
维多利亚湖流域不断增长的人口严重依赖降雨和河水来满足他们的用水需求,这使得他们极易受到气候和土地利用变化的影响。为了制定适应和减缓气候变化的战略,迫切需要评估气候变化对流入维多利亚湖的河流水量的影响。本研究采用半分布式水文SWAT模型,评估了1990-2019年当前土地利用和气候变化的影响,并评估了近期(2030-2060年)气候变化对流入坦桑尼亚北部维多利亚湖的斯米尤河流量的可能影响。在RCPs 4.5、6.0和8.5下的环流模式预测,2030年的年平均气温将上升1.4°C至2060年的2°C,流域降雨量将平均减少7.8%。在rcp 4.5、6.0和8.5条件下,水文模型模拟的年平均流量从2019年的5.66 m3/s减少到2060年的4.0 m3/s,减少幅度为1.6 m3/s。温度升高引起的蒸散量增加是河流流量减少的主要原因。该模型还预测极端排放事件的增加,从1990年至2019年的32.1至232.8立方米/秒的范围增加到2030年至2060年的10.9至451.3立方米/秒的范围。当前气候和土地利用变化对不同回归期(Q5 ~ Q100)峰值流量的影响分别为213.7 m3/s (Q5)、310.2 m3/s (Q25)和400.4 m3/s (Q100),高于单纯气候变化情景的峰值流量212.1 m3/s (Q5)、300.2 m3/s (Q25)和390.2 m3/s (Q100),以及单纯土地利用变化的峰值流量295.5 m3/s (Q5)、207.1 m3/s (Q25)和367.3 m3/s (Q100)。但气候变化的贡献率大于土地利用变化。SWAT模型被证明是预测流向维多利亚湖的复杂半干旱集水区河流流量的有用工具。这些发现强调了在维多利亚湖盆地制定全流域水资源管理计划的必要性。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Accounts of Chemical Research
Accounts of Chemical Research 化学-化学综合
CiteScore
31.40
自引率
1.10%
发文量
312
审稿时长
2 months
期刊介绍: Accounts of Chemical Research presents short, concise and critical articles offering easy-to-read overviews of basic research and applications in all areas of chemistry and biochemistry. These short reviews focus on research from the author’s own laboratory and are designed to teach the reader about a research project. In addition, Accounts of Chemical Research publishes commentaries that give an informed opinion on a current research problem. Special Issues online are devoted to a single topic of unusual activity and significance. Accounts of Chemical Research replaces the traditional article abstract with an article "Conspectus." These entries synopsize the research affording the reader a closer look at the content and significance of an article. Through this provision of a more detailed description of the article contents, the Conspectus enhances the article's discoverability by search engines and the exposure for the research.
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