Basin scale sources of siltation in a contaminated hydropower reservoir.
Basin scale sources of siltation in a contaminated hydropower reservoir.
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DOI：
10.1016/j.scitotenv.2024.169952
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发表时间：
2024-01
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通讯作者：
C. Bravo-Linares;L. Ovando-Fuentealba;E. Muñoz-Arcos;J. Kitch;Geoffrey E. Millward;Ricardo López-Gajardo;Marcela Cañoles-Zambrano;A. del Valle;Claire Kelly;William H. Blake
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作者：
C. Bravo-Linares;L. Ovando-Fuentealba;E. Muñoz-Arcos;J. Kitch;Geoffrey E. Millward;Ricardo López-Gajardo;Marcela Cañoles-Zambrano;A. del Valle;Claire Kelly;William H. Blake
泥沙淤积和水电水库容量的损失是一个全球性的挑战，预计到2050年全球范围内的存储损失将达到26%。像许多其他拉丁美洲国家一样，土壤侵蚀是智利最严重的水污染问题之一，对下游造成严重淤积后果。确定影响水电淤塞和水污染的来源和驱动因素是为适应和缓解战略提供信息的关键需要，特别是在气候制度（如降雨模式）不断变化的背景下。我们利用时空地球化学指纹图谱方法，在流域尺度上研究了南美洲最大的水电站之一的沉积物的主要来源。采矿活动贡献了水电湖近期沉积物总量的9%，在矿山支流和水库沉积物柱之间的河床沉积物中，与沉积物有关的污染物浓度显著，如铜和钼。农业来源约占沉积物输入的60%，其中畜牧业生产和农业促进了磷向湖泊的输入。根据支流网络对湖泊沉积物柱的评价表明，与主要的人类活动（采矿和农业）相关的支流贡献了更多的沉积物，但来源随时间而变化：由于水坝建设，采矿活动的比例贡献减少了，而近年来农业的比例投入增加了，这主要是由于最近陡坡地从原生植被转向农业。主要水电流域的淤积是一个全球性的挑战，以拉佩尔盆地为例。这里面临的具体挑战突出表明，迫切需要共同设计以证据为导向的、针对具体情况的解决方案，解决流域内外及其社区驱动因素的相互作用，提高社会对沉积物管理战略的接受度，以支持清洁水电能源生产的可持续性。
Siltation and the loss of hydropower reservoir capacity is a global challenge with a predicted 26 % loss of storage at the global scale by 2050. Like in many other Latin American contexts, soil erosion constitutes one of the most significant water pollution problems in Chile with serious siltation consequences downstream. Identifying the sources and drivers affecting hydropower siltation and water pollution is a critical need to inform adaptation and mitigation strategies especially in the context of changing climate regimes e.g. rainfall patterns. We investigated, at basin scale, the main sources of sediments delivered to one of the largest hydropower reservoirs in South America using a spatio-temporal geochemical fingerprinting approach. Mining activities contributed equivalent to 9 % of total recent sediment deposited in the hydropower lake with notable concentrations of sediment-associated pollutants e.g. Cu and Mo in bed sediment between the mine tributary and the reservoir sediment column. Agricultural sources represented ca. 60 % of sediment input wherein livestock production and agriculture promoted the input of phosphorus to the lake. Evaluation of the lake sediment column against the tributary network showed that the tributary associated with both dominant anthropogenic activities (mining and agriculture) contributed substantially more sediment, but sources varied through time: mining activities have reduced in proportional contribution since dam construction and proportional inputs from agriculture have increased in recent years, mainly promoted by recent conversion of steep lands from native vegetation to agriculture. Siltation of major hydropower basins presents a global challenge exemplified by the Rapel basin. The specific challenges faced here highlight the urgent need for co-design of evidence-led, context-specific solutions that address the interplay of drivers both within and without the basin and its communities, enhancing the social acceptability of sediment management strategies to support the sustainability of clean, hydropower energy production.