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| 流域土地利用及“源-汇”景观格局对水质的影响——以千岛湖上梧溪流域为例 |
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张西兑1, 王裕成2, 刘明亮3, 蒋男凯4, 李恒鹏5, 张汪寿5
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1.南京信息工程大学环境科学与工程学院;2.杭州市淳安生态环境监测站;3.杭州市生态环境科学研究院，杭州市城区生态环境监测站;4.淳安千岛湖建设集团有限公司;5.中国科学院南京地理与湖泊研究所，湖泊与流域水安全重点实验室
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| 摘要: |
| 流域土地利用及“源-汇”景观格局通过影响污染物的产生、输移和消纳过程，从而对水质产生复杂影响。认识河流水质对流域土地利用及“源-汇”格局的响应关系，是优化流域景观配置的前提和关键。本文以千岛湖上梧溪流域为研究对象，分析了河流总氮、总磷、硝态氮和磷酸盐等水质指标时空变化特征，解析了子流域尺度土地利用及“源-汇”景观格局及其对河流水质的影响。结果表明，上梧溪流域主要河流水质指标呈现出由上游到下游、由外侧支流到主河道污染物浓度逐渐上升的空间特征。非汛期氮浓度显著高于汛期，而汛期高锰酸盐指数和磷浓度略高于非汛期。进一步采用景观格局指数和源汇景观空间负荷比指数(LWLI)，研究发现LWLI与多项水质指标之间呈现显著正相关性，说明LWLI可有效解释水质的时空变异，子流域中“源”景观面积比例越高、距离流域集水口越近、所处坡度越陡则LWLI也越高，氮磷的潜在流失风险更大。汛期总氮(TN)浓度与水田、旱地和村庄的面积占比显著正相关总磷(TP)与茶园和旱地的面积占比也呈显著正相关，而林地面积占比与TN和TP呈负相关，而非汛期除TP外其他水质指标与景观指标的相关性均有所下降。从“源-汇”景观格局的角度来看上梧溪流域存在显著的“源-汇”景观空间失调现象，“源”景观集中于中下游的河道附近，“汇”景观则多分布于距离河道较远的坡地上，这导致“汇”景观难以充分发挥截流净化的作用，建议通过调整土地利用结构和优化景观配置来实现千岛湖流域水质的改善和生态环境的可持续发展。 |
| 关键词: 非点源污染 土地利用 源汇景观空间负荷比指数(LWLI) 氮磷浓度 |
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| 基金项目:国家自然科学基金项目（42071143）、中科院青促会项目（2023330）和中科院“一四五”自主部署项目（NIGLAS2022TJ16）联合资助 |
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| The Impact of Watershed Land Use and |
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ZhangXiDui1, WangYuCheng2, LiuMingLiang3, JiangNanKai4, LiHengPeng5, ZhangWangShou5
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1.School of Environmental Science and Engineering, Nanjing University of Information Science and Technology;2.Chun’an Ecological Environment Monitoring Station;3.Hangzhou Institute of Environmental Science, Urban Ecological Environment Monitoring Station of Hangzhou;4.Chun’an Qiandao Lake Construction Group Co, Ltd;5.Key Laboratory of Lake and Watershed Science for Water Security, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences
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| Abstract: |
| The land use and "source-sink" landscape pattern of watershed have complex effects on water quality by influencing the production, transport and absorption of pollutants. Understanding the response relationship of river water quality to watershed land use and source-sink pattern is the prerequisite and key to optimize watershed landscape allocation. Taking Shangwuxi Basin of Qiandao Lake as the research object, this paper analyzes the spatio-temporal variation characteristics of river total nitrogen, total phosphorus, nitrate nitrogen and phosphate, and analyzes the subcatchment scale land use and "source-sink" landscape pattern and its impact on river water quality. The results show that the water quality index of the main rivers in Shangwuxi Basin presents the spatial characteristics of gradually increasing pollutant concentration from the upper reaches to the lower reaches and from the outer tributaries to the main river. Nitrogen concentration in non-flood season was significantly higher than that in floo |
| Key words: Non-point source pollution Land use Source-sink landscape spatial load ratio index (LWLI) Nitrogen and phosphorus concentration |
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