共查询到19条相似文献，搜索用时 125 毫秒
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模拟暴雨条件下农田磷素迁移特征 总被引：10，自引：0，他引：10
开展三次重复人工暴雨试验,研究太湖流域平原河网区农田磷素在暴雨径流过程中的迁移输出特征,结果表明,地表径流是暴雨径流过程农田磷素迁移的主要途径,地表径流水相和侵蚀相磷素迁移量分别占总磷输出量的58.50%和34.69%;随壤中水流输移的磷素仅占总磷输出量的6.81%,磷素迁移以颗粒态为主,约占总磷输出量的60.73%,溶解态磷素以无机磷酸盐输出为主,溶解态磷素更易于在土壤中运动,地表径流与壤中流磷素输出特征对比分析显示,土壤对磷素具有较强的滤减作用,尤其对总颗粒态附着磷浓度的消减效果明显,可达80%以上,尽管暴雨径流过程中磷素迁移以地表径流为主,然而在降雨丰富的太湖地区,一般降雨条件下壤中流是产流的主要形式,同时壤中流溶解态磷流失占有较大的比例,对区域水环境恶化具有重要贡献,因此加强壤中流溶解态磷素输移和控制研究具有重要意义. 相似文献
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基于修正SWAT模型的岩溶地区非点源污染模拟初探——以横港河流域为例 总被引：3，自引：0，他引：3
岩溶流域含水系统的主要特征之一是连通地表的落水洞等垂直管道将近水平的地下暗河联系起来，降水及其形成的地表径流可以通过这些管道迅速地灌入地下河系，从而改变了水及其所携带的非点源污染物质在垂直与水平方向的传输速度与数量，使岩溶流域内地表-地下之间的物质交换与传输过程变得比较复杂；应用广泛的SWAT模型在模拟岩溶地区的水文、水质时会存在一些不足与局限.为此，本文针对岩溶水系统特征，引入落水洞、伏流、暗河的水文过程以及主要营养盐的输移过程，修正SWAT模型原有的水文循环过程及相关算法，改变其只适用于松散均匀介质流域非点源污染模拟的单一特征，并研究建立适合于岩溶流域的非点源污染模型和相应的模拟方法.选取横港河流域岩溶地区作为非点源污染的对象，应用修正后的模型通过控制性的模拟方法和敏感性性分析，定量评估落水洞、伏流、暗河等岩溶特征对氮、磷等主要非点源污染物质输移的影响及其带来的时空效应，并进一步探讨落水洞、伏流、暗河等对地表-地下水文与营养盐的交互作用及转换机理.结果表明，岩溶特征对流域的氮、磷负荷有增加作用，其中总磷的增加明显大于总氮的增加，总磷和总氮的增量分别为0.86%和2.12%；植被岩溶指数的增加会导致流域可溶性磷、有机磷的产出量增加，有机氮、地表产流中硝酸氮和沉积磷的产出量则居其次，落水洞改变了降雨的产流方式，增加了落水洞所在流域的有机磷和有机氮的产出，其增量变化在0~0.7和0~0.3 kg/hm2之间. 相似文献
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高山融雪是塔里木河源流区重要的产流方式,4个山区流域具有面积大、测站稀少、降雨与融雪混合补给径流和显著局部降雨等特征.以开都河流域为研究区,分析流域特征对SRM融雪径流模型参变量的影响,确定相应选取策略以提高融雪径流模拟预报精度,为相似流域融雪径流模拟提供参考.研究结果表明:(i)气温输入控制模拟径流的整体趋势,对模拟精度起决定性作用.但测站日均气温数据通常不能代表流域同高程的平均水平,直接作为输入会导致很大误差.基于遥感积雪图和模拟结果分析,开都河流域选择0.5倍巴音布鲁克站日最大气温作为流域平均气温较为合理.(ii)由于雨量站稀少和局部降雨特征显著,计算各高程分带平均降水并不现实.将测站降雨乘以放大系数,并借助参数"降雨径流系数"进行校正,可以满足模型对降雨输入的需求.(iii)根据融雪和降雨位置变化,调整参数"滞时"取值对提高局部洪峰过程的模拟精度非常重要.(iv)随气温升高,降雨增多,未能被有限测站完全监测,导致模拟精度逐步降低. 相似文献
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开都河流域融雪径流模拟研究 总被引：1，自引：0，他引：1
高山融雪是塔里木河源流区重要的产流方式,4个山区流域具有面积大、测站稀少、降雨与融雪混合补给径流和显著局部降雨等特征.以开都河流域为研究区,分析流域特征对SRM融雪径流模型参变量的影响,确定相应选取策略以提高融雪径流模拟预报精度,为相似流域融雪径流模拟提供参考.研究结果表明(i)气温输入控制模拟径流的整体趋势,对模拟精度起决定性作用.但测站日均气温数据通常不能代表流域同高程的平均水平,直接作为输入会导致很大误差.基于遥感积雪图和模拟结果分析,开都河流域选择0.5倍巴音布鲁克站日最大气温作为流域平均气温较为合理.(ii)由于雨量站稀少和局部降雨特征显著,计算各高程分带平均降水并不现实.将测站降雨乘以放大系数,并借助参数"降雨径流系数"进行校正,可以满足模型对降雨输入的需求.(iii)根据融雪和降雨位置变化,调整参数"滞时"取值对提高局部洪峰过程的模拟精度非常重要.(iv)随气温升高,降雨增多,未能被有限测站完全监测,导致模拟精度逐步降低. 相似文献
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天目湖流域丘陵山区典型土地利用类型氮流失特征 总被引：4，自引：2，他引：2
天目湖丘陵山区农业综合开发持续推进,大量林地转变为茶园,迫切需要认识茶园扩张对流域氮流失的影响.本研究选取茶园、次生马尾松林和毛竹林开展自然降雨条件下的径流小区实验,分析天目湖丘陵山区典型用地类型径流氮流失规律,为评估丘陵山区综合开发的水环境影响提供实测参数.研究表明:茶园、次生马尾松林和毛竹林地表径流TN浓度分别为11.25、2.83和3.60 mg/L,均以溶解态为主;壤中流TN浓度分别为27.16、3.59和1.06 mg/L,茶园和次生马尾松林均以溶解性无机氮(尤其是硝态氮)为主,毛竹林以溶解性有机氮为主;茶园、次生马尾松林和毛竹林的小区尺度地表径流系数均不到0.03,壤中流是丘陵山区径流的主要来源;茶园开发加剧了丘陵山区的氮素流失,茶园径流TN流失强度高达103.08 kg/(hm2·a),分别是次生马尾松林和毛竹林的7.6和23.2倍,壤中流贡献了流失总量的86.7%~99.7%.防治茶园径流氮流失需重点关注壤中流输出,在减量施肥的基础上,采取坡脚构建毛竹林生态缓冲带/在小流域出口布设塘坝等原位拦截措施,实现流域氮流失综合防控. 相似文献
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长江中下游地区浅水湖泊群中无机氮和TN/TP变化的模式及生物调控机制 总被引：2，自引：2，他引：2
对长江中下游地区33个浅水性湖泊的氨态氮(NH3-N)、硝态氮(NO3-N)、亚硝氮(NO2-N)和氮磷比(TN/TP)在生长季节和非生长季节的变化进行了研究.各营养盐浓度之间均呈显著正相关,整体上生长季节的相关性较好.当TP>0.1 mg l-1时, 随TP浓度的升高,非生长季节氨态氮浓度增加较快, 硝态氮在生长季节呈增长趋势而在非生长季节有下降的趋势,这主要因为非生长季节超富营养湖泊中的溶氧和温度较生长季节低, 而硝化作用对溶氧和温度较敏感所致.当TP为0.035 mg·l-1~0.1 mg·l-1时,生长季节总氮和各种无机氮均低于非生长季节,浮游植物可能是关键的调控因子;当TP<
0.035mg·1-1时,各无机氮的浓度较低,且生长季节和非生长季节浮游植物与氨氮、亚硝氮呈著正相关,说明在低营养状态下氨氮和亚亚硝氮可能成为浮游植物的限制因子.此外,TN/TP比随TP浓度呈降低的趋势,生长季节总氮及各种无机氮的浓度明显低于非生长季节,说明氮(尤其是氨氮和硝太氮)在生长季节的降低是TN/TP低于非生长季节的现象在富营养、超富营养状态十分明显.由浮游植物和细菌的作用所导致氮的减少及沉积物磷的释放是生长季节TN/TP降低的重要原因,即生长季节氮磷比的降低是湖泊生态系统生命过程综合作用的结果. 相似文献
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巢湖四条入湖河流硝态氮污染来源的氮稳定同位素解析 总被引：6，自引：1，他引：5
采用氮稳定同位素技术对巢湖四条主要污染输入河流(南淝河、十五里河、派河和双桥河)的氮污染状况和硝态氮来源进行研究.结果表明,巢湖四条入湖河流氮污染最严重的是十五里河,其次是南淝河和派河,双桥河的污染相对较轻.硝态氮的稳定同位素分析结果表明,巢湖四条入湖河流的硝态氮污染物在季节上受到不同因子的影响.十五里河和南淝河的硝态氮污染主要来源于城市生活污水和工业废水;派河的硝态氮污染在冬季主要来源于工业废水,春季来源于农业面源,而在夏季主要受到雨水的影响;双桥河的硝态氮污染冬、春季主要来源于农业面源,夏季主要受雨水的影响.此外本研究结果还表明巢湖四条主要入湖河流的氮污染源主要为铵态氮,因此今后要对铵态氮的来源进行同位素示踪. 相似文献
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降雨径流过程驱动因子的室内模拟实验研究 总被引：9，自引：1，他引：9
降雨径流过程的驱动作用可以归结为两个方面: 第一是降雨过程的影响, 第二是下垫面变化的影响. 通过179场室内降雨径流模拟实验发现, 无论是降雨历时还是降雨强度都会影响汇流的滞时, 这与传统的假设有明显的矛盾. 尤其是在降雨历时小于全面汇流时间和较小的降雨强度下这种非线性关系的影响十分明显. 由此可以推定, 单位线用于南方湿润地区的降雨径流过程模拟更为合理, 而在北方的干旱、半干旱地区, 由于降雨强度变化快, 降雨历时短, 所以使用时要特别注意降水条件. 这也说明了过去的水文模型在北方地区的产汇流效果不好的原因. 降水历时较小时, 流域的汇流特性有较为剧烈的变化, 因为此时流域未达到全流域汇流, 这反映了实际北方降雨径流情况, 因此单位线使用时必须进行适当的非线性校正. 当降雨历时大于流域的全面汇流时间以后整个流域达到蓄泄平衡, 适用于南方长时间降雨径流关系和产汇流的基础理论研究. 在充分降雨条件下, 洪峰流量、降雨强度呈线性关系, 而与下垫面无关, 降雨强度与峰现时间成负线性关系. 流域的调蓄量与降雨强度和洪峰流量呈线性关系, 受下垫面影响和作物截留作用十分明显, 而与作物截留的位置关系不大. 相似文献
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不同水生植物对湿地无机氮素去除效果的模拟 总被引：7，自引：1，他引：6
分别以芦苇、花叶水葱和苦草构建成小规模人工湿地模拟系统,开展不同类型水生植物湿地中无机氮（硝态氮和铵态氮）去除效果的试验。试验结果表明：在分别以芦苇、花叶水葱和苦草构成的模拟湿地单元中,虽然氧化还原等环境条件呈现较大差异,但不同类型水生植物湿地单元的铵态氮和硝态氮的去除率并没有显著差别,这与以往关于不同类型水生植物对氮素去除贡献的认识有所不同;水生植物对模拟湿地体系中氮素的去除具有重要作用,在相对较低的氮负荷（NH4^＋-N约为2.85mg／L,NO3^-N约为1.07mg／L,相当于一般城市污染河流）条件下,有水生植物湿地单元中铵态氮和硝态氮的10d去除率分别在39.32％和21.91％以上,而无水生植物的空白湿地单元对铵态氮和硝态氮的10d去除率分别只有34.68％和13.86％;在提高模拟湿地体系水体氮（NH4^＋-N约为5.50mg／L,NO3^-N约为3.37mg／L,是一般城市污染程度的2倍）负荷条件下,有水生植物湿地单元中铵态氮和硝态氮的10d去除率分别大于或等于66.87％和78.92％以上,而无水生植物的空白湿地单元对铵态氮和硝态氮的10d去除率仅为40.62％和31.77％,为人工湿地对原污水或初沉池出水的处理提供了有力依据。试验结果还表明,水生植物能有效促进湿地的氮素转化过程,显著缩短无机氮素在湿地中的寄宿时间。 相似文献
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The non-point source pollution in livestock-breeding areas of the Heihe River basin in Yellow River 总被引：4，自引：0，他引：4
Hongguang Cheng Wei Ouyang Fanghua Hao Xiyan Ren Shengtian Yang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2007,21(3):213-221
A GIS-based distributed soil and water assessment tools (SWAT) model was used to simulate the runoff, sediment yield and the
load of the non-point source pollution in the Heihe River basin, which is a tributary and main water supply source of the
Yellow River. It is a typical stockbreeding area, and its industry and agriculture are not well developed. The main pollution
source of the Heihe River was livestock related non-point source pollution. With GIS and remote sensing techniques, a database
of non-point source pollution in the Heihe River basin was established. The SWAT model was parameterized for this area. The
pollution load and transportation rules such as nitrogen were illustrated. After several years of hard work, the situations
of point source pollution were more and more accurate. This paper provided an effective way to assess and calculate the pollution
load in the wide agriculture area in China. With the help of historical data formulated parameters, the non-point source load
and the theory of pollution load distribution were illustrated about the Heihe River basin. In 2000, the soluble N load in this area was 1.06 × 106 kg. By the simulation, the main pollution sources were in the south east of the basin, where
the pasturing areas located in the south-east of Ruoergai County and in north of the Hongyuan County. 相似文献
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太湖流域非点源污染特征与控制 总被引：1，自引：1，他引：1
太湖流域非点源污染已经相当严重,直接威胁太湖流域的水环境安全.本文综述了太湖流域非点源污染来源于:农业生产的化肥、农药污染;畜禽水产养殖污染;城市地表径流面源和道路线源污染;城镇、农村生活污水的非达标排放;大气的干湿沉降等.并分析了太湖流域非点源污染的影响因素以及时空分布特点,最后从控制非点源污染源和污染物输移过程提出控制和治理非点源污染的措施. 相似文献
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不同尺度流域地表径流氮、磷浓度比较 总被引：16，自引：2，他引：16
选择太湖上游为研究对象,采集了1-400 km2不同尺度小流域产出径流TN、TP浓度实测数据,结合前期开展的地表坡面流人工暴雨实验监测结果,开展不同尺度流域水质监测对水体面源污染产出浓度估算影响的比较研究,探讨流域尺度之间入渗、汇流以及伴随的流域生态系统营养盐调节机制的差异．结果表明,流域监测尺度对土地利用面源污染产出浓度估算有较大影响．地表坡面流由于未经过流域汇流过程伴随的下渗滤过与吸附等过程,产出径流TN、TP浓度一般高于小流域．小流域林地生态系统具有较强的入渗机制、接近自然的生态沟谷汇流网络,对面源污染TN、TP有较强的削减作用．农业生态系统较弱的入渗机制、人工沟渠汇流网络对面源污染TN、TP的削减作用较弱．现代农业造成流域面源污染增加不仅仅是因为人类农业活动对流域局部土体及养分的改变,农业生态系统改变流域自然生态系统整体水文过程及营养盐调节机制也是面源污染增加的重要因素之一,恢复小尺度的生态沟谷网络系统对削减流域面源污染具有重要的意义． 相似文献
14.
Preliminary study on assessment of nutrient transport in the Taihu Basin based on SWAT modeling 总被引：4，自引：0，他引：4
With the Taihu Basin as a study area, using the spatially distributed and mechanism-based SWAT model, preliminary simulations of nutrient transport in the Taihu Basin during the period of 1995-2002 has been carried out. The topography, soil, meteorology and land use with industrial point pollution discharge, the loss of agricultural fertilizers, urban sewerage, and livestock drainages were all considered in the boundary conditions of the simulations. The model was calibrated and validated against water quality monitoring data from 2001 to 2002. The results show that the annual total productions of nitrogen (TN) and phosphorus (TP) into Lake Taihu are 40000t and 2000t respectively. Nutrient from the Huxi Region is a major resource for Lake Taihu. The non-point source (surface source) pollution is the main form of catchment sources of nutrients into Lake Taihu, occupied TN 53% and TP 56% respectively. TN and TP nutrients from industrial point pollution discharge are 30% and 16%, and sewerage in both forms of point source and non-point source are TN 31 % and TP 47%. Both the loss of agricultural fertilizers and livestock drainages from the catchment should be paid more attention as an important nutrient source. The results also show that SWAT is an effective model for the simulation of temporally and spatially nutrient changes and for the assessment of the trends in a catchment scale. 相似文献
15.
With the Taihu Basin as a study area, using the spatially distributed and mechanism-based SWAT model, preliminary simulations of nutrient transport in the Taihu Basin during the period of 1995:_2002 has been carried out. The topography, soil, meteorology and land use with industrial point pollution discharge, the loss of agricultural fertilizers, urban sewerage, and livestock drainages were all considered in the boundary conditions of the simulations. The model was calibrated and validated against water quality monitoring data from 2001 to 2002. The results show that the annual total productions of nitrogen (TN) and phosphorus (TP) into Lake Taihu are 40000t and 2000t respectively. Nutrient from the Huxi Region is a major resource for Lake Taihu. The non-point source (surface source) pollution is the main form of catchment sources of nutrients into Lake Taihu, occupied TN 53% and TP 56% respectively. TN and TP nutrients from industrial point pollution discharge are 30% and 16%, and sewerage in both forms of point source and non-point source are TN 31% and TP 47%. Both the loss of agricultural fertilizers and livestock drainages from the catchment should be paid more attention as an important nutrient source. The results also show that SWAT is an effective model for the simulation of temporally and spatially nutrient changes and for the assessment of the trends in a catchment scale. 相似文献
16.
For efficient and targeted management, this study demonstrates a recently developed non-point source (NPS) pollution model for a year-long estimation in the Pingqiao River Basin (22.3 km2) in China. This simple but physically reasonable model estimates NPS export in terms of land use by reflecting spatial hydrological features and source runoff measurements under different land-use types. The NPS export was separately analysed by a distributed hydrological model, a spatial hydrograph-separation technique, and an empirical water quality sub-model. Simulation results suggest that 57 890 kg of total nitrogen (TN) and 1148 kg of total phosphorus (TP) were delivered. The results, validated with observed stream concentrations, show relative errors of 23.3% for TN and 47.4% for TP. Countermeasures for urban areas (5.3% of total area) were prioritized because of the high contribution rate to TN (14.1%) and TP (26.2%) which is caused by the high degree of runoff (8.5%) and pollution source. 相似文献
17.
内蒙古呼伦湖水量平衡计算与分析 总被引：2，自引：2，他引：0
根据呼伦湖的实际水文过程,计算1963-1980年月水量平衡,在此基础上,分析库容与径流、径流+降雨、径流+降雨-蒸发的相关性.利用累积和分析水位、径流、降雨、蒸发年均值的突变情况,进而重点论述了2000年后水位持续降低的原因.同时,探讨各水平衡项的年内分布规律及相互关系.结果表明,2000年后水位的急剧降低是气候变化(暖干化)造成的.河川径流对水位的影响程度最大,其次为湖面降雨.每年4、5月,冰封期积累的降雪融化渗入地下补给湖泊,其他时间则由湖泊补给地下水. 相似文献
18.
Jiayi Huo Changjun Liu Xinxiao Yu Lihua Chen Wenge Zheng Yuanhui Yang Changwen Yin 《水文研究》2021,35(1):e13985
Soil and nutrient loss play a vital role in eutrophication of water bodies. Several simulated rainfall experiments have been conducted to investigate the effects of a single controlling factor on soil and nutrient loss. However, the role of precipitation and vegetation coverage in quantifying soil and nutrient loss is still unclear. We monitored runoff, soil loss, and soil nutrient loss under natural rainfall conditions from 2004 to 2015 for 50–100 m2 runoff plots around Beijing. Results showed that soil erosion was significantly reduced when vegetation coverage reached 20% and 60%. At levels below 30%, nutrient loss did not differ among different vegetation cover levels. Minimum soil N and P losses were observed at cover levels above 60%. Irrespective of the management measure, soil nutrient losses were higher at high-intensity rainfall (Imax30>15 mm/h) events compared to low-intensity events (p < 0.05). We applied structural equation modelling (SEM) to systematically analyze the relative effects of rainfall characteristics and environmental factors on runoff, soil loss, and soil nutrient loss. At high-intensity rainfall events, neither vegetation cover nor antecedent soil moisture content (ASMC) affected runoff and soil loss. After log-transformation, soil nutrient loss was significantly linearly correlated with runoff and soil loss (p < 0.01). In addition, we identified the direct and indirect relationships among the influencing factors of soil nutrient loss on runoff plots and constructed a structural diagram of these relationships. The factors positively impacting soil nutrient loss were runoff (44%–48%), maximum rainfall intensity over a 30-min period (18%–29%), rainfall depth (20%–27%), and soil loss (10%–14%). Studying the effects of rainfall and vegetation coverage factors on runoff, soil loss, and nutrient loss can improve our understanding of the underlying mechanism of slope non-point source pollution. 相似文献
19.
《水文科学杂志》2013,58(3)
Abstract Abstract Current research suggests that strategies to control sediment and phosphorus loss from non-point sources should focus on different runoff components and their spatial and temporal variations within the river basin. This is a prerequisite for determining effective management measures for reducing diffuse source pollution. Therefore, non-point source models, especially in humid climatic regions, should consider variable hydrologically active source areas. These models should be able to consider runoff generation by saturated overland flow, as well as Hortonian overland flow. A combination of the hydrological model WaSiM-ETH and the erosion and P-transport model AGNPS was chosen for this study. The models were run in the WaSiM runoff generation mode (Green & Ampt/TOPMODEL or Richards equation approach) and the SCS curve number mode to assess the effect of these different runoff calculation procedures on the dissolved phosphorus yield. A small and a medium-sized river basin, of the area of 1.44 and 128.9 km2, respectively, in central Germany were selected for the investigation. The results show that the WaSiM–AGNPS coupling produces more accurate results than the SCS curve number method. For the spatial distribution, the more physically-based model approach computed a much more realistic distribution of water and phosphorus yield-producing areas. 相似文献