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1.
城镇化流域氮、磷污染特征及影响因素——以宁波北仑区小浃江为例 总被引：2，自引：0，他引：2
我国快速的城镇化过程造成了河流氮、磷等营养盐的污染和潜在的水体富营养化问题.对城镇流域水体氮、磷污染特征及其演变趋势的识别具有重要意义.本研究选取长三角典型城镇地区宁波市北仑区小浃江流域为研究对象,在流域内根据空间分布、土地利用类型、人类活动强度等情况布设样点,于2017年夏季和冬季采集水样,研究流域水体氮、磷污染的时空分布特征并分析其污染来源和评估其富营养化水平.结果表明：流域内铵态氮（NH4+-N）、;硝态氮（NO3--N）、亚硝态氮（NO2--N）、总氮（TN）、总磷（TP）和叶绿素a（Chl.a）浓度范围分别为0.63~3.25 mg/L、0.52~3.75 mg/L、0.02~0.22 mg/L、1.61~12.86 mg/L、0.02~0.74 mg/L和0.6~60.57 μg/L.各个采样点氮、磷分布具有较大的空间异质性和季节变化规律.富营养化综合指数EI评估结果显示,整个流域富营养化程度属于贫至中营养级.氮、磷浓度与土地类型面积占比的Spearman相关性统计表明,100 m缓冲区建设用地面积占比与NH4+-N、NO2--N、TN、溶解氧（DO）浓度具有显著相关性,湿地面积占比与DO浓度呈显著正相关.汇水区域内林地面积占比与NH4+-N、NO2--N、TP、PO43--P、COD、Chl.a浓度呈显著负相关,与DO浓度呈显著正相关.相关性分析和冗余分析表明城镇化的面源污染及可能存在的点源污染是小浃江流域氮、磷污染的主要来源.因此,在小浃江流域100 m范围内,控制建设用地的规模和污染排放是减轻流域氮、磷污染的主要途径.在汇水区域内,增加林地植被的面积对减少氮、磷污染具有重要影响. 相似文献
2.
运用三维荧光光谱（EEMs）技术结合平行因子分析法（PARAFAC）以及紫外-可见光谱技术（UV-vis）,对周村水库季节演替过程中沉积物上覆水溶解性有机物（DOM）的紫外-可见以及三维荧光光谱特征进行分析.结果表明：周村水库上覆水的总氮、溶解性总氮、总有机碳和溶解性有机碳的季节性差异显著,并且冬季总氮浓度最高、夏秋季总有机碳浓度较高;夏秋季上覆水DOM的吸收系数a254和a355均高于冬春季,与有机物的分布相一致;4个季节上覆水DOM的E3/E4均大于3.5,说明DOM以富里酸为主,E2/E3（富里酸占DOM的比例）在夏秋季低于冬春季,而且各季节SR均大于1,表明DOM主要为生物源;三维荧光通过PARAFAC解析出3种组分：类腐殖质（C1）、可见区富里酸（C2）和类蛋白（C3）;对3个组分进行相关性分析,结果显示C1、C2、C3之间具有显著的相关性;DOM的总荧光强度以及各组分的荧光强度均呈现出夏秋季高、冬春季低的特征,且各季节间差异显著;周村水库4个季节的DOM生物源指数（BIX）在0.8~1.0之间,表明水库DOM具有较强的自生源特征,与腐殖程度指标（HIX）的结果相吻合;主成分分析显示周村水库上覆水DOM的光谱特征差异明显,夏秋季的DOM光谱特征相近、冬春季的水体DOM特征相似;并且组分C1、C2、C3与DOM特征参数（a254、SUVA280、HIX、FI、BIX）以及溶解性有机碳呈显著相关.各荧光组分与水质参数（溶解性总氮和溶解性有机碳）的多元线性回归呈现很好的拟合,通过建立回归方程可以为以后研究周村水库水体四季的DOM光谱特征,分析水库水体的有机物污染特征,并为水库水质管理提供技术支持. 相似文献
3.
峡谷分层型水源水库表层沉积物溶解性有机物光谱特征 总被引：7，自引：1，他引：6
结合三维荧光光谱技术（EEMs）与紫外吸收光谱（UV-vis）,并利用平行因子分析（PARAFAC）的方法,对金盆水库表层沉积物中溶解性有机质（DOM）光谱的空间分布特征及来源进行分析,并探讨沉积物DOM的荧光组分与可溶性有机氮（SON）、可溶性无机氮（SIN）之间的相关性.结果表明,金盆水库表层沉积物DOM由3类荧光组分组成,分别是类富里酸C1（235 nm,315 nm/430 nm）、类色氨酸C2（220 nm,275 nm/330 nm）和类胡敏酸C3（265 nm/520 nm）,各组分荧光强度占总荧光强度百分比的平均值分别为43.15%、31.54%和25.31%.表层沉积物DOM浓度在空间上呈现从上游到主库区先减少后增加的趋势.光谱斜率S275-295、S350-400和光谱斜率比SR反映出各采样点陆源与内源占比的差异性.荧光指数、自生源指标和腐殖化指标都表明金盆水库沉积物DOM的来源具有内源与陆源双重特征.相关性分析表明,表层沉积物DOM各组分与SON和SIN均呈显著正相关,说明DOM与氮元素的迁移转化密切相关. 相似文献
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内陆水体是大气CO2收支估算的重要组成部分。农业流域分布着大量池塘景观水体,且具备蓄洪抗旱、消纳污染、水产养殖等多种功能。但是,农业流域不同功能的小型池塘CO2排放特征尚不清楚。本研究以极具农业流域代表性的烔炀河流域为研究对象,选取流域中用于水产养殖(养殖塘)、生活污水承纳(村塘)、农业灌溉(农塘)、蓄水(水塘)的4个功能不同的景观池塘,基于为期1年的野外实地观测,以明确农业流域小型池塘CO2排放特征。结果表明,不同功能池塘水体CO2排放差异显著,受养殖活动、生活污水输入和农田灌溉等人类活动影响,养殖塘((80.37±100.39) mmol/(m2·d))、村塘((48.69±65.89) mmol/(m2·d))和农塘((13.50±15.81) mmol/(m2·d))是大气CO2的热点排放源,其CO2排放通量分别是自然蓄水塘((4.52±23.26) mmol/(m2·d))的18、11和3倍。统计分析也表明,该流域池塘CO2排放变化总体上受溶解氧、营养盐等因素驱动。4个不同景观池塘CO2排放通量全年均值为(37.31±67.47) mmol/(m2·d),是不容忽视的CO2排放源,其中养殖塘和村塘具有较高的CO2排放潜力,在未来研究中需要重点关注。 相似文献
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湿地的水文和水化学在时空尺度上会呈现显著差异,进而会引发光化学反应的变化,光活性中间体(PPRIs)是水体间接光反应的产物,具有极强的氧化性,对水环境中有机物和污染物的归驱具有重要的影响,因此迫切需要探究湿地中PPRIs的产生过程。本研究通过捕获剂法监测了鄱阳湖湿地4个季节水体中3种PPRIs(1O2、·OH及3CDOM*)的产生速率和稳态浓度的变化,并通过紫外吸收光谱、三维荧光光谱、以及傅立叶变换离子回旋共振质谱等技术对水体中可溶性有机质(DOM)组分的化学特征进行分析,揭示了鄱阳湖湿地不同季节水体中的DOM的光化学反应特性及与PPRIs产生的相关性。结果发现:鄱阳湖夏季和秋季水体的pH值、溶解有机碳(DOC)浓度较高,相反,硝酸盐、亚硝酸盐浓度在夏季和秋季较低。夏季和秋季的DOM中芳香族化合物丰度较高,并且木质素丰度明显高于冬季和春季。不同季节鄱阳湖水体有色可溶性有机物产生能力依次为秋季>夏季>冬季>春季。夏季和秋季水体中1O2和·OH产生速率和稳态浓度显著高于春季和冬季水体。pH、DOC、E2/E3、脂类、蛋白类及木质素类与PPRIs产生速率展现出了良好的正相关关系,尤其是其中的DOC与木质素类组分;另外在三维荧光指标结果中,荧光指数(FI)和新鲜度指数(β/α)与PPRIs呈现负相关关系,证明FI值越低即DOM陆源性越高、非新生DOM比例越高,则PPRIs产生速率越高。综上,PPRIs的光化学产生与植物源DOM密切相关。与春季和冬季相比,夏季和秋季鄱阳湖水体的有机质高,而其中DOM组分中芳香族化合物丰度较高,主要来自陆生植物和土壤有机质,其有机质的腐殖化水平较高,而在春季和冬季水体有机质主要来自湖泊本身和微生物产生的有机质,属于内源。淹水植物残体降解过程释放的有机组分,对夏、秋季DOM的来源和组成有着极易被忽视的影响和作用,而其中光化学活性较强的有机组分如木质素是造成其PPRIs产率更高的主要原因。 相似文献
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三峡库区拥有目前世界上规模最大的水利枢纽工程,自投入使用以来,为长江流域提供了丰富的水源及电力,促进了经济的发展,但同时也对该区域的生态环境造成了严重的冲击。澎溪河流域作为三峡库区长江流域干流的典型回水区和消落带,是众多学者研究三峡库区生态环境变化的重点区域。为探究不同时空尺度下土地利用对河流溶解性有机质（DOM）的影响,以澎溪河流域为研究对象,基于紫外-可见光谱分析和三维荧光光谱矩阵-平行因子分析,结合河段缓冲区、河岸带缓冲区及子流域3种空间尺度的二级土地利用类型,解析了旱雨季水体DOM的组成及来源特征,并采用相关分析和冗余分析方法探讨了3种空间尺度下土地利用方式对旱雨季水体DOM的多时空尺度影响。结果表明：（1）旱季水体DOM荧光组分以陆源类腐殖质所占比例更大,雨季水体DOM荧光组分以富里酸贡献为主。（2）流域内陆源输入和内源产生对水体DOM丰度均有贡献,雨季较旱季水体DOM的陆源性更强,自生源特征较弱。（3）土地利用在雨季和子流域尺度下对水体DOM的影响更显著,其中,雨季子流域尺度下,土地利用指数对水体DOM参数的解释率为90.35%。（4）不同土地利用方式对水体DOM产生的影响... 相似文献
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官厅水库秋季悬浮颗粒物和CDOM吸收特性 总被引：2，自引：0，他引：2
利用2012年9月5日在官厅水库采集的水体吸收系数数据,对总悬浮颗粒物、浮游植物色素颗粒物、非色素颗粒物和有色可溶性有机物的吸收特性进行研究.结果表明:秋季官厅水库的颗粒物吸收以浮游植物色素吸收为主,总颗粒物吸收光谱与浮游藻类吸收光谱相似;非色素颗粒物和有色可溶性有机物的吸收系数随波长的增大接近指数规律衰减;ad(440)、ad(675)与CChl.a呈显著相关,表明官厅水库秋季的非色素颗粒物主要来源于浮游藻类降解产物,陆源性输入较少;a ph(440)、a ph(675)与CChl.a存在显著线性关系,但其比吸收系数较为恒定,与CChl.a基本无关;不同采样点的不同组分吸收系数对总吸收系数的贡献不同,大致有4种表现类型.在富营养程度较高的妫库区,浮游植物色素是水体光谱吸收的主导因子;在富营养程度较低的中库区,颗粒物与有色可溶性有机物共同主导水体光谱吸收. 相似文献
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以艾比湖流域主要入湖河流为研究对象,在5月（丰水期）和8月（枯水期）分别沿博尔塔拉河（博河）和精河进行采样,采用平行因子模型（PARAFAC）和三维荧光区域积分法对水体三维荧光特性进行研究并对其与水质的关系在枯、丰水期下的变化进行探讨.结果表明①河流DOM在枯水期与丰水期都含有C1（240、425 nm） UVC类腐殖质,C2（225、290 nm）紫外区内络氨酸类有机物,C3（230/280、330 nm）蛋白类有机物,C4（265、260 nm）腐殖质类共4种组分.通过对水体三维荧光进行区域积分可以看出DOM荧光成分的占比在不同时期的变化.博河在枯水期时EEM光谱中的区域Ⅲ富里酸含量低于丰水期,枯水期时区域Ⅱ芳香类蛋白质、区域Ⅳ可溶性微生物代谢物以及区域Ⅴ类腐殖质酸高于丰水期;对于精河来说,区域Ⅱ芳香类蛋白质和区域Ⅳ可溶性微生物代谢物在枯水期的含量高于丰水期,区域Ⅲ富里酸和区域Ⅴ类腐殖质酸的含量枯水期低于丰水期,这表明水体腐质化程度较高.②本研究选取了一些常规的荧光指数来描述枯、丰水期水体的荧光指数特性.经研究发现,精河的荧光指数、自生源指数和腐殖化指数在不同时期的变化幅度较小,而博河的变化幅度较大.③将荧光指数与水质参数进行相关性分析并建模,结果表明枯水期自生源指数（BIX）与化学需氧量呈显著正相关,相关系数R=0.688;丰水期时BIX与铵态氮浓度呈显著负相关,相关系数R=-0.493.通过对比分析艾比湖主要入湖河流的三维荧光光谱特性与水质在枯、丰水期时的关系进一步表明水体中DOM的特性以及在枯、丰水期下的差异,为艾比湖流域的治理改善提供一定的理论支持和参考依据. 相似文献
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为揭示太湖流域降雨和湖水酸根阴离子长期变化特征及环境意义,通过历史数据收集和采样分析,对太湖流域降雨和湖水中的SO42-、NO3-变化特征和来源进行了研究.结果表明：自1990s以来太湖流域降雨中SO42-呈显著下降趋势,年平均下降率为0.28 mg/（L·a）;NO3-浓度却呈显著上升趋势,年平均增长率为0.05 mg/（L·a）,降雨中氮污染呈现加重的趋势.与之相反,湖水中SO42-呈显著上升趋势,年平均增长率为1.24 mg/（L·a）;NO3-浓度却呈显著下降趋势,年平均下降率为0.02 mg/（L·a）.30年以来,太湖水体SO42-/NO3-比值不断升高,远高于降水SO42-/NO3-比值.研究认为：流域SO2排放引起的酸沉降是湖水SO42-浓度增长的最重要原因,但氮氧化物排放并未引起湖水NO3-浓度升高,说明太湖流域对大气沉降的氮氧化物有滞留作用,而太湖水体是流域大气沉降硫酸盐的重要汇.综合治理太湖流域酸性物质排放对防止太湖水体酸化和治理富营养化都具有重要意义. 相似文献
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鄱阳湖湖泊流域系统水文水动力联合模拟 总被引：5，自引：5，他引：0
本文以鄱阳湖湖泊流域系统为研究对象,鉴于该湖泊流域系统尺度较大,下垫面自然属性呈现高度空间异质性且具有流域-平原区-湖泊不同机制的水文水动力过程,为了真实描述湖泊流域间的水文水动力联系及反映不同过程间的作用机制,构建了鄱阳湖湖泊流域联合模拟模型.该模型基于自主研发的流域分布式水文模型WATLAC和湖滨平原区产流模型以及水动力模型MIKE 21 3个不同功能子模型的连接来实现该复杂系统的模拟.模型的联合采用输入-输出驱动及子模型的顺序执行进程,即将五大子流域与平原区入湖径流量作为输入条件来驱动湖泊水动力模型,模拟湖泊水位对流域入湖径流量的响应.以2000-2005年鄱阳湖流域6个水文站点的河道径流量、流域基流指数以及湖泊4个站点的水位资料来率定模型,其中各站点日径流量拟合的纳希效率系数Ens为0.71~0.84,确定性系数R2介于0.70~0.88之间,而湖泊各站点水位拟合的纳希效率系数Ens变化为0.88~0.98,确定性系数R2为0.96~0.98,均取得令人满意的率定结果.本文提出的鄱阳湖湖泊流域系统水文水动力联合模拟模型能较为理想再现湖泊水位对流域降雨-径流过程的响应.水位模拟结果进一步表明,该联合模型能用来获取重要的水动力空间变化特征.该模型可作为有效工具定量揭示湖泊流域系统水文水动力过程对气候变化和流域人类活动的响应. 相似文献
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12.
Doreen Franke Michael W. Hamilton Susan E. Ziegler 《Aquatic Sciences - Research Across Boundaries》2012,74(4):751-768
Boreal watersheds contain a vast quantity of terrestrially derived dissolved organic matter (DOM) originating from wetland and forest soils, yet variation in the potential for photochemical transformation of boreal aquatic DOM sources remains poorly understood. Laboratory solar radiation exposure experiments were conducted on DOM samples collected in three seasons, across nine sites, representing contrasting catchment composition and watershed position to assess variation in the photochemical lability of boreal DOM source and stable carbon isotopic signature (δ13C) of photomineralized DOM. Dissolved organic carbon (DOC) loss rates during laboratory exposure were lowest in summer, suggesting that DOM may have been more photo-degraded during summer. DOM from upstream portions of forested stream sites and wetland-influenced sites was more photolabile relative to downstream portions and the river DOM, suggesting potential losses in photolabile DOM downstream and in the lower reaches of the watershed. Increased a254:a350 and spectral slope following sample exposure suggest photoproduction of low molecular weight (LMW) CDOM and/or a higher photoreactivity of high molecular weight versus LMW compounds. Photomineralization of nitrogen was regulated by organic nitrogen concentration and resulted in NH4 +-photoproduction rates between 0.01 and 0.3?μM N?h?1 and ecologically significant increases in NH4 + for these waters. The δ13C of the photomineralized DOM was positively correlated to initial DOC concentration and generally lower when initial DOC concentrations were lower, suggesting variation in photomineralized DOM δ13C may be a result of kinetic isotope fractionation. Results from this study demonstrate significant variation in the photochemical lability of boreal watershed sources of DOM. Such variation suggests landscape and environmental change has the potential to alter the biogeochemical role photochemical transformations play in downstream portions of boreal watersheds. 相似文献
13.
Effects of watershed land use on sources and nutritional value of particulate organic matter in temperate headwater streams 总被引：4，自引：0，他引：4
Yue Han Lu Elizabeth A. Canuel James E. Bauer R. M. Chambers 《Aquatic Sciences - Research Across Boundaries》2014,76(3):419-436
Suspended particulate organic matter (POM) in headwater streams is an important source of food and energy to stream food webs. In order to determine the effects of watershed land use on the sources and characteristics of POM, we compared the lipid composition of POM (fatty acid, aliphatic alcohol and sterol) from streams influenced by different types of watershed land use. Eight first-order streams discharging to the York River Estuary (Virginia, USA) were sampled during baseflow conditions bi-monthly from February to November 2009, including streams draining forest-dominated, pasture-dominated, cropland-dominated, and urban land-dominated watersheds. Allochthonous vs. autochthonous lipids showed that POM in most of these streams was dominated by allochthonous sources (59.5 ± 14.2 vs. 39.6 ± 14.5 % for aliphatic alcohols and 52.9 ± 11.5 vs. 34.1 ± 10.3 % for sterols). The relative abundance of allochthonous vs. autochthonous lipid inputs to POM varied as a function of land use type. POM in streams draining forest-dominated watersheds contained a higher proportion of allochthonous lipids and a lower proportion of autochthonous lipids than the streams influenced by human land use. The contribution of bacterial fatty acids differed significantly among sampling times (P = 0.003), but not among land use types (P = 0.547). Stepwise linear regression model selected nitrate and temperature as the best predictors of variation in bacterial inputs to POM. Proxies used to assess the nutritional value of POM potentially available to stream consumers included C:N ratios, and the concentrations of total long-chain polyunsaturated fatty acids, eicosapentaenoic acid, arachidonic acid, and cholesterol. None of these nutritional proxies differed among sampling months (P ≥ 0.171), but the proxies showed that the nutritional value of POM in forest streams was lower than in urban streams. Collectively, these findings suggest that human land use in upstream watersheds alters the source composition and nutritional value of stream POM, which not only impacts food quality for stream biota, but also potentially changes the characteristics of OM reaching downstream ecosystems. 相似文献
14.
Megan J. Macdonald Elizabeth C. Minor 《Aquatic Sciences - Research Across Boundaries》2013,75(4):509-522
The input and fate of dissolved organic matter (DOM) can have important consequences for coastal zone productivity in large lakes and oceans. Chromophoric DOM (CDOM) is often delivered to coastal zones from rivers and streams and affects light penetration in a water column. CDOM can protect biota from damaging ultraviolet (UV) light by acting as sunscreen, resulting in increased ecosystem productivity. Alternatively, CDOM can decrease ecosystem productivity by absorbing light needed for photosynthesis and forming photoreaction products that are harmful to coastal zone biota. Increased urbanization of watersheds and seasonal differences in weather patterns change the delivery pathways, reactivity, input, and energy flow of DOM (and its CDOM component) into aquatic systems. This study investigated the effects of watershed and season on the concentrations and potential photodegradation of stream-derived DOM in Lake Superior tributaries, chosen to be geographically and geologically similar but differing in land use. Organic carbon analysis, UV–Visible spectrophotometry, and terrestrial (land use) analysis were used to investigate differences among samples and sample treatments. The major differences in DOM concentration and photochemical response appeared seasonal rather than site specific, with snow-melt samples showing stronger and more consistent changes in UV–Visible parameters while base-flow samples showed stronger and more consistent losses in DOC. 相似文献
15.
Zhongwu Li Hao Peng Binggeng Xie Chun Liu Xiaodong Nie Danyang Wang Mei Huang Haibing Xiao Lin Shi Xuqin Zhang Jieyu Jiang 《水文研究》2020,34(6):1446-1459
Exploring the chemical characterization of dissolved organic matter (DOM) is important for understanding the fate of laterally transported organic matter in watersheds. We hypothesized that differences in water-extractable organic matter (WEOM) in soils of varying land uses and rainfall events may significantly affect the quality and the quantity of stream DOM. To test our hypotheses, characteristics of rainfall-runoff DOM and WEOM of source materials (topsoil from different land uses and gullies, as well as typical vegetation) were investigated at two adjacent catchments in the Loess Plateau of China, using ultraviolet–visible absorbance and excitation emission matrix fluorescence with parallel factor analysis (PARAFAC). Results indicated that land-use types may significantly affect the chemical composition of soil WEOM, including its aromaticity, molecular weight, and degree of humification. The PARAFAC analysis demonstrated that the soils and stream water were dominated by terrestrial/allochthonous humic-like substances and microbial transformable humic-like fluorophores. Shifts in the fluorescence properties of stream DOM suggested a pronounced change in the relative proportion of allochthonous versus autochthonous material under different rainfall patterns and land uses. For example, high proportions of forestland could provide more allochthonous DOM input. This study highlights the relevance of soils and hydrological dynamics on the composition and fluxes of DOM issuing from watersheds. The composition of DOM in soils was influenced by land-use type. Precipitation patterns influenced the proportion of terrestrial versus microbial origins of DOM in surface runoff. Contributions of allochthonous, terrestrially derived DOM inputs were highest from forested landscapes. 相似文献
16.
Projected 21st century climate change on snow conditions over Shasta Dam watershed by means of dynamical downscaling 
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下载免费PDF全文 Snow is an important component of the Earth's climate system and is particularly vulnerable to global warming. It has been suggested that warmer temperatures may cause significant declines in snow water content and snow cover duration. In this study, snowfall and snowmelt were projected by means of a regional climate model that was coupled to a physically based snow model over Shasta Dam watershed to assess changes in snow water content and snow cover duration during the 21st century. This physically based snow model requires both physical data and future climate projections. These physical data include topography, soils, vegetation, and land use/land cover, which were collected from associated organizations. The future climate projections were dynamically downscaled by means of the regional climate model under 4 emission scenarios simulated by 2 general circulation models (fifth‐generation of the ECHAM general circulation model and the third‐generation atmospheric general circulation model). The downscaled future projections were bias corrected before projecting snowfall and snowmelt processes over Shasta Dam watershed during 2010–2099. This study's results agree with those of previous studies that projected snow water equivalent is decreasing by 50–80% whereas the fraction of precipitation falling as snowfall is decreasing by 15% to 20%. The obtained projection results show that future snow water content will change in both time and space. Furthermore, the results confirm that physical data such as topography, land cover, and atmospheric–hydrologic data are instrumental in the studies on the impact of climate change on the water resources of a region. 相似文献
17.
鄱阳湖流域径流模型 总被引：8，自引：4，他引：4
流域径流是鄱阳湖主要来水,建立鄱阳湖流域径流模型对揭示湖泊水量平衡及其受流域自然和人类活动的影响具有重要意义.针对鄱阳湖-流域系统的特点:流域面积大(16.22×104km2)、多条入湖河流、湖滨区坡面入湖径流等,研究了相应的模拟方法,建立了考虑流域土壤属性和土地利用空间变化的鄱阳湖流域分布式径流模型.采用6个水文站1991-2001年的实测河道径流对模型进行了率定和验证.结果显示,模型整体模拟精度较高.其中,赣江、信江和饶河均取得了较好的模拟结果,月效率系数为0.82-0.95;抚河和修水模拟精度略低,为0.65-0.78.模型揭示了研究时段内年平均入湖径流总量为1623×108m3,其中,赣江最多,占47%,其次为信江和抚河,分别占13%和12%,湖滨区坡面入湖径流约占4%,其余24%来自饶河、修水以及其它入湖支流.模型将用于评估流域下垫面或气候变化引起的入湖水量变化,为湖泊水量平衡计算提供依据. 相似文献
18.
19.
This study was undertaken to test the utility of a geographical information systems (GIS) approach to problems of watershed mass balance. This approach proved most useful in exploring the effects that watershed scale, lithology and land use have on chemical weathering rates, and in assessing whether mass balance calculations could be applied to large multilithological watersheds. Water quality data from 52 stations were retrieved from STORET and a complete GIS database consisting of the watershed divide, lithology and land use was compiled for each station. Water quality data were also obtained from 7 experimental watersheds to develop a methodology to estimate annual fluxes from incomplete data sets. The methodology consists of preparing a composite of daily flux data, calculating a best fit sinusoid and integrating the equation to obtain an annual flux. Comparison with annual fluxes calculated from high resolution data sets suggests that this method predicts fluxes within about 10% of the true annual flux. Annual magnesium fluxes (moles km−2 yr−1) were calculated for all stations and adjusted for fluxes from atmospheric deposition. Magnesium flux was found to be a strong function of the amount of carbonate in the watershed, and silica fluxes were found to increase with the fraction of sandstone present in the watershed. All fluxes were strongly influenced by mining practices, with magnesium fluxes from affected watersheds being 6–10 times higher than fluxes from comparable pristine watersheds. Mining practices enhance chemical weathering by increasing the surface area of unweathered rock to which water has access and by increasing acidity and rate of mineral weathering. Fluxes were also found to increase with watershed size. This scale dependence is most likely caused by the sensitivity of weathering fluxes to even minor quantities of carbonates, which are likely to be found in all lithologies at larger scales. Mass balances were carried out in watersheds where gauged sub-watersheds made up more than 95% of the area. The calculations show large magnesium flux and water balance discrepancies. These errors may be a result of significant groundwater inputs to streams between gauges. The results suggest that improvements in how we measure discharge and estimate fluxes may be required before we can apply mass balance techniques to larger scales. © 1997 John Wiley & Sons, Ltd. 相似文献
20.
周村水库汛期暴雨中溶解有机物(DOM)的光谱特征及来源解析 总被引：2，自引：2，他引：0
运用三维荧光光谱（EEMs）技术结合平行因子分析法（PARAFAC）,对周村水库夏季两场暴雨不同降雨历时以及分子量的溶解有机物光谱特征和来源进行分析.结果表明：周村水库不同暴雨荧光光谱中出现了5种组分,分别为类腐殖质（C1、C2）、可见区富里酸（C3）和类蛋白（C4、C5）;相关性分析显示C1与C2、C3、C4以及C5具有显著的相关性,C2与C3具有显著的相关性,C3与C4以及C5具有显著的相关性;同一分子量下的雨水有机质总荧光强度以及各组分荧光强度随着降雨历时的增加均呈下降趋势,并且在各个历时和分子量间差异明显;同一降雨历时下,第一场暴雨总荧光强度随着分子量的减少而增加,第二场暴雨总荧光强度随着分子量的减少而减少;两场暴雨都呈现自生源的特征,其中第一场暴雨具有以陆源输入为主的特征;组分C1和C3与水质参数硝态氮、氨氮、总氮以及有机碳呈显著相关性.通过对暴雨在不同降雨历时以及分子量DOM光谱特征研究,可以进一步分析水库外源输入的天然有机质特征,为水库水质管理提供技术支持. 相似文献