微生物降解及自团聚作用对鄱阳湖流域瑶湖水中不同粒径胶体荧光物质变化的影响

了解城市内湖水中胶体的环境行为对研究湖泊水环境中污染物的迁移转化意义重大.微生物降解及自团聚过程是湖泊水体中胶体转化的重要途径,然而目前有关不同粒径胶体在微生物降解及自团聚作用下荧光特性变化的报道还非常少.基于此,本文选取南昌市内最大的湖泊(瑶湖)及其支流水体,通过切向超滤技术、三维荧光光谱法及平行因子分析法(PARAFAC),分析了在灭菌及微生物存在下两种水样含不同粒径胶体的水体(即W_原水、W_1μm、W_0.45μm和W_{1 kDa})中荧光特性的变化情况.通过PARAFAC模型共解析出3个类腐殖质组分(C1～C3)和1个类蛋白质组分(C4).初始时刻所有水样均以类腐殖质组分含量更高,且大都集中在1 kDa～0.45μm粒径胶体中.两种水样荧光物质的减少为微生物降解及自团聚作用共同主导,自团聚作用约占50%.相较于小粒径(W_{1 kDa})胶体,微生物降解对大(W_原水)、中(W_1μm)粒径胶体中荧光物质减少的影响更大.此外,类蛋白物质主要以微...     

Trends in suspended sediment grain size in the upper Yangtze River and its tributaries,as influenced by human activities

Abstract

Based on data from five hydrometric stations, Pingshan station on the Jinshajiang River, Gaochang station on the Minjiang River, Wulong station on the Wujiang River, Wusheng station on the Jialingjiang River and Yichang station on the Yangtze River, a study has been made of the temporal variation in grain size of suspended sediment load in the upper Yangtze River. The results show that in the past 40 years, the grain size of the suspended sediment load in the main stem and major tributaries of the upper Yangtze River has had a decreasing trend, that can be explained by the effect of reservoir construction and implementation of soil conservation measures. The reservoirs in the upper Yangtze River Basin, all used for water storage for hydro-electric generation and/or irrigation, have trapped coarse sediment from the drainage area above the dam and, thus, the sediment released now is much finer than before the construction of the reservoirs. The downstream channels are all gravel-bedded or even in bedrock, with little fine sediment, and thus, the released flow can hardly get a supply of fine sediment through eroding the bed. Then, after the downstream adjustment, the grain size of suspended sediment is still fine. Large-scale soil conservation measures have significantly reduced sediment yield in some major sediment source areas. The relatively coarse sediment is trapped and, thus, the sediment delivered to the river becomes finer.     

The particle size characteristics of fine‐grained channel deposits in the River Exe Basin,Devon, UK

Deposition and storage of fine‐grained (<62·5 μm) sediment in the hyporheic zone of gravel bed rivers frequently represents an important cause of aquatic habitat degradation. The particle size characteristics of such fine‐grained bed sediment (FGBS) exert an important control on its hydrodynamic properties and environmental impact. Traditionally, particle size analysis of FGBS in gravel bed rivers has focused on the absolute size distribution of the chemically dispersed mineral fraction. However, recent work has indicated that in common with fluvial suspended sediment, significant differences may exist between the absolute and the in situ, or effective, particle size composition of FGBS, as a result of the existence of aggregates, or composite particles. In the investigation reported in this paper, sealable bed traps that could be remotely opened to sample sediment deposited during specific storm runoff events and a laser back‐scatter probe were used to quantify the temporal and spatial variability of both the absolute and effective particle size composition of FGBS, and the associated suspended sediment from four gravel bed rivers in the Exe Basin, Devon, UK. The absolute particle size distributions of both the FGBS and suspended sediment evidenced c. >95%<62·5 μm sized primary particles and displayed a seasonal winter–summer fining, while the opposite trend was displayed by the effective particle size distribution of the FGBS and suspended sediment. The effective particle size distributions of both were typically highly aggregated, comprising up to 68%>62·5 μm sized particles. Spatial variation in the effective particle size and aggregation parameters was of secondary importance relative to temporal variation. The effective particle size distribution of the FGBS was consistently coarser and more aggregated than the associated suspended sediment and there was evidence of aggregate break‐up in samples of resuspended bed sediment. The implications of these findings for sediment transport modelling are considered. Copyright © 1999 John Wiley & Sons, Ltd.     

Sediment infiltration traps: their use to monitor salmonid spawning habitat in headwater tributaries of the Cascapédia River,Québec

Sediment infiltration can clog salmon nests and reduce egg survival. As a countermeasure, environmental managers often deploy infiltration traps to monitor sediment infiltration. Traps provide a repeatable means of measuring infiltration and enable comparisons to be made between sites. Results from infiltration rates measured with traps have also been used to estimate infilling rates into salmon nests. Application of these data is questionable, as the composition of the bed and the amount of fine sediment within the bed is known to affect infiltration rates. Thus, infiltration rates measured with infiltration traps may differ from the infiltration rates occurring in redd and riffle gravels. To examine how relationships between sediment infiltration rates varied between four watersheds, we continuously monitored suspended sediment transport, shear stress and infiltration rates at four sites over 5 months. We also compared infiltration rates measured with infiltration traps with changes in the hydraulic conductivity and subsurface grain size distribution of adjacent artificially constructed salmon nests and natural riffle gravels. Among the four watersheds, clear differences in sediment infiltration rates were observed. The differences correlated with the subsurface silt content but no strong relationship existed between land‐use or basin physiography/geology. Despite observing an average of 30 kg m⁻² of sediment finer than 2 mm being deposited in the infiltration traps during the study, no change in redd or riffle substrate was observed. If the deposition rates measured with the traps reflect the processes in redds, enough sediment would have been deposited to inhibit egg emergence. However, no reduction in egg survival to the eyed stage was observed. In summary, our results show that infiltration traps with clean gravels can be used to detect intersite differences in sediment transport regimes. Extrapolations of sediment infiltration rates measured with such collectors to estimate infiltration rates in redds or riffles is, however, flawed. Copyright © 2005 John Wiley & Sons, Ltd.     

Causes for the decline of suspended‐sediment discharge in the Mississippi River system, 1940–2007

Before 1900, the Missouri–Mississippi River system transported an estimated 400 million metric tons per year of sediment from the interior of the United States to coastal Louisiana. During the last two decades (1987–2006), this transport has averaged 145 million metric tons per year. The cause for this substantial decrease in sediment has been attributed to the trapping characteristics of dams constructed on the muddy part of the Missouri River during the 1950s. However, reexamination of more than 60 years of water‐ and sediment‐discharge data indicates that the dams alone are not the sole cause. These dams trap about 100–150 million metric tons per year, which represent about half the decrease in sediment discharge near the mouth of the Mississippi. Changes in relations between water discharge and suspended‐sediment concentration suggest that the Missouri–Mississippi has been transformed from a transport‐limited to a supply‐limited system. Thus, other engineering activities such as meander cutoffs, river‐training structures, and bank revetments as well as soil erosion controls have trapped sediment, eliminated sediment sources, or protected sediment that was once available for transport episodically throughout the year. Removing major engineering structures such as dams probably would not restore sediment discharges to pre‐1900 state, mainly because of the numerous smaller engineering structures and other soil‐retention works throughout the Missouri–Mississippi system. Published in 2009 by John Wiley & Sons, Ltd.     

Magnitude and variation in the contribution of bank erosion to the suspended sediment load of the River Severn,UK

The wide range of studies describing the role of bank erosion in fluvial sediment supply have mostly lumped amounts of bank erosion into coarse temporal units, such as years. This paper investigates sediment yields from individual bank erosion events within the upper River Severn, UK (basin area 380 km²). Manual erosion pins and photo-electronic erosion pins were used to estimate bank erosion, and turbidity meters were used to determine suspended sediment transport. At the annual time-scale, the silt-clay fraction of bank-derived sediment accounted for an equivalent of 17 per cent of the suspended load, increasing to an average of 38 per cent at the monthly timescale, and then to an average of 64 per cent at the event timescale. This research highlighted that for an upland catchment, bank erosion was an important supply of suspended sediment, and that for some flood events bank erosion can supply more sediment than is transported. © 1997 John Wiley & Sons, Ltd.     

2017—2022年雅砻江甘孜以下干流及部分支流鱼类种类组成及群落结构

基于2017—2022年在雅砻江甘孜以下干流及部分支流的鱼类监测数据,采用多样性指数和多元统计方法分析了该流域的鱼类群落结构。通过在雅砻江干流和6条支流21个采样点的监测及相关文献调研共获得鱼类98种,包括9种国家二级重点保护鱼类和28种长江上游特有鱼类。除干流下游Margalef丰富度指数外,其他区域多样性指数值相差不大;干流上、中、下游和6条支流间鱼类生物多样性不存在显著差异。Cluster分析和NMDS分析表明鱼类群落可以分成6组,ANOSIM检验表明6组间存在显著性差异,6组在海拔和河流等级上存在极显著和显著性差异。分别计算6个聚类组的优势种和常见种,并从栖息类型、食性和产卵类型上进行分析,结果显示6组在栖息类型和产卵类型上差异显著。二滩库区和鳡鱼河静缓流河段优势种为翘嘴鲌(Culter alburnus)、尼罗罗非鱼(Oreochromis niloticus)等,建议加强对下游流域外来物种的监测,避免发生大规模生物入侵现象。自1980s以来,雅砻江下游流域鱼类种类组成发生了明显变化,推测与梯级电站修建运行等造成生境改变有关。     

Predictability of river flow and suspended sediment transport in the Mississippi River basin: a non‐linear deterministic approach

As the Mississippi River plays a major role in fulfilling various water demands in North America, accurate prediction of river flow and sediment transport in the basin is crucial for undertaking both short‐term emergency measures and long‐term management efforts. To this effect, the present study investigates the predictability of river flow and suspended sediment transport in the basin. As most of the existing approaches that link water discharge, suspended sediment concentration and suspended sediment load possess certain limitations (absence of consensus on linkages), this study employs an approach that presents predictions of a variable based on history of the variable alone. The approach, based on non‐linear determinism, involves: (1) reconstruction of single‐dimensional series in multi‐dimensional phase‐space for representing the underlying dynamics; and (2) use of the local approximation technique for prediction. For implementation, river flow and suspended sediment transport variables observed at the St. Louis (Missouri) station are studied. Specifically, daily water discharge, suspended sediment concentration and suspended sediment load data are analysed for their predictability and range, by making predictions from one day to ten days ahead. The results lead to the following conclusions: (1) extremely good one‐day ahead predictions are possible for all the series; (2) prediction accuracy decreases with increasing lead time for all the series, but the decrease is much more significant for suspended sediment concentration and suspended sediment load; and (3) the number of mechanisms dominantly governing the dynamics is three for each of the series. Copyright © 2005 John Wiley & Sons, Ltd.     

A quarter century of declining suspended sediment fluxes in the Mississippi River and the effect of the 1993 flood

Annual fluxes, flow‐weighted concentrations and linear least squares trendline calculations for a number of long‐term Mississippi River Basin (MRB) sampling sites covering 1981 through 2007, whilst somewhat ‘noisy’, display long‐term patterns of decline. Annual flow‐weighted concentration plots display the same long‐term patterns of decline, but are less noisy because they reduce/eliminate variations due to interannual discharge differences. The declines appear greatest in the middle MRB, but also are evident elsewhere. The pattern for the lower Ohio River differs and may reflect ongoing construction at the Olmsted lock and dam that began in 1993 and currently is ongoing. The ‘Great Flood of 1993’ appears to have superimposed a step function (a sharp drop) on the long‐term rate of decline in suspended sediment concentrations (SSC), annual fluxes and flow‐weighted concentrations in the middle MRB at St Louis and Thebes, Missouri and Vicksburg, Mississippi, and in the lower MRB at St Francisville, Louisiana. Evidence for a step function at other sites is less substantial, but may have occurred. The step function appears to have resulted from losses in available (erodible) sediment, rather than to a reduction in discharge; hence, the MRB appears to be supply limited rather than discharge limited. These evaluations support the need for daily discharge and SSC data collections in the MRB to better address questions regarding long‐term trends in sediment‐related issues. This is apparent when the results for the Mississippi River at Thebes and St Louis sites are compared with those from other MRB sites where intensive (daily) data collections are lacking. Published in 2009 by John Wiley & Sons, Ltd.     

Floodplain effects on the transport of dissolved and colloidal trace elements in the East Pearl River,Mississippi

Substantial work suggests that floodplain wetlands could play a role in modifying fluvial fluxes of dissolved and colloidal trace elements. Yet, few studies have directly addressed this issue. We examined trace elements in the East Pearl River (Mississippi or Louisiana, USA), which is surrounded by wetlands that are temporally more or less connected to the river depending on river stage. Dissolved and colloidal trace element samples, along with ancillary data, including dissolved organic carbon and nutrients, were collected during eight surveys of this system at different flow stages from November 2007 to September 2008. Hydrology of the system is complex due to seasonal changes in water sources as well as potential inputs from the floodplain wetlands and the hyporheic zone. We therefore considered effects including nonconservative mixing of water sources, saltwater intrusion, and floodplain wetland flux requirements needed to support observed downstream concentration changes. During moderately high discharge, fluxes of many elements (e.g., Cd, Fe, Mn, and Zn) increased downstream by 20% or more, with inputs from the floodplain wetlands as the apparent source. At the highest discharge, however, wetland inputs to the river may have been rate‐limited (i.e., the wetland source was flushed faster than biogeochemical processes could regenerate dissolved or colloidal material). At low discharge, other effects, including saltwater intrusion and hyporheic zone interactions, are important. Both redox processes and organic ligands (or dissolved organic carbon), along with the supply of wetland inputs (or removal) relative to river fluxes, appear to be key factors determining floodplain wetland effects. While the behavior of some elements suggests they were dominantly affected by redox processes (Mn and V) or by organic complexation (dissolved Fe and light rare earths), other elements were affected by more than one process in ways that remain obscure (Cu). Overall our results are broadly consistent with previous field, laboratory, and modeling studies and suggest that a better understanding of the sources and transformations of Fe is a key area for future research.     

Influence of storm-related sediment storage on the sediment delivery from tributary catchments in the upper Waipaoa River,New Zealand

Although much is known about overall sediment delivery ratios for catchments as components of sediment production and sediment yield, little is known about the component of temporary sediment storage. Sediment delivery ratios focused on the influence of storm-related sediment storage are measured at Matakonekone and Oil Springs tributaries of the Waipaoa River basin, east coast of New Zealand. The terrace deposits of both tributaries show abundant evidence of storm-related sedimentation, especially sediment delivered from Cyclone Bola, a 50 year return rainfall event which occurred in 1988. The sediment delivery ratio is calculated by dividing the volume of sediment transported from a tributary to the main stream by the volume of sediment generated at erosion sites in the tributary catchment. Because the sediment delivery volume is unknown, it can be calculated as the difference between sediment generation volume and sediment storage volume in the channel reach of the tributary. The volume of sediment generated from erosion sites in each tributary catchment was calculated from measurements made on aerial photographs dating from 1960 (1:44 000) and 1988 (1:27 000). The volume of sediment stored in the tributary can be calculated from measurements of cross-sections located along the tributary channel, which are accompanied by terrace deposits dated by counting annual growth rings of trees on terrace surfaces. Sediment delivery ratios are 0·93 for both Matakonekone catchment and Oil Springs catchment. Results indicate that Oil Springs catchment has contributed more than twice the volume of sediment to the Waipaoa River than the Matakonekone catchment (2·75 × 10⁶ m³ vs 1·22 × 10⁶ m³). Although large volumes of sediment are initially deposited during floods, subsequent smaller flows scour away much of these deposits. The sediment scouring rate from storage is 1·25 × 10⁴ m³ a⁻¹ for Matakonekone stream and 0·83 × 10⁴ m³ a⁻¹ for Oil Springs stream. Matakonekone and Oil Springs channels respond to extreme storms by instantaneously aggrading, then gradually excavating the temporarily stored sediment. Results from Matakonekone and Oil Springs streams suggest a mechanism by which event recurrence interval can strongly influence the magnitude of a geomorphic change. Matakonekone stream with its higher stream power is expected to excavate sediment deposits more rapidly and allow more rapid re-establishment of storage capacity. Copyright © 1999 John Wiley & Sons, Ltd.     

Changes in run‐off and sediment load in the three parts of the Yellow River basin,in response to climate change and human activities

Hydrological regimes in the Yellow River have changed significantly because of climate change and intensive human interventions. These changes present severe challenges to water resource utilization and ecological development. Variation of run‐off, suspended sediment load (SSL), and eight precipitation indices (P1: 0–12 mm·day^?1, P12: 12–25 mm·day^?1, P25: 25–50 mm·day^?1, P50: P ≥ 50 mm·day^?1 and corresponding rainfall day: Pd1, Pd12, Pd25, Pd50 day year^?1) in three critical parts of the Yellow River basin (source region: SRYRB, upper reaches: URYRB, middle reaches: MRYRB) were investigated for the period from 1960 to 2015. The results show that run‐off and SSL significantly decreased (P < 0.01) in the URYRB and the MRYRB, whereas their decline in the SRYRB was insignificant (P > 0.05). Moreover, run‐off in the URYRB had one change point in 1987, and SSL in the URYRB as well as run‐off and SSL in the MRYRB had two change points (in the 1970s and the 1990s). Over the same period, only Pd1 and Pd12 in the SRYRB showed significant increasing trends, and an abrupt change appeared in 1981. The optimal precipitation indices for assessing the effects of precipitation on run‐off and SSL in the URYRB and MRYRB were Pd50 and P12, respectively. A double‐mass curve analysis showed that precipitation and human activities contributed to approximately 20% and 80% of the reduction in run‐off, respectively, for both the SRYRB and the MRYRB. However, the contribution rate of precipitation and human activities on SSL reduction was approximately 40% and 60% in the URYRB and 5% and 95% in the MRYRB, respectively. Human activities, primarily soil and water conservation measures and water extraction (diversion), were the main factors (>50%) that reduced the run‐off. However, the dominant driving factors for SSL reduction were soil and water conservation measures and reservoir interception, for which the contribution rate was higher than 70% in the MRYRB. This work strengthens the understanding of hydrological responses to precipitation change and provides a useful reference for regional water resource utilization.     

Spatial and temporal variability in the concentration and speciation of metals in suspended sediment transported by the River Aire,Yorkshire, UK

In recent years, there has been an increasing awareness of the important role of fine sediment in the transport and storage of metals in fluvial systems. However, there has been little research on the behaviour of contaminated sediment in industrial rivers in the UK. This paper examines spatial and temporal variations in the concentration and speciation of lead, copper and chromium associated with suspended sediment in the River Aire in Yorkshire, UK. An increase in the total concentration of all three metals in sediment was identified in the lower reaches, which reflected inputs of road dust, sewage and industrial effluents. Spatial variations in the chemical speciation of the metals were also identified. The iron–manganese oxides and organic fractions were the most significant for the adsorption of metals by sediment. Both the concentrations and speciation of sediment‐associated metals exhibited substantial temporal variation. Such variation reflected the accumulation of metals and organic matter on the river‐bed during low flows, the subsequent remobilization of the sediment at high flows and the additional supply of sediment from uncontaminated and contaminated sources, including pulse inputs of road dust, sewage and industrial effluent. The findings presented have important implications for the development of effective catchment management strategies for the control of point‐ and diffuse‐source pollution. Copyright © 2006 John Wiley & Sons, Ltd.     

渭河干流与其秦岭北麓典型支流浮游动物群落结构及影响因素

浮游动物作为食物链中重要的初级消费者,其群落结构特征是水生态系统健康评价的重要指标之一.本研究于2017年秋季和2018年春季对渭河干流及秦岭北麓五条典型支流开展了系统的水环境及浮游动物群落调查.结果表明,渭河干流营养盐浓度整体高于秦岭北麓支流,干流浊度远高于支流.两次调查共鉴定出浮游动物种类数136种(原生动物65种,轮虫44种,枝角类15种,桡足类12种),其中2017年秋季渭河干流浮游动物种类数、密度和生物量分别为14种、9.02 ind./L和0.0051 mg/L,秦岭北麓支流为37种、42.78 ind./L和0.0229 mg/L;2018年春季渭河干流浮游动物种类数、密度和生物量分别为52种、292.89 ind./L和0.1734 mg/L,秦岭北麓支流为68种、70.15 ind./L和0.0508 mg/L.秋季渭河干流下游浮游动物种类数、密度和生物量最低,而春季随上、中、下游三者均依次增大;秋季秦岭支流中罗敷河浮游动物密度和生物量最高,而春季灞河最高.春、秋两季干支流间浮游动物优势种差异较小,但秋季优势种种类数少于春季.秋季渭河干流中游Shannon-Wiene...     

Time‐varying,nonlinear suspended sediment rating curves to characterize trends in water quality: An application to the Upper Hudson and Mohawk Rivers,New York

This work proposes two modelling frameworks for diagnosing temporal variations in nonlinear rating curves that describe suspended sediment–discharge relationships. A variant of the weighted regression on time, discharge, and season model is proposed and is compared against dynamic nonlinear modelling, a newly developed nonlinear time series filter based on sequential Monte Carlo sampling. Both approaches estimate a time series of rating curve parameters, with uncertainty, that can be used to diagnose variability in the sediment–discharge relationship over time. We evaluate the models with a variety of synthetic scenarios to highlight their ability to estimate signals of known rating curve change. Results reveal important bias‐variance trade‐offs unique to each approach, and in general, suggest that dynamic nonlinear modelling is better suited for rapid rating curve changes, whereas the weighted regression on time, discharge, and season variant more precisely estimates slow change. The techniques are then applied in two case studies in the Upper Hudson and Mohawk Rivers in New York. We conclude with a discussion of the implications of dynamic rating curves for the management of water quality in riverine and estuary systems.     

Retrieval of suspended sediment concentrations in large turbid rivers using Landsat ETM+: an example from the Yangtze River,China

Suspended sediment concentration (SSC) is a critical parameter in the study of river sediment transport and water quality variation, but traditional measurement methods are costly and time‐consuming. This paper is focused on presenting a methodology that may be useful in estimating SSC which is of key importance in process geomorphology and hydrology. In previous studies, remote sensing has been applied to estimate the SSC of sea waters as well as low turbid inland waters like lakes, reservoirs and short river reaches visible within a single Landsat satellite image coverage. Rivers, especially highly turbid large rivers, have largely been ignored. The dataset used in this paper includes measured SSC and multi‐temporal Landsat ETM+ images covering most part of the Yangtze River. Using an effective easy‐to‐use atmospheric correction method that does not require in situ atmospheric conditions, retrieved water reflectance of Band 4 was found to be a good SSC indicator within the large SSC range 22–2610 mg l^–1. The newly developed regression relation between SSC and water reflectance of Band 4 appears to be able to provide a relatively accurate SSC estimate directly from Landsat ETM+ images for the Yangtze River from the upper, the middle to the lower reaches. With the relation it is possible to estimate or map out SSC dynamics of large rivers which lack SSC data due to constraints of conventional measurements. Copyright © 2009 John Wiley & Sons, Ltd.     

渭河干流和秦岭北麓典型支流底栖动物群落结构及水质生物评价

为摸清渭河干流及源于秦岭北麓典型支流的大型底栖动物群落特征,本研究于2017年10月和2018年5月对渭河干流及秦岭北麓5条典型支流共40个样点的大型底栖动物进行调查,并利用Margalef丰富度指数和生物指数BI生物指数对河流水质进行评价.共鉴定大型底栖动物210种,属于5门8纲75科187属.水生昆虫为优势类群,其物种数占总物种数的89.0%,且四节蜉属一种（Baetis sp.）作为绝对优势的物种出现在所有调查河流中.源于秦岭北麓的支流石头河底栖动物总密度最高（616.3 ind./m²）,总生物量最大（5.265 g/m²）;而渭河干流底栖动物总密度最低（125.6 ind./m²）,总生物量最小（0.289 g/m²）.水质较好的秦岭北麓典型支流底栖动物的Shannon-Wiener多样性指数、Margalef丰富度指数显著高于渭河干流,而Pielou均匀度指数在干支流间的差异性不大.通过Pearson相关分析和多元逐步回归分析得出,淤泥型底质、电导率、pH和硝酸盐氮是影响调查河流底栖动物群落特征的主导因子.丰富度指数法和生物指数法水质评价结果分别显示,渭河干流有73.3%和80.0%的采样点呈中度-重度污染状态,秦岭北麓典型支流有80.0%和68.0%的采样点呈无污染-轻度污染状态.本研究可为渭河流域生态管理与保护提供基础的数据支撑.     

太湖流域上游西苕溪支流的营养状态特征及成因分析

为了解太湖流域上游支流水体的营养状态特征及流域附近土地利用对水质的影响,选取了入湖水系西苕溪的10条主要支流进行了野外采样和实验室研究.研究结果表明,支流总磷(TP)、颗粒磷(PP)、总溶解性磷(TDP)、总氮(TN)、铵态氮(NH+4-N)、硝态氮(NO-3-N)含量季节间差异较大,TP含量范围为0.033~0.205 mg/L,PP含量范围为0.007~0.104 mg/L,TN含量范围为2.014~5.921 mg/L,NH+4-N含量范围0.021~1.659 mg/L,NO-3-N含量范围1.082~3.415mg/L,COD范围为6.5~15.5 mg/L.总体上呈现为枯水期平水期丰水期.部分支流受到不同程度的氮污染.利用水质参数进行聚类分析,可以将10条支流分成4类,其水体营养特征与周围环境相联系.支流营养盐、COD的通量明显受流量控制,表现为丰水期平水期枯水期.土地利用类型的差异是导致其水质变化的主要原因,耕地和居民地主要起源的作用,林地和草地主要起汇的作用.在丰水期和枯水期,对各指标影响最大的土地利用类型为耕地和林地;在平水期,对TP影响最大的是居民地,而对TN影响最大的是林地.