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1.
非点源污染是导致流域水体水质恶化的关键污染来源之一,为了估算流域非点源污染负荷,本文提出将一维水质模型应用于分离监测断面点源污染负荷和非点源污染负荷的方法,并结合了改进的输出系数法,以CODMn和NH3-N为代表性指标,将该模型应用于潮河下游流域,并与传统的水文分割法结合改进的输出系数法估算非点源污染负荷的结果进行对比。结果表明,一维水质模型结合改进的输出系数法估算流域非点源CODMn和NH3-N污染负荷模拟值的纳什系数均在0.800以上,具有良好的模拟精度,同时避免了水文分割法无法较好地模拟枯水期非点源污染负荷的弊端。该方法在运用SWAT（soil and water assessment tool）模型预测得到水文数据的情况下,能够预测流域非点源污染负荷,作为SWAT模型对COD模拟的补充。  相似文献   

2.
Agricultural nonpoint source (NPS) pollution at the Three Gorges reservoir area in China has been increasingly recognized as a threat to aquatic environment in recent years due to the serious eutrophication problem. Adsorbed NPS pollution is one of the major forms of NPS pollution in mountainous regions, the essential of the adsorbed NPS pollution is soil loss. Thus, simple, highly sensitive and continuous methods are required to simulate and quantify sediments yield at watershed scales. It is imperative to construct an integrated model to estimate the sediment yield and adsorbed NPS pollution load. According to the characteristics of climate, hydrology, topography, geology, geomorphology and land use types in Three Gorges reservoir area, a GIS-based dynamic-integrated-distributed model of annual adsorbed NPS load was presented in view of impacts of the rainfall intensity, sediment delivery ratio (SDR) and land management, where the temporally dynamic-continuous model of annual sediment yield was established by modifying the revised Universal Soil Loss Equation (RUSLE), and the spatially integrated-distributed model of annual adsorbed NPS load was then developed via the correlation between sediment yield and adsorbed NPS load. Furthermore, a case study of the Jialing River basin in China was applied to validate the integrated model, the dynamic-distributed coupling among GIS technology, sediment yield model, and adsorbed NPS load model was achieved successfully. The simulation results demonstrate the following: (1) runoff and sediment are influenced greatly by rainfall intensity, SDR and vegetation cover; rainfall and land management show high sensitivities to the integrated model; the average annual adsorbed TN and TP pollution loads from 2006 to 2010 decreased by 76 and 74 % compared with the previous treatment (1990), respectively. (2) Spatio-temporal variations of adsorbed NPS nitrogen and phosphorus load are mainly related to different land use types and the background level of nutriments in topsoil; different land use types have different contribution rates; the largest contribution rates of adsorbed total nitrogen (TN, 58.9 %) and total phosphorus (TP, 53 %) loads are both from the dryland cropland. (3) The identification of critical source areas can help to implement the prevention and control measures aiming at the reduction of water environmental pollution. These results will provide useful and valuable information for decision makers and planners to take sustainable land use management and soil conservation measures for the control of sediment pollution in the Three Gorges reservoir area. The application of this model in the catchment shows that the integrated model may be used as a major tool to assess sediment yield risks and adsorbed NPS pollution load at mountainous watersheds.  相似文献   

3.
Jialing River, which covers a basin area of 160,000 km2 and a length of 1,280 km, is the largest tributary of the catchment area in Three Gorges Reservoir Area, China. In recent years, water quality in the reservoir area section of Jialing River has been degraded due to land use and the rural residential area induced by non-point source pollution. Therefore, the semi-distributed land-use runoff process (SLURP) hydrological model has been introduced and used to simulate the integrated hydrological cycle of the Jialing River Watershed (JRW). A coupling watershed model between the SLURP hydrological model and dissolved non-point source pollution model has been proposed in an attempt to evaluate the potential dissolved non-point source pollution load; it enhances the simulation precision of runoff and pollution load which are both based on the same division of land use types in the watershed. The proposed model has been applied in JRW to simulate the temporal and spatial distribution of the dissolved total nitrogen (DTN) and dissolved total phosphorus (DTP) pollution load for the period 1990–2007. It is shown that both the temporal and spatial distribution of DTN and DTP load are positively correlated to annual rainfall height. Land use is the key factor controlling the distribution of DTN and DTP load. The source compositions of DTN and DTP are different, where average DTN pollution load in descending order is land use 67.2%, livestock and poultry breeding 30.5%, and rural settlements 2.2%; and for DTP, livestock and poultry breeding is 50%, land use 48.8%, and rural settlements 1.2%. The contribution rates of DTN and DTP load in each sub-basin indicate the sensitivity of the results to the temporal and spatial distribution of different pollution sources. These data were of great significance for the prediction and estimation of the future changing trends of dissolved non-point source pollution load carried by rainfall runoff in the JRW and for studies of their transport and influence in the Three Gorges Reservoir.  相似文献   

4.
中国非点源污染负荷计算研究现状与存在问题   总被引：13，自引：0，他引：13       下载免费PDF全文
非点源污染负荷计算对水污染总量控制具有重要意义,为分析中国非点源污染负荷计算研究的现状与问题,在系统调研相关文献的基础上,将中国常用的非点源污染负荷计算方法总结为三大类:输出系数模型、实证模型和机理模型,阐述了各种模型的特点及其在中国的研究和应用情况;从非点源污染的界定、产污量和排污量的区别、国内和国外非点源污染产生环境的差异以及平原河网地区非点源污染负荷的计算4个方面分析了中国非点源污染负荷计算研究存在的主要问题;认为模型和计算方法适应研究区的环境特征是研究工作取得成功的关键,今后要加强实证研究、理论研究与模型开发的结合,逐步建立适应中国环境特点的非点源污染负荷计算方法体系。  相似文献   

5.
Diffuse or nonpoint source (NPS) pollution results in different pollutant concentrations, which depend on river catchments, land use and precipitation events and may vary along a single event. This study aimed to assess NPS pollution loads of organic matter, nutrients, bacteria and heavy metals in four river catchments associated with different types of land use in Southern Brazil. Cluster analysis was used to identify similarities between basins and main component analysis (PCA) to identify the main variables that characterize diffuse pollution in each basin. The use and occupation of the soil were determinant in the formation of the clusters. The basins with rural characteristics formed one group, whereas the basin with urban characteristic generated another group. PCA suggests that changes in the water quality of the catchments in this study can be explained by organic pollutants and farming activities. The Rancho do Amaral catchment, with 55.8% of native forest, displayed the lowest NPS pollution load for all tested parameters. The Alto da Colina catchment, with the largest urban area and largest agricultural land use (50%), showed the highest NPS for all variables in the study, even though it has the smallest area. The differences in pollutant loads can be attributed to the intense degradation processes associated with anthropic activities, such as urbanization, agricultural activity and the discharge of effluents, which are different for each catchment.  相似文献   

6.
Nonpoint source pollution generated by agricultural production and city construction has been studied for decades, but very few researches have been conducted on the regional assessment of nonpoint source pollution in the acid rain regions, particularly relating to the control of pollutant in the drinking water source areas. In this study, an integrated framework was applied to estimate nitrogen and phosphorous load in a typical acid rain influenced reservoir, China. The method comprised three separate steps: (1) a watershed model—soil and water assessment tools—was used to estimate nitrogen and phosphorous load from the upper stream watershed; (2) collection of acid rain samples, together with a GIS-based calculation to estimate the atmospheric deposition flux; (3) introduction of a simple export coefficient method. The case study indicated atmospheric deposition accounted for 56.75 % of total nitrogen load during the year, with the highest level of deposition load taking place during the wet season. Maximum phosphorous (93.37 %) was linked to the upstream runoff, originating from the upper watershed. Further analysis by watershed model and export coefficient method indicated forest exported most total nitrogen (27.72 %) and total phosphorous (58.78 %) in the upstream watershed. Results indicated that in the region influenced by acid rain, the nitrogen management should encompass the management of land use practices and the control of acid rain in catchments feeding into drinking water storage areas. It could be inferred that NOX emissions might cause both globe warming and eutrophication in the drinking water sources. This paper could provide a basis for water quality management in such regions.  相似文献   

7.
Non-point source (NPS) pollution has been increasingly recognized as a major contributor to the declining quality of aquatic environment in recent years. Because of the data shortage, the non-point source loads estimation in the large-scale watershed is always difficult in most developing countries. In this study, small-scale watershed extended method (SWEM) was introduced with a case study in the middle part of Three Gorges Reservoir Region (TGRR). Small-scale watershed extended method is the method which uses physical-based models in some small typical catchments of the targeted large watershed, and then the parameters obtained from those small catchments are extended to the surrounding area until the non-point source pollution loads in the entire watershed or region are obtained. The selected small catchments should have sufficient data. Here, the middle part of the Three Gorges Reservoir Region, about 12,500?km2, was chosen as the targeted region for the case study. In this region, considering the data availability, Xiaojiang River was screened as a typical watershed and was simulated with Soil and Water Assessment Tool model through accurate parameter calibration and validation. And then the parameter group obtained in Xiaojiang River Watershed was extended to the entire study area to quantify the total non-point source pollution loads. After which, the spatio-temporal characteristics of the non-point source pollution in the middle part of the Three Gorges Reservoir Region were analyzed, as well as the pollution from each tributary and different under layer surface conditions. The small-scale watershed extended method provides a practical approach for non-point source pollution loads estimation in the large-scale watershed or region.  相似文献   

8.
辽河大伙房水库汇水区农业非点源污染入库模拟   总被引：1，自引：0，他引：1  
利用输出系数法和SWAT模型,对大伙房水库汇水区农业非点源污染(ANSP)进行了入库模拟研究,并用2006—2009年的水文和水质监测数据对模型进行了校准和验证。研究结果表明:汇水区年均输入到水库的泥沙量、总氮和总磷负荷分别为82.65×103 t、1 873.49t和81.97t;月入库泥沙量、总氮和总磷负荷与径流量有着较强的相关性,ANSP的产生和迁移受降水、径流过程影响很大,每年7、8月份的氮、磷和泥沙流失量达到年内最大值,分别占全年流失总量的42.64%、44.42%和67.91%。水库汇水区各流域对水库氮、磷污染的贡献率由大到小依次为:浑河流域(清原段)、苏子河流域、社河流域和水库周边小流域。  相似文献   

9.
This study presents the diffuse pollution profile of a coastal watershed with respect to the dominating sector of agriculture including forestry. A rough estimation of the diffuse loads expressed by two major nutrients of nitrogen and phosphorous is realized by calculations based on unit loads obtained from the literature for each land-use activity. The key concern is to rank the different diffuse loads arising from the watershed. The major diffuse nitrogen loads are estimated to arise from agricultural activities with 54 %, followed by livestock breeding that contribute to the nitrogen budget by 11 %. Almost 7 % of the nitrogen loads come from meadows and pasture, and 5 % from forests. In the distribution of diffuse phosphorus loads, it is estimated that 48 % of the loads arise from agricultural activities, and 18 % from livestock breeding. Almost 14 % of the phosphorous loads come from septic tank effluents; however, 13 % of the loads are due to rural run-off. The future loads for 2028 and 2039 are also estimated; 30–40 % decrease is foreseen in the agricultural pollutants and animal manure through the stepwise application of ecological agriculture and livestock breeding. The basic aim of this study is to put forth a practical methodology for estimating diffuse loads in a watershed for the decision-makers and local administrative authorities with especially limited available data. Through such, distribution of various diffuse loads becomes available among the administrative units composing the watershed.  相似文献   

10.
Defining the control that hydrology exerts on organic carbon (OC) export at the watershed scale is important for understanding how the source and quantity of OC in streams and rivers is influenced by climate change or by landscape drainage. To this end, molecular (lignin phenol), stable carbon isotope, and dissolved organic carbon (DOC) data were collected over a range of flow conditions to examine the influence of hydrology on annual OC export from an 850 km2 Midwestern United States agricultural watershed located in west central Indiana. In years 2002 and 2003, modeled annual DOC loads were 19.5 and 14.1 kg ha−1yr−1, while 71% and 85%, respectively, of the total annual OC was exported in flow events occurring during less than 20% of that time. These results highlight the importance of short-duration, high-discharge events (common in smaller watersheds) in controlling annual OC export. Based on reported increases in annual stream discharge coupled with current estimates of DOC export, annual DOC loads in this watershed may have increased by up to 40% over the past 50 years. Molecular (lignin phenol) characterization of quantity and relative degradation state of terrestrial OC shows as much temporal variability of lignin parameters (in high molecular weight dissolved organic carbon) in this one watershed as that demonstrated in previously published studies of dissolved organic matter in the Mississippi and Amazon Rivers. These results suggest that hydrologic variability is at least as important in determining the nature and extent of OC export as geographic variability. Moreover, molecular and bulk stable carbon isotope data from high molecular weight dissolved organic carbon and colloidal organic carbon showed that increased stream flow from the study watershed was responsible for increased export of agriculturally derived OC. When considered in the context of results from other studies that show the importance of flood events and in-stream processing of terrestrial organic carbon, our results show how hydrologic variability in smaller watersheds can reflect landscape-scale carbon dynamics in ways that cannot necessarily be measured at the outlets of large rivers due to multiple source signals and attenuated hydrology.  相似文献   

11.
Diffuse pollution from livestock production in China   总被引：2，自引：0，他引：2  
With economic development and living standard improvement, livestock and poultry production has grown up rapidly, also has become the leading source of pollution in vast rural areas in China.The estimated annual loss amount of COD, BOD, NH3-N from manure in 2001 is 7.28 million ton, 4.99 million ton and 1.32 million ton, respectively. The COD loss amount from manure is close to the sum of COD from industrial and domestic wastewater. Because animal waste and wastewater can enter water bodies from spills or breaks of waste storage structures ( due to accidents or excessive rain) , and non-agricultural application of manure to cropland, this contamination has resulted in quality degradation of surface and underground drinking water supplies. Areas with concentrated livestock operations are showing elevated nutrients and organic pollutant contents in surface waters. This widespread contamination of water has prompted governments at various levels to adopt regulations and measures to control the spreading of livestock pollution.  相似文献   

12.
Nutrient loading to estuaries with heavily populated watersheds can have profound ecological consequences. In evaluating policy options for managing nitrogen (N), it is helpful to understand current and historic spatial loading patterns to the system. We modeled N inputs to Narragansett Bay from 1850 to 2000, using data on population, human waste disposal, livestock, fertilizer, and atmospheric deposition. We found that total N loading to the bay increased 250% from 1850 to 2000, and 80% from 1900 to 2000. Loading to the upper bay increased far more than that to the lower bay, and the most important source shifted from non-point animal waste to human waste concentrated at sewage treatment facilities. We also modeled future N loads in 2015 under four management scenarios. Planned improvements in sewage treatment would reduce N loads 9% below business-as-usual, to the 1990 loading rate. Greater reductions, to circa 1900 rates of loading, may be possible.  相似文献   

13.
农业非点源污染模型AnnAGNPS适用性检验   总被引：3，自引：0，他引：3       下载免费PDF全文
以大沽河典型小流域为研究区,借助GIS和相关资料提取参数,建立模型数据库。在此基础上,采用2001～2002年小流域出口径流量、泥沙和总氮监测数据优化参数、校准和验证模型,分析AnnAGNPS模型在大沽河典型小流域的适用性。结果表明,模型对日均径流量、泥沙及总氮输出的模拟能力较差,而对年均污染负荷估算结果比较理想。当前AnnAGNPS模型主要被用于评价流域非点源污染的长期影响及最佳管理措施的选择精度足矣。  相似文献   

14.
宋墩福  张孝金  彭欣  黄红兰 《水文》2015,35(3):31-37
将东江源沿线18个水环境功能区划分成寻乌控制单元、安远控制单元和定南控制单元,2011~2012年间进行东江源地表水水质监测和污染负荷核算,结果表明,影响最广的主要污染源包括农业面源污染、城镇化加剧的区域生活污染和矿产企业工业点源污染,东江源地表水水质污染趋重,污染物以COD、氨氮和总氮为主,这些污染物指标均值分别为21.86mg·L-1、0.90mg·L-1、0.96mg·L-1,污染负荷分别达1 235.9t·a-1、622.8t·a-1和3 361.8t·a-1;筛选确定了寻乌、定南控制单元2个优先治理单元,以及寻乌县石排下游、定南下历河砂头下游2个重点监控点。其中寻乌控制单元主要污染物的年污染输出最大,分别占东江源流域的56.5%、51.5%、44.9%;安远控制单元的水质监测和年污染负荷量相对较低;定南控制单元主要污染物指标分别为26.4mg·L-1、1.41mg·L-1和1.13mg·L-1,劣Ⅴ类水质的功能区2个,数量最多。  相似文献   

15.
颗粒态氮磷负荷模型研究   总被引：11，自引：0，他引：11       下载免费PDF全文
为研究妫水河流域的颗粒态氮磷非点源污染来源,以控制非点源污染,在官厅水库周围进行了野外人工降雨试验。试验数据表明,氮磷输移率与产沙率具有很好的相关性,颗粒态氮、磷的平均相关系数分别为0.9594和0.9772。建立了新的颗粒态氮磷负荷模型,其中富集系数等于泥沙中总氮总磷百分含量与土壤中百分含量之比。根据妫水河流域的土壤图、土地利用图及数字高程模型,应用新的模型研究了妫水河流域颗粒态氮磷污染负荷的空间分布。结果表明,颗粒态氮磷主要来自地表植被覆盖差的丘陵和山地。  相似文献   

16.
Taking advantage of the opportunity provided by the nationally funded Water Resources Integrated Planning and Investigation of China program (WRIPI), a model was established to estimate non-point source pollutant loads in a large-scale basin (ENPS-LSB) on the basis of hydrological processes and pollutant transport. The model made use of Environment for Visualizing Images software (ENVI) and Interactive Data Language (IDL) and took the characteristics of present-day China into account: a huge rural population scattered widely, marginal rural infrastructure and livestock cultivation based on scatter-feeding. The model was divided into two sections: one on dissolved and one on adsorbed pollutant loads. The dissolved loads were divided into four different types: those originating from agricultural fields, urban areas, rural residential areas, and livestock. The study was undertaken in the Yangtze River Basin. The results showed the chemical oxygen demand (COD), the total nitrogen (TN), the total phosphorous (TP), and the ammonia nitrogen (NH3–N) loads to be 2.6 × 106, 1.6 × 106, 9.3 × 105 and 3.1 × 105 tons, respectively, in the year 2000. The dissolved COD resulted mainly from rural residential areas and livestock; 76.8% of the dissolved TN and 86.4% of the dissolved TP produced were from agricultural fields. The Yangtze River Delta, the lower reaches of the Han River, and part of the Dongting Lake, Taihu Lake and Poyang Lake basins all had relatively high dissolved pollutant loads; adsorbed nitrogen and phosphorus loads were mainly observed in the middle and upper reaches of the Yangtze River Basin. Dissolved loads were most affected by human activity, whereas adsorbed loads were most affected by natural factors. The results showed that the model performed well on large scale, describing pollutant loads effectively. This makes it possible to properly consider not only point source pollutant discharge but also non-point source pollution in the Yangtze River Basin. Combining point source discharge investigation with the ENPS-LSB model could assist environmental management with controlling water pollution.  相似文献   

17.
West Falmouth Harbor, a shallow lagoon on Cape Cod, has experienced a threefold increase in nitrogen load since the mid- to late 1990s due to input from a groundwater plume contaminated by a municipal wastewater treatment plant. We measured the exchange of nitrogen and phosphorus between the harbor and the coastal waters of Buzzards Bay over several years when the harbor was experiencing this elevated nitrogen load. During summer months, the harbor not only retained the entire watershed nitrogen load but also had a net import of nitrogen from Buzzards Bay. During the spring and fall, the harbor had a net export of nitrogen to Buzzards Bay. We did not measure the export in winter, but assuming the winter net export was less than 112 % of the load, the harbor exported less than half of the watershed nitrogen load on an annual basis. For phosphorus, the harbor had a net import from coastal waters in the spring and summer months and a net export in the fall. Despite the large increase in nitrogen load to the harbor, the summertime import of phosphorus from Buzzards Bay was sufficient to maintain nitrogen limitation of primary productivity during the summer. Our findings illustrate that shallow systems dominated by benthic producers have the potential to retain large terrestrial nitrogen loads when there is sufficient supply of phosphorus from exchange with coastal waters.  相似文献   

18.
流域面源集成管理系统的设计与应用   总被引：1，自引：0，他引：1       下载免费PDF全文
利用矢量数据结构的地理信息系统(GIS)软件和模拟模型集成开发流域面源污染管理系统.以上海市苏州河流域为例,通过土地利用类型、土壤类型、子流域等图层的叠加,将流域空间分割为一系列不规则的矢量多边形,并将这些矢量多边形作为非点源模拟的空间单元;利用组件式地理信息系统平台MapX、Surfer等,设计和开发了无缝集成的苏州河面源管理信息系统的结构、功能和数据库组成,并初步建立了可运行的苏州河流域面源管理信息系统.在系统的支持下,可有效地实现流域面源污染负荷估算、面源污染指数评价、单位面源负荷的等值线绘制以及面源污染的总量控制等功能.所开发的系统,既是面源污染专业软件开发的有益尝试,同时也是流域数字化环境管理的有益探索.  相似文献   

19.
The goal of the current study is to better understand the role of storm dynamics on stream water chemical variability in a highly polluted urban-fringe watershed. The study was conducted in the upper reach of the Arroyo Seco watershed located on the eastern edge of the densely urbanized Los Angeles basin in California. During the 2008–2009 study period, high-frequency stream water observations of chloride, fluoride, sulfate, and nitrate were monitored through a series of storm events and were compared to pre- and post-winter storm season geochemical soil profiles. Of the four solutes measured, nitrate demonstrated hydrologically enhanced behavior. Chloride, fluoride, and sulfate exhibited enhanced behavior initially (first flush), but transitioned to dilution behavior as the season progressed. Soil chemistry analyses in the riparian zone confirmed the abundance of nitrate on the soil surface, serving as a source for stream water nitrate. Observations and analyses collectively suggest that the chemical variability observed during the storms is dependent not only on discharge, but also on the magnitude and intensity of rainfall, the length of the antecedent dry period, and riparian soil composition. A further understanding of these factors will ultimately improve geochemical models for prediction of downstream chemical loads from regional urban-fringe watersheds.  相似文献   

20.
流域非点源磷素输出负荷估算方法研究   总被引：2，自引：1，他引：1       下载免费PDF全文
张丽  邹鹰  陆海明  张鸿  彭辉  田英 《水文》2013,33(6):11-15
目前水质常规监测频率较低,难以客观反映流域非点源污染物浓度随降雨径流过程的变化情况,结果会低估了流域非点源污染物的输出负荷。本文利用流域次降雨过程的连续水质水量同步监测资料,研究分析次降雨过程与流域非点源磷素输出负荷之间的因果关系,并建立次降雨总量与磷素输出负荷的定量相关关系。研究结果表明,流域次降雨总量与非点源磷素输出负荷之间存在较好的相关关系。通过这种定量关系,以流域次降雨总量为输入,可以更为合理地估算出流域非点源磷素输出负荷。  相似文献   

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