清水河流域农业非点源污染模拟及特征分析

为探讨冬奥核心区所在的清水河流域农业非点源污染特征,利用SWAT模型对清水河流域进行污染模拟及特征分析.通过前期对流域内河流水质监测和评价分析可知,该流域农业非点源是重要污染来源,且降雨和径流会对水质影响较大.借助ArcGIS平台构建清水河流域SWAT非点源污染模型,并利用实测径流数据对模型进行了率定和验证,结果表明S...     

基于SWAT模型的伊通河流域农业非点源污染损失估算

选取伊通河流域为研究区,在构建伊通河流域数字化平台的基础上,将SWAT模型与环境经济学方法相结合定量估算了研究区的农业非点源污染损失,为伊通河流域农业非点源污染的防治与管理提供科学依据与决策支持。研究结果表明:构建的伊通河流域农业非点源污染模型达到了精度要求。研究区2010年农业非点源泥沙负荷、总氮负荷以及总磷负荷均为最高,2011年均为最低;研究区的土壤侵蚀主要是由耕地引起的,占总量的96%以上。研究区农业非点源污染损失折算成人民币约为52 845.42万元/a,年降雨量越大的年份损失越严重;总体上,伊通河流域内农业非点源污染价值损失的大小顺序为:总氮污染价值损失泥沙淤积价值损失总磷污染价值损失土地废弃价值损失。     

基于SWAT模型的布尔哈通河流域面源污染的变化研究

【目的】揭示土地利用变化下面源污染时空变化特征,探究流域景观格局与面源污染的关系。【方法】以布尔哈通河流域为研究对象,利用SWAT分布式水文模型模拟1986-2016年4期土地利用变化下面源污染分布特征,运用Fragstats4.2软件计算了1986年和2016年布尔哈通河各子流域的景观格局指数,最后使用CANOCO5.0软件分析子流域面源污染和景观指数之间的关系。【结果】①构建的SWAT模型模拟的径流量和总磷量在校准期和验证期的决定系数R²和纳什效率系数NSE都达到0.6以上,模型能很好地模拟流域水文水质状况,1986-2016年,SWAT模拟的总磷年负荷分别为74.04、73.78、82.50 t和128.31 t。②面源污染与景观格局存在密切关系,景观组成格局方面,林地面积与总磷负荷负相关,农田和建设用地面积与总磷负荷正相关;景观空间格局方面,林地斑块破碎化程度与总磷负荷正相关,而农田斑块的破碎化程度与总磷负荷负相关。流域斑块之间的越高流通性和聚集性,对养分流失改善有积极作用,而流域内景观异质性的增加和形状的复杂化,则会导致污染负荷输出风险的增加。【结论】流域面源污染负荷急剧增加,面源污染防治的关键控制区域在坡度较高的北部区域和农田及城镇集中的东部区域,该区域规划土地利用和优化景观格局时,应优先考虑防止林地斑块破碎化程度的提高和控制城镇面源污染源。     

基于SWAT和CLUE-S模型的不同土地利用方式对排涝模数的影响

【目的】研究土地利用方式变化对排涝模数的影响,优化区域排涝管理。【方法】选取湖北四湖流域螺山排区为研究区域,将流域水文模型SWAT和土地利用变化模型CLUE-S联合应用,设置了6种水旱比、5种水面率及5种城市化率的单因素变化(即其他2个因素不发生变化)条件下不同土地利用情景,应用CLUE-S模型模拟生成各情景下的土地利用空间分布图,建立了SWAT模型模拟不同土地利用情景的降雨径流过程,分析了不同土地利用方式对排涝模数的影响。【结果】在相同的设计暴雨、其他因素维持现状条件下:当水旱比由0增加到1时,排涝模数减小了0.117 m~3/(s·km~2);当水面率由0增加到20%时,排涝模数减小了0.111 m~3/(s·km~2);当城市化率由0增加到10%时,排涝模数增加了0.104 m~3/(s·km~2)。排涝模数随着水旱比和水面率的增大均呈减小趋势,随着城市化率的增大呈增大趋势。在相同设计暴雨、其他因素维持现状条件下:当水旱比由0增加到0.2时,排涝模数只减小了3.06%;当水面率由0增加到10%时,排涝模数减小了14.03%;当城市化率由0增大到10%时,排涝模数增大了16.67%。3种引起土地利用方式变化的因素中,排涝模数对水面率和城市化率变化的敏感程度相当,对二者的敏感程度明显大于水旱比。【结论】在未来区域规划中,可以通过增大水旱比、增大水面面积和限制城市扩张来减轻排涝压力,其中适当增大水面面积和限制城市扩张更加有效。     

Development of a pathogen transport model for Irish catchments using SWAT

SWAT (Soil and Water Assessment Tool) represents a dynamic catchment modelling application that can be applied to any river basin and used to quantify the impact of land management practices on water quality over a continuous period. The objective of this study is to apply the Soil and Water Assessment Tool (SWAT) to model pathogen transport, simulate management practices affecting water quality and predict pathogen loads in Irish catchments. Based on input data regarding agricultural practice, demographics and hydrological parameters for the river Fergus catchment, SWAT was run to predict concentrations of Escherichia coli. Hydrometric validation results display a very good linear relationship between observed and predicted data (Coefficient of determination R² = 0.83, Nash-Sutcliffe efficiency E = 0.78) and indicate satisfactory simulation of hydrologic processes within the catchment. To date, pathogen predictions have proved variable between observed and simulated figures. Based on recommended values for the quantification of catchment modelling accuracy, predictions for E. coli can be described as acceptable and satisfactory with R² = 0.68 and E = 0.59. Extensive monitoring is required for such simulations and the current study represents partial validation. Results suggest that although the capabilities exist to simulate pathogen transport in catchments, the capacity to accurately account for all factors that can contribute to water degradation is uncertain. The sensitivity analysis identified the bacteria partition coefficient (BACTKDDB) as the most important input parameter. In addition it reveals areas where further research is required, particularly in assessing the initial concentration of E. coli in human/animal waste. The developed model provides a tool capable of protecting water sources and human health from waterborne pathogens.     

SWAT模型及其在灌区管理中的应用

SWAT模型是一个具有物理基础的分布式水文生态评价模型，可长时间、连续模拟和预测复杂的流域在不同土壤类型、不同土地利用和管理条件下，流域内水分、泥沙和农业化学物质的流失量。介绍了SWAT的发展历程、建模原理、模块功能及其在灌区水资源管理、土地利用管理评价、非点源污染管理等方面的应用前景。     

The ionic composition of the streams of the mid-Murrumbidgee River: Implications for the management of downstream salinity

The Murrumbidgee River catchment is a major region of both dryland and irrigated agricultural production in eastern Australia. The salinity of water in the lower reaches of the river is the subject of concern; changing land management upstream is one option to minimise accessions of salt to the river but this must be done in a way that provides an adequate quantity of water for downstream users and the environment.

We examined 30 years of sporadic data on the ionic composition of water for 7 subcatchments contributing to the mid-Murrumbidgee River and for 2 gauging stations on the river itself. Despite the common local presumption that salinity, measured as electrical conductivity (EC), is primarily due to NaCl from cyclic marine salt, we found that NaCl was the dominant salt in only some streams. The presence of HCO₃⁻'s of Ca²⁺ and Mg²⁺ in all streams, and their dominance in 2 streams, indicates that mineral weathering is also a major contributor to the salt load of water in the catchment. However, Ca²⁺ and Mg²⁺ bicarbonates have limited solubility and so their concentrations will not become a cause of osmotic stress when the water is used for drinking or irrigation. Therefore, in our efforts to prioritise lower order catchments of the Murrumbidgee River for changed land management, it will be necessary to examine the nature of the salts they discharge, not just EC. By distinguishing between Cl⁻/Na⁺ dominated streams and Ca²⁺, Mg²⁺/HCO₃⁻ dominated streams we can refine our search for sources of osmotic stress which might potentially worsen with time. This will enable us to target particular land management units so as to obtain the maximum reduction in downstream salinity with a minimal decrease in flow volume and minimal area of land undergoing changed landuse.     

宁夏引黄灌区农田退水污染现状分析

通过对宁夏引黄灌区农田退水污染、农业生产污染源头和污染负荷结构的现状分析,结果表明,化肥与规模养殖是灌区水体TN和TP的主要污染源,工业废水和城市生活污水对水体质量仍然具有重要影响,农村生活废弃物对灌区水质的目前影响不明显。     

气候与土地覆被变化下的水文响应模拟——以太行山八一水库流域为例

太行山区是华北平原的重要水源地,但近年来山区来水的逐渐减少已成为该地区水资源缺乏的重要原因之一。利用分布式水文模型SWAT,根据野外实际调查及室内实验获得了模型所需的水文地质参数,通过模型校准和验证,建立了太行山八一水库流域的水文模型,Nash-Sutteclife模型效率系数等评价结果显示,SWAT模型在该流域具有很好的适用性。结合该区历史气候与土地覆被变化趋势,分别假定了25种气候情景和4种土地覆被情景,模拟结果表明,气温降低和降水增加的情景下,流域的径流量明显增加,并且随着土地覆被的好转,径流量逐渐减少,蒸发量增加。从水文角度探查了太行山区径流变化的原因。     

基于PMF模型的山区农用地土壤重金属来源分析

为了解山区农用地土壤重金属的污染情况以及查明八种重金属的污染来源,在研究区内采集土壤表层(0-20cm)样品1311个,分析化验了pH、As、Cd、Cr、Cu、Hg、Ni、Pb、Zn等指标。采用了内梅罗综合指数法、地统计学法、相关分析、单因素方差分析以及正定矩阵(PMF)模型等方法,研究山区农用地土壤重金属污染特征及可能的污染来源。结果表明：研究区土壤中八种重金属含量均明显高于重庆市土壤背景值；除局部区域呈现重度污染之外,研究区土壤整体上呈清洁或轻度污染,主要污染元素为Cd；PMF模型结果显示,研究区土壤重金属污染来源主要有三种,分别为Cd、Cr、Cu、Ni、Pb、Zn(自然母质源)、As、Cr、Hg、Pb、Zn(采矿活动源)、As、Cd、Cr、Hg(农业活动源)。     

基于SWAT的浑河流域上游地区硝态氮淋失量估算

以浑河流域上游地区为研究流域,应用SWAT模型估算了该流域硝态氮淋失量的空间和时间分布以及不同土地利用类型硝态氮的淋失量。利用2008—2010年实测径流资料对模型进行了校核与验证,结果表明,流域硝态氮的淋失量与施氮量在空间分布上是一致的,且与水分渗漏有较好的相关关系,降雨、施肥是影响流域硝态氮淋失的主要因素;此外,不同土地利用类型的硝态氮淋失量的差异也非常明显,耕地的硝态氮淋失量最高,林地次子,居民区、裸地等最小。     

河南省氮素农业面源污染风险评价与关键管控区识别

农业面源污染是我国水环境保护面临的重要问题,风险评价对于农业面源污染防治具有重要意义。本研究以河南省为研究区域,采用层次分析法的分级赋值方法,基于熵值法和专家打分确定各影响因子权重,构建河南省氮素农业面源污染风险多因子综合评价模型,计算河南省氮素农业面源污染风险指数并在流域尺度上进行验证,划分氮素农业面源污染的风险等级并识别关键管控区。结果表明：种植源、养殖源和生活源分别贡献河南省31.52%、38.47%和30.01%的氮素流失负荷,流失负荷呈现为西低,中、东部高的特点。河南省有39 429 km²的区域存在中风险,约占河南省总面积的23.61%,有17 318 km²的区域存在高风险,约占总面积的10.37%;划定距河流2 km以内的中、高风险区为一般管控区和重点管控区,面积分别为10 982 km²和9 285 km²。通过与同期水质自动监测数据进行相关分析,决定系数为0.82,表明模型模拟结果具有较高的精准度。综合结果表明,建立的多因子综合评价模型具有科学性和准确性,可用于氮素农业面源污染风...     

基于GIS/RS的不同土地利用类型重金属面源污染比较

针对不同土地利用类型,采样测定土壤重金属质量比背景值;基于DEM数据和遥感影像数据,结合空间信息技术（GIS/RS）,利用RUSLE模型和SCS-CN模型分别核算流域内不同土地利用类型的土壤流失量和地表径流量,在验证模型准确性的基础上,估算重金属非点源污染负荷。研究结果表明：研究区域不同土地利用类型的重金属质量比背景值差异较大,重金属Cu和Pb在工矿用地、草地和住宅用地的背景值较高,在有林地的背景值较低。综合估算随2种主要迁移途径输出的重金属面源污染负荷,重金属Cu总污染负荷量大约为651913kg/a,重金属Pb总污染负荷量大约为268004kg/a。不同土地利用类型中,随土壤侵蚀输出的重金属污染负荷,以疏林地和草地的贡献率最大,有林地和水浇地最小;随地表径流输出的重金属污染负荷,以草地和疏林地的贡献率最大,有林地和旱地最小。     

Seasonal and land use impacts on the nitrate budget and export of a mesoscale catchment in Southern Portugal

Stream nitrate nitrogen exports are an important indicator of agricultural impacts on aquatic health in catchments. Quantitative assessment of factors and processes affecting stream nitrate loadings is complex because of the large number of causal factors and processes, such as weather and rainfall, catchment hydrological behavior, soils, land use practices and biogeochemical processes. An eco-hydrological catchment modeling approach, using the SWAT model driven by detailed field data, was used to analyze the nitrate export and the components of the nitrogen budget of the 352 km² upper Roxo river catchment in Southern Portugal. A detailed eight-year record (2001–2008) of the monitoring of weather, reservoir inflow, stream biogeochemistry, soils, in-stream and groundwater quality, and fertilizer application was used to calibrate and validate the streamflow and nitrate loadings obtained by the model. Results indicated a strong seasonal variation in nitrate exports, closely related to temperature and rainfall. Monthly nitrate loadings varied from 0.02 to 2.48 kg N ha⁻¹ during summer and between 0.03 and 14 kg N ha⁻¹ during late autumn and winter. Stream nitrate values, ranging from 1.5 to 16.5 mg N L⁻¹, were strongly related to extreme rainfall occurrences and wet periods. Detailed analysis of nitrate budget components at the sub-catchment level enabled evaluation of the impacts of the various processes affecting the nitrate nitrogen pool of the catchment. Besides high fertilizer inputs for annual crops, it was shown that biological nitrogen fixation and wet deposition by rainfall should be accounted for in input balances. Where denitrification naturally reduces nitrate levels in soils, streams and the reservoir, the largest contribution to stream nitrate originates from leached soil nitrate reappearing in groundwater baseflow, compared with less than 2% from direct surface runoff during high rainfall events. A fertilizer reduction scenario was effectively implemented to evaluate remedial nitrate control policies in accordance with the European Nitrate and Water Framework Directives. Agricultural practices and seasonal weather fluctuations were the main reasons for temporal variations in nitrate export via small streams to the main reservoir.     

Least cost land-use changes for targeted catchment salt load and water yield impacts in south eastern Australia

This study reports an analysis of the economics of options for strategic land-use change to attain future catchment level target combinations of salt load and water yield. Farm level survey information on land use, productivity, prices and costs of production were integrated with spatially specific soil, rainfall, topography, hydrology and salinity results of the simulation model CAT (Catchment Analysis Tool). This information was used to populate a two stage economic optimization model in which subcatchment economic results were combined for catchment level analyses. This study is the first to exploit CAT results in an economic framework and the first in which economic results are mapped using CAT. The 64,000 ha Bet Bet Catchment in Victoria, Australia, once deemed among the highest priority areas in the Murray Darling Basin for dryland salinity reduction, is the focus of this study. The calculated current net present value (NPV) of agricultural production in the catchment is AU$ 78 million³ while providing 42 GL of water yield⁴ annually for use downstream with a salt load of 22,600 t. Results show that salt loads may be reduced to 18,600 t (reduction of 4000 t) through expansion of tree plantations and lucerne production, reducing water yield to 31 GL (11 GL reduction) and NPV to AU$ 63 million (AU$ 15 million reduction). Water yields could be increased from current levels by 2 GL while maintaining current salt loads. Alternatively, catchment NPV could be increased by approximately AU$ 7 million with little or no reduction in water yield; but there may be reasons (small farm size) why this is unlikely. For this catchment, the maximum reduction in salt load appears insufficient to justify public investment in tree planting and perennial pasture establishment, particularly when the reduced NPV and reduced water yields are taken into account. The results for this catchment do not support regulation of land use for the sake of lowering river salinity. However, the capacity of tree plantations to reduce water yields may support a regulation requiring purchase of water entitlements from downstream entitlement holders for new plantations. Despite millions of dollars of past public investment, it is now clear that Bet Bet Catchment was never one where land-use changes could benefit downstream water users. The approach described in this paper enables catchment management authorities to weigh costs of land-use change against downstream benefits and natural resource management (NRM) options elsewhere.     

农业生态经济系统结构优化方法研究

开发了基于地理信息系统和遥感技术的流域农业生态经济系统结构优化的方法。该方法运用遥感数据 ,并以地理信息系统软件为平台集成了水库营养盐负荷浓度响应关系模型、农业非点源污染模拟模型和线性规划模型。运用该方法能够实现对全流域的土地利用现状进行评价 ,并以流域农业土地利用系统的经济产出为目标 ,以流域的生态环境为约束 ,对流域土地资源进行优化配置 ,使农业草地的结构更加合理 ,从而改善生态环境 ,实现经济和环境协调发展。     

北运河流域非点源氮磷污染模拟分析及灌溉模式优化

为了减轻北运河流域农田灌溉引起的非点源污染,探索良性农田管理模式,选取北运河流域武清区为研究对象,采用改进的SWAT模型模拟不同灌溉方案下武清区地表径流非点源氮磷污染。结果表明：同一灌溉定额下,随着污灌次数的增加,流域水体内氮磷负荷总量呈先降后升的趋势;在所制定的灌溉情景中,冬小麦越冬、拔节期和夏玉米抽雄期进行污灌,其...     

Use of treated municipal wastewater in irrigated agriculture—Review of some practices in Spain and Greece

Approximately, seventy (70) percent of world water use including all the water diverted from rivers and pumped from underground is used for agricultural irrigation, so that the reuse of treated municipal wastewater for purposes such as agricultural and landscape irrigation reduces the amount of water that needs to be extracted from natural water sources as well as reducing discharge of wastewater to the environment. Thus, treated municipal wastewater is a valuable water source for recycling and reuse in the Mediterranean countries and other arid and semi-arid regions which are confronting increasing water shortages. Treated wastewater reuse in agriculture is a common practice in the Mediterranean countries and there is a considerable interest in the long-term effects of treated wastewater on crops intended for human consumption. This paper reviews the fundamentals of agricultural irrigation using treated municipal wastewater and the status of municipal wastewater reuse in Greece and Spain with studies related to the effects on soils and plants.     

Influence of conservation measures on groundwater regime in a semi arid tract of South India

A study was conducted in peninsular India in a predominantly agricultural watershed treated with soil and water conservation measures such as diversion drains and staggered contour trenches in nonarable land, terraces of trapezoidal cross section with graded channel on the upstream side (locally termed as graded bund) and stone checks in arable lands and rockfill dams, archweir and nala bund (a local term used for earthen embankment across the drainage channel) across the gully. Hydrological analysis has revealed that integrated management of land and water resources has consistently improved the groundwater regime. Surface runoff from the treated forest and agricultural catchment were only 27.4 and 57.4% of the untreated agricultural catchment, reflecting in high infiltration of rain water due to enhanced opportunity time. Consequently, water levels in the open wells rose by 0.5 to 1.0 m, thereby increasing the area irrigated by the wells by 172% when compared to the preproject period, which in turn improved crop yields by 70%. Hypssometric analysis indicated that water surface levels do not follow the trend of land surface levels due to the nature of the underground geological formation.     

焦作地区浅层地下水中“三氮”污染特征及机制研究

通过研究焦作地区浅层地下水中“三氮”污染量、污染分布特征,分析研究了污染源、水文地质条件对地下水“三氮”的形成、迁移、转化、分布规律的影响。结果表明,硝酸盐氮、氨氮、亚硝酸盐氮的污染分布分别呈现面状、条带状和点状分布;农业上含氮化肥和农药的过量使用是浅层地下水“三氮”污染的主要原因,工业污水直接排入含水层是污染中心浓度极高的重要原因;包气带的碱性氧化环境是硝酸盐氮广泛分布的重要条件,大沙河侧漏补给是氨氮呈现条状分布的主要因素。