Assessing pollution prevention program by QUAL2E simulation analysis for the Kao-Ping River Basin, Taiwan

Wise and sustainable uses of water resources are essential for an effective river-basin-management planning. Recent management strategy further addresses the fact that quantity and quality of water are closely interrelated, and both must be considered simultaneously for all water resources and water quality management practices. The aim of this paper is to explore the impacts of water resources redistribution and pollution prevention actions between and within river basins simultaneously in South Taiwan. Much emphasis will be placed on assessing the impacts of water transfer over natural boundary to satisfy the needs of industrial development in the Tseng-Wen River system and its resultant influence on the water quality in the downstream area of the Kao-Ping River system where the pollution prevention program is to be implemented. The Kao-Ping River was further characterized hydraulically and environmentally, based on a full investigation of discharges and withdrawals in the river reaches. QUAL2E was successfully calibrated and validated using data collected between 1998 and 1999, and the model was capable of predicting the concentrations of biochemical oxygen demand, dissolved oxygen, total phosphate-phosphorus, and ammonia-nitrogen (NH3-N) for the entire river system. With the aid of QUAL2E simulation model, it shows eliminating the pig farming activities and constructing the sewer systems in the upstream area of Kao-Ping River cannot guarantee the full compliance with water quality standards in the downstream area and water transfer in the upstream area further increases negative impacts on the water quality in the wet season. The predicted situation of water quality in the dry season may even present worse condition. Additional water pollution control policy, such as the use of economic instruments, for controlling and reducing the waste-load of biochemical oxygen demand and ammonia-nitrogen is needed in the Kao-Ping River system in the long run.     

An analysis of urban development and its environmental impact on the Tampa Bay watershed

Urbanization has transformed natural landscapes into anthropogenic impervious surfaces. Urban land use has become a major driving force for land cover and land use change in the Tampa Bay watershed of west-central Florida. This study investigates urban land use change and its impact on the watershed. The spatial and temporal changes, as well as the development density of urban land use are determined by analyzing the impervious surface distribution using Landsat satellite imagery. Population distribution and density are extracted from the 2000 census data. Non-point source pollution parameters used for measuring water quality are analyzed for the sub-drainage basins of Hillsborough County. The relationships between 2002 urban land use, population distribution and their environmental influences are explored using regression analysis against various non-point source pollutant loadings in these sub-drainage basins. The results suggest that strong associations existed between most pollutant loadings and the extent of impervious surface within each sub-drainage basin in 2002. Population density also exhibits apparent correlations with loading rates of several pollutants. Spatial variations of selected non-point source pollutant loadings are also assessed.     

Forecasting land use change and its environmental impact at a watershed scale

Urban expansion is a major driving force altering local and regional hydrology and increasing non-point source (NPS) pollution. To explore these environmental consequences of urbanization, land use change was forecast, and long-term runoff and NPS pollution were assessed in the Muskegon River watershed, located on the eastern coast of Lake Michigan. A land use change model, LTM, and a web-based environmental impact model, L-THIA, were used in this study. The outcomes indicated the watershed would likely be subjected to impacts from urbanization on runoff and some types of NPS pollution. Urbanization will slightly or considerably increase runoff volume, depending on the development rate, slightly increase nutrient losses in runoff, but significantly increase losses of oil and grease and certain heavy metals in runoff. The spatial variation of urbanization and its impact were also evaluated at the subwatershed scale and showed subwatersheds along the coast of the lake and close to cities would have runoff and nitrogen impact. The results of this study have significant implications for urban planning and decision making in an effort to protect and remediate water and habitat quality of Muskegon Lake, which is one of Lake Michigan's Areas of Concern (AOC), and the techniques described here can be used in other areas.     

流域非点源水污染排放清单估算系统构建

基于流域水质改善与水环境管理需求,结合目前流域非点源水污染排放存在的问题,本研究采用SOA-B/S架构,运用MVC6和GIS与环境模型集成关键技术,构建流域非点源水污染排放清单估算系统,并系统梳理了地形数据、污染源环境统计数据、气象数据等基础信息,采用基于输出系数法的非点源水污染负荷估算模型,实现了对全年及年内各分水期非点源水污染排放清单的处理分析和估算。系统通过数据库、GIS平台、模型集成和业务系统建设,实现了对不同时间和空间尺度下不同地区的非点源水污染负荷估算,推进了流域非点源污染排放的信息化、科学化及可视化管理,为决策者制定流域水环境管理措施和方案提供了有力的技术支持。     

濑溪河泸县段水质评价与治理建议

本文运用综合污染指数法对濑溪河泸县段天竺寺大桥和官渡大桥上、下两个断面的水质进行现状评价和污染变化规律分析,表明濑溪河泸县段污染情况逐年恶化,超标频率和倍数都成上升趋势,枯水月份、平水月份、丰水月份分别对水体污染起着不同的作用,在丰水月份来临之前、之后的平水月份非点源污染污染突出,可见濑溪河泸县段非点源污染在濑溪河的水体污染中占有一定的比重,濑溪河泸县段水质状况不容乐观,亟待加强水质污染的防治和控制力度,并提出治理的建议。     

四川省出川断面主要污染物通量及来源研究

以2001～2007年实测水文、水质数据为基础,计算了四川省主要出川断面高锰酸盐指数(CODMn)和氨氮(NH3-N)污染负荷通量;利用断面水质目标约束,通过污染负荷历时曲线,分析了区域水环境承载力;在基流分割的基础上,利用水文分割法,识别了区域污染物的主要来源,为从源头上开展三峡水库水环境保护提供数据支撑。分析结果表明,各出川断面干流主要污染物(CODMn、NH3-N)大致在可接受的范围内,2001年以来,出川断面CODMn通量呈降低的趋势,有效的减缓了输入三峡库区的污染物总量,氨氮通量整体稳定。嘉陵江、涪江、渠江流域污染物来源主要为非点源,应重点加强面源的污染防控;长江干流为点面源混合型,简单的削减点源已不能保证高功能水体要求,应加强点源和面源污染的综合防控。     

IDENTIFICATION OF CRITICAL NONPOINT POLLUTION SOURCE AREAS USING GEOGRAPHIC INFORMATION SYSTEMS AND WATER QUALITY MODELING1

n integrated approach coupling water quality computer simulation modeling with a geographic information system (GIS) was used to delineate critical areas of nonpoint source (NPS) pollution at the watershed level. Two simplified pollutant export models were integrated with the Virginia Geographic Information System (VirGIS) to estimate soil erosion, sediment yield, and phosphorus (P) loading from the Nomini Creek watershed located in Westmoreland County, Virginia. On the basis of selected criteria for soil erosion rate, sediment yield, and P loading, model outputs were used to identily watershed areas which exhibit three categories (low, medium, high) of non-point source pollution potentials. The percentage of the watershed area in each category, and the land area with critical pollution problems were also identified. For the 1505-ha Nomini Creek watershed, about 15, 16, and 21 percent of the watershed area were delineated as sources of critical soil erosion, sediment, and phosphorus pollution problems, respectively. In general, the study demonstrated the usefulness of integrating GIS with simulation modeling for nonpoint source pollution control and planning. Such techniques can facilitate making priorities and targeting nonpoint source pollution control programs.     

Spatial and temporal variation in nutrient parameters in stream water in a rural-urban catchment, Shikoku, Japan: effects of land cover and human impact

Seasonal and spatial variations in major ion chemistry and isotope composition in the rural-urban catchment of the Shigenobu River were monitored to determine the influences of agricultural and urban sewage systems on water quality. Temporal patterns of biochemical oxygen demand (BOD), total nitrogen (TN), total phosphorus (TP), and suspended sediment (SS) were examined at four sites in the rural-urban catchment. Urban land cover, incorporating the effects of increased population, domestic water use, and industrial wastewater, was positively associated with increases in water pollution and was included as an important explanatory variable for the variations in all water quality parameters. Significant trends were found in each parameter. BOD concentrations ranged widely, and were high in urban regions, due to the presence of a waste water treatment plant. TN and SS showed various trends, but did not vary widely, unlike TP. TP concentrations varied greatly, with high concentrations in cultivated areas, due to fertilizer use. Local water quality management or geology could further explain some of the variations in water quality. Non-point-source pollution exhibited strong positive spatial autocorrelation, indicating that incorporating spatial dimensions into water quality assessment enhances our understanding of spatial patterns of water quality. Data from the Ministry of Land Infrastructure and Transport (MLIT) and Environment Ministry (EM) were used to investigate trends in land management. Stepwise regression analysis was used to test the correlation between specific management practises and substance concentrations in surface water and sediment. MLIT and EM data for 1981-2003 showed an increase in TN, TP, and SS concentrations in surface water. High levels of fertilizer in dormant sprays and domestic water use were associated with high pesticide concentrations in water and sediment. This paper presents a novel method of studying the environmental impact of various agricultural management practises and recommends a management strategy that combines the use of reduced-risk pesticides with irrigation and non-irrigation periods in paddy fields.     

AN INTERACTWE MODELING ENVIRONMENT FOR NON-POINT SOURCE POLLUTION CONTROL1

ABSTRACT: Non-point source pollution cuntinues to be an important environmental and water quality management problem. For the moat part, analysis of non-point source pollution in watersheds has depended on the use of distributed models to identify potential problem areas and to assess the effectiveness of alternative management practices. To effectively use these models for watershed water quality management, users depend on integrated geographic information systems (GIS)-based interfaces for input/output data management. However, existing interfaces are ad-hoc and the utility of GIS is limited to organization of input data and display of output data. A highly interactive water quality modeling interface that utilizes the functional components and analytical capability of GIS is highly desirable. This paper describes the tight coupling of the Agricultural Non-point Source (AGNPS) water quality model and ARC/INFO GIS software to provide an interactive hybrid modeling environment for evaluation of non-point source pollution in a watershed. The modeling environment is designed to generate AGNPS input parameters from user-specified GIS coverages, create AGNPS input data files, control AGNPS model simulations, and extract and organize AGNPS model output data for display. An example application involving the estimation of pesticide loading in a southern Iowa agricultural watershed demonstrates the capability of the modeling environment. Compared with traditional methods of watershed water quality modeling using the AGNPS model or other ad-hoc interfaces between a distributed model and GIS, the interactive modeling environment system is efficient and significantly reduces the task of watershed analysis using tightly coupled GIS databases and distributed models.     

我国非点源污染的基本特征与时空分布规律研究综述

随着点源污染控制的逐步完善,非点源污染对环境造成的危害日益突出,成为了目前我国水质环境恶化的又一重大因素。为有效控制非点源污染,本研究对非点源污染的基本特征进行了概述,分析了非点源污染的研究方法。根据国内学者对非点源污染负荷时空分布的调查、计算及研究成果,总结分析了我国非点源污染负荷时空分布规律的特征,并针对性地提出了非点源污染的控制需从源头减量、过程控制及末端治理等方面进行,从而为非点源污染的预防和治理提供相应的指导。     

SIMULATION OF URBAN NON-POINT SOURCE POLLUTION1

ABSTRACT: Public Law 92–00 has mandated the need for evaluating the impact of nonpoint source pollution on receiving water quality, primarily through Section 208 Areawide Planning. The Management of Urban Non-Point Pollution (MUNP) model was developed to estimate the accumulation of eight non-point pollutants on urban streets, their removal by both rainfall and street sweeping operations. The model can simulate the following pollutants: total solids or sediment-like material, volatile solids, five-day biochemical oxygen demand, chemical oxygen demand, Kjeldahl nitrogen, nitrates, phosphates, and total heavy metals. The simulated results can be used for investigation of non-point pollution management alternatives. The model is capable of reflecting variation in such diverse factors as physical and chemical characteristics of accumulated pollutants, land use characteristics, rainfall characteristics, street sweeper characteristics, roadway characteristics, and traffic conditions. By using mean estimates of many input variables for large segments of a city, the MUNP model could be used to quickly assess the magnitude of pollutants annually entering receiving waterways due to nonpoint source pollution alone. If the results indicate that non-point pollution loadings are sizeable and require futher analysis, the MUNP model could be used to define the specific nonpoint source pollution areas within a city. Hypothetical locations and actual rainfall data for Washigton D.C. were used to demonstrate some capabilities of the MUNP model.     

A GEOGRAPHIC INFORMATION SYSTEM TO PREDICT NON-POINT SOURCE POLLUTION POTENTIAL1

ABSTRACT: Bacterial densities (total coliform, fecal coliform, and fecal streptococci) and suspended solids in runoff from a feedlot, pasture, and corn field were measured. Densities of fecal coliform were highest from the feedlot but were 1000 to 10,000 times greater than the water quality standard for swimmable waters from all three land uses. Densities of fecal streptococci were highest from the corn field, which suggests that wildlife are the source of bacteria. Fecal coliform/fecal streptococci ratios distinguished cattle from wildlife as the source of bacterial pollution both among land uses and among seasons of the year. Suspended solids concentrations in runoff ranged from 423 to 925 mg/l and were highest from the corn field. A Geographic Information System (GIS), which utilizes a raster or grid-cell format, was developed to include algorithms associated with non-point source pollution. The system accepts digitally mapped information on soil type, topography, and land use. It calculates characteristics such as slope and slope length, and relates these characteristics to soils and land use parameters in order to produce three dimensional maps of runoff potential, sediment pollution potential, and bacterial pollution potential. It offers the advantages of retaining the geographic character of pollution potential information and of conveying in three-dimensional graphical terms the effects of topography, soil type, land use, and land management practices.     

LAND USE AND AQUATIC BIOINTEGRITY IN THE BLACKFOOT RWER WATERSHED,MONTANA1

ABSTRACT: Benthic macroinvertebrate samples representing 151 taxa were collected in August 1995 to examine the linkage between land use, water quality, and aquatic biointegrity in seven tributaries of the Blackfoot River watershed, Montana. The tributaries represent silvicultural (timber harvesting), agricultural (irrigated alfalfa and hay and livestock grazing), and wilderness land uses. A 2.4 km (1.5 mile) reach of a recently restored tributary also was sampled for comparison with the other six sites. A geographic information system (GIS) was used to characterize the seven subwatersheds and estimate soil erosion, using the Modified Universal Soil Loss Equation, and sediment delivery. The wilderness stream had the highest aquatic biointegrity. Two agricultural streams had the largest estimated soil erosion and sediment delivery rates, the greatest habitat impairment from nonpoint source pollution, and the most impoverished macroinvertebrate communities. The silvicultural subwatersheds had greater rates of estimated soil erosion and sediment delivery and lower aquatic biointegrity than the wilderness reference site but evinced better conditions than the agricultural sites. A multiple-use (forestry, grazing, and wildlife management) watershed and the restored site ranked between the silvicultural and agricultural sites. This spectrum of land use and aquatic biointegrity illustrates both the challenges and opportunities that define watershed management.     

Land Use, Climate and Transport of Nutrients: Evidence Emerging from the Lake Vicocase Study

Soil erosion is a Europe-wide problem, causing both loss of soil fertility and pollution due to nutrient transport into water bodies. This process is particularly important in the Mediterranean area, where the climate, characterised by long periods of drought followed by intense precipitation, favours soil erosion. Research carried out in this field has amply described this process, showing that climate and land use/land cover (LU/LC) are the two main factors regulating this phenomenon. However, the interaction between these factors is complex and experimental research is needed to understand the nutrient loads deriving from different land uses. This paper shows the results of a long-term monitoring project carried out in the Lake Vico basin (central Italy), using high resolution data and runoff samples to determine the phosphorus (P) export from four different LU/LC classes resulting from the same climatic event. The results highlight the fundamental role that LU/LC plays in terms of phosphorus load. Furthermore, the results appear to indicate that the maximum rainfall registered for 30′ (I _{30, max}), rather than the total quantity of precipitation, has the greatest effect on levels of erosion, and consequently on the migration of nutrients rather than the total quantity of precipitation can affect on erosion and therefore the migration of nutrients. These data could contribute to scientific planning support for land management choices aimed at controlling water pollution from non-point pollution sources.     

Nonpoint Source Pollution Responses Simulation for Conversion Cropland to Forest in Mountains by SWAT in China

Several environmental protection policies have been implemented to prevent soil erosion and nonpoint source (NPS) pollutions in China. After severe Yangtze River floods, the “conversion cropland to forest policy” (CCFP) was carried out throughout China, especially in the middle and upper reaches of Yangtze River. The research area of the current study is located in Bazhong City, Sichuan Province in Yangtze River watershed, where soil erosion and NPS pollution are serious concerns. Major NPS pollutants include nitrogen (N) and phosphorus (P). The objective of this study is to evaluate the long-term impact of implementation of the CCFP on stream flow, sediment yields, and the main NPS pollutant loading at watershed level. The Soil and Water Assessment Tool (SWAT) is a watershed environmental model and is applied here to simulate and quantify the impacts. Four scenarios are constructed representing different patterns of conversion from cropland to forest under various conditions set by the CCFP. Scenario A represented the baseline, i.e., the cropland and forest area conditions before the implementation of CCFP. Scenario B represents the condition under which all hillside cropland with slope larger than 25° was converted into forest. In scenario C and D, hillside cropland with slope larger than 15° and 7.5° was substituted by forest, respectively. Under the various scenarios, the NPS pollution reduction due to CCFP implementation from 1996–2005 is estimated by SWAT. The results are presented as percentage change of water flow, sediment, organic N, and organic P at watershed level. Furthermore, a regression analysis is conducted between forest area ratio and ten years’ average NPS load estimations, which confirmed the benefits of implementing CCFP in reducing nonpoint source pollution by increasing forest area in mountainous areas. The reduction of organic N and organic P is significant (decrease 42.1% and 62.7%, respectively) at watershed level. In addition, this study also proves that SWAT modeling approach can be used to estimate NPS pollutants’ impacts of land use conversions in large watershed.     

Nonpoint source water pollution abatement and the feasibility of voluntary programs

This article details a case study of a voluntary, decentralized institutional arrangement for nonpint source water pollution control used in the Root River watershed in southeastern Wisconsin. This watershed was chosen because of its mix of urban, agricultural, and urbanizing land uses. The project objectives were to monitor and draw conclusions about the effectiveness of a voluntary, decentralized institutional system, to specify deficiencies of the approach and suggest means to correct them, and to use the conclusions to speculate about the need for regulations regarding nonpoint source pollution control or the appropriateness of financial incentives for nonpoint source control. Institutional factors considered include diversity of land uses in the watershed, educational needs, economic conditions, personality, water quality, number of agencies involved, definition of authority, and bureaucratic requirements     

Integrating water-quality management and land-use planning in a watershed context

The spatial relationships between land uses and river-water quality measured with biological, water chemistry, and habitat indicators were analyzed in the Little Miami River watershed, OH, USA. Data obtained from various federal and state agencies were integrated with Geographic Information System spatial analysis functions. After statistically analyzing the spatial patterns of the water quality in receiving rivers and land uses and other point pollution sources in the watershed, the results showed that the water biotic quality did not degrade significantly below wastewater treatment plants. However, significantly lower water quality was found in areas downstream from high human impact areas where urban land was dominated or near point pollution sources. The study exhibits the importance of integrating water-quality management and land-use planning. Planners and policy-makers at different levels should bring stakeholders together, based on the understanding of land-water relationship in a watershed, to prevent pollution from happening and to plan for a sustainable future.     

人工湿地控制非点源污染的应用

随着点源污染的有效管理和控制，非点源污染已成为水环境污染的主要原因。人工湿地作为一种控制水环境非点源污染的有效工具，已被世界上很多国家所认可。本文首先简述了非点源污染的危害，其次对人工湿地的概念和类型进行了介绍，论述了人工湿地对非点源污染中氮、磷、重金属和农药等主要污染物的去除机理，最后对人工湿地处理系统的附属设施、水力因素、表土层以及植物收割等应用问题进行了探讨。     

Estimating the effects of urban residential development on water quality using microdata

In this study, we examine the impact on water quality of urbanization using disaggregate data from Wake County, North Carolina. We use a unique panel data set tracing the conversion of individual residentially zoned land parcels to relate the density of residential development and the change in residential land use to three measures of water quality. Using a spatial econometrics model, we relate spatially and temporally referenced monitoring station readings to our measures of residential land use while controlling for other factors affecting water quality. We find that both the density of residential land use and the rate of land conversion have a negative impact on water quality. The impacts of these non-point sources are found to be larger in magnitude than those from urban point sources.     

非点源污染模型中土壤侵蚀因子研究进展

非点源污染模型是进行非点源污染模拟研究的重要手段，而土壤侵蚀模型是非点源污染模型的基础，土壤侵蚀因子的研究是土壤侵蚀模型的重要基础。本文对国内外主要土壤侵蚀因子研究的成果进行了概述，并指出在今后相当一段时期内，土壤侵蚀因子的研究仍是土壤侵蚀模型研究的重要工作。