城市面源污染形成过程及其排放特征研究进展

随着城市的迅速发展,城市面源污染日益成为影响城市水体水质的重要因素。本文按照地表累积—降水—径流冲刷—输送这一城市面源污染的形成过程对次降雨径流平均浓度、初始冲刷效益等污染特征进行了研究,分析了不同下垫面及不同功能区的污染特性。     

成都市中心城区非渗透下垫面降雨径流污染物特性研究

为进一步分析成都市中心城区河流受降雨径流面源污染的影响,在2016年和2017年共监测了8场次降雨事件,结果发现:(1)成都市中心城区非渗透性下垫面径流中的COD和TN浓度基本高于地表V类水质标准; TP高于Ⅲ类水质标准的频次为41. 8%,重金属指标基本在地表Ⅲ类水以内,近年来成都市中心城区降雨径流面源污染有所缓解,但污染程度总体与上海市近似,但显著高于美国大中城市监测结果;(2)除屋顶外(30%),各下垫面固液分配比例基本表现出初期的颗粒态冲刷效应。马路和小区路面TP颗粒态比例大于50%,COD颗粒态比例为60%左右;(3)相关性分析表明,颗粒态物质是降雨径流污染物的重要来源,且大多源于有机耗氧物质。     

降雨径流对柴河水库总磷、总氮的水质影响分析

为研究降雨产生的地表径流对水库水质中总磷、总氮的影响,以铁岭市入柴河水库的柴河流域集雨面积内的降雨径流为研究对象,分别在雨季汛期的三个时期(雨前、雨时及雨后)对柴河流域下游入库前的柴河堡断面采集水样进行分析,以期为铁岭市柴河水库的面源污染治理提供科学依据。     

成都市径流污染的概念性模型

概念性模型是根据城市径流形成过程及对水体影响变化的物理机理建立的一套数学模型，模型及参数均有明确的物理意义。本文用概念性模型求出了成都市街道地表物的累积量，降雨径流污染负荷量，并模拟了污染物对受纳水体的影响。     

沱江流域农村径流污染因素分析及防治措施

本文分析了沱江流域农村径流的污染因素和农村径流对沱江的影响,并提出了防治径流污染的措施,通过两年逐月沱江监测数据表明,雨季沱江受到农村径流污染。根据分析,降雨冲刷时段集中、地形坡度加剧径流冲刷、农作物种植安排抗蚀能力差、农药化肥流失严重等是造成沱江流域农村径流污染的主要因素。在农村径流污染因素分析的基础上提出防治农村径流污染的措施。     

三峡库区中小城镇城市降雨径流污染特征及现状研究

本研究采用从微观到宏观，在库区沿岸城镇诸多相关因素相似前提下，选择涪陵市为典型试验区；从水文因素，街道地表物累积冲刷规律研究着手，建立累积、冲刷计算模式，计算出涪陵市年降雨径流污染负荷和库区污染荷载因子，同时选择具有代表性的集水闭合小区进行水质、水量同步观测试验进行验证；确定外推因子，计算三峡库区城市降雨径流年冲刷入长江的总固体，ＳＳ，ＢＯＤ５，ＣＯＤ，Ｔ－Ｎ，Ｔ－Ｐ３量分别为５３９６８吨，３８０     

成都市某区暴雨径流过程模拟分析

为提高城市雨洪管理的效率,最大限度地减少暴雨洪水带来的危害,针对城市防洪排涝的需要,在分析成都市某区降雨径流规律后,建立了该区暴雨径流模拟的数学模型,有助于采取相应措施充分利用雨洪资源。通过对雨洪过程模拟验证表明,模型适合该区域的实际情况,具有一定的合理性和可靠性。     

雨水自流过滤净化技术实际工程应用效果分析

我国城市径流所导致的面源污染问题严重,雨水自流过滤设施因其占地面积小、易于维护成为控制径流污染的末端处理设施之一。上海市临港新城某桥下建立雨水自流过滤净化设施示范工程,以控制进入滴水湖引清河道的水质。对该示范工程进行了处理效果监测,在长达一年半的时间里实地取样分析了六次有效降雨和两次模拟降雨数据,得到道路雨水径流经滤井处理前后的水质情况,分析结果表明:该自流过滤净化设施能够有效去除径流中的SS、石油类等污染物,去除率可达60%以上;对TN、COD_(Cr)、NH_4~+-N、TP等污染物有部分去除效果。     

城市暴雨径流量研究的方法

为了对城市暴雨径流污染有进一步的了解笔者收集了最近几年国内外有关方面的文献集中在城市暴雨径流量研究的方法和方法学问题上加以综述试图为我国城市暴雨污染控制提供一些值得借鉴的思想和方法。一、城市径流污染物质的来源 1.城市街道地表物污染物质以各种不同的方式在城市非渗透表面上累积例如人行道清扫、居民抛弃的废物垃圾、建筑或拆除房屋而产生的废物垃圾、鸟类牲畜以及其动物的排泄物等等。如北京市交通繁华地区地表物中主要污染物含量(见表1)。城市街道地表物的数量和质量与许多因     

运用生态经济系统思想，开展城市水环境污染的综合整治

本文运用生态经济系统思想有计划，有步骤地解决水环境问题，针对当前城市水质污染的状况和趋势，找出城市水污染的主要原因，并对城市水环境污染进行经济分析及采取的经济对策，根据城市污水总量污染趋势预测，提出了防治措施，同时，在解决水环境问题时，重视环境效益，经济效益和社会效益的统一。     

SIMULATION OF RUNOFF FROM URBAN WATERSHEDS1

ABSTRACT. .A mathematical model for urban watersheds is being developed in stages at the Utah Water Research Laboratory, Utah State University at Logan. In verifying the watershed as a unit, watershed coefficients are determined on the computer, and related to the urbanization characteristics. The second stage of verification consists of dividing the watershed into subzones, and determining the urban parameters within each subzone. Each subzone is then individually modeled, and outflow hydrographs are routed through succeeding downstream subzones to the gaging point. The model thus makes it possible to: (a) develop runoff models for subzone hydrographs within the urban watershed, and (b) account for spatial variations of storm and watershed characteristics. An attempt was also made to analytically model the outflow hydrograph based on storm and watershed characteristics.     

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.     

Management of Urban Road Runoff Containing PAHs: Probabilistic Modeling and Its Application in Beijing,China1

Abstract: Pollutant loading from storm runoff is considered to be an important component of nonpoint source pollution in urban areas. In developing countries, because of the accelerated urbanization and motorization, storm runoff pollution has become a challenge for improving aquatic environmental quality. An effective storm runoff management plan needs to be developed, and questions concerning how much and which proportion of a storm should be treated need to be answered. In this study, a model is developed to determine the fraction of storm runoff that needs to be treated to meet the discharge standard within a given probability. The model considers that the pollutants can be mobilized during the early stage of a storm. The model is applied to a field study of polycyclic aromatic hydrocarbons (PAHs) in road runoff in Beijing, China. In this case, the probability that the PAH load will be mobilized with suspended sediments by the earlier portion of the flush is 73%. Given the high PAH loading in the study area and the referenced discharge standard, the probability that the entire runoff should be captured and treated is 94%. Thus, urban planners need to consider treatment systems for the majority of the storms in this area, whether the PAH load is in the first flush or not. This methodology can be applied to other regions where PAH loads may result in different management outcomes.     

Modeling Watershed‐Wide Bioretention Stormwater Retrofits to Achieve Thermal Pollution Mitigation Goals

Stream ecosystems are increasingly at risk for thermal impairment as urbanization intensifies, resulting in more heated runoff from impervious cover that is less likely to be cooled naturally. While several best management practices, including bioretention filters, have been able to reduce thermal pollution, success has been limited. The extent of thermal mitigation required to prevent ecological damage remains unknown. A calibrated runoff temperature model of a case study watershed in Blacksburg, VA was developed to determine the cumulative treatment volume of bioretention filters required to reduce thermal impacts caused by runoff from development in the watershed to regulated biologically acceptable levels. A future build out scenario of the study watershed was also analyzed. Results from this study established that runoff thermal pollution cannot be fully reduced to goal thresholds during all storms using bioretention filter retrofits. While retrofitting significantly decreased temperatures and heat exports relative to the controls, increasing treatment volumes did not really enhance mitigation. Alternate thermal mitigation methods that actively remove runoff volume should be considered where more thermal mitigation is required.     

CALIBRATION OF STORM LOADS IN THE SOUTH PRONG WATERSHED,FLORIDA, USING BASINS/HSPF1

ABSTRACT: The South Prong watershed is a major tributary system of the Sebastian River and adjacent Indian River Lagoon. Continued urbanization of the Sebastian River drainage basin and other watersheds of the Indian River Lagoon is expected to increase runoff and nonpoint source pollutant loads. The St. Johns River Water Management District developed watershed simulation models to estimate potential impacts on the ecological systems of receiving waters and to assist planners in devising strategies to prevent further degradation of water resources. In the South Prong system, a storm water sampling program was carried out to calibrate the water quality components of the watershed model for total suspended solids (TSS), total phosphorous (TP), and total nitrogen (TN). During the period of May to November 1999, water quality and flow data were collected at three locations within the watershed. Two of the sampling stations were located at the downstream end of major watercourses. The third station was located at the watershed outlet. Five storm events were sampled and measured at each station. Sampling was conducted at appropriate intervals to represent the rising limb, peak, and recession limb of each storm event. The simulations were handled by HSPF (Hydrologic Simulation Program‐Fortran). Results include calibration of the hydrology and calibration of the individual storm loads. The hydrologic calibration was continuous over the period 1994 through 1999. Simulated storm runoff, storm loads, and event mean concentrations were compared with their corresponding observed values. The hydrologic calibration showed good results. The outcome of the individual storm calibrations was mixed. Overall, however, the simulated storm loads agreed reasonably well with measured loads for a majority of the storms.     

A STRATEGY FOR IMPLEMENTING BMPs FOR CONTROLLING NONPOINT SOURCE POLLUTION: THE CASE OF THE FEI‐TSUI RESERVOIR WATERSHED IN TAIWAN1

ABSTRACT: This paper describes a concerted effort by the Taiwan Water Resources Bureau, the City of Taipei, and the Bureau of Fei‐tsui Reservoir Management to protect the water quality in the Fei‐tsui Reservoir.The reservoir is the major source of water supply for over two million people in the metropolitan area of Taipei. Over the years the reservoir has suffered from siltation and more recently eutrophication. The sources of the pollution are traced to the hundreds of tea gardens, rice fields and other agricultural areas in the watershed and to urban sources such as construction sites. Large amounts of nutrients enter the reservoir by way of storm water runoff during storm or typhoon events. Since 1999, various agencies have worked to initiate an effort to reduce nonpoint pollution in the Fei‐Tsui Reservoir watershed. Practices being considered include nonstructural measures such as nutrient management, and structural measures such as swales, detention basins, and wetlands, in addition to erosion and sediment control methods. A number of field tests have been completed on the performance of selected best management practices (BMPs). A strategy for implementing the BMPs at the watershed scale has been developed based on a total maximum daily load (TMDL) analysis that is reported in this paper.     

The Control of Land-Use Patterns for Stormwater Management at Multiple Spatial Scales

While most research about the relationship between land use and watershed hydrological output has focused primarily on land-use types and their impact on hydrological processes, the relationship between characteristics of land-use patterns (such as pattern fragmentation, connectivity, and coherence) and hydrological processes has not been well examined. Using historical stormwater data, this study evaluates the hydrological effects of different land-use scenarios in the Qing-shui watershed in Beijing, China, at a variety of spatial scales. This study demonstrates that planning and managing land-use patterns can significantly reduce runoff under different scales, particularly for small storm events. In contrast to other aspects of land-use structure characteristics, such as the shape complexity of land-use patches, fragmented level of the patches of land-use types appear as dominant drivers of runoff. The results of the study suggest that land-use pattern management should be an important component of Best Management Practices to reduce the impacts of urbanization on natural hydrological processes.     

EVALUATION OF HYDROLOGIC BENEFITS OF INFILTRATION BASED URBAN STORM WATER MANAGEMENT1

ABSTRACT: As watersheds are urbanized, their surfaces are made less pervious and more channelized, which reduces infiltration and speeds up the removal of excess runoff. Traditional storm water management seeks to remove runoff as quickly as possible, gathering excess runoff in detention basins for peak reduction where necessary. In contrast, more recently developed “low impact” alternatives manage rainfall where it falls, through a combination of enhancing infiltration properties of pervious areas and rerouting impervious runoff across pervious areas to allow an opportunity for infiltration. In this paper, we investigate the potential for reducing the hydrologic impacts of urbanization by using infiltration based, low impact storm water management. We describe a group of preliminary experiments using relatively simple engineering tools to compare three basic scenarios of development: an undeveloped landscape; a fully developed landscape using traditional, high impact storm water management; and a fully developed landscape using infiltration based, low impact design. Based on these experiments, it appears that by manipulating the layout of urbanized landscapes, it is possible to reduce impacts on hydrology relative to traditional, fully connected storm water systems. However, the amount of reduction in impact is sensitive to both rainfall event size and soil texture, with greatest reductions being possible for small, relatively frequent rainfall events and more pervious soil textures. Thus, low impact techniques appear to provide a valuable tool for reducing runoff for the events that see the greatest relative increases from urbanization: those generated by the small, relatively frequent rainfall events that are small enough to produce little or no runoff from pervious surfaces, but produce runoff from impervious areas. However, it is clear that there still needs to be measures in place for flood management for larger, more intense, and relatively rarer storm events, which are capable of producing significant runoff even for undeveloped basins.     

DUAL URBAN AND RURAL HYDROGRAPH SIGNALS IN THREE SMALL WATERSHEDS1

ABSTRACT: Many studies can be found in the literature pertaining to the effects of urbanization on surface runoff in small watersheds and the hydrologic response of undeveloped watersheds. However, an extensive literature review yielded few published studies that illustrate differing hydrologic responses from multiple source areas within a watershed. The concepts discussed here are not new, but the methods used provide a unique, basic procedure for investigating stormwater hydrology in topographically diverse basins. Six storm hydrographs from three small central Pennsylvania watersheds were analyzed for this paper; five are presented. Two important conclusions are deduced from this investigation. First, in all cases we found two distinct peaks in stream discharge, each representing different contributing areas to direct discharge with greatly differing curve numbers and lags representative of urban and rural source regions. Second, the direct discharge represents only a small fraction of the total drainage area with the urban peak becoming increasingly important with respect to the rural peak with the amount of urbanization and as the magnitude of the rain event decreases.     

NONPARAMETRIC STATISTICAL METHODS IN URBAN HYDROLOGIC RESEARCH1

ABSTRACT. In urban hydrologic studies, it is often necessary to determine the effect of changes in urban land use patterns on such runoff characteristics as flood peaks and flow volumes. Nonparametric statistical methods have certain properties that make them a valuable tool for detecting hydrologic change caused by a treatment, such as urbanization, that changes watershed over a period of time. As many hydrologists do not have a working familiarity with nonparametric methods, a number of them are used for illustrative purposes to analyze the effect of urbanization on 24 years of annual flood peaks for a Louisville, Kentucky, watershed. In the example, urbanization was found to increase the central tendency, but not the dispersion of the peaks. Peak flows modeled by holding watershed parameters constant were also found to be increasing because of an upward trend in precipitation. By following the numerical examples in the paper and looking up test statistics in referenced sources, the reader can easily apply these methods to other situations.