A simulation framework for water allocation to meet the environmental requirements of urban rivers: model development and a case study for the Liming River in Daqing City,China

In this paper, we describe the development of a simulation framework for allocating water from different sources to meet the environmental flows of an urban river. The model permits the development of a rational balance in the utilization of storm water, reclaimed water from wastewater treatment plants, and freshwater from reservoirs with consideration of the limited capacities of different water resources. It is designed to permit the full utilization of unconventional water sources for the restoration of river water quality by increasing river flow and improving water quality. To demonstrate practical use of the model, a case study is presented in which the model was used to simulate the environmental water allocation for the Liming River in Daqing City, China, based on the three water sources mentioned above. The results demonstrate that the model provides an effective approach for helping managers allocate water to satisfy the river’s environmental water requirements.     

Modeling agricultural non-point source pollution in a high-precipitation coastal area of China

Non-point source （NPS） pollution simulation in the high-precipitation coastal areas of China is difficult because varying annual typhoon incidence leads to highly contrasting rainfall patterns in dry years and wet years. An IMPULSE （Integrated Model of Non-point Sources Pollution Processes） based NPS model of the Changtan Reservoir watershed, which is a typical high-precipitation coastal area in China, was established based on the analysis of point and NPS pollution data, a digital elevation model, and data on land-use, soil, meteorology, economy, and agricultural management practice. Pre-processed pre-rain- fall soil moisture levels were introduced during the simulation to model the effects of typhoons on hydrology. Rainfall events were simulated sequentially through the year and the model was calibrated and verified using hydrological and water quality data. Accuracy of the simulated rainfall runoff and water quality in the Changtan watershed was found to be acceptable. The study showed that the NPS modeling system could be applied to the simulation and prediction ofNPS loadings in the Changtan Reservoir watershed.     

Loss coefficient of nitrogenous non-point source pollution under various precipitation conditions

In this study, calibrations of non-point source (NPS) pollution models are performed based on Black River basin historical real-time runoff data, sedimentation record data, and NPS sources survey information. The concept of NPS loss coefficient for the watershed or the loss coefficients (LC) for simplicity is brought up by examining NPS build-up and migration processes along riverbanks in natural river systems. The historical data is used for determining the nitrogenous NPS loss coefficient for five land use types including farmland, urban land, grassland, shrub land, and forest under different precipitation conditions. The comparison of outputs from Soil and Water Assessment Tool (SWAT) model and coefficient export method showed that both methods could obtain reasonable LC. The high Pearson correlation coefficient (0.94722) between those two sets of calculation results justified the consistency of those two models. Another result in the study is that different combinations of precipitation condition and land use types could significantly affect the calculated loss coefficient. As for the adsorptive nitrogen, the order of impact on LC for different land use types can be sorted as: farm land > urban land > grassland > shrub land > forest while the order was farmland > grass land > shrub land > forest s>urban land for soluble nitrogen.     

长三角城郊樟溪流域水体氮磷分布特征及其影响因素

快速城镇化和人类活动导致城郊流域水体营养盐污染和富营养化问题加重,识别氮、磷污染对流域水质的管控具有重要的意义。本研究选取长三角典型城郊地区宁波樟溪流域,在流域内根据土地利用类型、地形特征等布设样点,于2016年连续4个季度进行水样采集,研究樟溪流域河流水体氮、磷的含量及形态,及氮、磷在该流域的时空分布特征,并对其来源和影响因素进行分析。研究结果表明,流域内氮、磷分布具有较大的空间差异性,其中NH+4-N(n.d.~1.375 mg·L~(-1))、TN-N(0.570~11.363 mg·L~(-1))、DIP(n.d.~0.169 mg·L~(-1))、TP(0.010~1.908 mg·L~(-1))。在子流域空间分布上,人类活动频度越高的区域氮、磷的浓度越高,各采样点水体不同形态氮含量和磷含量具有明显的季节变化规律:春季和秋季的含量要高于夏季和冬季。本研究选取采样点距城镇距离、距源头距离以及土地利用类型所占采样点缓冲区的比例来表征人类活动的影响,结果表明,TN和TP含量与距城镇距离呈显著负相关关系,表明城镇化水平对流域氮、磷污染的重要影响。另外,典型城郊流域河流水体氮、磷污染主要受土地利用类型的影响,其含量与农业和城镇用地呈显著正相关关系(P0.01),其含量随人类活动频度的增加而升高。     

特定小流域水质模型的选择

根据特定小流域的水文特点和实际要求，建立一个流域综合水质模型，它由三个子模型支持，即：河流水质模型、水库富养营化模型和非点源污染模型。本工作对河流水质模型（ＱＵＡＬ２ＥＵ）加以改进，使之适应Ｗ河的具体情况，并在ＱＵＡＬ２ＥＵ增加了模拟ＣＯＤ、网箱养鱼和底泥泛起的功能。完成了作了水源地的水库地的水库富营养化模型，解决了流域内农业耕作、污水灌溉等造成的非点源污染随降雨径流进入水体过程的模拟和计算，使之     

天津市景观水体底泥重金属污染状况综合评价

针对天津市景观河道底泥重金属污染进行了调研,分析了各采样点Zn、Cr、Pb、Cu、Cd 5种重金属的污染情况,采用美国NOAA标准对底泥重金属污染进行生物安全性评估和模糊综合评价,以及采用地积累指数法（排除背景值的影响）对重金属的富集程度进行了评价。结果显示：除子牙河外,天津市景观河道重金属污染都比较严重;重金属Zn、Cu、Cd对河道底泥污染的贡献较大,而Pb、Cr对河道底泥污染的贡献较小;城市工业化和开发是造成河道重金属污染的一个重要原因;＂城市水环境改善与水源保护示范工程研究＂的工程示范对河道水体改善作用有明显的效果,建议政府大力推广。     

Watershed land use effects on lake water quality in Denmark

Mitigating nutrient losses from anthropogenic nonpoint sources is today of particular importance for improving the water quality of numerous freshwater lakes worldwide. Several empirical relationships between land use and in-lake water quality variables have been developed, but they are often weak, which can in part be attributed to lack of detailed information about land use activities or point sources. We examined a comprehensive data set comprising land use data, point-source information, and in-lake water quality for 414 Danish lakes. By excluding point-source-influenced lakes (n = 210), the strength in relationship (R2) between in-lake total nitrogen (TN) and total phosphorus (TP) concentrations and the proportion of agricultural land use in the watershed increased markedly, from 10-12% to 39-42% for deep lakes and from 10-12% to 21-23% for shallow lakes, with the highest increase for TN. Relationships between TP and agricultural land use were even stronger for lakes with rivers in their watershed (55%) compared to lakes without (28%), indicating that rivers mediate a stronger linkage between landscape activity and lake water quality by providing a "delivery" mechanism for excess nutrients in the watershed. When examining the effect of different near-freshwater land zones in contrast to the entire watershed, relationships generally improved with size of zone (25, 50, 100, 200, and 400 m from the edge of lake and streams) but were by far strongest using the entire watershed. The proportion of agricultural land use in the entire watershed was best in explaining lake water quality, both relative to estimated nutrient surplus at agricultural field level and near-lake land use, which somewhat contrasts typical strategies of management policies that mainly target agricultural nutrient applications and implementation of near-water buffer zones. This study suggests that transport mechanisms within the whole catchment are important for the nutrient export to lakes. Hence, the whole watershed should be considered when managing nutrient loadings to lakes, and future policies should ideally target measures that reduce the proportion of cultivated land in the watershed to successfully improve lake water quality.     

The relationships of urbanization to surface water quality in four lakes of Hanyang,China

By converting rural land into urban land, urbanization impacts on surface water quality, because cities produce more pollutants than farmlands, especially heavy metals. Ways to reduce urbanization impacts on water quality are now being highlighted worldwide. Considering that land use can be a source or sink in pollution runoff, an understanding of the relationship between urbanization and surface water quality, as well as effects of specific land uses on water quality, is crucial. Corresponding management and controlling steps can then be put forward towards non-point source (NPS) pollution control and urban sustainable development. China has experienced rapid urbanization, especially since the 1980s. However, the environmental impacts of this process are not fully investigated. Hanyang, Hubei Province was selected as a typical city to study the impacts of urbanization on lake water quality. Pearson's correlation analysis was performed to elucidate the correlation between different land uses and water quality indicators at both whole lake watershed and small catchment scales. The results indicated that land uses play different roles, either source or sink, in pollution flow processes. Bottomland had a negative and residential land a positive correlation to most water quality indicators, especially heavy metals. These proved to be indicative and crucial land uses in NPS pollution control. Finally, a strategy for regulating urban land uses is proposed for improving surface water quality in cities similar to Hanyang, in southern China.     

Evaluation of aquatic rehabilitation technologies for polluted urban rivers and the case study of the Foshan Channel

An index system for evaluation of technologies for urban river rehabilitation was proposed and discussed. The index system includes indicators of cost, resources, environmental improvement, and social effects. The calculation method for an objective value of each index based on its attributes and weights was presented. The Foshan Channel, which is a seriously polluted, black and malodorous urban river in Foshan City, China, was selected as a case study. The values of the attributes and the weights of the indices for the Foshan Channel were determined. The technologies for the rehabilitation of the Foshan Channel were evaluated based on this index system. Finally, a rehabilitation scheme for the Foshan Channel was proposed.     

广州市南沙区海岸防护林群落构建技术研究

森林是稳固和改善生态环境的重要载体,因其能提供巨大的生态服务功能而备受各国政府和学界的关注。珠江三角洲地区城市化进程的步伐逐渐加快,带来一系列环境问题。以广州市南沙区海岸景观防护林（也即河涌水网林、公路隔离林、海岸防风林）建设为例,主要研究了防护林的关键构建模式、林分群落结构等方面内容。结果显示,采用多层次的乔灌草配置,遵循适地适树的原则,以本土树种为主,搭配部分优良的引进树种,采取适合的营林措施,可构建出具有一定防护功能的人工林群落。广州南沙防护林建设是珠三角地区城市森林建设的一个缩影和代表,为我国南方城市森林建设理论的创建提供了一定的参考经验。破解城市化危机,创建宜居城市环境,实现城市可持续发展,应综合考虑城市的人口集中程度,经济发展规模,环境污染模式,针对具体的水分、气候和土壤等要素,运用多学科理论和技术,制定合适的森林构建模式,并需要政府、社会组织、以及公众的协同努力。     

Control division of agricultural non-point source pollution at medium-sized watershed scale in Southeast China

This paper presents the study carried out for controlling agricultural non-point source pollution (NSP) in a medium-sized watershed covering 1.47 × 10⁴ km² in Southeast China using quantitative analysis coupled with geographic information system (GIS), universal soil loss equation (USLE), soil conservation service-curve number (SCS-CN), nutrient loss equations, and annualized agricultural nonpoint source model (AnnAGNPS). Based on the quantitative results derived from GIS and environmental models, five control division units were generated for NSP control in Jiulong River watershed, namely, controlling unit for soil losses, controlling unit for livestock breeding and soil losses, controlling unit for excessive fertilizer use and livestock breeding, controlling unit for soil losses and fertilizer use, and controlling unit for excessive fertilizer use and soil losses. This study proved that integrating GIS with environmental models can be adopted to efficiently evaluate major sources and contributors of NSP, and identify the critical source areas of NSP, which enables adjusting measures to local conditions by further control division units developed through such study for control and management of water quality degradation induced by NSP in the Jiulong River watershed.     

The development of a multi-species algal ecodynamic model for urban surface water systems and its application

An ecodynamic model that can simulate four phytoplankton species has been developed to deal with the unique characteristics of urban river systems which has manmade river profile, flow controlled by gates, severe eutrophication status, and fragile aquatic ecosystem. The ecodynamic model was developed referencing two typical models: the water quality simulation model WASP and ecological model CAEDYM. The model can simulate 11 state variables: dissolved oxygen, carbonaceous biochemical oxygen demand, ammonia nitrogen, nitrate nitrogen, organic nitrogen, inorganic phosphorus, organic phosphorus and four phytoplankton species with zooplankton as a boundary condition. The ecodynamic model was applied to Sihai section of the Beijing urban river system, where serious algal blooms broke out in recent years. The dominant phytoplankton species are Cyanophyta, Chlorophyta, Bacillariophyta, and Cryptophyta. Site-specific data on geometry, meteorology, pollution sources, and existing ecosystem parameters were collected and used for model calibration and verification The model results mimic observed trends of water quality and phytoplankton species succession and can be used for forecasting algal blooms as well as assessment of river management measures.     

Integrated biogeochemical modelling of nitrogen load from anthropogenic and natural sources in Japan

This study proposed an integrated biogeochemical modelling of nitrogen loads from anthropogenic and natural sources in Japan. Firstly, the nitrogen load (NL) from different sources such as crop, livestock, industrial plant, urban and rural resident was calculated by using datasets of fertilizer utilization, population distribution, land use map, and social census. Then, the nitrate leaching from soil layers in farmland, grassland and natural conditions was calculated by using a terrestrial nitrogen cycle model (TNCM). The Total Runoff Integrating Pathways (TRIP) was used to transport nitrogen from natural and anthropogenic sources through river channels, as well as collect and route nitrogen to the river mouths. The forcing meteorological and hydrological data is a 30-year (1976–2005) dataset for Japan which were obtained by the land surface model, Minimal Advanced Treatments of Surface Interaction and Runoff (MATSIRO). For the model validation, we collected total nitrogen (TN) concentration data from 59 rivers in Japan. As a comparison result, calculated TN concentration values were in good agreement with the observed ones, which shows the reliability of the proposed model. Finally, the TN loads from point and nonpoint sources were summarized and evaluated for 59 river basins in Japan. The proposed modelling framework can be used as a tool for quantitative evaluation of nitrogen load in terrestrial ecosystems at a national scale. The connection to land use and climate data provides a possibility to use this model for analysis of climate change and land use change impacts on hydrology and water quality.     

Simulating the impacts of land-use changes on non-point source pollution in Lugu Lake watershed

Protection of the water quality of Lugu Lake is important because it is a unique geographic and cultural resource. Not only point source pollution but also non-point source pollution contribute to degradation of water quality. A GIS-NPS model, with long-term hydrologic impact assessment (L-THIA), was used to evaluate long-term implications of land-use change impacts on non-point source (NPS) pollution. The land-use patterns of 1995 and 2005 were analysed to determine the changes in Lugu Lake watershed. A 30-year (1974–2003) precipitation dataset was used to estimate mean annual surface runoff and NPS pollutant loads. The contributions of different land-use categories to average annual runoff and NPS pollutant production were assessed with a unit contribution index (UCI). Results show loss of agricultural land (by 44.9%), while forest, grass/pasture and residential land increased to different degrees from 1995 to 2005. At the same time, annual average NPS pollutants, TN, TP, TSS and BOD loads all decreased, while heavy metal lead increased by 6.87%. The UCI formulated in this research was a more useful method to assess land-use impact on NPS pollutants than simple investigations of the percentage land-use change. Agricultural and residential land changes had more impact on NPS pollutants and were identified as the main source types. Suggestions on regulating land uses and management proposals for protecting lake water quality in Lugu Lake watershed are made.     

Management of nutrient emissions of Axios River catchment: Their effect in the coastal zone of Thermaikos Gulf,Greece

The estimation of nutrient fluxes, the determination of spatial and temporal response and the understanding of biogeochemical changes in the past, present and future in the Axios River catchment, in Greece, as well as the impacts to the coastal zone of Thermaikos Gulf were accomplished by the use of harmonized watershed and coastal zone models. The mathematical model MONERIS was the watershed management model that was used to model the export loads of nutrients in Axios River. MONERIS was developed to estimate the nutrient inputs into river basins by point sources and various diffuse pathways. Watershed hydrologic and water quality data were collected and synthesized to develop input data sets for the simulation of Axios River catchment. The model was modified to better assess organic nitrogen export loads in Mediterranean watersheds. The results showed the importance of agricultural and livestock activities, concerning their nutrients emissions in the River. MONERIS was integrated with the coastal zone model WASP 6.0 to assess the impacts of the nutrient loads to the eutrophication status of the coastal zone. Several management scenarios were assessed. Management scenarios included measures for reduction in the emissions from the fertilizer plant of Veles, removal of phosphorous from the detergents in FYROM, treatment of urban wastes to EU Standards, reduction in N-fertilizer input, reduction in erosion and the green scenario that represented the maximum reduction scenario of all the measures together. The model simulations indicated that the coastal zone of Axios mouth will be eutrophic for nitrate (2.69–3.34 μM) and phosphate (0.2–0.68 μM) and upper mesotrophic for chlorophyll-a (0.74–1.45 μg/l) for the scenarios tested. The results suggest that the impact of the management scenarios will be largely negligible (no change in trophic status) for the Thermaikos Gulf sector nearby the Axios River due to additional sources such as the loads from Thessaloniki's waste water treatment plant which appear to affect the region to a greater extent. The integration of watershed and coastal zone models can be used to assess management scenarios in order to illustrate the significance of various land use practices to the eutrophication of the Gulf.     

Assessment of non-point source pollution using a spatial multicriteria analysis approach

Eutrophication caused by the enrichment of nutrients from diffusing sources is degrading surface water quality throughout the world. Assessing the potential contributions of different land areas in diffuse nutrient export has become an important task in non-point source (NPS) pollution control. Existing methods were often limited by the availability of local data and the complexity of model formulation. This study developed a spatial multicriteria method to evaluate the nitrogen loss potential at the basin level. Four criteria were formulated to characterize the source capacity of nitrogen export, the flow path to water body, the efficiency of runoff generation and the climatic driving force. The proposed method is a low-effort approach since the required data is either already available in a global context or easily produced with limited inputs. Being implemented in GIS environment, this method generates maps that can be easily interpreted to provide decision support. The method was applied to the Huai River Basin, China. The results were validated based on the correlation between the nitrogen loss potential of sub-basin and the water quality class of river. The maps of nitrogen loss potential were helpful for examining the regional pattern of diffuse nitrogen loss, and could facilitate the decisions of NPS pollution management at the provincial or basin level.     

邯郸市沁河水污染治理方案

本文对邯郸市沁河水污染现状进行了调查分析，总结了城市内河治理经验，通过方案比较，推荐“清淤，护坡，建坝，分质截污，邯钢废水混凝沉淀处理”为沁河治理方案。     

永定河(北京段)生态修复工程运行管理机制研究

在充分调查永定河生态修复运行管理现状的基础上,以阈值跃迁、适应性管理为指导,对现有运行管理现状及存在问题进行深入分析。研究发现目前运行管理存在缺乏理论指导,管理权责不明晰,资金来源不明确以及生态监测体系、原水买卖平台缺失等问题。为实现运行管理目标,研究提出从构建基于适应性管理的流域委员会管理模式、确定管理机构权责、管理资金配置及建立生态修复管理评估体系4个方面完善运行管理机制,为永定河生态修复工程的运行管理及北方缺水城市的水生态修复工程运行管理提供参考与借鉴。     

A linear program model for point-nonpoint source control decisions: Theoretical development

A linear programming model for point-nonpoint pollutant source control decisions has been developed. Total phosphorus was highlighted as the water quality substance of concern, although the methodology presented is general enough to permit its use for other substances.The linear program was formulated to minimize the cost of meeting established constraints. Methods to achieve removal of pollutant sources included point and nonpoint (urban and rural) techniques. Constraints were established on the basis of available removal technologies and water quality considerations. The final model is presented in a form such that use of existing linear and separable program software is possible.     

Calculation of the minimum ecological water requirement of an urban river system and its deployment: A case study in Beijing central region

The minimum ecological water requirements of an urban river system and water deployment are key elements in integrated water resources planning and urban ecological construction. Based on a review of ecological water requirement calculation methods and considering the different ecological functions of an urban river system, the ecological function method was used in this paper to calculate the components of the ecological water requirements of an urban river. An envelope curve-based method was proposed for assessing the minimum ecological water requirements of an urban river system. Water resources deployment strategies designed to meet the minimum ecological water requirements were described. Then, the minimum ecological water requirements of the urban river system in Beijing central region, selected as a case study, were investigated. The key parameters for assessing the minimum ecological water requirement in the Beijing urban river system were determined. Based on the ecological objectives and the current status of the different urban river systems within the Beijing central region, the minimum ecological water requirements were calculated. Different types of water sources, including rainwater, upstream water, and reclaimed water, were deployed to meet the ecological water requirements for the urban river system in the Beijing central region.