基于栅格DEM 的沙兰河流域河网提取及局地暴雨洪水模拟

本文基于美国Global Land Cover Facility（GLCF）的全球90m精度的DEM数据源，采用作者开发的DEM凹陷区域识别与处理、河网自动生成与流域划分软件，提取了黑龙江省沙兰镇以上沙兰河流域河网相关信息。同时结合沙兰河暴雨洪水的相关报道，采用内含简化水文过程的二维水动力学模型，直接用假设的降水过程作为输入，估算了沙兰河流域局地暴雨的洪水过程与低洼地的洪水淹没过程。结果表明，从公开的高分辨率全球DEM数据自动提取指定流域信息，并利用降雨数据作为模型输入，采用上述模型，可以为山洪灾害防治分析提供有力的技术工具和手段。     

Mass balance analysis and water quality model development for loading estimates from paddy fields.

Mass balance analysis and water quality model development for paddy field were performed using field experimental data during 2001-2002. About half (47-62%) of the total outflow was lost by surface drainage, with the remainder (490-530 mm) occurring by evapotranspiration. Most of nutrient inflow and outflow were mediated by fertilization and plant uptake, respectively. Nutrient outflow by surface drainage runoff was substantial about 15%-29% for T-N and 6%-13% for T-P. However, the responses of yield and drainage outflow to fertilization were not significant in this study. A water quality model applicable to paddy fields was developed and it demonstrates good agreement with observed data. The nutrient concentration of ponded water was high by fertilization at early culture periods, so reducing surface drainage during fertilization period can reduce nutrient loading from paddy fields. Shallow irrigation, raising the weir height in diked rice fields, and minimizing forced surface drainage are suggested to reduce surface drainage outflow.     

Modelling Scenarios to Estimate the Potential Impact of Hydrological Standards on Nutrient Retention in the Tobacco Creek Watershed,Manitoba, Canada

Nutrient loading from agricultural drainage systems into downstream aquatic ecosystems, like Lake Winnipeg in the prairie province of Manitoba, Canada, represents a major challenge for water quality management. In order to improve water quality in downstream waterbodies, the Manitoba government is currently investigating the relationship between hydrological standard of agricultural drainage network and nutrient retention in the drainage systems. Briefly, oversized drains have more capacity to transport nutrients, which can increase nutrient loading to downstream waterbodies, especially during rainfall events. Currently, the hydrological standards of agricultural drainage design in Manitoba were mainly developed according to cost-benefit analysis without considering nutrient retention. The purpose of this study was to use computer modelling techniques to simulate the impact of drain size (based on different hydrological standards) on nutrient retention within an agricultural drainage network. The site chosen was the Tobacco Creek Watershed, an agricultural area which drains into the Red River, and thence into Lake Winnipeg. Suspended sediment, nutrient and flow data, from several locations along the Brown drain within this watershed, were used to calibrate a water quality model. Scenarios were then simulated with the model to estimate how different drain sizes affect nutrient transport and retention. Sampling took place during the spring and summer of 2013 starting with freshet and ending when the drains dried up near mid-summer. Study results indicated that the amount of nutrients transported was generally greater during freshet and summer rain storms. Occasionally, however, nutrients in summer discharge exceeded those transported during freshet. The water quality model was applied to the Brown drain to investigate the effects of different drain sizes for rainfall amounts under 2, 5, 10, 15, and 20 year return periods. Generally the results indicate that as the return periods became larger (in larger channels) lower nutrients concentrations were predicted downstream (higher decay rates). On average, the model predicted a 15%–20% decline in nutrient concentration with a 20-year return channel design compared to a 2-year return. The research from this study may provide an impetus to the policy-making process of drainage design.     

Estimating Sediment Budget at a River Basin Scale Using a Process-Based Distributed Modelling Approach

The paper presents a process-based distributed modelling approach for estimating sediment budget at a river basin scale with partitions of suspended and bed loads by simulating sediment loads and their interactions. In this approach, a river basin is represented by hillslopes and a network of channels. Hillslopes are divided into an array of homogeneous grid cells for modelling surface runoff and suspended sediments. Channels are defined by incorporating flow hydraulic properties into the respective hillslope grids as sub-grid attributes for modelling both suspended and bed loads. Suspended sediment transport is modelled using one dimensional kinematic wave approximation of Saint-Venant’s principles of conservation of mass and momentum. Transport capacity of runoff or streamflow is used to set the limit of suspended sediment transport rate. Bed load in channels is estimated based on the instantaneous water and hydraulic parameters. Fractional interchange between suspended load and bed load is then back calculated. The performance of the model was evaluated through a case study application in a large river basin in Japan. The model satisfactorily calculated the sediment transport and total sediment budget in the basin. The simulated bed load was found to be reasonable and consistent with the water flow and suspended sediment flux. The results showed the bed load can be expressed as a linear function of the suspended load. The fractions of different sediment loads also exhibit linear relationships with water discharge for the rising and recession limbs of the flood hydrographs. The case study has demonstrated that the process-based distributed modelling approach can efficiently describe the basin-scale sediment budgets with due consideration of the suspended and bed loads and their interactions in the hillslopes and channels.     

广西入河排污口普查登记信息采集系统研制及应用

针对全国开展入河排污口普查登记工作新要求,为节约投资,自行研制出一套兼容水利数码通的设备,并开发了相应的"广西入河排污口普查登记信息采集系统".在工作中,将掌上电脑、GPS和数码相机与该系统有机地结合,顺利完成了广西入河排污口普查登记工作.     

Mathematical model to identify nitrogen variability in large rivers

The river Swale in Yorkshire, northern England has been the subject of many studies concerning water quality. This paper builds on existing data resources and previous 1D river water quality modelling applications at daily resolution (using QUESTOR) to provide a different perspective on understanding pollution, through simulation of the short‐term dynamics of nutrient transport along the river. The two main objectives are (1) building, calibration and evaluation of a detailed mathematical model (Advection‐Dispersion Model: ADModel), for nutrient transport under unsteady flow conditions and (2) the development of methods for estimating key parameters characterizing pollutant transport (velocity, dispersion coefficient and transformation rates) as functions of hydrological parameters and/or seasonality. The study of ammonium and nitrate has highlighted temporal variability in processes, with maximum nitrification and denitrification rates during autumn. Results show that ADModel is able to predict the main trend of measured concentration with reasonable accuracy and accounts for temporal changes in water flow and pollutant load along the river. Prediction accuracy could be improved through more detailed modelling of transformation processes by taking into account the variability of factors for which existing data were insufficient to allow representation. For example, modelling indicates that interactions with bed sediment may provide an additional source of nutrients during high spring flows. Copyright © 2010 John Wiley & Sons, Ltd.     

Integrated Surface–Subsurface Modeling of Fuxianhu Lake Catchment, Southwest China

This paper describes an integrated surface–subsurface modeling study of the Fuxianhu Lake catchment (southwest China). Pollution threats to this important water resource have led to the need to evaluate transport pathways and the overall water balance of the catchment. Catchment inputs to the lake include river inflows, direct overland flow and groundwater discharge, which are incorporated into a mathematical model of the system. Surface runoff and groundwater recharge are estimated using a parsimonious soil–vegetation modeling approach, while groundwater flow is based on the MODFLOW-2005 code. Overland flow and stream discharge are coupled to the groundwater regime through the soil layer and are routed through the catchment to account for surface water flow pathways. The model is tested using the V-catchment benchmark problem and is compared to existing models to demonstrate accuracy and capability. Application of the model to the Fuxianhu catchment provides for the first-order approximation of the average catchment water balance, which comprises such components as evapotranspiration losses (37% of rainfall), surface runoff to the lake (37% of rainfall), and groundwater discharge to the lake (8% of rainfall), amongst others. The computationally efficient approach to surface–subsurface modeling adopted in this investigation presents as an alternative to more complex methods, and allows for the rapid assessment of flow pathways at the catchment scale. An erratum to this article can be found at     

浓度及温度场问题三维数值模拟及应用

研究温度和污染物的扩散规律,对于健康河流具有十分重要的意义。在排水口附近,温度和污染物的扩散具有很强的三维性。在已开发的三维紊流水动力模型基础上,研制了浓度及温度场三维数学模型。在模型中,空度用来处理不规则边界,VOF用来处理自由面。另外,模型还采用了k-ε紊流模型和壁面函数。利用建立的模型,对水槽和天然的排水口附近的水位、流场、紊动能及其扩散率、温度场和浓度场的分布规律等进行了模拟和研究。通过研究进一步认识了排水口局部三维水流运动规律,浓度和温度扩散规律及分布。     

小型空心砼砌块在土石坝排水体中的应用

根据土石坝排水体除险加固设计实践,借鉴砌体结构设计相关成果,论述了合理引进混凝土小型空心砌块,对土石坝排水体出水面进行优化设计的方法,使得坝体排水更通畅,施工更方便,外观更整齐漂亮。     

Nitrogen removal function of recycling irrigation system.

The purpose of this study was to clarify the nitrogen (N) purification capacity of a paddy field in a recycling irrigation system. Irrigation water was sampled at 12-h intervals during the irrigation period from April to September 2003. In addition, ponded water in a paddy field was collected at three points (inlet, centre and outlet). Total amounts of N were 30.7 kg ha(-1) in inflow and 27.8 kg ha(-1) in outflow. Thus, the net outflow load was -2.9 kg ha(-1). The N removal rate constant when N removal is expressed as a 1st-order kinetic was 0.017-0.024 m d(-1). This value is close to values of wetlands and paddy fields in the literature. We found a good correlation between recycling ratio and N removal effect. These results indicate that the recycling irrigation system accumulates N in the irrigation/drainage system, and thus the paddy field does a good job of water purification by removing N.     

Estimation and comparison of nitrogen loads and attenuation in agricultural catchments of Japan and Korea.

To help in clarifying the relationship between the time lag and attenuation of nitrogen (N) loads generated in agricultural catchments, long-term trends in activities that generate N loads and in environmental N loads were estimated in catchments in Japan and Korea dominated by non-point-source emissions. Our approach used statistical data and geographical information system software to analyze pollutant loads. The method was successful in both countries because of the availability of well-developed statistics, geographical information, and weather and water quality monitoring systems, and the accumulation of research data concerning the generation of N loads and the fate of N in soils. Comparison of environmental loads with the loads observed in river water at the outlet of each catchment revealed that: (1) the effect of changes in the environmental load in a catchment appeared almost immediately in the river water quality in Korea, but did not appear clearly even 10 years later in Japan; and (2) the strength of the attenuation appeared to be much lower in Korea than in Japan. These findings suggest that regional characteristics play important roles in the sensitivity of water quality to load-generating activities.     

河道边界水位对管道排水能力的影响分析

为保证城市排水安全,缓解城市内涝,针对河道排涝水位对管道排水的动态影响问题,选用宿迁市马陵河排水片区为研究区,基于SWMM模型,模拟2、3和5 a重现期暴雨条件下出水口管道分别为自由出流、半淹没出流和完全淹没出流3种情形的管道相对排水能力变化,并在此基础上探求马陵河各分段控制水位。结果表明:管道水流主要受河道高水位作用,即管道完全淹没出流时,排水能力随水位的升高而不断减小,减小程度与末管道高差和水位动态顶托管道水流有关。此结论可为城市排水管网改造及河道调控水位除涝提供科学参考。     

鄱阳湖出口近10 年水沙特征及变化初析

利用湖口水文站2012～2021年实测水沙资料,分析近10年鄱阳湖出口水沙基本特征及变化趋势,并对变化原因进行初步分析。结果表明：近10年鄱阳湖出湖输沙量呈减小趋势,鄱阳湖出湖年输沙量和含沙量出现明显的突变点在2017年左右;长江倒灌进入鄱阳湖的水量和沙量呈减小趋势,影响了出湖径流量和输沙量年内分配,但对全年鄱阳湖出湖水量和输沙量影响较弱;鄱阳湖区的采砂活动、河道冲刷对出湖输沙量影响较大。     

Analysis of Bed Load Equations and River Bed Level Variations Using Basin-Scale Process-Based Modelling Approach

Bed load transport is a key process in maintaining the dynamically stable channel geometry for restoring the form and function of river ecosystems. Bed load consists of relatively large sediment particles that are moved along the streambed by rolling, sliding or saltation. Currently, various empirical correlations are used to estimate bed load transport rates since no single procedure, whether theoretical or empirical, has yet to be universally accepted as completely satisfactory in this aspect. Bed load particles are primarily sourced from river bed materials or banks. The amount of bed load and its spatial distribution contributes significantly to river bed level changes. Hillslope sediment contribution, mostly available to the river in the form of suspended load, also plays an important role in river bed level changes. This study aims to analyse different bed load equations and the resultant computations of river bed level variations using a process-based sediment dynamic model. Analyses have revealed that different bed load equations were mainly deduced from the concept of relating bed shear stresses to their critical values which are highly factored by the slope gradient, water discharge and particle sizes. In this study, river bed level variations are calculated by estimating total surplus or deficit sediment loads (suspended loads and bed loads) in a channel section. This paper describes the application of different widely used bed load equations, and evaluation of their various parameters and relative performances for a case study area (Abukuma River Basin, Japan) using a basin-scale process-based modelling approach. Relative performances of river bed level simulations obtained by using different bed load equations are also presented. This paper elaborates on the modelling approaches for river bed load and bed level simulations. Although verifications were not done due to unavailability of field data for bed load, qualitative evaluations were conducted vis-à-vis field data on flow and suspended sediment loads as well as the bed loads presented in different past studies.     

流网和一维动力学模型相结合模拟麦田暗管排水地段氮肥的流失

为研究麦田暗管排水地段氮肥运移转化及淋失规律，在地下水位以上的土壤非饱和带建立了氮素运移与转化的一维模型，在地下水位以下的饱和带采用流网与一维模型相结合近似模拟暗管排水地段的二维溶质运移问题，这样田间饱和非饱和流动区域即可作为一个整体进行研究，方法简单、实用。对方法及模型的正确性进行了田间试验验证。     

基于HEC-RAS的梧桐山河流域泥沙输移特性分析

本文基于HEC-RAS软件建立梧桐山河一维水力学及泥沙输移模型,并利用实测资料对模型进行验证。利用该模型分析河道沿程水面线变化情况及泥沙输移特征。模型泥沙淤积计算表明河道淤积部位主要位于河道转折处及下游出口处,假定无降雨情况下输沙量近似为零,通过模拟计算场次暴雨流域出口断面泥沙输沙量,估算出流域年输沙总量为190.50t。该数学模型可以较好地反映流域内泥沙输移情况,研究成果对于预测梧桐山河流域泥沙淤积状况有重要意义。     

Nitrogen retention in a river system and the effects of river morphology and lakes.

The mean annual transfer (loss and retention) of nitrogen in a river system was estimated using a conceptual approach based on water surface area and runoff. Two different approaches for the calculation of water surface area were applied to determine riverine nitrogen retention in four European catchments, ranging between 860-14,000 km2 in area, and differing considerably in the proportion and distribution of surface waters, specific runoff and specific nutrient emissions. The transfer rate was estimated sequentially as either the mean value for the total catchment, on a sub-catchment scale, or considering the distribution of water surface area within a sub-catchment. For the latter measure, nitrogen retention in larger lakes was calculated separately. Nitrogen emissions modelled with MONERIS and HBV-N were used to calculate nitrogen river loads and compare those with observed loads. Inclusion of the proportion of water area within a sub-catchment improved modelled results in catchment with large lakes in sub-catchments, but not where there was a homogenous distribution of surface waters among sub-catchments.     

基于数字高程模型的河网提取及子流域生成

提出新的从DEM直接提取河网与划分子流域的方法(AEDNM)。该方法与以往方法的不同之处在于不再对DEM进行填洼处理，而是结合图论与水文学的思想，从流域的出口直接向上游搜索，通过图的遍历来确定流向，使全流域形成一个有向无环图，这样提取的河网可以保证是连续的，同实际河网误差很小。根据河网划分的子流域大小也基本均匀，能够满足水文模型模拟的需求。经过黄河、泾河与白河流域的算例验证，表明该法简单可行。     

A SDSS-based Ecological-economic Modelling Approach for Integrated River Basin Management on Different Scale Levels – The Project FLUMAGIS

Spatial and planning support for the implementation of the European water framework directive (WFD) requires interdisciplinary approaches for assessment, deficit analysis, and scenario investigation. To support the implementation of the WFD, the paper presents the innovative spatial decision support system (SDSS) approach from the FLUMAGIS project which is based on the integration of methods for ecological and socio-economic assessment, scale-specific modelling, knowledge processing and techniques for visualization. The project has developed an interactive tool for the assessment and (three-dimensional) visualization of the hydrological and ecological conditions in river basins and economic aspects of river basin management measures. The tool is designed to increase awareness of catchment scale hydrological and ecological issues. The paper presents the structure of the FLUMAGIS prototype and provides examples of scale-specific recommendations for management measures to improve water quality and hydrologic conditions in the Upper Ems river basin (Northwest Germany).