Modelling Rainfall Runoff Relations Using HEC-HMS and IHACRES for a Single Rain Event in an Arid Region of Jordan

The HEC-HMS and IHACRES rainfall runoff models were applied to simulate a single streamflow event in Wadi Dhuliel arid catchment that occurred on 30–31/01/2008. Streamflow estimation was performed on the basis of an hourly scale. The aim of this study was to develop a new framework of rainfall-runoff model applications in arid catchments by integrating a re-adjusted satellite-derived rainfall dataset (GSMaP_MVK+) to determine the location of the rainfall storm. The HEC-HMS model was applied using the HEC-GeoHMS extension in ArcView 3.3 while the IHACRES is Java-based version model. The HEC-HMS model input data include soil type, land use/land cover, and slope. By contrast, the lumped model IHACRES was also applied, based on hourly rainfall and temperature data. Both models were calibrated and validated using the observed streamflow data set collected at Al-Za’atari discharge station. The performance of IHACRES showed some weaknesses, while the flow comparison between the calibrated streamflow results fits well with the observed streamflow data in HEC-HMS. The Nash-Sutcliffe efficiency (E_f) for the two models was 0.51 and 0.88 respectively.     

Runoff quality and pollution loadings from a tropical urban catchment.

Runoff quality draining from 17.14 km2 urban catchment in Johor Bahru, Malaysia, was analysed. The land-use consists of residential (30.3%), agricultural (27.3%), open space (27.9%), industrial (8.1%) and commercial (6.4%) areas. Three storm events were sampled in detail. These storms produced stormflow between 0.84 mm and 27.82 mm, and peakflow from 2.19 m3/s to 42.36 m3/s. Water quality showed marked variation during storms especially for TSS, BOD and COD with maximum concentrations of 778 mg/l, 135 mg/l and 358 mg/l, respectively. Concentrations of TOC, DOC, NH3-N, Fe and level of colour were also high. In general, the river quality is badly polluted and falls in Class V based on the Malaysian Interim National Water Quality Standards. Event Mean Concentrations (EMC) for various parameters varied considerably between storms. The largest storm produced higher EMC for TSS, NO3-N and SS whereas the smaller storms tend to register higher EMC for BOD, COD, NH3-N, TOC, Ca, K, Mg, Fe and Zn. Such variations could be explained in terms of pollutant availability and the effects of flushing and dilution. Based on a three-month average recurrence interval (ARI) of rainfall, the estimated event loadings (ton/ha) of TSS, BOD, COD, TOC, NH3-N and NO3-N were 0.055, 0.016, 0.012, 0.039, 0.010, 0.0007 and 0.0002, respectively. Heavy metals present in trace quantities. Storms with 3 months ARI could capture about 70% of the total annual loads of major pollutants.     

Runoff and infiltration characteristics of pavement structures--review of an extensive monitoring program.

The stormwater runoff and infiltration performance of permeable pavements has been systematically evaluated within an intensive monitoring program. The primary objective of the investigation was to generate a broad database, which enables the development of an advanced simulation module for urban drainage modelling. Over 160 field and lab scale experiments have been completed and analyzed for surface runoff and infiltration characteristics. The test series include several pavement types under various boundary conditions such as diverse precipitation impacts, varying surface slope and layer construction as well as different stages of surface clogging and several base and subgrade layer characteristics. The results represent a reliable and comprehensive database that allows profound conclusions and substantial recommendations.     

地貌净雨单位线理论及应用

本文以水分子在土壤中受重力、土壤和气体共同作用的角度,分析了水分在土壤中水平向的运动和受力特征,提出了以重力作用为主要特征的地貌单位线模型.该模型以简化地形参数为主要参数,具有基于降雨、地形地貌和土壤特性的分布式流域汇流水文模型特征.运用该模型计算了尼尔基水库净雨单位线,比较了尼尔基水库运用历史洪水率定的单位线,给出了...     

地貌气候瞬时单位线及其应用

传统瞬时单位线法是采用系统分析观点解释流域汇流,流域单位线就是流域的水文响应。运用经验统计分析,建立了流域单位线的主要特征,如单位线峰值、峰值滞时等流域地形地貌参数,如流域坡度、流域面积等之间的经验关系,以确定缺乏水文资料情况下的流域单位线的方法。由于没有涉及到流域汇流的机理,缺乏严格的理论基础。本文介绍了地貌气候瞬时单位线,并对该方法进行了研究,获得了较好的应用价值。     

Planning, modelling and assessing source control concepts on catchment scale.

Today's water management practice was identified often not to be consistently structured. Usually the decision space is not clearly depicted and then systematically explored. Often stakeholders are involved too late and many objectives are neglected. An adaptive DSS is being developed to help overcoming these problems. Core of the DSS is a "decision matrix", which has been implemented as a web based application (www.wsm300.de). The management objectives are represented by the indicators labelling the rows. They will be the result of a discussion of the objectives and problems in the specific sub-basin, which is supported by the catalogue of indicators. The columns of the matrix are specified by the scenarios whose development is supported by the database of measures and a Geographical Information System (GIS). The matrix, once the labels are defined, serves as a plot for the planning process, defining clearly which objectives have to be considered and which indicator-values have to be calculated. The DSS further includes a concept and tools for the combination of existing software components and supports the processing of model-outputs to indicator-values. Filled with the indicator-values the matrix allows a comparison of the scenarios and provides a good base for a decision. Multi-criteria decision aid methods can (if desired) further help to find the optimal scenario and to mediate between stakeholders. Finding the optimal scenario will likely be an iterative process.     

Developing an independent, generic, phosphorus modelling component for use with grid-oriented, physically based distributed catchment models.

Grid-oriented, physically based catchment models calculate fields of various hydrological variables relevant to phosphorus detachment and transport. These include (i) for surface transport: overland flow depth and flow in the coordinate directions, sediment load, and sediment concentration and (ii) for subsurface transport: soil moisture and hydraulic head at various depths in the soil. These variables can be considered as decoupled from any chemical phosphorus model since phosphorus concentrations, either as dissolved or particulate, do not influence the model calculations of the hydrological fields. Thus the phosphorus concentration calculations can be carried out independently from and after the hydrological calculations. This makes it possible to produce a separate phosphorus modelling component which takes as input the hydrological fields produced by the catchment model and which calculates, at each simulation time step, the phosphorus concentrations in the flows. This paper summarises the equations and structure of such a Grid Oriented Phosphorus Component (GOPC) developed by the authors for simulating phosphorus concentrations and loads using the outputs of a fully distributed physical based hydrological model. The GOPC performance is illustrated by an example of a simplified hypothetical catchment subjected to some ideal conditions.     

Runoff modelling using radar data and flow measurements in a stochastic state space approach.

In urban drainage the estimation of runoff with the help of models is a complex task. This is in part due to the fact that rainfall, the most important input to urban drainage modelling, is highly uncertain. Added to the uncertainty of rainfall is the complexity of performing accurate flow measurements. In terms of deterministic modelling techniques these are needed for calibration and evaluation of the applied model. Therefore, the uncertainties of rainfall and flow measurements have a severe impact on the model parameters and results. To overcome these problems a new methodology has been developed which is based on simple rain plane and runoff models that are incorporated into a stochastic state space model approach. The state estimation is done by using the extended Kalman filter in combination with a maximum likelihood criterion and an off-line optimization routine. This paper presents the results of this new methodology with respect to the combined consideration of uncertainties in distributed rainfall derived from radar data and uncertainties in measured flows in an urban catchment within the Emscher river basin, Germany.     

东江上游河流水沙分析

分析了东江上游地区河流水沙特性,并阐述了水库的修建和运用对该地区水沙输移的影响。东江上游地区是整个流域泥沙的重要来源区,该地区地表径流主要来自于降水,河流泥沙也主要来自于降水和径流所造成的土壤侵蚀。从长系列看,东江上游地区径流量虽然在不同时期波动较大,但相对稳定,而河流输沙量呈下降趋势。东江上游来水来沙主要集中在每年的汛期,其汛期来水来沙量分别占全年的70%和88%。枫树坝水库和枕头寨水库建成运用,减小了径流量的季节差异,降低了河流流量脉动特性。同时其河流输沙率在枫树坝水库和枕头寨水库建成以及枕头寨水库调整后分别下降了30%和50%。近年来,东江下游进行的大规模无序采沙,其采砂量已经远大于上游来沙量。在东江流域进行水沙管理时,不仅要采取措施遏制这种无序采沙行动,同时也要进一步研究流域水沙输移问题,以达到维持整个河流系统的水沙平衡。     

Application of HEC-HMS for flood forecasting in Misai and Wan'an catchments in China

The hydrologic model HEC-HMS(Hydrologic Engineering Center,Hydrologic Modeling System),used in combination with the Geospatial Hydrologic Modeling Extension,HEC-GeoHMS,is not a site-specific hydrologic model.Although China has seen the applications of many hydrologic and hydraulic models,HEC-HMS is seldom applied in China,and where it is applied,it is not applied holistically.This paper presents a holistic application of HEC-HMS.Its applicability,capability and suitability for flood forecasting in catchments were examined.The DEMs(digital elevation models)of the study areas were processed using HEC-GeoHMS,an ArcView GIS extension for catchment delineation,terrain pre-processing,and basin processing.The model was calibrated and verified using historical observed data.The determination coefficients and coefficients of agreement for all the flood events were above 0.9,and the relative errors in peak discharges were all within the acceptable range.     

A case study of regional catchment water quality modelling to identify pollution control requirements.

There are four ecologically important river catchments that contain candidate Special Areas of Conservation (cSACs) under the Habitats Directive in the Lake District National Park located in the North of England. These are the rivers Ehen, Kent, Derwent and Eden. For each cSAC, there are defined ecological criteria that include water quality targets to protect the designated species. Stretches of the riverine cSACs in each catchment are failing to meet these and other water quality targets. The Environment Agency commissioned a study of each catchment to provide the underpinning scientific knowledge to allow it to deliver its statutory obligations under the Habitats Directive. SIMCAT river water quality models were produced and used to predict the water quality impacts resulting from a number of water quality planning scenarios aimed at achieving full compliance with the Habitats Directive and other national and EEC water quality targets. The results indicated that further controls on effluent discharges will allow the majority of targets to be met but other sources of pollution will also need to be controlled. The outcome of the study also recognised that water quality improvements alone will not necessarily produce the required improvement to the ecological interest features in each cSAC.     

A multiobjective model for non-point source pollution control for an off-stream reservoir catchment.

Phosphorus loads from agricultural non-point source pollution (NPSP) significantly degrade reservoir water quality, making adequate control of agricultural NPSP necessary for improving the water quality. Controlling NPSP is generally accomplished using various Best Management Practices (BMPs). The present study applies the Agricultural Non-Point Source Pollution (AGNPS) model to simulate NPSP loading and BMP efficiencies and establishes an enhanced multiobjective mixed-integer programming model for NPSP control strategy analyses based on these results. Cost, phosphorus load, sediment load and equity are the four major objectives considered. A case study for the Posan reservoir is presented. Four commonly proposed and applicable BMPs are chosen. Non-inferior solutions obtained using the constraint method and trade-off relationships among different control objectives are described and discussed. Compared with a previously proposed fertilizer control model, results show that the model established herein is more cost-effective and achieves better phosphorus and sediment loading reduction and equity goals. Furthermore, the current model is expected to facilitate decision-making analysis for development of an appropriate cost-sharing program to encourage adoption of appropriate BMPs by farmers.     

Impact of agricultural practices and river catchment characteristics on river and bathing water quality.

The objective was to investigate the potential risk of faecal indicator organism (FIO) bacteriological contamination of river catchments and coastal bathing waters from farm management practices and to develop practices to reduce the risk. A risk assessment on 117 farms was carried out in two river catchments in south-west Scotland. Manure storage facilities, farming practices, field conditions and catchment characteristics were assessed. River samples at 33 locations were regularly taken and analysed for FIOs. Available manure storage capacity and farm management practices are inadequate on a high proportion of farms and FIO contamination of watercourses was likely the result of effluent transported into watercourses due to non-collection or poor containment. In addition, surface run-off or leaching following land application of manure or intensive stocking in adverse conditions was a high risk on up to 50% of farms. The concentrations of FIOs in the streams of two sub-catchments with high livestock intensity was 4 to 8 times higher compared to the two sub-catchments which had a low livestock intensity. The majority of potential risks of agricultural pollution to watercourses may be eliminated through improved manure and dirty water management, forward planning of manure spreading activities and improved operational procedures.     

基于水蚀模型WEPP和GIS的高原小流域侵蚀模拟--以延安地区向阳沟小流域为例

根据延安地区向阳沟小流域的资料，利用水蚀模型WEPP结合GIS对该地区的水土侵蚀状况进行模拟。研究首先利用ArcGIS软件由数字高程模型DEM中提取诸如：流域的划分、水流网络等与流域特征相关的数据作为坡面资料；同时应用GIS矢量化向阳沟流域治理措施图作为土地管理资料；然后利用BPCDG程序整理气象资料。最后将上述成果整理后输入WEPP进行模拟。模型的模拟结果表明WEPP能够较为合理的模拟向阳沟小流域的水土侵蚀的发生，同时对应用不同的管理措施降低侵蚀量和径流量给出了定量评价。本研究表明GIS这种先进工具的介入可以很好地为WEPP这种机理模型提供数据，并且使得模拟结果的展示具体、直观、生动。     

Application of HEC-HMS Model for Evaluation of Rainwater Harvesting Potential in a Semi-arid City

Water Resources Management - With many countries facing water scarcity and the demand for water ever-increasing, more people are turning to rainwater harvesting (RWH) as a feasible way of...     

Performance of cellulose acetate - polyethersulphone blend membrane prepared using microwave heating for palm oil mill effluent treatment.

The objective of this research is to investigate the performance of blend cellulose acetate (CA)-polyethersulphone (PES) membranes prepared using microwave heating (MWH) techniques and then compare it with blend CA-PES membranes prepared using conventional heating (CH) methods using bovine serum albumin solution. The superior membranes were then used in the treatment of palm oil mill effluent (POME). Various blends of CA-PES have been blended with PES in the range of 1-5 wt%. This distinctive series of dope formulations of blend CA/PES and pure CA was prepared using N, N-dimethylformamide (DMF) as solvent. The dope solution was prepared by MW heating for 5 min at a high pulse and the membranes were prepared by phase inversion method. The performances of these membranes were evaluated in terms of pure water and permeate flux, percentage removal of total suspended solids (TSS), chemical oxygen demand (COD) and biochemical oxygen demand (BOD). The results indicate that blend membranes prepared using the microwave technique is far more superior compared to that prepared using CH. Blend membranes with 19% CA, 1-3% PES and 80% of DMF solvent were found to be the best membrane formulation.     

Runoff and loads of nutrients and heavy metals from an urbanized area.

To investigate the run-off characteristics of dissolved and particulate substances from a heavily urbanized area (basin area: 95 ha, percentage of impervious surfaces: 60%), sensors for measuring water level, water temperature, DO, pH, electric conductivity (EC), turbidity and ammonium ion were placed in the channel connecting storm sewers and natural river, together with water sampling for analyzing SS, nutrients and metals. While both turbidity and EC showed apparent "first flush", the peaks of EC were always earlier than those of turbidity. In a similar manner, dissolved nutrients and metals exhibited earlier "first flush" compared with particulate nutrients and acid-extractable metals. Significantly positive correlations between EC and dissolved substances as well as those between turbidity and particulate (acid-extractable minus dissolved) substances were usually observed, and two distinct different regressions were found between the two datasets separated before and after the concentration peaks. Using these relationships, the total loads during the respective rainfall events were calculated on the basis of EC and turbidity changes. The total loads of nitrogen, zinc, etc. were nearly proportional to the lengths of non-rainfall periods before the events, indicating that these loads derived from the atmospheric deposition.     

疏勒河流域三大水库自动化模拟调度系统设计与应用

疏勒河流域三大水库自动化模拟调度系统是疏勒河灌区信息化系统建设的重要组成部分。该系统的建设和应用为实现灌区大型水库的信息采集自动化、数据传输网络化、应用服务智能化、决策支持最优化提供了基础信息支撑平台,为实现灌区水库群联合优化调度、合理配置灌区水资源、保护流域生态环境、实现流域可持续发展提供了重要的信息技术手段,从而全面提升了灌区的现代化管理水平和科学决策能力。图3幅。     

Calculation of energy recovery and greenhouse gas emission reduction from palm oil mill effluent treatment by an anaerobic granular-sludge process

Conventional aerobic and low-rate anaerobic processes such as pond and open-tank systems have been widely used in wastewater treatment. In order to improve treatment efficacy and to avoid greenhouse gas emissions, conventional treatment can be upgraded to a high performance anaerobic granular-sludge system. The anaerobic granular-sludge systems are designed to capture the biogas produced, rendering a potential for claims of carbon credits under the Kyoto Protocol for reducing emissions of greenhouse gases. Certified Emission Reductions (CERs) would be issued, which can be exchanged between businesses or bought and sold in international markets at the prevailing market prices. As the advanced anaerobic granular systems are capable of handling high organic loadings concomitant with high strength wastewater and short hydraulic retention time, they render more carbon credits than other conventional anaerobic systems. In addition to efficient waste degradation, the carbon credits can be used to generate revenue and to finance the project. This paper presents a scenario on emission avoidance based on a methane recovery and utilization project. An example analysis on emission reduction and an overview of the global emission market are also outlined.