HSPF模型在滇池流域水文模拟中的应用

针对滇池流域入河河道较多、人为因素影响突出等特点,提出基于HSPF模型的入湖水量模拟方法,采用资料较齐全的2个子流域、连续3年的逐日流量数据对模型进行了校准,在此基础上采用连续3年的流量数据对模型进行验证,选择相对误差(RE)、相关系数(R2)、Nash-Suttcliffe效率系数(Ens)对模型的适用性进行评价。研究结果表明,模型在滇池流域的水文模拟结果比较理想,在年径流量、季度流量还是日径流量模拟都得到较好的效果,这表明HSPF模型在研究区对流域长期连续的径流量模拟具有较好的适用性。     

EasyDHM模型参数识别研究

模型参数取值的准确与否直接影响模拟精度的高低,为了提高乌鲁木齐河流域流量模拟精度,根据LH-OAT分析法筛选出对流域流量模拟精度影响较大的参数,利用SCE-UA方法计算出这些参数的最优值,并用1990—2009年实测日资料进行了参数率定及模型验证。结果表明:1土壤田间持水率、河道长度修正系数、径流曲线系数、土壤深度占总土层厚度的比例对流量模拟的影响最为敏感;2模型在率定期和验证期的模拟值与实测值的日相对误差均低于5%,纳什效率系数均超过0.80,相关系数在0.90以上,表明EasyDHM模型在乌鲁木齐河流域流量模拟的精度较高且适应性良好。     

涪江流域分布式日径流模型

以长江上游支流涪江流域为研究对象,建立分布式时变增益日径流模型(Distributed Time Variant Gain Model,简记为DTVGM).对涪江流域的概况,模型的构成,河网的提取、参数的选择进行了介绍.利用1981年和1998年的实测资料检验模型,模型效率系数达到0.8,取得较好的模拟效果,模拟流量过程线与实测流量过程线吻合较好.模型可以提供各个空间网格上水文变量的分布.     

分布式水文模型EasyDHM在海河阜平流域的应用

目前很多分布式水文模型还主要应用在科研领域,缺乏在实际的水管理业务中的应用。分布式水文模型EasyDHM的开发则以实用为目的,着重关注模拟效果及建模效率。模型具有友好的操作界面,适用于各种时空尺度的流域水文模拟,并且模型易于扩展,可进行水资源评价。以海河流域阜平水文站以上流域为研究对象,应用EasyDHM模型进行流域水文模拟,通过对模型参数进行敏感性分析及率定,使阜平流域率定期及验证期Nash效率系数达到0．96。分析表明,EasyDHM模型在阜平流域具有很好的适用性。     

TRMM雨量在汉江上游大尺度水文模型中的应用

将TRMM（Tropic Rainfall Measurement Mission）卫星收集分析的降雨资料，利用大尺度水文模型对汉江白河以上流域进行流量模拟与预测，研究TRMM降雨资料应用于大尺度水文模型（LSHM）进行流量预测的可行性。对比分析了TRMM年、月、日系列降雨资料与气象站网降水观测资料，以及将其作为输入数据源的大尺度模型降雨径流模拟预测结果，分析表明：大尺度水文模型概念基本适合汉江上游的流量预测，水库对模拟预测结果影响显著，TRMM日降雨资料尚不满足利用该模型进行洪峰流量预报精度的要求。     

株树桥水库的洪水预报方案

株树桥水库流域为雨源型河流，属于湿润地区，其预报方案选择三水源新安江模型，参数优选方法应用采用罗森布洛克法、基因法和单纯形法进行自动参数优选。文章介绍了新安江模型的结构，分析了三种优选方法的优缺点，最后选用日资料进行参数优选和径流模拟，模型模拟的效率系数86％，水量平衡系数0．998。结果表明，模型在株树桥水库流域模拟精度高，能够进一步在实际中应用。     

SWAT模型在缺资料地区的应用——以高明河为例

将SWAT分布式水文模型应用于珠江三角洲地区的佛山市高明河流域,利用GIS强大的空间分析与数据处理能力,对流域流量、气象、DEM、土地利用、土壤等水文气象和下垫面资料进行分析处理,率定模型参数,研究SWAT模型在降雨资料系列短、无长系列实测的河道水位流量数据、缺少有效的水文预报方案等缺资料的中小流域或区域的适用性,并分析误差原因。采用相对误差、相关系数以及Nash-Sutcliffe效率系数三项指标对模型进行评价检验,率定期和验证期的相对误差均在0.2以下,相关系数均在0.6以上,Nash-Sutcliffe效率系数均在0.5以上。结果表明,SWAT分布式水文模型能够对高明河流域日时间尺度水文过程进行准确模拟,达到GB/T 22482—2008《水文情报预报规范》中精度评定的丙级,在缺资料的珠三角中小流域具有较好的适用性。     

基于ＳＷＡＴ模型的汉江流域径流模拟

为建立可靠的水文水动力耦合模型,首先探讨水文模型在汉江流域的适用效果。以汉江流域汉中水文站以上区域为研究范围,以中国大气同化数据集（ＣＭＡＤＳＶ１．０）为气象驱动,建立分布式水文模型,并以水文站实测日径流资料进行参数的率定及验证。结果表明:模拟结果与实测值吻合较好,日径流模拟在校准期（２０１０年—２０１３年）纳什效率系数和决定系数达到了０．７７和０．７８,在验证期（２０１４年—２０１７年）纳什效率系数和决定系数分别为０．７４和０．７５,表明ＳＷＡＴ模型在该地区有良好的适用性。     

不同水文模型在双桥流域的应用比较

新安江模型、SWAT模型和BTOPMC模型分别代表集总式、响应单元式和网格分布式三种不同结构的流域水文模型。以Nash效率系数为目标函数,采用SCE-UA自动优化算法率定模型参数,对双桥流域的日径流进行了模拟。结果表明:新安江模型、SWAT模型和BTOPMC模型都能较好反映双桥流域的日径流过程。从总体效果来看,新安江模型的模拟效果比SWAT模型和BTOPMC模型的好,三个模型对总体水量的模拟误差都在±10%以内,水量模拟比较平衡。在不同流量级的模拟中,SWAT模型的水量平衡效果均比新安江模型和BTOPMC模型的好;大流量模拟时,新安江模型的模拟均方根误差较小,模拟效果最好;中流量和小流量模拟时,BTOPMC模型的均方根误差较小,模拟效果最好。     

滦河流域分布式水文模型开发与验证

以WEP模型为基础,构建了基于物理机制的滦河流域分布式水文模型,采用500 m×500 m正方形网格,将流域离散为215 353个基本计算单元,采用“马赛克”法进行土地利用类型重归类,对冠层截留、地表过程、土壤过程、地下水过程以及汇流过程等水文过程进行连续30 a的模拟计算,并以桃林口水库水文站和滦县水文站的还原流量为准对模型进行了校验.结果表明:模型校验期模拟月径流与观测月径流之间的相关系数为0.85～0.94,纳什效率系数在0.72以上,模拟年径流误差控制在5％左右,表明该模型具有较高精度,可为流域水资源综合开发和管理提供支撑.     

Development and Integration of Sub-hourly Rainfall–Runoff Modeling Capability Within a Watershed Model

Increasing urbanization changes runoff patterns to be flashy and instantaneous with decreased base flow. A model with the ability to simulate sub-daily rainfall–runoff processes and continuous simulation capability is required to realistically capture the long-term flow and water quality trends in watersheds that are experiencing urbanization. Soil and Water Assessment Tool (SWAT) has been widely used in hydrologic and nonpoint sources modeling. However, its subdaily modeling capability is limited to hourly flow simulation. This paper presents the development and testing of a sub-hourly rainfall–runoff model in SWAT. SWAT algorithms for infiltration, surface runoff, flow routing, impoundments, and lagging of surface runoff have been modified to allow flow simulations with a sub-hourly time interval as small as one minute. Evapotranspiration, soil water contents, base flow, and lateral flow are estimated on a daily basis and distributed equally for each time step. The sub-hourly routines were tested on a 1.9 km² watershed (70% undeveloped) near Lost Creek in Austin Texas USA. Sensitivity analysis shows that channel flow parameters are more sensitive in sub-hourly simulations (Δt = 15 min) while base flow parameters are more important in daily simulations (Δt = 1 day). A case study shows that the sub-hourly SWAT model reasonably reproduces stream flow hydrograph under multiple storm events. Calibrated stream flow for 1 year period with 15 min simulation (R ² = 0.93) shows better performance compared to daily simulation for the same period (R ² = 0.72). A statistical analysis shows that the improvement in the model performance with sub-hourly time interval is mostly due to the improvement in predicting high flows. The sub-hourly version of SWAT is a promising tool for hydrology and non-point source pollution assessment studies, although more development on water quality modeling is still needed.     

WetSpa Model Application for Assessing Reforestation Impacts on Floods in Margecany–Hornad Watershed,Slovakia

The spatially distributed hydrologic model WetSpa working on a daily or hourly time scale combines elevation, soil and landuse data within GIS, to predict flood hydrographs and spatial distribution of hydrologic characteristics in a watershed. The model is applied to the Margecany–Hornad river basin (1,131 km²) located in Slovakia. Daily hydrometeorological data from 1991 to 2000, including precipitation data from nine stations, temperature data from four stations and evaporation data measured at one station are used as input to the model. Three base maps, i.e., DEM, landuse and soil types are prepared in GIS form, using 100×100 m cell size. Results of the simulations show good agreement between calculated and measured hydrographs at the outlet of the basin. The model predicts the daily/hourly hydrographs with good accuracy, between 75–80% according to the Nash–Sutcliff criteria. For assessing the impact of forests on floods, the calibrated model is applied for a reforestation scenario using the hourly data of the summer of 2001. The scenario considers a 50% increase of forest areas. The model results show that the reforestation scenario decreases the peak discharge by 12%. Investigation of peak discharges from the whole simulation period, shows that the scenario results are reduced by 18% on average. Also, the time to peak of the simulated hydrograph of the reforestation scenario is 14 h longer than for the present landuse. The results show that the effect of land cover on flood is strongly related to storm characteristics and antecedent soil moisture.     

Evaluating performance dependency of a geomorphologic instantaneous unit hydrograph-based hydrological model on DEM resolution

The digital elevation model (DEM) is a type of model that has been widely used in terrain analysis and hydrological modeling. DEM resolution influences the hydrological and geomorphologic features of delineated catchments and consequently affects hydrological simulations. This study investigated the impacts of DEM resolution on the performance of the XAJ-GIUH hydrological model, a model coupling the widely used Xinanjiang (XAJ) hydrological model with the geomorphologic instantaneous unit hydrograph (GIUH), in flood simulations in small and medium-sized catchments. To test the model performance, the model parameters were calibrated at a fine DEM resolution (30 m) and then directly transferred to the simulation runs using coarser DEMs. Afterwards, model recalibration was conducted at coarser DEM resolutions. In the simulation runs with the model parameters calibrated at the 30-m resolution, the DEM resolution slightly affected the overall shape of the simulated flood hydrographs but presented a greater impact on the simulated peak discharges in the two study catchments. The XAJ-GIUH model consistently underestimated the peak discharges when the DEM resolution became coarser. The qualified ratio of peak simulations decreased by 35% when the DEM resolution changed from 30 m to 600 m. However, model recalibration produced comparable model performances when DEMs with different resolutions were used. This study showed that the impact of DEM resolution on model performance can be mitigated by model recalibration to some extent, if the DEM resolution is not too coarse.     

Downscaling of the flood discharge in a probabilistic framework

Many modeled and observed data are in coarse resolution, which are required to be downscaled. This study develops a probabilistic method to downscale 3-hourly runoff to hourly resolution. Hourly data recorded at the Poldokhtar Stream gauge (Karkheh River basin, Iran) during flood events (2009–2019) are divided into two groups including calibration and validation. Statistical tests including Chi-Square and Kolmogorov–Smirnov test indicate that the Burr distribution is proper distribution functions for rising and falling limbs of the floods’ hydrograph in calibration (2009–2013). A conditional ascending/descending random sampling from the constructed distributions on rising/falling limb is applied to produce hourly runoff. The hourly-downscaled runoff is rescaled based on observation to adjust mean three-hourly data. To evaluate the efficiency of the developed method, statistical measures including root mean square error, Nash–Sutcliffe efficiency, Kolmogorov-Smirnov, and correlation are used to assess the performance of the downscaling method not only in calibration but also in validation (2014–2019). Results show that the hourly downscaled runoff is in close agreement with observations in both calibration and validation periods. In addition, cumulative distribution functions of the downscaled runoff closely follow the observed ones in rising and falling limb in two periods. Although the performance of many statistical downscaling methods decreases in extreme values, the developed model performs well at different quantiles (less and more frequent values). This developed method that can properly downscale other hydroclimatological variables at any time and location is useful to provide high-resolution inputs to drive other models. Furthermore, high-resolution data are required for valid and reliable analysis, risk assessment, and management plans.     

小流域暴雨山洪水文模型与水动力学方法计算比较分析

针对小流域暴雨山洪精细模拟问题,提出了小流域时空变源混合产流模型,以小流域为单元构建了暴雨山洪分布式模拟模型,开发了可视化时空变源分布式水文模型软件FFMS和水动力学计算软件FHMS。以宝盖寺小流域场次暴雨洪水计算为例,分别采用水文学和水动力学方法计算了小流域暴雨山洪过程,并分析了两种方法的计算精度、效率、实用性等。案例研究结果表明:(1)水文与水动力学方法均可实现小流域暴雨山洪的模拟,模拟结果与实测基本一致;(2)对于无资料小流域暴雨洪水计算,水文学建模速度快,计算效率更高,水动力学方法建模和计算效率更低;(3)在复杂地形条件下暴雨洪水形成机理、演进过程模拟方面,水动力学计算结果更加精细和准确;在山区中小流域洪水预报预警方面,水文学方法更加实用。     

Application of Muskingum routing method with variable parameters in ungauged basin

This paper describes a flood routing method applied in an ungauged basin, utilizing the Muskingum model with variable parameters of wave travel time K and weight coefficient of discharge x based on the physical characteristics of the river reach and flood, including the reach slope, length, width, and flood discharge. Three formulas for estimating parameters of wide rectangular, triangular, and parabolic cross sections are proposed. The influence of the flood on channel flow routing parameters is taken into account. The HEC-HMS hydrological model and the geospatial hydrologic analysis module HEC-GeoHMS were used to extract channel or watershed characteristics and to divide sub-basins. In addition, the initial and constant-rate method, user synthetic unit hydrograph method, and exponential recession method were used to estimate runoff volumes, the direct runoff hydrograph, and the baseflow hydrograph, respectively. The Muskingum model with variable parameters was then applied in the Louzigou Basin in Henan Province of China,and of the results, the percentages of flood events with a relative error of peak discharge less than 20% and runoff volume less than 10% are both 100%. They also show that the percentages of flood events with coefficients of determination greater than 0.8 are 83.33%, 91.67%, and 87.5%,respectively, for rectangular, triangular, and parabolic cross sections in 24 flood events. Therefore,this method is applicable to ungauged basins.     

北江飞来峡库区典型流域非点源污染特征分析及模拟

为分析飞来峡库区典型流域非点源污染状况,开展社岗流域场次降雨径流水量水质监测试验,采用平均浓度法估算非点源污染负荷量,分析各场次降雨径流污染物特征并计算非点源污染贡献率,应用SWAT模型进行径流及非点源污染模拟。结果表明,径流量对SS、BOD_5等浓度和负荷量均有较强的主导作用,TN、NH_3-N等初期冲刷效应较为明显,污染物负荷量与径流量的相关性好于污染物浓度与径流量的相关性,各污染物的非点源污染贡献率均达到80%以上。SWAT模型径流模拟的率定期和验证期效率系数分别为0.85和0.73,表明所构建的SWAT模型精度良好。在污染物率定期,雨强较大的典型日污染物模拟效果最佳,污染物相对误差基本在10%以内,而在雨强较小时,TN、TP等均出现较大程度的低估现象;在污染物验证期,由于该时期正处于春耕施肥期,TN、TP模拟结果相对误差较大,且均为低估。总体而言,SWAT模型模拟精度良好,基本能反映该流域非点源污染状况,可为飞来峡库区流域的非点源污染模拟与控制提供参考。     

Generation of Runoff Components from Exponential Expressions of Serial Reservoirs

Taiwan frequently experiences heavy rainfall events during the summer. The rainfall–runoff regeneration is an important job in specific areas where excessive rainfall causes serious flooding. The primary goal of this study is to generate and understand runoff components of the watershed outlet by using a conceptual model of three linear cascade reservoirs. The conceptual model is needless to determine direct runoff and excess rainfall in advance. Every linear cascade reservoir has an independent response function with an exponential expression. The outflows of the linear reservoirs represent streamflow components of a watershed outlet during rainfall–runoff processes, in which surface runoff is considered as quick runoff, whereas subsurface and groundwater runoffs are slow runoffs. In the simulation process, mean rainfall as model inputs were estimated using the block Kriging method. Available recordings of 68 rainfall–runoff events during 1966–2002 were used as the study sample. Fifty-four events were calibrated to determine the best hydrograph parameters and were used to compare simulation precision resulting from the model with those based on the Nash with NLP. The efficacy of the proposed model was verified using the remaining 14 observed rainfall–runoff data from an actual basin. The seven averaged parameters, which were applied for verification, show that the IUH shape of quick flow is more sharp-pointed with the peak shifted forward than that of slow flow. In rainfall–runoff processes, peak discharge of quick runoff is far larger than that of slow runoff, the time it takes for the peak discharge for a quick flow is earlier than that for a slow runoff, and the base time of a slow flow is longer than that of a quick flow. Furthermore, this study also found: (1) the base time of a slow runoff hydrograph is the same as that of a total runoff hydrograph; (2) the base time of a quick runoff hydrograph is contrariwise to the value of the soil antecedent moisture; (3) an amount of quick runoff is directly proportional to that of total runoff. These analytical results reveal that the model used in this study is suitable to evaluate hydrological conditions in this and other watersheds and can be further applied to watershed management in Taiwan.     

Analysis of influence of observation operator on sequential data assimilation through soil temperature simulation with common land model

An observation operator is a bridge linking the system state vector and observations in a data assimilation system. Despite its importance, the degree to which an observation operator influences the performance of data assimilation methods is still poorly understood. This study aimed to analyze the influences of linear and nonlinear observation operators on the sequential data assimilation through soil temperature simulation using the unscented particle filter (UPF) and the common land model. The linear observation operator between unprocessed simulations and observations was first established. To improve the correlation between simulations and observations, both were processed based on a series of equations. This processing essentially resulted in a nonlinear observation operator. The linear and nonlinear observation operators were then used along with the UPF in three assimilation experiments: an hourly in situ soil surface temperature assimilation, a daily in situ soil surface temperature assimilation, and a moderate resolution imaging spectroradiometer (MODIS) land surface temperature (LST) assimilation. The results show that the filter improved the soil temperature simulation significantly with the linear and nonlinear observation operators. The nonlinear observation operator improved the UPF's performance more significantly for the hourly and daily in situ observation assimilations than the linear observation operator did, while the situation was opposite for the MODIS LST assimilation. Because of the high assimilation frequency and data quality, the simulation accuracy was significantly improved in all soil layers for hourly in situ soil surface temperature assimilation, while the significant improvements of the simulation accuracy were limited to the lower soil layers for the assimilation experiments with low assimilation frequency or low data quality.     

Application of WetSpa model for assessing land use impacts on floods in the Margecany-Hornad watershed, Slovakia.

The spatially distributed hydrologic model WetSpa combines elevation, soil and land use data within GIS, to predict flood hydrographs and spatial distribution of hydrologic characteristics in a watershed. The model is applied to the Margecany-Hornad river basin (1131 km2) in Slovakia. Daily hydrometeorological data from 1991-2000, including precipitation data from nine stations, temperature data from four stations and evaporation data measured at one station are used as input to the model. Three base maps, i.e. DEM, land use and soil type are prepared in GIS form, using 100 x 100 m cell size. Results of the simulations show good agreement between calculated and measured hydrographs. The model predicts the daily/hourly hydrographs with 75-80% accuracy according to the Nash-Sutcliff criteria. For assessing the impact of land use changes on floods, the calibrated model is applied for a reforestation scenario, which considers a 50% increase of forest areas. The model results show that the reforestation scenario decreases the peak discharge by 12%. Investigation of peak discharges from the whole simulation period, shows that the scenario results are reduced by 18% on average, while for small discharges the reduction is even about 34%. The time to peak of the simulated hydrograph of the reforestation scenario is 20 hours longer than for the present land use.