Direct Surface Runoff Hydrographs Research Articles

Estimation of Runoff in Data Scare Watershed of Middle Gujarat, India Using HEC-HMS Model

The accurate estimation of the hydrologic response in water resources planning and development is crucial. In this study, the rainfall-runoff relationship and hydrologic response of the Devgadh Baria watershed in the Panam river catchment were investigated. Due to limited availability and accuracy of runoff data, Clark UH, and SCS UH models were explored for runoff estimation. Remote sensing and GIS techniques were integrated to assess the ungauged watershed in the Middle Gujarat region.
 Rainfall and discharge data, Sentinel-2 data, 12.5m ALOS PALSAR DEM, base maps, and soil maps were collected from various sources. The study area's five different events were randomly selected, and a Thiessen map was prepared to calculate weighted rainfall. Geomorphological parameters and Horton's ratios were estimated using remote sensing and GIS software ILWIS.
 The composite curve number (CN) for the watershed was found to be 77.69. Excess-rainfall hyetographs were separated using the SCS-loss method, and the time to peak estimated by the models matched well with observed data, except for a one-day delay in the HEC-HMS based Clark UH model.
 Four performance indices, namely NSE, PBIAS, RMSE, and d, were used to compare model performance. The SCS UH model demonstrated the highest NSE value (-0.28) for event-1, while the HEC-HMS based SCS UH model showed the lowest NSE value (-0.28) for event-1. The SCS model outperformed the other models based on performance indicators NSE, RMSE, and d. Overall, the SCS UH approach provided the best estimation of peak discharge and time to peak discharge. The direct surface runoff hydrographs estimated using.

Examining the implications of spatial variability of saturated soil hydraulic conductivity on direct surface runoff hydrographs

Saturated soil hydraulic conductivity (Ksat) and soil moisture content (Θ) are key soil hydraulic properties for the understanding of hydrological processes at the watershed scale. Previous approaches in the use of Ksat to describe hydrological processes have mainly applied standardized or derived Ksat values, although the high spatial variability of this soil parameter has been frequently reported. Hence, this study aims to assess the influence of Ksat and Θ spatial variabilities on direct surface runoff (DSR) hydrographs resulting from isolated rainfall events using the Limburg Soil Erosion Model (LISEM) in conjunction with measured Ksat data. Data sets were obtained from a grid of 179 points established in the Ellert creek watershed (ECW), with a drainage area of 0.7 km2. The hydrological monitoring in the ECW consists of an automatic rain gauge and a water level gauging station, which provides rainfall-runoff data every 5 min. Ordinary Kriging was used to map Ksat in the area. Five 5-minute interval rainfall-runoff events were selected from 2017 to 2019 for the hydrological modeling in LISEM, whose water level did not go beyond the reliable applicability of the stage-discharge rating curve generated for the ECW’s outlet. The rainfall depth of these events varied from 24.0 to 66.4 mm, and peak discharge varied from 0.49 to 4.92 m3/s. The effects of Ksat spatial variability and its uncertainties on DSR hydrographs were assessed using the Sequential Gaussian Simulation. As the depth and average intensity of rainfall decreased, there was a greater propagation of the uncertainties of Ksat to peak discharges. The simulated DSR hydrographs and their peak discharges were adequately represented by LISEM. However, LISEM was unable to simulate the hydrological response of the watershed to a two peaks event separated by lower rainfall intensity.

Spatial discretization influence on flood modeling using unit hydrograph theory

ABSTRACT The Unit Hydrograph (UH) is the most popular method for flood related applications. There are several conceptual and geomorphological models based on UH and coupled with different spatial discretizations. However, there are few studies concerning the evaluation of UH models according to semi-distributed approaches. This study aimed to assess the influence of lumped and semi-distributed modeling on the applicability of Soil Conservation Service UH (SCS UH) and Clark’s Instantaneous UH (Clark’s IUH) for estimation of flood hydrographs. The methodological procedures were conducted in the Hydrological Modeling System (HEC-HMS) using rainfall-runoff events of a gauged watershed in Southern Brazil. The main conclusions were: a) CIUH under the semi-distributed approach provided slightly superior performance; b) CIUH was able to effectively estimate the direct surface runoff hydrographs even for long duration rainfall events; c) SCS UH presented more accurate hydrographs for lumped modeling; d) the Nelder and Mead algorithm may have limited application.

Comparison of methods for estimation of flood hydrograph characteristics

This research has been carried out for investigation and comparison of the accuracy and reliability of different methods of unit hydrograph estimation, including geomorphologic (GIUH) and geomorphoclimatic (GCIUH) methods as well as methods by Nash (Nash-IUH), Rosso (Rosso-IUH) and the Soil Conservation Service (SCS); the methods simulated the rainfall-runoff process over the Manshad River basin located in central Iran. The first six equivalent rainfall-runoff events were selected, and a hydrograph of outlet runoff was calculated for each event. Compared were peak time, peak discharge, base time, W50 and W75 parameters (hydrograph widths at 50% and 75% of peak discharge) and the volume of outlet runoff simulated by the models; then determined was the model that most efficiently estimated the hydrograph of outlet flow. The comparison of calculated and observed hydrographs showed that the Nash model was more efficient in estimating peak discharge, peak time, outlet runoff volume and the shape of direct surface runoff (DSRO) hydrographs, though it could not precisely simulate base time and W50 and W75 parameters. The other methods were more accurate in simulating outlet runoff volume of the hydrographs. The Rosso-IUH and SCS models could estimate the base time parameter better than the others. GIUH performance was comparable to the Nash method and was relatively suitable. In spite of these results, the GIUH, GCIUH, Rosso-IUH and SCS models had weak performance for estimating other characteristics of outlet DSRO hydrographs.

Changeability of simulated hydrograph from a steep watershed resulted from applying Clark’s IUH and different time–area histograms

Reflecting the shape and drainage characteristics of the watershed, time–area histogram (TAH) seems to be the most important parameter for derivation of the transformation hydrograph. In this study, a semi-distributed instantaneous unit hydrograph was established and applied to the steep 103 km2-Galazchai watershed in Iran to improve the results of the rainfall–runoff modelling. Towards this attempt, twenty-three runoff producing events with wide different characteristics were used for the analysis. The direct surface runoff hydrographs (DSRHs) were obtained and consequently compared for the study area using Clark’s instantaneous unit hydrograph (IUH) and through applying different TAHs calculated based on channel profile, dimensionless TAH, average velocity and spatially distributed travel time methods. A weight grid developed from kinematic wave travel time equation for overland flow was prepared and used as input to derive the spatial TAH of the watershed. The results indicated that the different TAHs had noticeable impacts on the estimated hydrographs. The results also proved that the spatial TAH method performed well with efficiency criteria of 0.75 and 0.69 in calibration and validation steps. The implemented method also offered the advantages of flexibility, efficiency and physically powerful links to the spatial data set and GIS software.

A comparative study for prediction of direct runoff for a river basin using geomorphological approach and artificial neural networks

Traditional techniques for estimation of flood using historical rainfall–runoff data are restricted in application for small basins due to poor stream gauging network. To overcome such difficulties, various techniques including those involving the morphologic details of the ungauged basin have been evolved. The geomorphologic instantaneous unit hydrograph method belongs to the latter approach. In this study, a gamma geomorphologic instantaneous unit hydrograph (GGIUH) model (based on geomorphologic characteristics of the basin and the Nash instantaneous unit hydrograph model) was calibrated and validated for prediction of direct runoff (flood) from the catchment of the Dulung-Nala (a tributary of the Subarnarekha River System) at Phekoghat station in the state of West Bengal in the eastern part of India. Sensitivity analysis revealed that a change in the model parameters viz., n, RA and RB by 1–20% resulted in the peak discharge to vary from 1.1 to 27.2%, 3.4 to 21.2% and 3.4 to 21.6%, respectively, and the runoff volume to vary from 0.3 to 12.5%, 2.1 to 2.6% and 2.2 to 2.7%, respectively. The Nash–Sutcliffe model efficiency criterion, percentage error in volume, the percentage error in peak, and net difference of observed and simulated time to peak which were used for performance evaluation, have been found to range from 74.2 to 95.1%, 2.9 to 20.9%, 0.1 to 20.8% and −1 to 3 h, respectively, indicating a good performance of the GGIUH model for prediction of runoff hydrograph. Again, an artificial neural network (ANN) model was prepared to predict ordinates of discharge hydrograph using calibrative approach. Both the ANN and GGIUH models were found to have predicted the hydrograph characteristics in a satisfactory manner. Further, direct surface runoff hydrographs computed using the GGIUH model at two map scales (viz. 1:50,000 and 1:250,000) were found to yield comparable results for the two map scales. For a final clarification, the probability density function of the actual and predicted data from the two models was prepared to compare the pattern identification ability of both the models. The GGIUH model was found to identify the distribution pattern better than the ANN model, although both the models were found to be ably replicating the data patterns of the observed dataset.

COMPARISON BETWEEN CHARACTERISTICS OF GEOMORPHOCLIMATIC INSTANTANEOUS UNIT HYDROGRAPH BE PRODUCED BY GcIUH BASED CLARK MODEL AND CLARK IUH MODEL

A great number of developing countries do not have sufficient rainfall-rainoff data of watersheds. For designing a hydraullic structure, considering the basic characteristics of synthetic unit hydrograph is quite indispensable. The geomorphoclimatic approach considers the rainfall and the properties of the watershed. This method can provide a better representation of the runoff estimation. In this study, a geomorphoclimatic instantaneous unit hydrograph (GcIUH) model has been developed. It's derived from the parameters of the CLARK instantaneous unit hydrograph (IUH) which completes its shape. GcIUH based Clark model was applied from the Kasilian watershed in northern part of Iran, The Direct Surface Run Off (DSRO) hydrographs are estimated by the GcIUN based Clark model. Its DSRO hydrographs have been compared with the DSRO hydrographs computed by the Clark IUH model option of the HEC-HMS package. On the basis of quantitative evaluation of the model, it was found that the model is applicable for predicting storm surface runoff in the study area.

COMPARISON BETWEEN CHARACTERISTICS OF GEOMORPHOCLIMATIC INSTANTANEOUS UNIT HYDROGRAPH BE PRODUCED BY GcIUH BASED CLARK MODEL AND CLARK IUH MODEL

A great number of developing countries do not have sufficient rainfall-rainoff data of watersheds. For designing a hydraullic structure, considering the basic characteristics of synthetic unit hydrograph is quite indispensable. The geomorphoclimatic approach considers the rainfall and the properties of the watershed. This method can provide a better representation of the runoff estimation. In this study, a geomorphoclimatic instantaneous unit hydrograph (GcIUH) model has been developed. It's derived from the parameters of the CLARK instantaneous unit hydrograph (IUH) which completes its shape. GcIUH based Clark model was applied from the Kasilian watershed in northern part of Iran, The Direct Surface Run Off (DSRO) hydrographs are estimated by the GcIUN based Clark model. Its DSRO hydrographs have been compared with the DSRO hydrographs computed by the Clark IUH model option of the HEC-HMS package. On the basis of quantitative evaluation of the model, it was found that the model is applicable for predicting storm surface runoff in the study area.

Runoff estimation for an ungauged catchment using geomorphological instantaneous unit hydrograph (GIUH) models

AbstractA geomorphological instantaneous unit hydrograph (GIUH) is derived from the geomorphological characteristics of a catchment and it is related to the parameters of the Clark instantaneous unit hydrograph (IUH) model as well as the Nash IUH model for deriving its complete shape. The developed GIUH based Clark and Nash models are applied for simulation of the direct surface run‐off (DSRO) hydrographs for ten rainfall‐runoff events of the Ajay catchment up to the Sarath gauging site of eastern India. The geomorphological characteristics of the Ajay catchment are evaluated using the GIS package, Integrated Land and Water Information System (ILWIS). The performances of the GIUH based Clark and Nash models in simulating the DSRO hydrographs are compared with the Clark IUH model option of HEC‐1 package and the Nash IUH model, using some commonly used objective functions. The DSRO hydrographs are computed with reasonable accuracy by the GIUH based Clark and Nash models, which simulate the DSRO hydrographs of the catchment considering it to be ungauged. Inter comparison of the performances of the GIUH based Clark and Nash models shows that the DSRO hydrographs are estimated with comparable accuracy by both the models. Copyright © 2007 John Wiley & Sons, Ltd.

Flood Estimation by GIUH-Based Clark and Nash Models

With the recent and drastic decline of hydrological in situ networks, flood estimation from ungauged basins is an imperative research area in scientific hydrology. In this regard, geomorphologic instantaneous unit hydrograph (GIUH) based on models by Clark in 1945 and Nash in 1957 are developed and applied to the Ajay River Basin at Jamtara in northern India. The geomorphologic parameters of the basin were estimated using ERDAS Imagine 8.5 image processing and geographic information system (GIS) software. The direct surface runoff (DSRO) hydrographs derived by the GIUH-based models without using historical runoff data, the conventional Clark IUH model option of the HEC-1 package, and the Nash IUH model, were compared with observed DSRO hydrographs employing four performance criteria. The DSRO hydrographs are computed with reasonable accuracy by the GIUH-based Clark and Nash models, when compared to the Clark IUH model option of the HEC-1 package and the Nash IUH model. It is observed that the GIS supporte...

Development of Optimal and Physically Realizable Unit Hydrograph

Optimization techniques for deriving a unit hydrograph (UH) have received considerable attention. But the UHs derived in some studies are not physically justifiable as the recession limb has a wavy shape. This study extends an existing optimization model by introducing additional constraints to ensure a monotonic decline in the recession limb of the UH. Although there is a marginal deterioration of the objective function, the shape of the developed UH is physically correct. Moreover, the match between the observed and computed direct surface runoff hydrographs is close.

GIUH based Clark and Nash models for runoff estimation for an ungauged basin and their uncertainty analysis

Runoff estimation is an important aspect of river basin planning, development and management. Geomorphological instantaneous unit hydrograph (GIUH) approach holds a great potential for estimation of runoff from ungauged basins because of its direct application to ungauged basins, without going for cumbersome procedure of regionalization. In this study, GIUH is derived from the geomorphological characteristics of a basin and it is related to the parameters of the Clark instantaneous unit hydrograph (IUH) model as well as Nash IUH model for deriving its complete shape. The developed GIUH based Clark and Nash models are applied for simulation of the direct surface runoff (DSRO) hydrographs for ten rainfall‐runoff events of the Ajay basin upto Sarath gauging site of eastern India. The geomorphological characteristics of the Ajay basin are evaluated using the GIS package, Integrated Land and Water Information System (ILWIS). A comparison of the performances of the GIUH based Clark and Nash models in simulating the DSRO hydrographs by employing some of the commonly used error functions reveals that the DSRO hydrographs are computed with reasonable accuracy by both the models, which simulate the DSRO hydrographs of the basin considering it to be ungauged. The relative sensitivity and the degree of uncertainty associated with each of the input parameters of the GIUH based Clark and Nash models have been quantified. The uncertainty analysis reveals that apart from the velocity (V) parameter, the length of the highest order stream (LO) is the only geomorphological parameter which results in higher degree of uncertainty in derivation of unit hydrograph using the GIUH based Clark and Nash models, and hence, it is to be evaluated with greater precision for accurate runoff estimation from ungauged basins.

Application of a Cell Model to the Bellebeek Watershed

A new version of a semi-distributed routing model has been applied to the Bellebeek watershed in Belgium, where runoff data were available for a number of internal gauging stations in addition to the outlet runoff data. The new version has provisions for separately routing the rainfall excess input and the channel inflow input to each unit of area represented in the model by a cell. The cells are interconnected in a tree-like structure reflecting the main drainage pattern of the watershed. The semi-distributed nature of the model makes it possible to simulate spatially variable rainfalls or moving storms. The cell model was calibrated by adjusting its three parameters to reproduce, as nearly as possible, the outflow at the main gauging station of the watershed. The direct surface runoff hydrographs for internal points of the model were then compared to the measured runoff at the internal gauging stations.

A representation of an instantaneous unit hydrograph from geomorphology

The channel network and the overland flow regions in a river basin satisfy Horton's empirical geo‐morphologic laws when ordered according to the Strahler ordering scheme. This setting is presently employed in a kinetic theoretic framework for obtaining an explicit mathematical representation for the instantaneous unit hydrograph (iuh) at the basin outlet. Two examples are developed which lead to explicit formulae for the iuh. These examples are formally analogous to the solutions that would result if a basin is represented in terms of linear reservoirs and channels, respectively, in series and in parallel. However, this analogy is only formal, and it does not carry through physically. All but one of the parameters appearing in the iuh formulae are obtained in terms of Horton's bifurcation ratio, stream length ratio, and stream area ratio. The one unknown parameter is obtained through specifying the basin mean lag time independently. Three basins from Illinois are selected to check the theoretical results with the observed direct surface runoff hydrographs. The theory provided excellent agreement for two basins with areas of the order of 1100 mi2 (1770 km2) but underestimates the peak flow for the smaller basin with 300‐mi2 (483‐km2) area. This relative lack of agreement for the smaller basin may be used to question the validity of the linearity assumption in the rainfall runoff transformation which is embedded in the above development.

UNIT HYDROGRAPHS – A COMPARATIVE STUDY1

ABSTRACT. Unit hydrographs derived by using two methods, linear programming and least squares, are compared. Test data comprise rainfall and runoff information from four storms over the North Branch Potomac River near Cumberland, Maryland. The mathematical bases of these methods for unit‐hydrograph derivation are explained. The linear programming method minimizes the sum of absolute deviations, and the least squares method minimizes the sum of the squares of deviations. Computer subroutines are readily available for application of these methods. The unit hydrographs derived with the two methods are practically the same for storms 2 and 3, but differ somewhat for storms 1 and 4. However, the reconstituted direct surface runoff hydrographs are similar to those observed with the exception of the hydrograph for storm 4 which had a relatively more non‐uniform rainfall excess of a considerably larger duration.

The Kernel function of linear nonstationary surface runoff systems

Adopting a linear nonstationary model for the surface runoff system gives a better fit to a set of observed direct surface runoff hydrographs than adopting a stationary linear model. The kernel of this model, which is a function of two time variables, can be considered to be an assembly of impulse response functions for unit pulses acting at various time intervals after the beginning of the storm. Each of these impulse response functions must have the properties of an ordinary instantaneous unit hydrograph. The kernel function is evaluated by an optimization procedure that seeks to minimize the sum of squared deviations between the observed and computed hydrographs for a number of independent storms, subject to given constraints. The procedure is based on a discretization scheme for the functions involved. The set of equations for the unknown kernel values can be partitioned into independent subsets, each of which is solved individually. The complete equation set need be considered only when area constraints of the kernel function are imposed.