Geomorphological Instantaneous Unit Hydrograph

Introduction

A significant portion of the flow of perennial rivers originates from groundwater. The changes that occur in a watershed due to natural and human factors are indicative of physical changes and artificial mismanagement of water resources. These situations change the contribution of groundwater to streamflow. Therefore, understanding baseflow allows for the identification of the potential and dynamics of the groundwater system. In principle, the separation of base flow and quick flow is difficult to distinguish from the measured discharge data in a river, because the measured discharge in a river is a combination of the two flow components. Separation of riverbed flow is essential for water resources management and can significantly contribute to the calculation of water availability in the dry season (relatively short discharge period). In addition, comparing different watersheds in terms of flow recession characteristics can provide valuable information about storage and recharge properties in the watershed. The main objective of this research is to estimate base flow using several hydrograph analysis techniques, as there has been neither organized research on groundwater resources at the watershed level nor studies on different methods for estimating the base flow contribution in these streams.

Materials and Methods

The current research includes estimating base flow from daily streamflow data using the Flow Duration Curve (FDC) technique, the Web-based Hydrograph Analysis Tool (WHAT), and the Baseflow Index (BFI+) program. Using the FDC technique, the long-term annual average fraction of flow from base flow is estimated after obtaining the values of Q90 and Q50. The Web-based Hydrograph Analysis Tool includes three algorithms: the local minimum algorithm, the one-parameter algorithm, and the two-parameter algorithm. The web-based WHAT system provides an efficient tool for hydrologic model calibration and validation. Baseflow information from the WHAT system can also play an important role in sustainable groundwater and surface water management, including irrigation and industrial uses, and estimating pollutant loads from both baseflow and direct runoff. The Baseflow Index program also uses the following algorithms: Fix Interval, Sliding Interval, Local Minima, Lynne-Hollick, Chapman, One Parameter Algorithm, Two Parameter Algorithm, Exp. Weighted Moving Average, Eckhardt, BFLOW, IHACRES, and Fure & gupta. For this purpose, daily streamflow and precipitation data were obtained from the Regional Water Organization of Lorestan Province. The time series of data for streamflow and precipitation was selected from 2009 to 2019.

Results and Discussion

The results of the data analysis indicate that most of the automatic filter techniques used with assumed parameters have overestimated the baseflow above the average compared to the FDC. In addition, the FDC analysis showed that the contribution of groundwater storage to streamflow was below average. The WHAT automatic digital filter tool has been widely used for long-term baseflow separation using a two-parameter digital filter (α and BFImax). In this study, the BFImax value was set to 0.80 for alluvial streams and the filter parameter (α) was set to 0.995 for the Rahim Abad stream. The BFI values for the Rahim Abad River are consistent and are estimated to be around 45% for the entire watershed. The results obtained from BFI+ showed that the calculated baseflow values for the one-parameter and two-parameter algorithms, except for RDF-IHACRES, BF-BFLOW, BF-Chapman, and BF-Furey, were higher than the mean flow. In addition, the long-term baseflow to flow ratio or BFI is equal to the ratio of Q90/Q50. This ratio indicates the discharge of groundwater or other delayed sources to the streamflow. Hydraulic structures built upstream of hydrological gauging stations can affect flow conditions. These BFI values are related to the geology and hydrogeology of the watershed. The Q90/Q50 ratio has an annually varying decreasing and increasing trend for flow, indicating that the contribution of groundwater to streamflow varies from year to year with decreasing and increasing changes. Finally, by employing all methods, the range of groundwater contribution to Rahim Abad streamflow was obtained between 2 and 84 percent, and its average value was also determined to be 63 percent.

Conclusion

Considering the average of all BFI values obtained from all methods with values less than the mean, an overall average of 45% was obtained, which provided a better estimate for the entire watershed. In this regard, the modified RDF methods (one-parameter and two-parameter algorithms), IHACRES, BF-BFLOW, BF-Chapman, and BF-Furey were selected as the top algorithms for the entire watershed. Further studies are necessary for future groundwater resource problems in the watershed. The interaction of groundwater and surface water and pollution problems, water quality management of rivers, estimation of groundwater potential using other techniques, and estimation of the contribution of groundwater under climate change are among those that can be mentioned. Introduction of suitable methods of separation of daily flow in hydrological modeling, regional analysis of minimum flows and determination of base flow share can be used. It is hoped that the output of this study will help the planning, development and management of water resources in the Silakhor watershed.

Development of precise and simple methods in flood simulation has greatly reduced financial damage and life loss. Various methods and procedures have been implemented based on Saint-Venant's one-dimensional equation governing unsteady flows. To simplify the solution for these flows, analytical and numerical methods have been used. In the present study, a new method that provides the optimal outcome is introduced using non-linear programming. Penalty function has also been used to convert nonlinear programming (NLP) constrained problems into unconstrained optimal issues. To verify the accuracy of decision variables, the study covered 60 cross-sections of Gharasu River and 25-year flood hydrographs. After determining the model correctness, the 50 and 100-year flood hydrograph were routed in 18 Kilometers. The results were statistically compared with hydraulic and Muskingum hydrological methods. To sum up; the routed hydrographs introduced by NLP method were very close to the hydrographs produced by dynamic wave method. The R 2 of calculated discharge of routed hydrograph by NLP and dynamic wave method were 0.948, 0.990, and 0.989, respectively, with the return period of 25, 50 and 100-year flood being 0.989. It can be concluded that NLP method is more accurate than Muskingum method, especially when predicting the peak discharge of flood hydrograph.

The predictability of unit hydrograph (UH) models that are based on the concepts of land morphology and isochrones to generate direct runoff hydrograph (DRH) were evaluated in this paper. The intention of this study was to evaluate the models for accurate runoff prediction from ungauged watershed using the ArcGIS R tool. Three models such as Water Resour Manage (2007Manage ( ) 21:1127Manage ( -1143 DRHs for ungauged watersheds that have similar geomorphology as that of the St. Esprit watershed.

Water scarcity and low per capita water allocation are the major characteristics of arid and semi-arid regions. This paper provides a methodology to determine runoff from ungauged catchments. The basic approach involves the utilization of a simple event-based Geomorphological Instantaneous Unit Hydrograph model (GIUH) that is capable of determining the hydrograph based on rainfall data and on catchment geomorphological characteristics obtained from GIS tools. A GIUH model has been developed for the Badan and Faria subcatchments within the Faria catchment in Palestine, and successfully applied and validated against observed flow data. The model estimated that peak discharge increased as the overland flow roughness coefficient decreased, which reflects the surface roughness conditions in the catchment. However, when compared with the overland flow roughness coefficient, the channel flow roughness coefficient had a smaller effect on simulated peak flow. Results of the sensitivity test ...

Among the most basic challenges of hydrology are the quantitative understanding of the processes of runoff generation and prediction of flow hydrographs. Traditional techniques have been widely applied for the estimation of runoff hydrographs of gauged catchments using historical rainfall-runoff data and unit hydrographs. Such procedures are questioned as to their reliability and their application to ungauged, arid, and semiarid catchments. To overcome such difficulties, the use of physically based rainfall-runoff estimation methods such as the Geomorphologic Instantaneous Unit Hydrograph (GIUH) approach has evolved. This paper models the rainfall-runoff process of Faria catchment using the lately developed KW-GIUH. Faria catchment, located in the northeastern part of the West Bank, Palestine, is characterized as a semiarid region with annual rainfall depths ranging on average from 150 to 640 mm at both ends of the catchment. The Geographical Information System (GIS) techniques were used to shape the geomorphological features of the catchment. A GIS-based KW-GIUH hydrological model was used to simulate the rainfall-runoff process in the three sub-catchments of Faria, namely: Al-Badan, Al-Faria, and Al-Malaqi. The simulated runoff hydrographs proved that the GIS-based KW-GIUH model is applicable to semiarid regions and can be used to estimate the unit hydrographs in the West Bank catchments.

Among the most basic challenges of hydrology are the quantitative understanding of the processes of runoff generation and prediction of the flow hydrographs and their transmission to the outlet. Traditional techniques have been widely applied for the estimation of runoff hydrographs at the outlets of gauged watersheds using historical rainfall-runoff data and unit hydrographs derived from them. Such procedures are questioned for their reliability due to the climatic and physical changes in the watershed and their application to ungauged, arid and semiarid catchments. To overcome such difficulties, the use of physically based rainfall-runoff estimation methods such as the Geomorphologic Instantaneous Unit Hydrograph (GIUH) approach has evolved. In this study, the lately developed GIUH model is applied to Al-Badan watershed of Faria catchment located in the northeastern part of the West Bank, Palestine. The Faria catchment characterizes a semiarid region, with annual rainfall depths ranging on average from about 150 to 600 mm. The Geographical Information System (GIS) techniques are used to shape the geomorphological features of the catchment. The application of the GIS supported GIUH model has proved reasonable agreement between the simulated runoff hydrograph and the recorded flows. The paper has elaborated on the applicability of the unit hydrograph theory and the GIUH to semiarid regions.

This paper aims to investigate the potential existence of wadi-aquifer interaction in the 320 km 2 semiarid Faria catchment using a tracer-based methodology. Faria catchment is located in the northeastern part of the West Bank and accounts for 6 % of the total West Bank's area. Surface runoff in the catchment consists mainly from springs discharge, runoff generated from winter storms, untreated wastewater effluent from the eastern part of Nablus City and Al-Faria refugee camp, and the return flow from the adjacent agricultural areas. As such, wadi-aquifer interaction may pose serious pressures on groundwater quality which is the only water source for the agricultural and domestic uses in the area. In this study, and in order to investigate the potential existence of wadi-aquifer interaction in the Faria catchment, a tracer-based experiment was conducted. The experiment was carried out using Uranine as a conservative tracer material. A representative reach of 600 m was chosen and was divided into four equal distances. A concentration curve was plotted at each section (monitoring point) with the help of OTIS (solute transport model for streams and rivers) which was used to calibrate the measured concentration curves. Accordingly, the flow rates were estimated at the different monitoring points. The obtained results proved that transmission losses took place in the wadi bed sediments of the selected reach and with different ratios. The percent loss in the flow rates' values in the different sections ranged from 4.8 to 68.3 %. It was found that the largest transmission losses took place in the section between the first and the second monitoring points. In conclusion, tracer-based methodology is considered as a modern and innovative technique that was used via this research to understand the nature of the wadiaquifer interaction in Faria catchment and to quantify it as well.

The geomorphological instantaneous unit hydrograph (GIUH) is a useful tool to describe basin response. In the present study, results of tracer experiments on a hillslope and the channel network were used to determine the GIUH. The area weighting function of the GIUH was determined using digital elevation data. The combination of hillslope pathway and channel length distributions were used as area weighting function. The resulting GIUH provides a reasonable production of an observed runoff event.

This paper is an open access and licenced under the CC BY NC licence.
Hydrological models serve as effective tools for managing water sources and assessing water components. Although basin hydrological models have been developed, selecting suitable software for modeling specific areas remains challenging. Hence, it's essential to opt for software capable of simulating the hydrological cycle with a simple structure and minimal input parameters. In northwest Iran, AWBM and ARCSWAT software were employed for simulation. AWBM is a simplistic program estimating runoff using precipitation and evaporation indicators, while ARCSWAT is a semi-distributed software for continuous flow simulation. ARCSWAT necessitates various inputs, including geological, land use, and slope maps, along with precipitation, temperature, relative humidity, and radiation statistics. The runoff simulation results during calibration and validation periods were assessed using two statistical indices: Nash Sutcliffe Efficiency (NSE) and the coefficient of determination (R2). A comparison of the statistical indicators revealed NSE values of 0.83 and 0.7 for calibration and validation periods, respectively, and R2 values of 0.83 and 0.8 for calibration and validation periods, respectively, for the semi-distributed SWAT model. In contrast, for the AWBM integrated model in the basin, NSE values were 0.63 and 0.48, and R2 values were 0.48 and 0.48 for calibration and validation periods, respectively, indicating better results in runoff simulation at the monthly time scale.

The problem of estimation of the velocity parameter in the exponential distribution geomorphological instantaneous unit hydrograph (ED-GIUH) is investigated in this study. The main difficulty in applying the ED-GIUH model is the estimation of this parameter. In the present study, the ED-GIUH model is applied to six watersheds in Indiana, U.S.A. The relationships between the velocity parameter and climatic as

Study on natural processes related to water as well as knowledge about runoff and hydrological conditions is necessary for improvement of water management in Iran. Since most of watersheds in Iran are ungauged, so using hydrologic models to simulate the runoff is inevitable. In this study, continuous distributed hydrologic model WetSpa was used to simulate Zoshk watershed runoff. Three basic maps including digital elevation model (DEM), landuse and soil texture are the model inputs. Required meteorological data are potential evapotranspiration, precipitation and temperature. The basin outlet discharge in Zoahk gauging station is used to calibrate and evaluate the model. Calibration period is from 2009/01/01 to 2011/31/12 and validation period is from 2012/01/01 to 2014/31/12. PEST software was used to calibrate the model parameter. Results show good agreement between calculated and measured hydrographs. The model predicts the hourly hydrographs with a good accuracy, so that according to the Nash-Sutcliff criterion the accuracy is more than 85% and 83% for calibration and validation periods, respectively. The result shows that this model only simulates the high flows well and the simulation result is not appropriate for low flows. This is due to the use of river flow for dry season irrigation.

In this paper, the main features and performances of a new numerical scheme, ILILPM (Improved Locally and Instantaneously Linearized Parabolic Model) are described. ILILPM is an improved version of the Parabolic and Backwater (PAB) and Linearized Parabolic Model (LPM) schemes, proposed in literature for the approximate solution of the Parabolic Wave model. The algorithm presented is able to take into account transcritical flow regime and transitions from free-surface to pressurized flow in tree-like channel networks. Due to its unconditional stability, the model allows large computational time steps, leading to very fast simulations during transients for a class of flow conditions larger than those solved by the parent schemes. The model is demonstrated by comparing its results with experimental observations and with the results provided by the numerical solution of the full De Saint-Venant equations.

Among the most basic challenges of hydrology are the quantitative understanding of the processes of runoff generation and prediction of the flow hydrographs and their transmission to the outlet. Traditional techniques have been widely applied for the estimation of runoff hydrographs at the outlets of gauged watersheds using historical rainfall-runoff data and unit hydrographs derived from them. Such procedures are questioned for their reliability due to the climatic and physical changes in the watershed and their application to ungauged, arid and semiarid catchments. To overcome such difficulties, the use of physically based rainfall-runoff estimation methods such as the Geomorphologic Instantaneous Unit Hydrograph (GIUH) approach has evolved. In this study, the lately developed GIUH model is applied to Al-Badan watershed of Faria catchment located in the northeastern part of the West Bank, Palestine. The Faria catchment characterizes a semiarid region, with annual rainfall depths ranging on average from about 150 to 600 mm. The Geographical Information System (GIS) techniques are used to shape the geomorphological features of the catchment. The application of the GIS supported GIUH model has proved reasonable agreement between the simulated runoff hydrograph and the recorded flows. The paper has elaborated on the applicability of the unit hydrograph theory and the GIUH to semiarid regions.

Among the most basic challenges of hydrology are the quantitative understanding of the processes of runoff generation and prediction of the flow hydrographs and their transmission to the outlet. Traditional techniques have been widely applied for the estimation of runoff hydrographs at the outlets of gauged watersheds using historical rainfall-runoff data and unit hydrographs derived from them. Such procedures are questioned for their reliability due to the climatic and physical changes in the watershed and their application to ungauged, arid and semiarid catchments. To overcome such difficulties, the use of physically based rainfall-runoff estimation methods such as the Geomorphologic Instantaneous Unit Hydrograph (GIUH) approach has evolved. In this study, the lately developed GIUH model is applied to Al-Badan watershed of Faria catchment located in the northeastern part of the West Bank, Palestine. The Faria catchment characterizes a semiarid region, with annual rainfall depths ranging on average from about 150 to 600 mm. The Geographical Information System (GIS) techniques are used to shape the geomorphological features of the catchment. The application of the GIS supported GIUH model has proved reasonable agreement between the simulated runoff hydrograph and the recorded flows. The paper has elaborated on the applicability of the unit hydrograph theory and the GIUH to semiarid regions.

Introdução Materiais e Métodos Área em Estudo Escolha do Modelo Hidrológico Desenvolvimento do Modelo Computacional Resultados e Discussões Simulações Conclusões Referências Bibliográficas RESUMO-Diversos locais permanecem desprovidos ou com dados escassos de precipitação impossibilitando a obtenção de dados de vazão por meio do método convencional do hidrograma unitário. Deste modo, este trabalho teve por objetivo a obtenção de hidrogramas da Bacia do Ribeirão Salobra-MS, a partir de suas características geomorfológicas. Para tanto, foi desenvolvido um modelo matemático, baseado em conceitos probabilísticos do Hidrograma Unitário Instantâneo Geomorfológico (HUIG), que utilizou dados provenientes de mapas topográficos. As simulações foram desenvolvidas para duas velocidades de escoamento, calculadas a partir equações distintas de tempo de concentração. Verifica-se que a velocidade de escoamento é diretamente proporcional a vazão de pico e inversamente proporcional ao tempo de base. O modelo pode ser utilizado como estimativa inicial de dados de vazão para bacias hidrográficas não monitoradas por parâmetros hidrológicos. No entanto, é importante sua validação com dados hidrológicos coletados na bacia hidrográfica em estudo. Palavras-chave: geomorfologia, bacia hidrográfica, hidrograma unitário instantâneo geomorfológico.

The Linearized Parabolic Approximation of the Saint Venant Equations is often used for flood routing, but the corresponding analytic solutions usually neglect the downstream boundary conditions. This is an issue because the presence of hydraulic structures at the end of a river reach, or natural morphologic conditions, may influence the wave propagation. In order to take into account realistic boundary conditions, namely a stage-hydrograph upstream and a stage-discharge relationship downstream, a new set of exact solutions of the Linearized Parabolic Approximation of the Saint Venant Equations with uniformly distributed lateral inflows is presented. This exact solution is demonstrated by using it as a building block in a simplified flood routing model, whose numerical results are compared with those supplied by laboratory experiments from literature. Finally, the new solutions are used to analyze the range of validity of semi-infinite channel models. The comparison shows that semi-infinite channel models are accurate when convective effects are prevailing on diffusive effects, and the downstream boundary condition corresponds to uniform flow conditions. In addition, the results show that semi-infinite channel models based on the knowledge

A geomorphological instantaneous unit hydrograph (GIUH) model was developed for a watershed of Damodar valley corporation, Hazaribagh, using Nash (1959) and Itrube (1982) methods to compute peak discharge (qpeak) and time to peak (tpeak). The model was calibrated and validated for five storm events, i.e. June 24-25 (1992), October 12-13 (1993), November 2-3 (1993), June 28 (1994) and August 6 (1996) by comparing their ordinates with the ordinates of instantaneous unit hydrograph (IUH). The GIUH was tested with absolute prediction errors (APE) of the ordinate of peak discharge. On comparison, it was found that, most of the GIUH models overestimated the runoff at initial stage, while underestimated at the latter stage in comparison to the IUHs, which was mainly due to consideration of const ant value of Ф-index, for computation of effective rainfall. The absolute prediction errors (APE) were computed to be 5.97, 18.09, 23.32, 9.64 and 7.52% of the ordinates of peak discharge for the storm events

In recent years, geomorphological instantaneous unit hydrograph (GIUH) approach to estimate the runoff from a watershed due to different storm patterns has gained wide acceptability for watersheds with scanty data. In this study, a user-friendly event based computerized GIUH model, GIUH_CAL, was developed. GIUH_CAL model incorporates an infiltration component. Depending on the availability of soil and infiltration data, the model offers a choice among three methods of infiltration calculation, viz., Richards' equation, phi-index method and Philip two term model. The graphical user interface (GUI) of the model is based on mouse-driven approach with pop-up windows, pull-down menus, sub-menus, toolbar, statusbar and button controls including comprehensive context-sensitive help file. GIUH_CAL model displays generated instantaneous unit hydrograph (IUH), unit hydrograph (UH) and direct runoff hydrograph (DRH) of the watershed graphically and processes statistically. Modelling efficiency (ME), coefficient of residual mass (CRM), root mean square error (RMSE) and coefficient of determination (r 2) are used as the performance criteria. The model was tested for two distinctly different watersheds, i.e., a 4th order Guptamani watershed in tropical sub-humid region and a 3rd order Upper Chhokeranala watershed in semi-arid region of India. The results show that model performs satisfactorily for both test watersheds and performance is much better with Richards' equation option of infiltration calculation as compared to phi-index method and Philip two term model.Thus, GIUH_CAL model can be adopted as a standard tool for modelling rainfallerunoff transformation process in scantily gauged watersheds.

This paper introduces a new rainfall runoff model called ERM (Effective Rainfall routed by Muskingum method), which has been developed based on the popular IHACRES model. The IHACRES model consists of two main components to transfer rainfall to effective rainfall and then to streamflow. The second component of the IHACRES model is a linear unit hydrograph which has been replaced by the classic and well-known Muskingum method in the ERM model. With the effective rainfall by the first component of the IHACRES model, the Muskingum method is used to estimate the quick flow and slow flow separately. Two different sets of input data (temperature or evapotranspiration, rainfall and observed streamflow) and genetic algorithm (GA) as an optimization scheme have been selected to compare the performance of IHACRES and ERM models in calibration and validation. By testing the models in three different catchments, it is found that the ERM model has better performance over the IHACRES model across...

The Horton‐Strahler concept has been important in river basin geomorphology; it describes scaling properties and identifies GIUH but has also attracted criticisms, because it depends on the threshold area S, which is used to extract the channel network from digital elevation models (DEM), on the position of the outlet and on the few number of ratios used to identify the scaling laws. To overcome these limitations, this paper proposes new indices independently of S and which have similar properties than the Horton‐Strahler ratios. Applications were conducted on seven French basins. The methodology consists on analyzing the morphometric properties, such as the drained area, the number of sources, and the length of the channel network as a function of S. The results show that Horton‐Strahler ratios vary considerably with S. Particularly, while the Ω‐order length LΩ is a staircase function of S, results show that the channel network is articulated around two main nodes independent of S,...

Floods are among the most common natural disasters that if not controlled may cause severe damage and high costs. Flood control and management can be done using structural measures that should be designed based on the flood design studies. The simulation of outflow hydrograph using inflow hydrograph can provide useful information. In this study, a copula-based approach was applied to simulate the outflow hydrograph of various floods, including the Wilson River flood, the River Wye flood and the Karun River flood. In this regard, two-dimensional copula functions and their conditional density were used. The results of evaluating the dependence structure of the studied variables (inflow and outflow hydrographs) using Kendall's tau confirmed the applicability of copula functions for bivariate modeling of inflow and outflow hydrographs. The simulation results were evaluated using the root-mean-square error, the sum of squared errors and the Nash–Sutcliffe efficiency coefficient (NSE)...

The diffusion hydrodynamic model is applied for seven engineering applications that are commonly encountered in real-world applications. Of the seven applications, six relate to two-dimensional flows. The results are compared to other model results, where available. The results underscore the reliability of the DHM along with its limitation for modeling rapidly varying flows.

In any rainfall-runoff model, there is uncertainty associated to predictions of runoff. The stochastic integral equation method is used in this paper to represent the history of the rainfall-runoff modeling error as a convolution of model input (effective rainfall in this paper) with a frequency-distribution of transfer function realizations. In prediction, the expected runoff estimate is quantified by use of a distribution of runoff error estimates, each estimate of error based upona previous experience using the subject rainfall-runoff model. Although this paper focuses upon a simple unit-hydrograph rainfallrunoff model, the principles discussed apply, in generality, to other rainfall-runoff model structures.

His frequently referenced scientific contributions to the hydrologic, earth, and atmospheric sciences have been widely published in peer-reviewed scientific literature, including 30 books and more than 500 scientific papers, book chapters, and government reports. His professional engineering experience includes supervision and development of over 1500 engineering studies. He is currently a faculty member at the United States Military Academy at West Point, New York. Chung-Cheng Yen received his Ph.D. degree from the University of California, Irvine, in 1985. He has more than 35 years of experience in the field of water resource engineering, specializing in hydrology, hydraulics, dam breach, and groundwater modeling. His work experience includes rainfall analysis, flood frequency analysis, rainfall-runoff modeling, detention basin flood routing analysis, drainage master plan, FEMA floodplain evaluations and mapping, dam breach analysis and flood inundation mapping, and the USACE risk and uncertainty analysis. Dr. Yen has conducted floodplain analyses using 2-D hydrodynamic models (such as DHM, FLO-2D, HEC-RAS 1D/2D, and XPSWMM), prepared hydrologic and hydraulic studies for government and private entities, and drainage master plans for various cities in southern California.

de 1mm y duración de 1 hr resultando un caudal pico de 6.77 m /s/mm y un tiempo base de 4 hr; la rama ascendente presenta una pendiente promedio menor que la rama descendente, atribuyendo esta geometría a las características morfológicas y geológicas de la microcuenca; es decir, el volumen de escorrentía superficial bajo el hidrograma unitario a la izquierda del caudal pico es mayor al de la derecha.

Sustainable water management is crucial in the reduction of water pollution and floods. New techniques should be investigated in order to avoid present and future problems such as flood, drought, and water contamination. For this purpose, Low Impact Development-Best Management Practice (LID-BMP) has recently come into the stage in storm water management. Vegetative swales, green roofs, bioretentions, storm water wetlands, rain barrels, permeable asphalts and pavements are among LID-BMPs. Bioretention type of LID is implemented to diminish adverse effects of urbanization such as flood by reducing peak flows on surface and thus managing storm water runoff. The aim of this study is to investigate the hydrological performance of bioretentions by developing a hydrological model based on the data obtained using experimental setup called Rainfall-Watershed-Bioretention (RWB). The hydrological model of RWB (HM-RWB) consists of two main components: (i) rainfall-runoff model in which kinematic wave theory is used for simulation of surface runoff generated over the drainage area that reaches the bioretention as inflow; (ii) runoff-bioretention flow model in which Green-Ampt method under unsteady rainfall is employed and further improved by incorporating the effect of ponding depth on bioretention for the simulation of outflow at the exit of the bioretention. It is observed that the results of the hydrological model developed herein are in good agreement with the measured data obtained in the RWB experimental setup.

This paper presents a theoretical derivation of a dimensionless unit hydrograph using the kinematic wave approach. The dimensionless kinematic wave unit hydrograph ͑KWUH͒ is normalized by the parameters associated with the equilibrium condition and can be generated according to the selected rainfall duration. For comparison, a KWUH whose rainfall duration is equal to the time of equilibrium produces good agreement with the Soil Conservation Service dimensionless unit graph ͑SCSUH͒. Both the KWUH and SCSUH are kinematic in nature and have a 37.5% runoff volume that occurred before the time to peak. To verify the applicability of the KWUH derived in this study, a set of hypothetical rectangular watersheds ranging from 20 to 200 acres was investigated. The predicted 100-year peak flow rates from these five hypothetical rectangular watersheds are compared with the SCSUH method and the Colorado Unit Hydrograph Procedures ͑CUHP͒. In general, the KWUH produces good agreement with the CUHP when the catchment has an area between 60 and 120 acres. Based on the study of hypothetical rectangular watersheds, it is recommended that the KWUH be applicable to urban catchments with a drainage area of up to 120 acres.

Floods are among the most common natural disasters that if not controlled may cause severe damage and high costs. Flood control and management can be done using structural measures that should be designed based on the flood design studies. The simulation of outflow hydrograph using inflow hydrograph can provide useful information. In this study, a copula-based approach was applied to simulate the outflow hydrograph of various floods, including the Wilson River flood, the River Wye flood and the Karun River flood. In this regard, twodimensional copula functions and their conditional density were used. The results of evaluating the dependence structure of the studied variables (inflow and outflow hydrographs) using Kendall's tau confirmed the applicability of copula functions for bivariate modeling of inflow and outflow hydrographs. The simulation results were evaluated using the root-mean-square error, the sum of squared errors and the Nash-Sutcliffe efficiency coefficient (NSE). The results showed that the copula-based approach has high performance. In general, the copula-based approach has been able to simulate the peak flow and the rising and falling limbs of the outflow hydrographs well. Also, all simulated data are at the 95% confidence interval. The NSE values for the copula-based approach are 0.99 for all three case studies. According to NSE values and violin plots, it can be seen that the performance of the copula-based approach in simulating the outflow hydrograph in all three case studies is acceptable and shows a good performance.

When hydraulic design decisions are made in a watershed, engineers rely on estimation of the design discharge. Historically, they have applied empirical methods to do this, but empirical methods can only describe the hydrologic characteristics of the watersheds from which they were derived. Although more advanced methods now exist, engineers find them challenging to use because of the abundant data needed and intensive data analyses. In this study, we make the more advanced hydrological analysis methods simpler to use by linking them with DEM terrain analyses in a GIS platform. The system provides hydrologic and geomorphic information needed to create a design discharge at any location in a watershed. Since the system allows users to test several locations of subwatershed outlets, it is convenient for them to examine different aspects for engineering alternatives.

If the random model, in which all topologically distinct channel networks are equally likely, is assumed valid, then general explanations of network structure from basin geomorphic processes cannot be expected. Tests for the random model are therefore critical to the direction of future work. Proposed tests are based on frequencies of basins of different magnitudes or diameters, and on network maximum widths. Network topology is also shown to be potentially significant in the prediction of basin hydrographs. Network width commonly varies by a factor of 2 x for a given drainage area and drainage density, and is shown to influence peak discharge in proportion. Lag-to-peak can also be predicted better, using network topology. The paper pursues these applications of network topology using random walk theory and simulated random networks.

The determination of characteristic flow velocity is a hydrodynamic problem needs to be solved in the application of geomorphologic instantaneous unit hydrograph (GIUH) for runoff simulation in areas with no or limited data. In this study, 120 watersheds are collected to construct a regression model; 85 of these basins are used for regression analysis, and the 35 remaining basins are utilized to verify the feasibility of the constructed model. Random forest algorithm is applied to screen out important geomorphologic factors from the 16 extracted factors that may affect flow velocity. Multivariate regression is used to establish the numerical relationship between velocity and the selected factors. Sensitivity analysis of each adopted factor in the constructed model is conducted using the LH-OAT method. The rationality and feasibility of the regression model are validated by comparing the flow velocity calculation with a previous approach, which is also calculated based on geomorphological parameters. Subsequently, the runoff simulation based on the GIUH model is evaluated using the proposed technique. Results demonstrate that the proposed formula possesses high fitting accuracy and can be easily used to calculate flow velocity and generate GIUH.

Direct soil water retention curve (SWRC) measurement is laborious, timeconsuming, and expensive. To estimate its parameters, mathematical models and optimization approaches are applied. In this study, an improved alternative method to solve the optimization problem was introduced and developed. To evaluate the efficiency of this method, 12 soil samples with 6 different textures from 9 different regions of the world were used. The optimization equations were solved using a genetic algorithm (GA) and standard mathematical models, and the best model was chosen based on Taylor diagrams, R 2 , and computing time. The Bimodal versions of Fredlund-Xing (FX-b) and Brooks-Corney (BC) mathematical models represented the best and poorest findings of this stage, with R 2 values of 0.913 and 0.825, respectively. Then, the optimization problem is solved with differential evolution (DE), Salp Swarm Algorithm (SSA), Jaya, and improved Jaya (I-Jaya) method, and the mean values of R 2 were obtained 0.919, 0.931, 0.921, and 0.958, respectively. The results indicated a 16% improvement in the average R 2 , by selecting the suitable mathematical model and also using the I-Jaya.

Streamflow prediction of rivers is crucial for making decisions in watershed and inland waterways management. The US Army Corps of Engineers (USACE) uses a river routing model called RAPID to predict water discharges for thousands of rivers in the network for watershed and inland waterways management. However, the calibration of hydrological streamflow parameters in RAPID is time-consuming and requires streamflow measurement data which may not be available for some ungauged locations. In this study, we aim to address the calibration aspect of the RAPID model by exploring machine learning (ML)-based methods to facilitate efficient calibration of hydrological model parameters without the need for streamflow measurements. Various ML models are constructed and compared to learn a relationship between hydrological model parameters and various river parameters, such as length, slope, catchment size, percentage of vegetation, and elevation contours. The studied ML models include Gaussian p...

Erosion prediction tools are essential for many different aspects of land management. In this paper we examine the applicability of scaling relationships developed for river networks for the description of hillslope erosion channel networks. Eight erosion channel networks were studied on mine spoil sites in Kemmerer, Wyoming. We analysed these networks using well-known geomorphological relationships such as Horton's laws and Melton's law. An analysis of the erosion channel hydraulic geometry described by a series of power functions was also conducted. We found that the network geometry resembles larger river networks, and that the cross-sectional shapes of individual erosion channels exhibit statistical characteristics of their larger river counterparts.

Erg of Gavkhooni Playa is one of the important geomorphologic landforms of Quaternary period in Iran. The area is located on the western part of Gaovkhoni Playa and 140 km to the Southeast of Isfahan, Iran. This study presents a display of landform of Erg and the area has been divided into three parts (North-Central and South). The objective of this study is to identify geomorphologic facieses by GIS t and RS. The research method is a processing technique such as basis analyzing, a composite of panchromatic band with multi-spectral band, to examine line spectral curved, to examine optimum composites using an enhancement method such as filtering and contrast. As a result, to display sand landforms and geomorphologic facieses such as Barkhan, Safe, Star hill, playa's facieses, Skirt and Delta, Sand Zone and the sediment between the hills and geomorphologic landform map are based on Erg of Gavkhoni Playa and geomorphologic facieses of the area.

An initial step in flood hazard mapping is hydrological modelling. We present a recent river flood modelling approach in Bosnia and Herzegovina (BiH) for small ungauged catchments of drainage area up to 32 km2. To estimate peak flow of required probability in small catchments, we use the rational method. The paper focus is GIS based procedure for producing the runoff coefficient map for BiH from the DTM and land cover map. For validation of the peak flow modelling results in small ungauged catchments we use diagrams of peak flow per catchment area (specific runoff) versus catchment area in medium and large gauged catchments. The results indicate agreement in specific runoff for 100 and 500 years return period compared to reference runoff in gauged catchments and a mild drop in specific runoff for 20 years.

Hydrology, which deals with the study of water, is one of the fundamental courses to the undergraduate program of many disciplines: civil engineering, agricultural engineering, earth sciences, environmental sciences, geography, etc.  This course covers various events of the hydrological cycle, namely, rainfall, runoff, hydrograph, infiltration, evapotranspiration, and flood routing. These events involve a large number of techniques and methods for the analysis, which are time-consuming.  To enhance the learning, this study presents a tool called ‘Hydrologic Calculator’, an educational interface with eight modules for analyzing the various hydrological related events. In addition, ‘Help’ module in ‘Hydrologic Calculator’ provides a thorough understanding of the theory and methodology adopted for solving the different hydrological problems. Hydrologic Calculator includes a graphical user interface, which helps in input data preparation and output display in both graphical and tabular ...

Flood is the most devastating and frequent disaster in NorthEast India, resulting in loss of human life and damage of properties. Its deleterious effects can be minimized by appropriate modeling, analysis, and management methods. Such modeling and analyzing techniques are hindered in flood prediction in an ungauged basin due to the lack of hydro-meteorological data. The main objective of this work is to develop a numerical approach for flood routing in an ungauged basin using the rainfall-runoff model and the diffusive wave flood routing model (DWFRM). GIS approach is used to extract the geographical information of the study area. The SCS-CN rainfall-runoff model is employed to obtain the inflow, and lateral inflow hydrographs of the ungauged sub-basins and DWFRM is employed to anticipate the flood hydrograph at the outlet of the ungauged basin. A new form of diffusive wave momentum equation of the Saint-Venant equation is derived for cross-section having a parabolic and rectangular channel. The modeling approach is employed to the Kulsi River Basin, India hypothetically considered ungauged basin, and the results obtained are compared with the observed data at the outlet of the basin. The performance of the model is validated by considering four parameters RMSE, peak flow error, peak time error, and total volume error. The results reveal that the proposed model diffusive wave flood routing model (DWFRM) is efficient to predict the flood hydrograph at the outlet of an ungauged basin.

Andrijana Todorović 3 UDK: 556.532:551.501 DOI: 10.14415/konferencijaGFS2019.007 Summary: Design flood flows in small ungauged basins are traditionally estimated by calculating flood hydrographs resulting from design storms. This paper considers traditional application of the synthetic unit hydrograph and the SCS method and the choice of the design storm duration for a case study of the Obnica River basin. By comparing the design floods obtained from design storms and the observed flood flows, recommendations for the engineering practice are given.

Design flood flows in small ungauged basins are traditionally estimated by calculating flood hydrographs resulting from design storms. This paper considers traditional application of the synthetic unit hydrograph and the SCS method and the choice of the design storm duration for a case study of the Obnica River basin. By comparing the design floods obtained from design storms and the observed flood flows, recommendations for the engineering practice are given.

This paper develops a new framework to analyze the relevance of hillslope with respect to channel processes in the generation of the hydrologic response at different scales. The dependence between basin response and geomorphic features of channels and hillslopes is analyzed through the mean and variance of travel times under simple but realistic dynamical hypotheses and within the framework of the rescaled width function. The distribution of travel times is also studied in association with variations of the fraction of saturated areas: with small values of the saturated fraction, the channel network controls most of the mean and variance of travel time distribution. Vice versa, when the basin is saturated, the properties of this distribution may be significantly affected by hillslope processes. These properties depend also on the basin size, with the role of hillslope processes becoming more important in the smaller basins. Furthermore, the average residence time is related to contributing area and drainage density through a simple expression which is shown to be consistent with previous empirical laws.

The hydrologic response of a channel network is defined by decomposing the process of runoff formation into two distinct contributions, one accounting for the mechanisms of travel time within individual reaches (hydrodynamic dispersion), and the other accounting for the morphology of the network structure (geomorphological dispersion). Exact Laplace transforms of first passage time distributions at the outlet of a network are obtained by a consistent approximation of travel time distributions through individual reaches. The moments of such distributions are obtained analytically in the general case. Closed-form first-passage distributions are obtained in the particular case of basin-constant hydrodynamic dispersion. The variance of the resulting travel time distributions is shown in this paper to be made up of two additive contributions corresponding to the two dispersion mechanisms considered. The geomorpho}ogic dispersion coefficient is shown to depend on the ratios of bifurcation, length and area of the network suggesting that, at the scale of an organized network, heterogeneities other than those related to the convection field shape the dispersive character of transport. In particular, a significant application of the general solution to Hortonian channel networks suggests that models based on accurate specification of the geometry and the topology of the network and a simplified dynamics capture the foremost features of the travel time distributions in a broad range of dispersivities within individual reaches. different travel times which have a diffusive effect on firstpassage distributions defining the runoff response. An analytic definition for this effect is sought in this paper. The relative role and the mutual interactions of the mechanisms contributing to runoff formation are studied in relation to the synthesis of the geometry of drainage networks implied by Hortonian rules (scaling through length, bifurcation and contributing area ratios) and by the analysis of fractal channel networks [e.g.

Journal of Environmental Hydrology Volume 18 Paper 7 April 2010 1 The Horton-Strahler scheme for stream network classification was introduced into hydrological practice in the middle of the last century. It found a significant application in the process of defining the Geomorphologic Instantaneous Unit Hydrograph (GIUH) as the method aiming to relate geomorphological characteristics of a basin to basin response in the form of unit hydrograph, or direct runoff hydrograph. The paper analyzes the problems related to its implementation in the GIUH method, i.e. to determination of initial and transition probabilities, which, in turn, are used to define the probability distribution function for water flow paths in the basin. Many authors have agreed that this classification is rather rough and in some cases leads to certain irregularities, i.e. inaccuracies. The particular problem is that negative values may also result when calculating initial and transition probabilities at higher strea...

Technology Adaptation Program, which includes personnel at both MIT and Cairo University. Their administrative support over the entire period of this study has been more helpful. The very helpful suggestions given by Diana Kirshen are gratefully acknowledged. This work also profitted from discussions with Professor Peter Eagleson of MIT and the faculty of Cairo University. A thankful word goes to Ms. Antoinette DiRenzo for patiently typing this work.

Unit Hydrograph (UH) is the most popular and widely used method for predicting flood hydrograph resulting from a known storm in a basin area. However, the non-availability of UH due to poor network of raingauge stations in flood prone Indian river basins is a major concern. The computation of Horton's ratios and their application in generating the Geomorphological Instantaneous Unit

The variability of climate, increase in population, and lack of territorial plans in Costa Rica have caused intense disasters with human and economic losses. In 2016, Hurricane Otto hit the country’s northern area, leaving substantial damages, including landslides, debris flows, and flooding. The present study evaluated different scenarios to estimate flooded areas for Newtonian (clean water), and non-Newtonian flows with volumetric sediment concentrations (Cv) of 0.3, 0.45, 0.55, and 0.65 using Hydro-Estimator (HE), rain gauge station, and the 100-year return period event. HEC–HMS modeled the rainfall products, and FLO-2D modeled the hydrographs and Cv combinations. The simulation results were evaluated with continuous statistics, contingency table, Nash Sutcliffe Efficiency, measure of fit (F), and mean absolute differences (E) in the floodplains. Flow depths, velocities, and hazard intensities were obtained in the floodplain. The debris flood was validated with field data and cla...

Stream flow measurement in Rivers have significant effect on various applications in the field of water resources. Yet, in many parts of the world, Rivers are either poorly gauged or completely ungauged and in some cases the existing system is continuously declining. Stream flow prediction at such "ungauged" drainage basins require information transfer from donor catchments (gauged) to receiver catchments (ungauged) that are apparent to be hydrologically homogeneous to them. Geomorphologic instantaneous unit hydrograph (GIUH) approach can be used as a transfer function for modelling the rainfall-runoff process. The present study provides an effective approach which deals with the geomorphologic features of the ungauged drainage basin and derives the GIUH based transfer function and consequently geomorphologic unit hydrograph (GUH) for the study area. Koel River basin of India has been chosen as the study area. Before applying the approach on the Koel River basin it is applied on another basin where unit hydrograph data was available. To validate the derived GUH of the Koel River basin, a comparison was executed with the synthetic unit hydrograph (SUH) attained using the Central Water Commission (CWC) procedure. The closest GUH to the SUH was determined based on the comparison.