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Lisa Shevenell - One of the best experts on this subject based on the ideXlab platform.
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transmissivity estimates from well hydrographs in karst and fractured aquifers
Ground Water, 2000Co-Authors: Jefferey G Powers, Lisa ShevenellAbstract:Hydrograph recessions from rainfall events have been previously analyzed for discharge at springs and streams; however, relatively little quantitative research has been conducted with regard to hydrograph analysis of recessions from monitoring wells screened in karst aquifers. In previous work, a quantitative hydrograph analysis technique has been proposed from which matrix transmissivity (i.e., transmissivity of intergranular porosity) and specific yields of matrix, fracture, and conduit components of the aquifer may be determined from well hydrographs. The technique has yielded realistic results at three sites tested by the authors (Y-12, Oak Ridge, Tennessee; Crane, Indiana; and Fort Campbell, Kentucky). Observed field data, as well as theoretical considerations, show that karst well hydrographs are valid indicators of hydraulic properties of the associated karst aquifers. Results show matrix transmissivity (T) values to be in good agreement with values calculated using more traditional parameter estimation techniques, such as aquifer pumping tests and slug tests in matrix dominated wells. While the hydrograph analysis technique shows promise for obtaining reliable estimates of karst aquifer T with a simple, relatively inexpensive and passive method, the utility of the technique is limited in its application depending on site-specific hydrologic conditions, which include shallow, submerged conduit systems located in areas with sufficient rainfall for water levels to respond to precipitation events.
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analysis of well hydrographs in a karst aquifer estimates of specific yields and continuum transmissivities
Journal of Hydrology, 1996Co-Authors: Lisa ShevenellAbstract:Hydrograph analysis techniques have been well developed for hydrographs obtained from streams and springs, where data are cast in terms of total discharge. The data obtained from well hydrographs provide water level versus time; hence, a method of hydrograph analysis is required for situations in which only water level data are available. It is assumed here that three segments on a recession curve from wells in a karst aquifer represent drainage from three types of storage: conduit (C), fracture (F) and matrix (M). Hydrographs from several wells in a karst aquifer are used to estimate the specific yields (Sy) associated with each portion of the aquifer (C, F, M), as well as continuum transmissivities (T). Data from three short injection tests at one well indicate continuum T at this well bore is approximately 5 m2 day−1, and tests at numerous other wells in the aquifer yield results between 1 and 7 m2 day−1. The T estimated with well hydrographs from two storms indicates a T of 9.8 m2 day−1. Well-developed conduit systems in which water levels in wells show a flashy response typically show Sys of 1 × 10−4, 1 × 10−3, and 3 × 10−3 for C, F, and M, respectively. Less well-developed conduit areas show more nearly equal Sys (8.6 × 10−4, 1.3 × 10−3, 3 × 10−3). Areas with no evidence for the presence of conduits have only one, or in some cases two, slopes on the recession curve. In these cases, water-level responses are slow. Recession curves with a single slope represent drainage from only the lower T matrix. Those with two slopes have an additional, more rapid response segment on the recession curve which represents drainage from the higher T, lower Sy, fractures in the system.
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analysis of well hydrographs in a karst aquifer estimates of specific yields and continuum transmissivities
Other Information: PBD: Nov 1994, 1994Co-Authors: Lisa ShevenellAbstract:Hydrograph analysis techniques have been well developed for hydrographs obtained from streams and springs, where data are cast in terms of total discharge. The data obtained from well hydrographs provide water level versus time; hence, a method of hydrograph analysis is required for situations in which only water level data are available. It is hypothesized here that three segments on a recession curve from wells in a karst aquifer represent drainage from three types of storage: conduit (C), fracture (F), and matrix (M). Hydrographs from several wells in a karst aquifer at the U.S. Department of Energy Oak Ridge Y-12 Plant are used to estimate the specific yields (S{sub y}) associated with each portion of the aquifer (C, F, M), as well as continuum transmissivities (T). Data from three short injection tests at one well indicate continuum T at this well bore is {approximately} 5m{sup 2}/d, and tests at numerous other wells in the aquifer yield results between 1 and 7 M{sup 2}/d. The T estimated with well hydrographs from two storm events indicates a T of 9.8 m{sup 2}2/d. Well developed conduit systems in which water levels in wells show a flashy response typically show S{sub y} values of 1{times}10{sup -4}, 1{times}10{sup -3}, and 3{times}10{sup -3}, for C, F, and M. Less well developed conduit areas show more nearly equal S{sub y} values (8.6{times}10{sup -4}, 1.3{times}10{sup -3}, 3{times}10{sup -3}). Areas with no evidence for the presence of conduits have only one, or in some cases two, slopes on the recession curve. In these cases, water level responses are slow. Recession curves with a single slope represent drainage from only the lower T matrix. Those with two slopes have an additional, more rapid response, segment on the recession curve, which represents drainage from the higher T, lower S{sub y}, fractures in the system.
Salvatore Grimaldi - One of the best experts on this subject based on the ideXlab platform.
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design hydrograph estimation in small and ungauged watersheds continuous simulation method versus event based approach
Hydrological Processes, 2012Co-Authors: Andrea Petroselli, Salvatore Grimaldi, Francesco SerinaldiAbstract:The proper assessment of design hydrographs and their main properties (peak, volume and duration) in small and ungauged basins is a key point of many hydrological applications. In general, two types of methods can be used to evaluate the design hydrograph: one approach is based on the statistics of storm events, while the other relies on continuously simulating rainfall-runoff time series. In the first class of methods, the design hydrograph is obtained by applying a rainfall-runoff model to a design hyetograph that synthesises the storm event. In the second approach, the design hydrograph is quantified by analysing long synthetic runoff time series that are obtained by transforming synthetic rainfall sequences through a rainfall-runoff model. These simulation-based procedures overcome some of the unrealistic hypotheses which characterize the event-based approaches. In this paper, a simulation experiment is carried out to examine the differences between the two types of methods in terms of the design hydrograph's peak, volume and duration. The results conclude that the continuous simulation methods are preferable because the event-based approaches tend to underestimate the hydrograph's volume and duration. Copyright © 2011 John Wiley & Sons, Ltd.
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a parsimonious geomorphological unit hydrograph for rainfall runoff modelling in small ungauged basins
Hydrological Sciences Journal-journal Des Sciences Hydrologiques, 2012Co-Authors: Salvatore Grimaldi, Andrea Petroselli, Fernando NardiAbstract:Abstract In this study, a parsimonious hydrological modelling algorithm is proposed based on the automated DEM-based geomorphic characterization of runoff dynamics in scarcely monitored river basins. The proposed approach implements the instantaneous unit hydrograph (IUH) concept, estimated using the width function (WF), for characterizing the travel time distribution using just one parameter, the river network flow velocity. Hillslope velocities are defined using spatially-distributed empirical formulas based on slope and soil-use information extrapolated from digital topographic data. Case studies are presented for testing model performance and comparing simulated and observed hydrographs of 25 selected flood events, as well as investigating the differences with the geomorphological instantaneous unit hydrograph (GIUH) model results. The calibration of the WFIUH channel flow velocity parameter using the concentration time is investigated providing interesting insights for the use of such a method for hy...
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a parsimonious geomorphological unit hydrograph for rainfall runoff modelling in small ungauged basins
Hydrological Sciences Journal-journal Des Sciences Hydrologiques, 2012Co-Authors: Salvatore Grimaldi, Andrea Petroselli, Fernando NardiAbstract:Abstract In this study, a parsimonious hydrological modelling algorithm is proposed based on the automated DEM-based geomorphic characterization of runoff dynamics in scarcely monitored river basins. The proposed approach implements the instantaneous unit hydrograph (IUH) concept, estimated using the width function (WF), for characterizing the travel time distribution using just one parameter, the river network flow velocity. Hillslope velocities are defined using spatially-distributed empirical formulas based on slope and soil-use information extrapolated from digital topographic data. Case studies are presented for testing model performance and comparing simulated and observed hydrographs of 25 selected flood events, as well as investigating the differences with the geomorphological instantaneous unit hydrograph (GIUH) model results. The calibration of the WFIUH channel flow velocity parameter using the concentration time is investigated providing interesting insights for the use of such a method for hy...
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synthetic design hydrographs based on distribution functions with finite support
Journal of Hydrologic Engineering, 2011Co-Authors: Francesco Serinaldi, Salvatore GrimaldiAbstract:The primary characteristics that influence the potential of defining a synthetic design hydrograph (SDH), are the hydrograph shape, peak discharge (Qp), volume (V), and duration (D). This paper studies the advantages and shortcomings of using simple distribution functions with finite support (namely, beta and generalized standard two-sided power distributions) to represent and synthesize direct runoff hydrographs. The relationships among Qp, V, D, and distribution parameters are explored on a few flood events selected by a recursive digital filter algorithm and an overthreshold approach. The results obtained indicate that the adopted procedure provides a good compromise between simplicity and accuracy for building SDHs with two assigned flood characteristics (e.g., Qp and V) and a defined shape.
Manuela I. Brunner - One of the best experts on this subject based on the ideXlab platform.
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identification of flood reactivity regions via the functional clustering of hydrographs
Water Resources Research, 2018Co-Authors: Manuela I. Brunner, Jan Seibert, Daniel Viviroli, Reinhard Furrer, Annecatherine FavreAbstract:Flood hydrograph shapes contain valuable information on the flood-generation mechanisms of a catchment. To make good use of this information, we express flood hydrograph shapes as continuous functions using a functional data approach. We propose a clustering approach based on functional data for flood hydrograph shapes to identify a set of representative hydrograph shapes on a catchment scale and use these catchment-specific sets of representative hydrographs to establish regions of catchments with similar flood reactivity on a regional scale. We applied this approach to flood samples of 163 medium-size Swiss catchments. The results indicate that three representative hydrograph shapes sufficiently describe the hydrograph shape variability within a catchment and therefore can be used as a proxy for the flood behavior of a catchment. These catchment-specific sets of three hydrographs were used to group the catchments into three reactivity regions of similar flood behavior. These regions were not only characterized by similar hydrograph shapes and reactivity but also by event magnitudes and triggering event conditions. We envision these regions to be useful in regionalization studies, regional flood frequency analyses, and to allow for the construction of synthetic design hydrographs in ungauged catchments. The clustering approach based on functional data which establishes these regions is very flexible and has the potential to be extended to other geographical regions or towards the use in climate impact studies.
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synthetic design hydrographs for ungauged catchments a comparison of regionalization methods
Stochastic Environmental Research and Risk Assessment, 2018Co-Authors: Manuela I. Brunner, Anna E. Sikorska, Jan Seibert, Daniel Viviroli, Reinhard Furrer, Annecatherine FavreAbstract:Design flood estimates for a given return period are required in both gauged and ungauged catchments for hydraulic design and risk assessments. Contrary to classical design estimates, synthetic design hydrographs provide not only information on the peak magnitude of events but also on the corresponding hydrograph volumes together with the hydrograph shapes. In this study, we tested different regionalization approaches to transfer parameters of synthetic design hydrographs from gauged to ungauged catchments. These approaches include classical regionalization methods such as linear regression techniques, spatial methods, and methods based on the formation of homogeneous regions. In addition to these classical approaches, we tested nonlinear regression models not commonly used in hydrological regionalization studies, such as random forest, bagging, and boosting. We found that parameters related to the magnitude of the design event can be regionalized well using both linear and nonlinear regression techniques using catchment area, length of the main channel, maximum precipitation intensity, and relief energy as explanatory variables. The hydrograph shape, however, was found to be more difficult to regionalize due to its high variability within a catchment. Such variability might be better represented by looking at flood-type specific synthetic design hydrographs.
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representative sets of design hydrographs for ungauged catchments a regional approach using probabilistic region memberships
Advances in Water Resources, 2018Co-Authors: Manuela I. Brunner, Jan Seibert, Annecatherine FavreAbstract:Abstract Traditional design flood estimation approaches have focused on peak discharges and have often neglected other hydrograph characteristics such as hydrograph volume and shape. Synthetic design hydrograph estimation procedures overcome this deficiency by jointly considering peak discharge, hydrograph volume, and shape. Such procedures have recently been extended to allow for the consideration of process variability within a catchment by a flood-type specific construction of design hydrographs. However, they depend on observed runoff time series and are not directly applicable in ungauged catchments where such series are not available. To obtain reliable flood estimates, there is a need for an approach that allows for the consideration of process variability in the construction of synthetic design hydrographs in ungauged catchments. In this study, we therefore propose an approach that combines a bivariate index flood approach with event-type specific synthetic design hydrograph construction. First, regions of similar flood reactivity are delineated and a classification rule that enables the assignment of ungauged catchments to one of these reactivity regions is established. Second, event-type specific synthetic design hydrographs are constructed using the pooled data divided by event type from the corresponding reactivity region in a bivariate index flood procedure. The approach was tested and validated on a dataset of 163 Swiss catchments. The results indicated that 1) random forest is a suitable classification model for the assignment of an ungauged catchment to one of the reactivity regions, 2) the combination of a bivariate index flood approach and event-type specific synthetic design hydrograph construction enables the consideration of event types in ungauged catchments, and 3) the use of probabilistic class memberships in regional synthetic design hydrograph construction helps to alleviate the problem of misclassification. Event-type specific synthetic design hydrograph sets enable the inclusion of process variability into design flood estimation and can be used as a compromise between single best estimate synthetic design hydrographs and continuous simulation studies.
Sanjay Kumar - One of the best experts on this subject based on the ideXlab platform.
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runoff estimation for an ungauged catchment using geomorphological instantaneous unit hydrograph giuh models
Hydrological Processes, 2007Co-Authors: Rakesh Kumar, Chandranath Chatterjee, R Singh, A K Lohani, Sanjay KumarAbstract:A 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.
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runoff estimation for an ungauged catchment using geomorphological instantaneous unit hydrograph giuh models
Hydrological Processes, 2007Co-Authors: Rakesh Kumar, Chandranath Chatterjee, R Singh, A K Lohani, Sanjay KumarAbstract:A 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.
Annecatherine Favre - One of the best experts on this subject based on the ideXlab platform.
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identification of flood reactivity regions via the functional clustering of hydrographs
Water Resources Research, 2018Co-Authors: Manuela I. Brunner, Jan Seibert, Daniel Viviroli, Reinhard Furrer, Annecatherine FavreAbstract:Flood hydrograph shapes contain valuable information on the flood-generation mechanisms of a catchment. To make good use of this information, we express flood hydrograph shapes as continuous functions using a functional data approach. We propose a clustering approach based on functional data for flood hydrograph shapes to identify a set of representative hydrograph shapes on a catchment scale and use these catchment-specific sets of representative hydrographs to establish regions of catchments with similar flood reactivity on a regional scale. We applied this approach to flood samples of 163 medium-size Swiss catchments. The results indicate that three representative hydrograph shapes sufficiently describe the hydrograph shape variability within a catchment and therefore can be used as a proxy for the flood behavior of a catchment. These catchment-specific sets of three hydrographs were used to group the catchments into three reactivity regions of similar flood behavior. These regions were not only characterized by similar hydrograph shapes and reactivity but also by event magnitudes and triggering event conditions. We envision these regions to be useful in regionalization studies, regional flood frequency analyses, and to allow for the construction of synthetic design hydrographs in ungauged catchments. The clustering approach based on functional data which establishes these regions is very flexible and has the potential to be extended to other geographical regions or towards the use in climate impact studies.
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synthetic design hydrographs for ungauged catchments a comparison of regionalization methods
Stochastic Environmental Research and Risk Assessment, 2018Co-Authors: Manuela I. Brunner, Anna E. Sikorska, Jan Seibert, Daniel Viviroli, Reinhard Furrer, Annecatherine FavreAbstract:Design flood estimates for a given return period are required in both gauged and ungauged catchments for hydraulic design and risk assessments. Contrary to classical design estimates, synthetic design hydrographs provide not only information on the peak magnitude of events but also on the corresponding hydrograph volumes together with the hydrograph shapes. In this study, we tested different regionalization approaches to transfer parameters of synthetic design hydrographs from gauged to ungauged catchments. These approaches include classical regionalization methods such as linear regression techniques, spatial methods, and methods based on the formation of homogeneous regions. In addition to these classical approaches, we tested nonlinear regression models not commonly used in hydrological regionalization studies, such as random forest, bagging, and boosting. We found that parameters related to the magnitude of the design event can be regionalized well using both linear and nonlinear regression techniques using catchment area, length of the main channel, maximum precipitation intensity, and relief energy as explanatory variables. The hydrograph shape, however, was found to be more difficult to regionalize due to its high variability within a catchment. Such variability might be better represented by looking at flood-type specific synthetic design hydrographs.
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representative sets of design hydrographs for ungauged catchments a regional approach using probabilistic region memberships
Advances in Water Resources, 2018Co-Authors: Manuela I. Brunner, Jan Seibert, Annecatherine FavreAbstract:Abstract Traditional design flood estimation approaches have focused on peak discharges and have often neglected other hydrograph characteristics such as hydrograph volume and shape. Synthetic design hydrograph estimation procedures overcome this deficiency by jointly considering peak discharge, hydrograph volume, and shape. Such procedures have recently been extended to allow for the consideration of process variability within a catchment by a flood-type specific construction of design hydrographs. However, they depend on observed runoff time series and are not directly applicable in ungauged catchments where such series are not available. To obtain reliable flood estimates, there is a need for an approach that allows for the consideration of process variability in the construction of synthetic design hydrographs in ungauged catchments. In this study, we therefore propose an approach that combines a bivariate index flood approach with event-type specific synthetic design hydrograph construction. First, regions of similar flood reactivity are delineated and a classification rule that enables the assignment of ungauged catchments to one of these reactivity regions is established. Second, event-type specific synthetic design hydrographs are constructed using the pooled data divided by event type from the corresponding reactivity region in a bivariate index flood procedure. The approach was tested and validated on a dataset of 163 Swiss catchments. The results indicated that 1) random forest is a suitable classification model for the assignment of an ungauged catchment to one of the reactivity regions, 2) the combination of a bivariate index flood approach and event-type specific synthetic design hydrograph construction enables the consideration of event types in ungauged catchments, and 3) the use of probabilistic class memberships in regional synthetic design hydrograph construction helps to alleviate the problem of misclassification. Event-type specific synthetic design hydrograph sets enable the inclusion of process variability into design flood estimation and can be used as a compromise between single best estimate synthetic design hydrographs and continuous simulation studies.
