The cause of negative or reduced outflow formation at the beginning of a Muskingum solution is ex... more The cause of negative or reduced outflow formation at the beginning of a Muskingum solution is examined in two steps. The first step involves a physical interpretation of the Muskingum weighted discharge and the storage equation, using theory based on an extension of the Kalinin-Milyukov method. The second step involves the derivation of an analytical solution for the weighted discharge based on linear systems analysis theory, and then subsequently the Muskingum solution from that analytical solution using the assumption of linear variation of discharge within the reach. It is proved that this assumption causes the formation of negative or reduced outflow at the beginning of a Muskingum solution. Cause d'un débit de sortie négatif obtenu par la méthode de Muskingum Résumé La raison de la génération d'un débit de sortie négatif ou réduit au début de l'application de la méthode de Muskingum est analysée en deux étapes. La première étape met en oeuvre l'interprétati...
The Xinanjiang rainfall–run-off model is a popular model applied extensively in the humid and sub... more The Xinanjiang rainfall–run-off model is a popular model applied extensively in the humid and sub-humid regions of the world for forecasting of flood, climate change studies and water resources assessment, planning and management. However, its performance in the Indian climatic conditions has not been extensively studied. In the present study, attempt is made to evaluate the performance of the Xinanjiang model for run-off simulation in six Indian watersheds having different climatic conditions (wet, average and dry). The results of the study indicate better model performance in wet catchments with average values of NSE = 0.88 and average R 2 = 0.89. The average values of NSE and R 2 on watersheds with average climatic condition obtained as 0.67 and 0.68, respectively, indicating average performance of the model. The performance of the model may be considered poor on watersheds with dry climatic conditions as the average estimated values of NSE and R 2 being 0.49 and 0.52, respectively. The results indicate the suitability of the application of Xinanjiang model in catchments characterised by wet and average climatic conditions and poor in dry climate conditions of India. However, extensive study is required to arrive at a final inference about the suitability of application of this model considering a number of catchments in the country.
The Variable Parameter Muskingum-Cunge (VPMC) method and the Multilinear Muskingum (MM) method ar... more The Variable Parameter Muskingum-Cunge (VPMC) method and the Multilinear Muskingum (MM) method are compared for routing flood hydrographs in channels. Both methods attempt to account for nonlinearity in the flood wave movement by varying the physically based parameters. They are studied by routing two different shapes of hypothetical flood hydrographs, estimated using two different initial flows in the channel, for a reach length of 40 km in two uniform wide rectangular channels with widths of 100 m and 200 m, and each having four different combinations of bed slope and Manning's roughness values. Both methods are evaluated by comparing their routed solutions with the corresponding St Venant solutions. Based on the study, it is recommended that the MM method be used for routing in natural channels and the VPMC method for routing in urban storm drains.
The authors have stated that the following points are controversial: (1) the "dip" at the beginni... more The authors have stated that the following points are controversial: (1) the "dip" at the beginning of the outflow hydrograph;
Hydrological Sciences Journal-Journal des Sciences …, Jan 1, 1994
An approach is presented for directly deriving a variable parameter Muskingum method from the St.... more An approach is presented for directly deriving a variable parameter Muskingum method from the St. Venant equations for routing floods in channels having any shape of prismatic cross-section and flow following either Manning's or Chezy's friction law. The approach also allows the simultaneous computation of the stage hydrograph corresponding to a given inflow or the routed hydrograph. This first paper also describes the solution procedure for routing the discharge hydrograph. A second paper (Peramal, 1994b) presents a verification of the methodology.
The cause of negative or reduced outflow formation at the beginning of a Muskingum solution is ex... more The cause of negative or reduced outflow formation at the beginning of a Muskingum solution is examined in two steps. The first step involves a physical interpretation of the Muskingum weighted discharge and the storage equation, using theory based on an extension of the Kalinin-Milyukov method. The second step involves the derivation of an analytical solution for the weighted discharge based on linear systems analysis theory, and then subsequently the Muskingum solution from that analytical solution using the assumption of linear variation of discharge within the reach. It is proved that this assumption causes the formation of negative or reduced outflow at the beginning of a Muskingum solution. Cause d'un débit de sortie négatif obtenu par la méthode de Muskingum Résumé La raison de la génération d'un débit de sortie négatif ou réduit au début de l'application de la méthode de Muskingum est analysée en deux étapes. La première étape met en oeuvre l'interprétati...
The Xinanjiang rainfall–run-off model is a popular model applied extensively in the humid and sub... more The Xinanjiang rainfall–run-off model is a popular model applied extensively in the humid and sub-humid regions of the world for forecasting of flood, climate change studies and water resources assessment, planning and management. However, its performance in the Indian climatic conditions has not been extensively studied. In the present study, attempt is made to evaluate the performance of the Xinanjiang model for run-off simulation in six Indian watersheds having different climatic conditions (wet, average and dry). The results of the study indicate better model performance in wet catchments with average values of NSE = 0.88 and average R 2 = 0.89. The average values of NSE and R 2 on watersheds with average climatic condition obtained as 0.67 and 0.68, respectively, indicating average performance of the model. The performance of the model may be considered poor on watersheds with dry climatic conditions as the average estimated values of NSE and R 2 being 0.49 and 0.52, respectively. The results indicate the suitability of the application of Xinanjiang model in catchments characterised by wet and average climatic conditions and poor in dry climate conditions of India. However, extensive study is required to arrive at a final inference about the suitability of application of this model considering a number of catchments in the country.
The Variable Parameter Muskingum-Cunge (VPMC) method and the Multilinear Muskingum (MM) method ar... more The Variable Parameter Muskingum-Cunge (VPMC) method and the Multilinear Muskingum (MM) method are compared for routing flood hydrographs in channels. Both methods attempt to account for nonlinearity in the flood wave movement by varying the physically based parameters. They are studied by routing two different shapes of hypothetical flood hydrographs, estimated using two different initial flows in the channel, for a reach length of 40 km in two uniform wide rectangular channels with widths of 100 m and 200 m, and each having four different combinations of bed slope and Manning's roughness values. Both methods are evaluated by comparing their routed solutions with the corresponding St Venant solutions. Based on the study, it is recommended that the MM method be used for routing in natural channels and the VPMC method for routing in urban storm drains.
The authors have stated that the following points are controversial: (1) the "dip" at the beginni... more The authors have stated that the following points are controversial: (1) the "dip" at the beginning of the outflow hydrograph;
Hydrological Sciences Journal-Journal des Sciences …, Jan 1, 1994
An approach is presented for directly deriving a variable parameter Muskingum method from the St.... more An approach is presented for directly deriving a variable parameter Muskingum method from the St. Venant equations for routing floods in channels having any shape of prismatic cross-section and flow following either Manning's or Chezy's friction law. The approach also allows the simultaneous computation of the stage hydrograph corresponding to a given inflow or the routed hydrograph. This first paper also describes the solution procedure for routing the discharge hydrograph. A second paper (Peramal, 1994b) presents a verification of the methodology.
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Papers by Dr. M. Perumal