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Perumal M.,Indian Institute of Technology Roorkee | Kale R.V.,National Institute of Hydrology Roorkee | Sahoo B.,ICAR Research Complex for NEH Region
World Environmental and Water Resources Congress 2011: Bearing Knowledge for Sustainability - Proceedings of the 2011 World Environmental and Water Resources Congress | Year: 2011

This paper highlights the development and use of the approximate- convection-diffusion (ACD) equations in discharge and stage or flow depth formulations for hydrological modeling, specifically for flood routing, overland flow modeling, flood forecasting, at-site discharge estimation using the stage data, and for rating curve development at ungauged river sites using only limited stage data. The field applicability and limitations of these methods in studying hydrological problems are also brought out. The practical applications of the ACD equations are demonstrated. © 2011 ASCE. Source


Kale R.V.,National Institute of Hydrology Roorkee | Sahoo B.,ICAR Research Complex for NEH Region
Water Resources Management | Year: 2011

The Green-Ampt (GA) infiltration model is a simplified version of the physically based full hydrodynamic model, known as the Richards equation. The simplicity and accuracy of this model facilitates for its use in many field problems, such as, infiltration computation in rainfall-runoff modelling, effluent transport in groundwater modelling studies, irrigation management studies including drainage systems etc. The numerous infiltration models based on the Green-Ampt approach have been widely investigated for their applicability in various scenarios of homogeneous soils. However, recent advances in physically based distributed rainfall-runoff modeling demands for the use of improved infiltration models for layered soils with non-uniform initial moisture conditions under varying rainfall patterns to capture the actual infiltration process that exists in nature. The difficulty that modelers are facing now-a-days includes the estimation of time of ponding and the application of the infiltration model to unsteady rainfall events occurring in heterogeneous soil conditions. The investigation in this direction exhibits that only few infiltration models can handle these situations. Hence, it is of vital importance to analyze the usefulness of different variants of the Green-Ampt infiltration models in terms of their degree of accuracy, complexity and applicability limits. This paper provides a brief review of these infiltration models to bring out their usefulness in the rainfall-runoff and irrigation modeling studies as well as the drawbacks associated with these models. © 2011 Springer Science+Business Media B.V. Source


Duhan D.,Indian Institute of Technology Roorkee | Pandey A.,Indian Institute of Technology Roorkee | Gahalaut K.P.S.,Johann Radon Institute for Computational Applied Mathematics RICAM | Pandey R.P.,National Institute of Hydrology Roorkee
Comptes Rendus - Geoscience | Year: 2013

In the present study, an investigation has been made to study the spatial and temporal variability in the maximum, the minimum and the mean air temperatures at Madhya Pradesh (MP), in central India on monthly, annual and seasonal time scale from 1901 to 2002. Further, impact of urbanization and cloud cover on air temperature has been studied. The annual mean, maximum and minimum temperatures are increased by 0.60, 0.60 and 0.62. °C over the past 102 years, respectively. Seasonally, the warming is more pronounced during winter than summer. The temperature decreased during the less urbanized period (from 1901 to 1951) and increased during the more urbanized period (1961 to 2001). It is also found that the minimum temperature increased at higher rate (0.42. °C) followed by the mean (0.36. °C) and the maximum (0.32. °C) temperature during the more urbanized period. Furthermore, cloud cover is significantly negatively related with air temperature in monsoon season and as a whole of the year. © 2012 Académie des sciences. Source


Darshana,Indian Institute of Technology Roorkee | Pandey A.,Indian Institute of Technology Roorkee | Ostrowski M.,TU Darmstadt | Pandey R.P.,National Institute of Hydrology Roorkee
Irrigation and Drainage | Year: 2012

In this study, simulation and optimization models were assembled for the optimization of irrigation systems and their operation. The simulation model CROPWAT was used for estimation of the crop water requirement, time and depth. The evolutionary algorithm (GANetXL) was used for the optimal planning of cropping pattern, maximization of net benefits and minimization of irrigation water requirements for the study area of Holeta catchment, Ethiopia. The study area encompasses three command areas, i.e. farm A, farm B and Tsedey State Farm, and five different type of crops, i.e. potato, tomato, apple, peach and winter wheat. The simulation results of the CROPWAT model illustrated that crop water requirement for apple was highest (993mm), followed by peach (908mm), tomato (470mm), potato (443mm) and wheat (294mm). The study reveals that fruit crops have more crop water requirements than cereals. The results of the GANetXL show that when the cropped area and water allocated was varied between extreme values, 23% of water can be saved. The total benefit from the study area can be enhanced by USD 34ha-1 and can be helpful in improving the economic conditions of the farmers. © 2011 John Wiley & Sons, Ltd. Source


Singh A.,Indian Institute of Technology Roorkee | Srivastav S.K.,Indian Institute of Remote Sensing | Kumar S.,National Institute of Hydrology Roorkee | Chakrapani G.J.,Indian Institute of Technology Roorkee
Environmental Earth Sciences | Year: 2015

Groundwater contamination and vulnerability in urbanized areas are of major concern and need proper attention. Several models including the DRASTIC model are used to evaluate groundwater vulnerability. In the present study, a modified DRASTIC model named as DRASTICA was used, by including anthropogenic influence as a model parameter. The study included an innovative methodology to characterize the anthropogenic influence by using satellite observations of night-lights from human settlements as a proxy and land-use/land-cover surrounding the urbanized area in Lucknow, the capital city of the most populous State of Uttar Pradesh in India. Geographical information system was used for spatial integration of different parameter maps. The groundwater vulnerability to pollution indicated that about 0.7 % area is covered under very high vulnerable zone, 24.5 % area under high vulnerable zone, 66.6 % area under moderately vulnerable zone and 8.2 % area under low vulnerable zone. The results were validated using nitrate concentration in ground water. It was shown that the proposed DRASTICA model performed better than conventional DRASTIC model in an urbanized environment. Sensitivity analysis indicated that anthropogenic impact and depth to water table largely influenced the groundwater vulnerability to pollution, thereby signifying that anthropogenic influence has to be addressed precisely in such studies. The modified-DRASTIC/DRASTICA model proposed in this study will help in better categorization of groundwater vulnerable zones to pollution where anthropogenic contamination is high, particularly in and around urban centers. © 2015, Springer-Verlag Berlin Heidelberg. Source

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