Sharad K. Jain

Analysis of long-term rainfall trends in India

Abstract The study of precipitation trends is critically important for a country like India whose food security and economy are dependent on the timely availability of water. In this work, monthly, seasonal and annual trends of rainfall have been studied using monthly data series of 135 years (1871–2005) for 30 sub-divisions (sub-regions) in India. Half of the sub-divisions showed an increasing trend in annual rainfall, but for only three (Haryana, Punjab and Coastal Karnataka), this trend was statistically significant. Similarly, only one sub-division (Chattisgarh) indicated a significant decreasing trend out of the 15 sub-divisions showing decreasing trend in annual rainfall. In India, the monsoon months of June to September account for more than 80% of the annual rainfall. During June and July, the number of sub-divisions showing increasing rainfall is almost equal to those showing decreasing rainfall. In August, the number of sub-divisions showing an increasing trend exceeds those showing a decreasing trend, whereas in September, the situation is the opposite. The majority of sub-divisions showed very little change in rainfall in non-monsoon months. The five main regions of India showed no significant trend in annual, seasonal and monthly rainfall in most of the months. For the whole of India, no significant trend was detected for annual, seasonal, or monthly rainfall. Annual and monsoon rainfall decreased, while pre-monsoon, post-monsoon and winter rainfall increased at the national scale. Rainfall in June, July and September decreased, whereas in August it increased, at the national scale. Citation Kumar, V., Jain, S. K. & Singh, Y. (2010) Analysis of long-term rainfall trends in India. Hydrol. Sci. J. 55(4), 484–496.

Assessment of sediment deposition rate in Bargi Reservoir using digital image processing

Abstract A reservoir is an integral component of a water resources system. Periodic evaluation of the sediment deposition pattern and assessment of available storage capacity of reservoirs is an important aspect of water resources management. The conventional techniques of quantification of sediment deposition in a reservoir, such as hydrographic surveys and the inflow-outflow methods, are cumbersome, costly and time consuming. Further, prediction of sediment deposition profiles using empirical and numerical methods requires a large amount of input data and the results are still not encouraging. Due to sedimentation, the water-spread area of a reservoir at various elevations keeps on decreasing. Remote sensing, through its spatial, spectral and temporal attributes, provides synoptic and repetitive information on the water-spread area of a reservoir. By use of remote sensing data in conjunction with a geographic information system, the temporal change in water-spread area can be analysed to evaluate the sediment deposition pattern in a reservoir. A case study, related to the assessment of sediment deposition in Bargi Reservoir, Madhya Pradesh State, India, is presented. The reservoir was completed in 1988 and no hydrographic survey has yet been carried out. Under these circumstances, the sedimentation assessment using satellite data can guide the dam operators in updating the elevation-area-capacity table of the reservoir. The images for nine dates from the IRS-1C satellite, LISS-III sensor have been analysed using the ERDAS/IMAGINE software. The resulting sedimentation rate in the zone of study is about 229 m3 km−2 of catchment area per year.

Water Resources Under Climate Change in Himalayan Basins

Climate change has significant implications for glaciers and water resources in the Himalayan region. There is an urgent need to improve our current knowledge and methods in quantifying changes in water resources in this region. This study uses an integrated approach that couples a hydrological model and a glacier retreat model to assess the future water resources for two Himalayan basins. They are the Chamkhar Chhu basin in Bhutan (Eastern Himalayas) and the Beas basin in India (Western Himalayas). The future climate is simulated by two Regional Climate Models (RCMs) for south Asia under three Representative Concentration Pathways (Rcp2.6, Rcp4.5 and Rcp8.5). The six climate projections for the period 2010–2100 indicate significant warming effects; however, projected changes in precipitation are not consistent. Discrepancies in precipitation are noteworthy between the RCMs and greenhouse gases emissions scenarios. The glaciers in the Chamkhar Chhu basin are predicted to disappear or reduce to a small size before the 2050s, whereas the glaciers in the Beas basin are expected to lose mass before the 2060s, and afterwards to gain mass under Rcp2.6 and Rcp4.5, or to melt at a high rate under Rcp8.5. The available water resources per capita of two basins are projected to decrease in the period 2010–2050. The decreasing water resources are jointly induced by climate change and population growth. The latter is responsible for roughly 40 % of the water declines. Both basins are facing water shortages at present and the water shortages will intensify in the future.

Validation of a new meteorological forcing data in analysis of spatial and temporal variability of precipitation in India

During the past two decades, numerous datasets have been developed for global/regional hydrological assessment and modeling, but these datasets often show differences in their spatial and temporal distributions of precipitation, which is one of the most critical input variables in global/regional hydrological modeling. This paper is aimed to explore the precipitation characteristics of the Water and Global Change (WATCH) forcing data (WFD) and compare these with the corresponding characteristics derived from satellite-gauge data (TRMM 3B42 and GPCP 1DD) and rain gauge data. It compared the consistency and difference between the WFD and satellite-gauge data in India and examined whether the pattern of seasonal (winter, pre-monsoon, monsoon and post-monsoon) precipitation over six regions [e.g. North Mountainous India (NMI), Northwest India (NWI), North Central India (NCI), West Peninsular India (WPI), East Peninsular India (EPI) and South Peninsular India (SPI)] of India agrees well for the gridded data to be useful in precipitation variability analyses. The multi-time scale of precipitation in India was analysed by wavelet transformation method using gauged and WFD precipitation data. In general, precipitation from WFD is larger than that from satellite-gauge data in NMI and Western Ghats region whereas it is smaller in the dry region of NWI. Both WFD and satellite-gauge datasets underestimate precipitation compared to the measured data but the precipitation from WFD is better estimated than that from satellite-gauge data. It was found that the wavelet power spectrum of precipitation based on WFD is reasonably close to that of measured precipitation in NWI and NCI, while slightly different in NMI. It is felt that the WFD data can be used as a potential dataset for hydrological study in India.

Analysis of a large inter-basin water transfer system in India / Analyse d’un grand système de transfert d’eau inter-bassins en Inde

Inter-basin transfer of water in India is a long-term option to correct the spatial and temporal mismatch of water availability and demand, largely owing to the monsoon climate. This paper is concerned with analysis and preliminary design of a large inter-basin water transfer system in peninsular India. The system covers four major basins and involves operation of 13 major structures. The study was carried out in three stages. First, the surface water deficit in each basin was estimated. Then the net deficit was worked out by considering the availability of groundwater. Finally, the link systems were planned to transfer the amount of water needed to meet the demands with desired reliability.Abstract Abstract Inter-basin transfer of water in India is a long-term option to correct the spatial and temporal mismatch of water availability and demand, largely owing to the monsoon climate. This paper is concerned with analysis and preliminary design of a large inter-basin water transfer system in peninsular India. The system covers four major basins and involves operation of 13 major structures. The study was carried out in three stages. First, the surface water deficit in each basin was estimated. Then the net deficit was worked out by considering the availability of groundwater. Finally, the link systems were planned to transfer the amount of water needed to meet the demands with desired reliability.

A review of atmospheric and land surface processes with emphasis on flood generation in the Southern Himalayan rivers

Floods in the southern rim of the Indian Himalayas are a major cause of loss of life, property, crops, infrastructure, etc. They have long term socio-economic impacts on the habitat living along/across the Himalayas. In the recent decade extreme precipitation events have led to numerous flash floods in and around the Himalayan region. Sporadic case-based studies have tried to explain the mechanisms causing the floods. However, in some of the cases, the causative mechanisms have been elusive. Various types of flood events have been debated at different spatial and temporal scales. The present study provides an overview of mechanisms that lead to floods in and around the southern rim of the Indian Himalayas. Atmospheric processes, landuse interaction, and glacier-related outbreaks are considered in the overview.

Environmental flows in India: towards sustainable water management

Abstract The strong wet and dry seasons of tropical monsoon hydrology in India necessitate development of storage and flow diversion schemes for utilization of water to meet various social and economic needs. However, the river valley schemes may cause adverse flow-related impacts due to storage, flow diversion, tunnelling and spoil disposal. There may be critical reaches in which altered flows are not able to sustain the river channel ecology and riparian environment that existed prior to implementation of the storage and diversion schemes. In the past, environmental flows in India have usually been understood as the minimum flow to be released downstream from a dam as compensation for riparian rights, without considering the impacts on the river ecosystem. Rivers in India have been significantly influenced by anthropogenic activities over the past 60 years and have great social and religious significance to the vast population. This paper explores various aspects of past, present and future environmental flow assessment (EFA) in India highlighted by case studies from rivers across the nation. It demonstrates that multidisciplinary studies requiring expertise from a range of fields are needed for EFA, and that environmental flows are necessary for aquatic ecosystems to remain in a healthy state and for the sustainable use of water resources. The major focus areas for the development of EFA research in India are the creation of a shareable database for hydrological, ecological and socioeconomic data, developing hydrology–ecology relationships, evaluation of ecosystem services, addressing pollution due to anthropogenic activities and promotion of research on EFA. At the same time, efforts will be needed to develop new methods or refine existing methods for India. Editor D. Koutsoyiannis; Guest editor M. Acreman Citation Jain, S.K. and Kumar, P., 2014. Environmental flows in India: towards sustainable water management. Hydrological Sciences Journal, 59 (3–4), 751–769.

Genetic Algorithms and Their Applications to Water Resources Systems

Real-life water resource problems such as optimal allocation of scare water, watershed management, conjunctive use of surface and groundwater, reservoir operation, water distribution systems, and management of water quality have many complex features. The variables involved may be discrete, discontinuous, or both; frequently the variables are stochastic and highly nonlinear. These typical problems limit the use of traditional nonlinear algorithms, such as the gradient-based algorithms, since the solution may converge to local optima and the computational requirements may be very high. Evolutionary algorithms, such as genetic algorithms (GAs), do not rely on any mathematical properties of the functions employed in the model. This feature makes them robust and more generally applicable than the other directed search methods. GAs are a particular class of evolutionary algorithm based on mechanics of natural selection and natural genetics, and they use techniques inspired by evolutionary biology such as inheritance, mutation, selection, crossover, and survival of the fittest. Since GAs are heuristic search techniques, the global optimum solution is not guaranteed. Nevertheless, GAs give alternative solutions that are close to the optimum after a reasonable number of evolutions, which is acceptable for most real-life problems. This chapter introduces the art and applications of GAs to water resource optimization problems. An illustrative example of reservoir operation optimization has been included to clarify the concepts.

Comparing the stream re-aeration coefficient estimated from ANN and empirical models / Comparaison d'estimations par un RNA et par des modèles empiriques du coefficient de réaération en cours d'eau

Abstract Dissolved oxygen (DO) is one of the most useful indices of rivers health and the stream re-aeration coefficient is an important input to computations related to DO. Normally, this coefficient is expressed as a function of several variables, such as mean stream velocity, shear stress velocity, bed slope, flow depth, and Froude number. However, in free surface flows, some of these variables are interrelated, and it is possible to obtain simplified stream re-aeration equations. In recent years, different functional forms have been advanced to represent the re-aeration coefficient for different data sets. In the present study, the artificial neural network (ANN) technique has been applied to estimate the re-aeration coefficient (K 2) using data sets measured at different reaches of the Kali River in India and values obtained from the literature. Observed stream/channel velocity, bed slope, flow depth, cross-sectional area and re-aeration coefficient data were used for the analysis. Different combinations of variables were tested to obtain the re-aeration coefficient using an ANN. The performance of the ANN was compared with other estimation methods. It was found that the re-aeration coefficient estimated by using an ANN was much closer to the observed values as compared with the other techniques.

Impact of global warming and climate change on social development

In recent years there has been a lot of discussion on global warming and climate change and its implications for social development – an area that Mohan has devoted his life to. It is now accepted that climate change is real and its impacts will be felt across different sectors ranging from water resources to industries to social arenas. In coming years, people will be affected across the world even more irrespective of their contribution to the cause of global warming and climate change. The very fabric of our society and the goal of social work will be impacted just as well. Climate change is not just a scientific issue, it is just as much a social issue. This article briefly discusses global warming and climate change, their causes, effects on society, future projections and their effects on social development.