Water is a vital need for humans and a critical resource for the maintenance of social-ecological... more Water is a vital need for humans and a critical resource for the maintenance of social-ecological systems. Against the backdrop of global environmental and societal changes, water scarcity looms large in many parts of the world. Changes in water availability may heighten water con licts between users at different scales, from the local to the transnational level. Land and water, the most basic resources in food production have attracted much attention in the global change debate for various reasons. Most obviously, there is the question of how we will be able to feed a growing population that is increasingly demanding higher quality food and higher shares of livestock products. The scarce resources of fertile land and freshwater are also diminished by non-sustainable use. Climate change will also lead to changes in freshwater availability. As aquaculture production needs to be increased but water is in limited supply, there is a strong demand to increase aquacultural water productivity. Application of better management practices through intensi ication of existing aquaculture systems with emphasis on BMP is therefore, the main approach for improving the environmental performance of aquaculture. A wide-range of technical options is available to enhance aquacultural water productivity for a particular situation or hydro-ecological condition. The two major requirements in improving aquacultural water productivity are the blue water required for culture and the input management, especially the feed. Minimization of unnecessary water exchange/ replenishment and taking advantage of the compensatory growth response, also perceived as a way to increase water productivity and pro its in aquaculture operations. Sustainability of aquaculture does not contradict increasing production intensity. On the contrary, aquaculture sustainability depends on greater production intensity. Technologies reviewed in this bulletin can be applied by small scale farmers, and when combined, the effects on production are additive. Understanding the principles of pond water management and aquaculture with an effort to optimize, integrate and disseminate such a combined methodology is needed towards a sustainable blue revolution. We sincerely hope that our effort in bringing out this research bulletin based on on-farm ield trial will be helpful for all those engaged in aquacultural water budgeting and its management. This will also serve as a source of information to farmers, policy makers, entrepreneurs, researchers and extension workers as training guide.
Nearly one-fifth of the Earth's accessible freshwater is stored in the densely-populated, alluvia... more Nearly one-fifth of the Earth's accessible freshwater is stored in the densely-populated, alluvial floodplains of the Brahmaputra, Ganges, Indus, Irrawaddy and Meghna River Systems in the Himalayan region where extreme hydrological conditions exist due to the seasonal variability in terrestrial water storage (TWS). Groundwater storage (GWS)a hidden resource underneath the land surface, plays a critical role in sustaining irrigated agriculture in these river basins, particularly during the dry season when rice crops are generally grown in irrigated lands across South Asia. Although monitoring of groundwater levels has been operational in the region for a number of decades, a basin-wide comprehensive assessment of GWS is lacking in most river basins. The NASA's Gravity Recovery and Climate Experiment (GRACE) twin satellites offer an opportunity to map basinwide changes in GWS where in-situ observations are limited in time and space. GRACE-derived assessments of GWS vary substantially in these basins and have not been reconciled with in-situ observations in most cases. Recent declining trends in GWS over the Himalayan river basins are attributed primarily to over-abstraction of groundwater due to dry-season irrigation. Seasonal variability in terrestrial water is likely to increase or become unpredictable in the future as a result of increased climate variability. The consequent impacts may potentially threaten the security of water supply and food in the region, where there is currently a growing demand for food grains from irrigated agriculture, energy, and domestic and industrial water supplies.
The total water use (TWU) and consumptive water use index (CWUI) in monoculture of Penaeus monodo... more The total water use (TWU) and consumptive water use index (CWUI) in monoculture of Penaeus monodon under varying intensity levels [T1: 150,000 post larvae (PL) ha−1, T2: 200,000 PL ha−1, T3: 250,000 PL ha−1] were quantified. Treatment-wise-estimated TWU was 2.98 × 104, 3.24 × 104, and 3.59 × 104 m3 ha−1 125d−1, while the CWUI was 5.12, 4.72, and 4.96 m3 kg−1 shrimp production in T1, T2, and T3, respectively. The estimated evaporation and seepage loss ranged between 1.2–1.7 and 1.1–1.5 m3 water kg−1 shrimp production, respectively, and contributed significantly to consumptive water use (CWU). Higher the stocking density, lower was the water quality suitability index (WQSI) as in T3 followed by T2 and T1. WQSI up to 75 days of culture rated very good, ranged between 7.5–9.0 in T1 and T2, while rest of the period it was good (5.5–7.5) with moderate management requirements. Treatment-wise sediment load ranged between 39.0 and 45.3 m3 t−1 shrimp biomass. Among the treatments, minimization of total water use (3.24 × 104, m3), CWU (2.16 × 104, m3) and water exchange (0.90 × 104, m3) at stocking density 20 post-larvae m−2 (T2), resulted in higher (p < 0.05) growth rate (30.45 g), yield (4.58 t ha−1), output value - cost of cultivation ratio (2.46) and net consumptive water productivity (USD 0.65 m−3). Findings of this study would help in preventing wasteful use of water and would address the management and operational issues in coastal shrimp aquaculture.
Recent heat waves have been a matter of serious concern for India because of potential impacts on... more Recent heat waves have been a matter of serious concern for India because of potential impacts on agriculture, food security, and socioeconomic progress. This study examines the trends and variability in frequency, duration, and intensity of hot episodes during three time periods (1951-2013, 1981-2013 and 1998-2013) by defining heat waves based on the percentile of maximum, minimum, and mean temperatures. The study also explores heat waves and their relationships with hydroclimatic variables, such as rainfall, terrestrial water storage, Palmer drought severity index, and sea surface temperature. Results reveal that the number, frequency, and duration of daytime heat waves increased considerably during the post-1980 dry and hot phase over a large area. The densely populated and agriculturally dominated northern half of India stands out as a key region where the nighttime heat wave metrics reflected the most pronounced amplifications. Despite the recent warming hiatus in India and other parts of the world, we find that both daytime and nighttime extreme measures have undergone substantial changes during or in the year following a dry year since 2002, with the probability distribution functions manifesting a hotter-than-normal climate during 1998-2013. This study shows that a few months preceding the 2010 record-breaking heat wave in Russia, India experienced the largest hot episode in the country's history. Interestingly, both these mega events are comparable in terms of their evolution and amplification. These findings emphasize the importance of planning for strategies in the context of the rising cooccurrence of dry and hot events. Plain Language Summary Consistent with model projection and physical understanding, the multiaspect framework of heat wave and warm spells exhibits clear spatial and temporal patterns. Most perceptible change in heat waves is observed during the post-1998 warming hiatus period, mainly exacerabated by droughts. The 2009-2010 drought and heat wave in India can be compared with that of the 2010 record-breaking Russian hot episode in terms of evolution and amplification.
The mean and extreme matrices of the monsoon rainfall in India not only play an important role in... more The mean and extreme matrices of the monsoon rainfall in India not only play an important role in depicting the global monsoon climate, but also their spatiotemporal patterns influence the socioeconomic profile of a major proportion of the country's huge population. Given the reported conflicting trends at the global and national scales, the present study investigates the 20th century (1901-2004) changes in monsoon rainfall of India, particularly focusing the indices developed by the Expert Team on Climate Change Detection and Indices (ETCCDI) to facilitate a global comparison. Result of this comprehensive analysis, which includes the response of fifteen indices over two study periods (i.e., 1901-1940 and 1961-2004), indicates clear signals of change with respect to the period and region of study and the choice of the ETCCDI indices. While wet day frequency, low-tomoderate events and consecutive wet days (CWD) exhibit a prominent transition from a pre-1940 wetting to a post-1960 drying tendency over a large part of the central-north India (CNI), both the wet and dry extremes have occurred in a spatially less consistent manner during the recent decades. For consecutive dry days (CDD), the reported less clear global signals could be related to the timescale of analysis, as our sub-seasonal scale results display consistent changes compared to that of the seasonal and annual scales. The Palmer Drought Severity Index (PDSI) provides clear indications of a post-1960 non-stationarity, showing changes in the mean as well as variance. Based on the partial Mann-Kendall test (PMK), some of the identified rainfall trends during 1961-2004 are found to be influenced more by the tropical Indian Ocean sea surface temperatures than the El Niño-Southern Oscillation index. These results have important implications for formulating the water resource management strategy, particularly over the drying central and northern parts of the country.
In this study, the rainfall of Orissa, a tropical region in eastern India, and the cyclonic distu... more In this study, the rainfall of Orissa, a tropical region in eastern India, and the cyclonic disturbances over the Bay of Bengal were analyzed to assess the trends and variations using parametric statistical procedures. This study revealed noticeable changes in the last century (1901–2000) in regard to the rainfall of Orissa and in the cyclonic disturbances over the Bay of Bengal. Test of structural changes and the locally weighted regression technique (LOWESS) indicated that the spatially averaged annual rainfall of Orissa experienced three significant regime shifts: 1,487 mm with standard deviation 167 mm during 1901–1940, 1,412 mm with standard deviation 184 mm during 1940–1969, and 1,354 mm with standard deviation 241 mm during 1970–2000, respectively. The study of structural breaks in rainfall during the period 1901–1940 and 1941–1969 indicated a significant change in both slope and the intercepts. However, structural break analysis during the period 1941–1969 and 1970–2000 indicated a nonsignificant change. The annual depression in the Bay of Bengal also exhibited a structural change with occurrence of an average of 10.7 depressions during 1901–1948 in comparison to 9.6 during 1949–2000.
Investigating changes in terrestrial water storage (TWS) is important for understanding response ... more Investigating changes in terrestrial water storage (TWS) is important for understanding response of the hydrological cycle to recent climate variability worldwide. This is particularly critical in India where the current economic development and food security greatly depend on its water resources. We use 129 monthly gravity solutions from NASA's Gravity Recovery and Climate Experiment (GRACE) satellites for the period of January 2003 to May 2014 to characterize spatiotemporal variations of TWS and groundwater storage (GWS). The spatiotemporal evolution of GRACE data reflects consistent patterns with that of several hydroclimatic variables and also shows that most of the water loss has occurred in the northern parts of India. Substantial GWS depletion at the rate of 1.25 and 2.1 cm yr 21 has taken place, respectively in the Ganges Basin and Punjab state, which are known as the India's grain bowl. Of particular concern is the Ganges Basin's storage loss in drought years, primarily due to anthropogenic groundwater withdrawals that sustain rice and wheat cultivation. We estimate these losses to be approximately 41, 44, and 42 km 3 in 2004, 2009, and 2012, respectively. The GWS depletions that constitute about 90% of the observed TWS loss are also influenced by a marked rise in temperatures since 2008. A high degree of correspondence between GRACE-derived GWS and in situ groundwater levels from observation well validates the results. This validation increases confidence level in the application of GRACE observations in monitoring large-scale storage changes in intensely irrigated areas in India and other regions around the world.
Rainfed agriculture plays and will continue to play a dominant role in providing food and livelih... more Rainfed agriculture plays and will continue to play a dominant role in providing food and livelihoods for an increasing world population. Rainfall analyses are helpful for proper crop planning under changing environment in any region. Therefore, in this paper, an attempt has been made to analyse 16 years of rainfall (1995–2010) at the Daspalla region in Odisha, eastern India for prediction using six probability distribution functions, forecasting the probable date of onset and withdrawal of monsoon, occurrence of dry spells by using Markov chain model and finally crop planning for the region. For prediction of monsoon and post-monsoon rainfall, log Pearson type III and Gumbel distribution were the best-fit probability distribution functions. The earliest and most delayed week of the onset of rainy season was the 20th standard meteorological week (SMW) (14th–20th May) and 25th SMW (18th–24th June), respectively. Similarly, the earliest and most delayed week of withdrawal of rainfall ...
Water is a vital need for humans and a critical resource for the maintenance of social-ecological... more Water is a vital need for humans and a critical resource for the maintenance of social-ecological systems. Against the backdrop of global environmental and societal changes, water scarcity looms large in many parts of the world. Changes in water availability may heighten water con licts between users at different scales, from the local to the transnational level. Land and water, the most basic resources in food production have attracted much attention in the global change debate for various reasons. Most obviously, there is the question of how we will be able to feed a growing population that is increasingly demanding higher quality food and higher shares of livestock products. The scarce resources of fertile land and freshwater are also diminished by non-sustainable use. Climate change will also lead to changes in freshwater availability. As aquaculture production needs to be increased but water is in limited supply, there is a strong demand to increase aquacultural water productivity. Application of better management practices through intensi ication of existing aquaculture systems with emphasis on BMP is therefore, the main approach for improving the environmental performance of aquaculture. A wide-range of technical options is available to enhance aquacultural water productivity for a particular situation or hydro-ecological condition. The two major requirements in improving aquacultural water productivity are the blue water required for culture and the input management, especially the feed. Minimization of unnecessary water exchange/ replenishment and taking advantage of the compensatory growth response, also perceived as a way to increase water productivity and pro its in aquaculture operations. Sustainability of aquaculture does not contradict increasing production intensity. On the contrary, aquaculture sustainability depends on greater production intensity. Technologies reviewed in this bulletin can be applied by small scale farmers, and when combined, the effects on production are additive. Understanding the principles of pond water management and aquaculture with an effort to optimize, integrate and disseminate such a combined methodology is needed towards a sustainable blue revolution. We sincerely hope that our effort in bringing out this research bulletin based on on-farm ield trial will be helpful for all those engaged in aquacultural water budgeting and its management. This will also serve as a source of information to farmers, policy makers, entrepreneurs, researchers and extension workers as training guide.
Nearly one-fifth of the Earth's accessible freshwater is stored in the densely-populated, alluvia... more Nearly one-fifth of the Earth's accessible freshwater is stored in the densely-populated, alluvial floodplains of the Brahmaputra, Ganges, Indus, Irrawaddy and Meghna River Systems in the Himalayan region where extreme hydrological conditions exist due to the seasonal variability in terrestrial water storage (TWS). Groundwater storage (GWS)a hidden resource underneath the land surface, plays a critical role in sustaining irrigated agriculture in these river basins, particularly during the dry season when rice crops are generally grown in irrigated lands across South Asia. Although monitoring of groundwater levels has been operational in the region for a number of decades, a basin-wide comprehensive assessment of GWS is lacking in most river basins. The NASA's Gravity Recovery and Climate Experiment (GRACE) twin satellites offer an opportunity to map basinwide changes in GWS where in-situ observations are limited in time and space. GRACE-derived assessments of GWS vary substantially in these basins and have not been reconciled with in-situ observations in most cases. Recent declining trends in GWS over the Himalayan river basins are attributed primarily to over-abstraction of groundwater due to dry-season irrigation. Seasonal variability in terrestrial water is likely to increase or become unpredictable in the future as a result of increased climate variability. The consequent impacts may potentially threaten the security of water supply and food in the region, where there is currently a growing demand for food grains from irrigated agriculture, energy, and domestic and industrial water supplies.
The total water use (TWU) and consumptive water use index (CWUI) in monoculture of Penaeus monodo... more The total water use (TWU) and consumptive water use index (CWUI) in monoculture of Penaeus monodon under varying intensity levels [T1: 150,000 post larvae (PL) ha−1, T2: 200,000 PL ha−1, T3: 250,000 PL ha−1] were quantified. Treatment-wise-estimated TWU was 2.98 × 104, 3.24 × 104, and 3.59 × 104 m3 ha−1 125d−1, while the CWUI was 5.12, 4.72, and 4.96 m3 kg−1 shrimp production in T1, T2, and T3, respectively. The estimated evaporation and seepage loss ranged between 1.2–1.7 and 1.1–1.5 m3 water kg−1 shrimp production, respectively, and contributed significantly to consumptive water use (CWU). Higher the stocking density, lower was the water quality suitability index (WQSI) as in T3 followed by T2 and T1. WQSI up to 75 days of culture rated very good, ranged between 7.5–9.0 in T1 and T2, while rest of the period it was good (5.5–7.5) with moderate management requirements. Treatment-wise sediment load ranged between 39.0 and 45.3 m3 t−1 shrimp biomass. Among the treatments, minimization of total water use (3.24 × 104, m3), CWU (2.16 × 104, m3) and water exchange (0.90 × 104, m3) at stocking density 20 post-larvae m−2 (T2), resulted in higher (p < 0.05) growth rate (30.45 g), yield (4.58 t ha−1), output value - cost of cultivation ratio (2.46) and net consumptive water productivity (USD 0.65 m−3). Findings of this study would help in preventing wasteful use of water and would address the management and operational issues in coastal shrimp aquaculture.
Recent heat waves have been a matter of serious concern for India because of potential impacts on... more Recent heat waves have been a matter of serious concern for India because of potential impacts on agriculture, food security, and socioeconomic progress. This study examines the trends and variability in frequency, duration, and intensity of hot episodes during three time periods (1951-2013, 1981-2013 and 1998-2013) by defining heat waves based on the percentile of maximum, minimum, and mean temperatures. The study also explores heat waves and their relationships with hydroclimatic variables, such as rainfall, terrestrial water storage, Palmer drought severity index, and sea surface temperature. Results reveal that the number, frequency, and duration of daytime heat waves increased considerably during the post-1980 dry and hot phase over a large area. The densely populated and agriculturally dominated northern half of India stands out as a key region where the nighttime heat wave metrics reflected the most pronounced amplifications. Despite the recent warming hiatus in India and other parts of the world, we find that both daytime and nighttime extreme measures have undergone substantial changes during or in the year following a dry year since 2002, with the probability distribution functions manifesting a hotter-than-normal climate during 1998-2013. This study shows that a few months preceding the 2010 record-breaking heat wave in Russia, India experienced the largest hot episode in the country's history. Interestingly, both these mega events are comparable in terms of their evolution and amplification. These findings emphasize the importance of planning for strategies in the context of the rising cooccurrence of dry and hot events. Plain Language Summary Consistent with model projection and physical understanding, the multiaspect framework of heat wave and warm spells exhibits clear spatial and temporal patterns. Most perceptible change in heat waves is observed during the post-1998 warming hiatus period, mainly exacerabated by droughts. The 2009-2010 drought and heat wave in India can be compared with that of the 2010 record-breaking Russian hot episode in terms of evolution and amplification.
The mean and extreme matrices of the monsoon rainfall in India not only play an important role in... more The mean and extreme matrices of the monsoon rainfall in India not only play an important role in depicting the global monsoon climate, but also their spatiotemporal patterns influence the socioeconomic profile of a major proportion of the country's huge population. Given the reported conflicting trends at the global and national scales, the present study investigates the 20th century (1901-2004) changes in monsoon rainfall of India, particularly focusing the indices developed by the Expert Team on Climate Change Detection and Indices (ETCCDI) to facilitate a global comparison. Result of this comprehensive analysis, which includes the response of fifteen indices over two study periods (i.e., 1901-1940 and 1961-2004), indicates clear signals of change with respect to the period and region of study and the choice of the ETCCDI indices. While wet day frequency, low-tomoderate events and consecutive wet days (CWD) exhibit a prominent transition from a pre-1940 wetting to a post-1960 drying tendency over a large part of the central-north India (CNI), both the wet and dry extremes have occurred in a spatially less consistent manner during the recent decades. For consecutive dry days (CDD), the reported less clear global signals could be related to the timescale of analysis, as our sub-seasonal scale results display consistent changes compared to that of the seasonal and annual scales. The Palmer Drought Severity Index (PDSI) provides clear indications of a post-1960 non-stationarity, showing changes in the mean as well as variance. Based on the partial Mann-Kendall test (PMK), some of the identified rainfall trends during 1961-2004 are found to be influenced more by the tropical Indian Ocean sea surface temperatures than the El Niño-Southern Oscillation index. These results have important implications for formulating the water resource management strategy, particularly over the drying central and northern parts of the country.
In this study, the rainfall of Orissa, a tropical region in eastern India, and the cyclonic distu... more In this study, the rainfall of Orissa, a tropical region in eastern India, and the cyclonic disturbances over the Bay of Bengal were analyzed to assess the trends and variations using parametric statistical procedures. This study revealed noticeable changes in the last century (1901–2000) in regard to the rainfall of Orissa and in the cyclonic disturbances over the Bay of Bengal. Test of structural changes and the locally weighted regression technique (LOWESS) indicated that the spatially averaged annual rainfall of Orissa experienced three significant regime shifts: 1,487 mm with standard deviation 167 mm during 1901–1940, 1,412 mm with standard deviation 184 mm during 1940–1969, and 1,354 mm with standard deviation 241 mm during 1970–2000, respectively. The study of structural breaks in rainfall during the period 1901–1940 and 1941–1969 indicated a significant change in both slope and the intercepts. However, structural break analysis during the period 1941–1969 and 1970–2000 indicated a nonsignificant change. The annual depression in the Bay of Bengal also exhibited a structural change with occurrence of an average of 10.7 depressions during 1901–1948 in comparison to 9.6 during 1949–2000.
Investigating changes in terrestrial water storage (TWS) is important for understanding response ... more Investigating changes in terrestrial water storage (TWS) is important for understanding response of the hydrological cycle to recent climate variability worldwide. This is particularly critical in India where the current economic development and food security greatly depend on its water resources. We use 129 monthly gravity solutions from NASA's Gravity Recovery and Climate Experiment (GRACE) satellites for the period of January 2003 to May 2014 to characterize spatiotemporal variations of TWS and groundwater storage (GWS). The spatiotemporal evolution of GRACE data reflects consistent patterns with that of several hydroclimatic variables and also shows that most of the water loss has occurred in the northern parts of India. Substantial GWS depletion at the rate of 1.25 and 2.1 cm yr 21 has taken place, respectively in the Ganges Basin and Punjab state, which are known as the India's grain bowl. Of particular concern is the Ganges Basin's storage loss in drought years, primarily due to anthropogenic groundwater withdrawals that sustain rice and wheat cultivation. We estimate these losses to be approximately 41, 44, and 42 km 3 in 2004, 2009, and 2012, respectively. The GWS depletions that constitute about 90% of the observed TWS loss are also influenced by a marked rise in temperatures since 2008. A high degree of correspondence between GRACE-derived GWS and in situ groundwater levels from observation well validates the results. This validation increases confidence level in the application of GRACE observations in monitoring large-scale storage changes in intensely irrigated areas in India and other regions around the world.
Rainfed agriculture plays and will continue to play a dominant role in providing food and livelih... more Rainfed agriculture plays and will continue to play a dominant role in providing food and livelihoods for an increasing world population. Rainfall analyses are helpful for proper crop planning under changing environment in any region. Therefore, in this paper, an attempt has been made to analyse 16 years of rainfall (1995–2010) at the Daspalla region in Odisha, eastern India for prediction using six probability distribution functions, forecasting the probable date of onset and withdrawal of monsoon, occurrence of dry spells by using Markov chain model and finally crop planning for the region. For prediction of monsoon and post-monsoon rainfall, log Pearson type III and Gumbel distribution were the best-fit probability distribution functions. The earliest and most delayed week of the onset of rainy season was the 20th standard meteorological week (SMW) (14th–20th May) and 25th SMW (18th–24th June), respectively. Similarly, the earliest and most delayed week of withdrawal of rainfall ...
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