This page has only limited features, please log in for full access.

Dr. Sumit Sen
Associate Professor of Hydrology, Department of Hydrology, IIT Roorkee. India

Basic Info


Research Keywords & Expertise

0 Water Resources
0 Hillslope Hydrology
0 Himalayan Hydrology
0 Spring Hydrology
0 Watershed Management, Monitoring and Modelling

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 23 July 2021 in Climate
Reads 0
Downloads 0

The Indian Himalayan Region is home to nearly 50 million people, more than 50% of whom are dependent on springs for their sustenance. Sustainable management of the nearly 3 million springs in the region requires a framework to identify the springs most vulnerable to change agents which can be biophysical or socio-economic, internal or external. In this study, we conceptualize vulnerability in the Indian Himalayan springs. By way of a systematic review of the published literature and synthesis of research findings, a scheme of identifying and quantifying these change agents (stressors) is presented. The stressors are then causally linked to the characteristics of the springs using indicators, and the resulting impact and responses are discussed. These components, viz., stressors, state, impact, and response, and the linkages are used in the conceptual framework to assess the vulnerability of springs. A case study adopting the proposed conceptual model is discussed for Mathamali spring in the Western Himalayas. The conceptual model encourages quantification of stressors and promotes a convergence to an evidence-based decision support system for the management of springs and the dependent ecosystems from the threat due to human development and climate change.

ACS Style

Denzil Daniel; Aavudai Anandhi; Sumit Sen. Conceptual Model for the Vulnerability Assessment of Springs in the Indian Himalayas. Climate 2021, 9, 121 .

AMA Style

Denzil Daniel, Aavudai Anandhi, Sumit Sen. Conceptual Model for the Vulnerability Assessment of Springs in the Indian Himalayas. Climate. 2021; 9 (8):121.

Chicago/Turabian Style

Denzil Daniel; Aavudai Anandhi; Sumit Sen. 2021. "Conceptual Model for the Vulnerability Assessment of Springs in the Indian Himalayas." Climate 9, no. 8: 121.

Journal article
Published: 20 April 2021 in Journal of Hydrology
Reads 0
Downloads 0

Springs are an indispensable source of freshwater for mountain communities in the Indian Himalayan Region (IHR). Owing to the synergistic impact of anthropogenic and climatic factors, numerous perennial springs and streams in the region, are either becoming ephemeral or drying out, thus impacting the local people. Water scarcity, poverty, and limited scope of alternate livelihoods further reduce the communities’ resilience. Our focus is to assess the potential of reviving drying springs with the help of hydro-geological studies in water-scarce villages. The methodology involved high-resolution data monitoring of springs and first-order streams in two headwater micro-watersheds, namely, Shiv gadera and Haraita, in the rural Himalayas of Uttarakhand, India, with unalike topography and geology. To understand the hydro-geological processes and assess the flow regimes and aquifer storage dynamics, we applied water balance, correlation, flow duration, master recession curves analysis, and geological studies. The univariate and bivariate analysis shows that Shiv gadera has a better system memory, indicating a larger storage capacity than Haraita. The spring hydrograph responses also append that Shiv gadera has better storage and has a homogenous aquifer feed. The water balance, however, is in positive storage only during the rainy months in both the sites. The hydro-geological characterization from hydrograph analysis, recession analysis, and field surveys shows that Shiv gadera has intricate flow networks and slow flow velocities while Haraita is characteristic of transmissive fractured rocks. The spring flows in Shiv gadera are observed to be perennial and more groundwater contributes to spring discharges while Haraita exhibits intermittent to ephemeral nature. The recession curves also indicate uniform geology, a distinctive feed from recharge area, and slow emptying of the aquifer, while Haraita exhibits shallow storage and quick responses to storms. Spring flows in Shiv gadera show better stability than Haraita, as indicated by Q10/Q90 and Q50/Q90 measurements. These inferences qualify Shiv gadera as having a better chance of responding to management and treatments, thus a better potential for revival. The combination of hydrologic time series analysis and geological characterization used in this study could be a valuable approach for assessing spring revival in the IHR and has a potential for implementation across other parts of the Himalayas.

ACS Style

Bhargabnanda Dass; Abhishek; Sumit Sen; Vargish Bamola; Anita Sharma; Debashish Sen. Assessment of spring flows in Indian Himalayan micro-watersheds – A hydro-geological approach. Journal of Hydrology 2021, 598, 126354 .

AMA Style

Bhargabnanda Dass, Abhishek, Sumit Sen, Vargish Bamola, Anita Sharma, Debashish Sen. Assessment of spring flows in Indian Himalayan micro-watersheds – A hydro-geological approach. Journal of Hydrology. 2021; 598 ():126354.

Chicago/Turabian Style

Bhargabnanda Dass; Abhishek; Sumit Sen; Vargish Bamola; Anita Sharma; Debashish Sen. 2021. "Assessment of spring flows in Indian Himalayan micro-watersheds – A hydro-geological approach." Journal of Hydrology 598, no. : 126354.

Preprint content
Published: 04 March 2021
Reads 0
Downloads 0

The non-linear behaviour of soil moisture and rainfall influences the hillslope runoff generation mechanism and its thresholds. Inherent complexities of the hydrological processes at micro- to macro-scale hydrological systems need to be studied for identifying dominant connections. In this context, complex network theory is a beneficial tool to deal with all kinds of hydrological connections. To understand the practical implication of complex network theory and to explore out the runoff thresholds of infiltration-excess hillslope, we have selected two experimental hillslopes under two different landuse conditions i.e., agro-forested (AgF) and Grassed (GA) hillslopes. The hillslopes are situated at the Lesser Himalayan region of India. These are instrumented with ten soil moisture and water level sensors for capturing spatio-temporal variation of soil moisture and hillslope runoff at the outlet, respectively. After analyzing 59 rainfall events, we found that runoff generation in GA hillslope is significantly triggered when the 5-min peak rainfall intensity and initial soil moisture conditions exceed 50 mm/h and 0.25 m3/m3, respectively. The runoff generation in AgF hillslope is triggered when the 5-min peak rainfall intensity and initial soil moisture condition exceeds the mark of 12 mm/h and 0.20 m3/m3, accordingly. High intensity with very less duration event cannot generate any runoff at hillslope outlet; however, a low intensity with long duration (> 15h) event could generate small runoff volume at both the hillslopes. After analyzing the runoff threshold, we used complex network theory to understand the connection between runoff and soil moisture for different runoff generating groups. Further, events having high rainfall intensity and high soil moisture condition show the more robust network connectivity between the runoff and the soil moisture points and moderate connectivity among the soil moisture stations. Primarily, in high-intensity events, the strongly connected soil moisture and the runoff nodes represents less runoff from that zone in an infiltration-excess dominated hillslope. The low-intensity rainfall of both the hillslope shows stronger network connectivity among the soil moisture, and the weak network connectivity between the runoff points and the soil moisture points as the events result in less runoff. Networks often contain clusters among the nodes and to measure the local density of these nodes, we calculated the global clustering coefficient (GCC). The GCC of all the selected events declines with an increase in correlation threshold (CT) values which indicate a decrease in network connectivity between the nodes for higher CT. For CT≥ 0.8, the GCC values for the low-intensity events were higher than the high-intensity events, as the soil moisture networks are strong and dense during low-intensity events for high CT values. This study shows the first-time application of network theory to understand the linkage between network topology and hillslope runoff behaviour. However, we encourage the researchers to explore similar approaches in saturation-excess dominated hillslopes where the twining between soil moisture and runoff are different.

ACS Style

Aliva Nanda; Sumit Sen. Exploring Hydrological Connections: A Threshold and Complex Network Based Approach . 2021, 1 .

AMA Style

Aliva Nanda, Sumit Sen. Exploring Hydrological Connections: A Threshold and Complex Network Based Approach . . 2021; ():1.

Chicago/Turabian Style

Aliva Nanda; Sumit Sen. 2021. "Exploring Hydrological Connections: A Threshold and Complex Network Based Approach ." , no. : 1.

Article
Published: 17 February 2021 in Climatic Change
Reads 0
Downloads 0

Lake Ziway, the only freshwater lake in Ethiopia’s Central Rift Valley basin, has been the source for irrigation, floriculture, fish farming and domestic water supply in the region for the last few decades. This study examined the impacts of the planned future agricultural developments and climate change on the lake water balance by an integrated application of the Soil Water Assessment Tool and Water Evaluation and Planning models. The future projections of precipitation and temperature from the Coordinated Regional Downscaling Experiment, CORDEX-AFRICA, under the Representative Concentration Pathways 4.5 and 8.5 were used for the climate change impact assessment. Nine irrigation development and climate change scenarios were developed and simulated to examine the separate and combined impacts on the lake water balance and supply coverages. The study showed that the planned future agricultural developments could result in a mean annual lake water level decline by about 0.15 m, with a considerable reduction (27% to 32%) in the outflow to the downstream Bulbula River. Climate change could increase evaporation losses from the shallow lake resulting in a drastic decrease in the lake water level, especially during the dry season. It could also significantly reduce (by about 74%) the amount of water flowing out of the lake. The combined impacts of future development and climate change are likely to reduce the supply coverages of most of the competing demands. Approaches need to be studied to minimize the lake water evaporation losses and explore water demand/supply management options.

ACS Style

Mulugeta Musie; Andrea Momblanch; Sumit Sen. Exploring future global change-induced water imbalances in the Central Rift Valley Basin, Ethiopia. Climatic Change 2021, 164, 1 -19.

AMA Style

Mulugeta Musie, Andrea Momblanch, Sumit Sen. Exploring future global change-induced water imbalances in the Central Rift Valley Basin, Ethiopia. Climatic Change. 2021; 164 (3):1-19.

Chicago/Turabian Style

Mulugeta Musie; Andrea Momblanch; Sumit Sen. 2021. "Exploring future global change-induced water imbalances in the Central Rift Valley Basin, Ethiopia." Climatic Change 164, no. 3: 1-19.

Journal article
Published: 21 August 2020 in Journal of Hydrology: Regional Studies
Reads 0
Downloads 0

Lake Ziway sub-basin, Central Rift Valley basin, Ethiopia. This study evaluated the applicability of the NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) and the Coordinated Regional Downscaling Experiment (CORDEX-AFRICA) datasets for climate change impact assessment. It also evaluated the hydrologic impact of climate change in the sub-basin. The hydrologic model Soil and Water Assessment Tool (SWAT) was forced with the climate datasets to simulate the reference and future period streamflows under RCP 4.5 and RCP 8.5 scenarios. The seasonality and volumetric deviations of the average annual streamflows simulated using the climate models were used as criteria for selecting members of the ensemble. All the climate models in the bias-corrected NEX-GDDP datasets failed to satisfy the criteria. The ensemble average annual streamflows, simulated using the CORDEX-AFRICA dataset, are expected to increase towards the end of the century under both the climate scenarios. However, the ensemble average dry season streamflows are projected to decrease during the mid- and end-periods of the century. The expected decreases in streamflows during the dry and pre-wet seasons, along with excessive abstractions of water from Lake Ziway, would exacerbate water scarcity in the basin. Approaches need to be developed to capture the increase in water availability during the wet season to alleviate water scarcity during the dry season.

ACS Style

Mulugeta Musie; Sumit Sen; Puneet Srivastava. Application of CORDEX-AFRICA and NEX-GDDP datasets for hydrologic projections under climate change in Lake Ziway sub-basin, Ethiopia. Journal of Hydrology: Regional Studies 2020, 31, 100721 .

AMA Style

Mulugeta Musie, Sumit Sen, Puneet Srivastava. Application of CORDEX-AFRICA and NEX-GDDP datasets for hydrologic projections under climate change in Lake Ziway sub-basin, Ethiopia. Journal of Hydrology: Regional Studies. 2020; 31 ():100721.

Chicago/Turabian Style

Mulugeta Musie; Sumit Sen; Puneet Srivastava. 2020. "Application of CORDEX-AFRICA and NEX-GDDP datasets for hydrologic projections under climate change in Lake Ziway sub-basin, Ethiopia." Journal of Hydrology: Regional Studies 31, no. : 100721.

Journal article
Published: 05 March 2020 in Water
Reads 0
Downloads 0

Soil temperature plays an important role in understanding hydrological, ecological, meteorological, and land surface processes. However, studies related to soil temperature variability are very scarce in various parts of the world, especially in the Indian Himalayan Region (IHR). Thus, this study aims to analyze the spatio-temporal variability of soil temperature in two nested hillslopes of the lesser Himalaya and to check the efficiency of different machine learning algorithms to estimate soil temperature in the data-scarce region. To accomplish this goal, grassed (GA) and agro-forested (AgF) hillslopes were instrumented with Odyssey water level and decagon soil moisture and temperature sensors. The average soil temperature of the south aspect hillslope (i.e., GA hillslope) was higher than the north aspect hillslope (i.e., AgF hillslope). After analyzing 40 rainfall events from both hillslopes, it was observed that a rainfall duration of greater than 7.5 h or an event with an average rainfall intensity greater than 7.5 mm/h results in more than 2 °C soil temperature drop. Further, a drop in soil temperature less than 1 °C was also observed during very high-intensity rainfall which has a very short event duration. During the rainy season, the soil temperature drop of the GA hillslope is higher than the AgF hillslope as the former one infiltrates more water. This observation indicates the significant correlation between soil moisture rise and soil temperature drop. The potential of four machine learning algorithms was also explored in predicting soil temperature under data-scarce conditions. Among the four machine learning algorithms, an extreme gradient boosting system (XGBoost) performed better for both the hillslopes followed by random forests (RF), multilayer perceptron (MLP), and support vector machine (SVMs). The addition of rainfall to meteorological and meteorological + soil moisture datasets did not improve the models considerably. However, the addition of soil moisture to meteorological parameters improved the model significantly.

ACS Style

Aliva Nanda; Sumit Sen; Awshesh Nath Sharma; K. P. Sudheer. Soil Temperature Dynamics at Hillslope Scale—Field Observation and Machine Learning-Based Approach. Water 2020, 12, 713 .

AMA Style

Aliva Nanda, Sumit Sen, Awshesh Nath Sharma, K. P. Sudheer. Soil Temperature Dynamics at Hillslope Scale—Field Observation and Machine Learning-Based Approach. Water. 2020; 12 (3):713.

Chicago/Turabian Style

Aliva Nanda; Sumit Sen; Awshesh Nath Sharma; K. P. Sudheer. 2020. "Soil Temperature Dynamics at Hillslope Scale—Field Observation and Machine Learning-Based Approach." Water 12, no. 3: 713.

Journal article
Published: 05 January 2020 in Water
Reads 0
Downloads 0

Hydrological impacts of human activities and climate variability on Ketar and Meki watersheds of Lake Ziway basin, Ethiopia were studied using the soil and water assessment tool. Three land-use change and two climate variability scenarios were considered to analyze the separate and combined impacts on annual water balance, monthly streamflow, and spatial distributions of evapotranspiration and water yield. The evaluation showed that changes in land use resulted in an increase in annual surface runoff and water yield for Ketar watershed and an increase in annual ET for Meki. Similarly, the climate variability resulted in a decrease in annual ET, surface runoff, and water yield for Ketar watershed and a decrease in ET for Meki. Overall, climate variability has greater impacts on the monthly streamflow compared to land-use change impacts. Similarly, greater sensitivity in hydrologic response was observed for Ketar watershed compared to Meki watershed.

ACS Style

Mulugeta Musie; Sumit Sen; Indrajeet Chaubey. Hydrologic Responses to Climate Variability and Human Activities in Lake Ziway Basin, Ethiopia. Water 2020, 12, 164 .

AMA Style

Mulugeta Musie, Sumit Sen, Indrajeet Chaubey. Hydrologic Responses to Climate Variability and Human Activities in Lake Ziway Basin, Ethiopia. Water. 2020; 12 (1):164.

Chicago/Turabian Style

Mulugeta Musie; Sumit Sen; Indrajeet Chaubey. 2020. "Hydrologic Responses to Climate Variability and Human Activities in Lake Ziway Basin, Ethiopia." Water 12, no. 1: 164.

Journal article
Published: 20 September 2019 in Journal of Hydrology
Reads 0
Downloads 0

The objective of this study was to evaluate the hydrologic performance of gridded precipitation datasets for streamflow simulation in Ethiopia. Four products are prominent in the literature, namely Climate Forecast System Reanalysis (CFSR), Climate Hazards Group Infra-Red Precipitation with Station (CHIRPS), Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Climate Data Record (PERSIANN-CDR), and Tropical Rainfall Measuring Mission (TRMM) 3B42 Version 7 (3B42V7). The datasets from these products were compared statistically with the gauge observation dataset. Furthermore, the hydrologic performance of the products was evaluated using the Soil and Water Assessment Tool (SWAT) hydrologic model in two watersheds of the Lake Ziway basin. Four statistical and three contingency indices were used to compare the precipitation products statistically, and Nash-Sutcliffe efficiency (NSE), percent bias (PBIAS) and the ratio of mean square error (RSR) were used to compare streamflow simulations. All the satellite-based precipitation products (CHIRPS, PERSIANN-CDR, and TRMM) performed well for monthly streamflow simulations for both watersheds. The reanalysis product CFSR performed the worst with high mean error (ME) and relative bias ratio (BIAS). The high ME and BIAS values of CFSR adversely affected the hydrologic performance and resulted in unsatisfactory streamflow simulation. Performance of the CHIRPS precipitation product in capturing daily and monthly streamflows showed that it can provide valuable precipitation estimates for use as input in hydrologic models in data-sparse regions of developing countries such as Ethiopia.

ACS Style

Mulugeta Musie; Sumit Sen; Puneet Srivastava. Comparison and evaluation of gridded precipitation datasets for streamflow simulation in data scarce watersheds of Ethiopia. Journal of Hydrology 2019, 579, 124168 .

AMA Style

Mulugeta Musie, Sumit Sen, Puneet Srivastava. Comparison and evaluation of gridded precipitation datasets for streamflow simulation in data scarce watersheds of Ethiopia. Journal of Hydrology. 2019; 579 ():124168.

Chicago/Turabian Style

Mulugeta Musie; Sumit Sen; Puneet Srivastava. 2019. "Comparison and evaluation of gridded precipitation datasets for streamflow simulation in data scarce watersheds of Ethiopia." Journal of Hydrology 579, no. : 124168.

Journal article
Published: 14 September 2019 in Journal of Hydrology
Reads 0
Downloads 0

This study demonstrated the spatiotemporal variation in runoff generating areas in grassed and agro-forested hillslopes of Lesser Himalaya using soil moisture, soil hydraulic conductivity and rainfall datasets. Nine rainfall events of infiltration-excess dominated hillslopes were analysed and found that only high-intensity rainfall events were able to convert 1–5% of runoff at the outlet. The extremely low patch of soil hydraulic conductivity (<5 mm/h) was located at the outlet in agro-forested hillslope whereas similar low soil hydraulic conductivity patch is located at the end portion in a grassed hillslope. Therefore, the grassed hillslope generated less runoff than the agro-forested hillslope due to its surface resistance and heterogeneity in soil hydraulic conductivity. The runoff generated from the upper part of hillslope re-infiltrated into the middle part due to higher soil hydraulic conductivity. During low and medium intensity rainfall conditions, major runoff contribution was observed from low conductivity zones of the hillslope. Moreover, we analysed the correlation of spatial variation in soil moisture with topographic wetness index (TWI) and soil hydraulic conductivity in two different landuse conditions to examine the predictive potential of these attributes during the wet and dry season. The optimal formulation of TWI was obtained from 72 different combinations using linear mixed effects modelling. The correlation between optimal TWI formulation and soil moisture was found to be negative as the main streamline is located near low conductivity zones. Furthermore, the correlation between TWI and soil moisture is stronger in the dry season than the wet season. In comparison to grass cover hillslope, agro-forested landuse system shows better negative correlation between soil moisture and TWI during the wet season as the agro-forested hillslope produced more runoff than the grassed hillslope. The correlation strength of soil hydraulic conductivity and soil moisture was strongest after mid of the wet season which is directly correlated to the moisture content of hillslopes.

ACS Style

Aliva Nanda; Sumit Sen; James P McNamara. How spatiotemporal variation of soil moisture can explain hydrological connectivity of infiltration-excess dominated hillslope: Observations from lesser Himalayan landscape. Journal of Hydrology 2019, 579, 124146 .

AMA Style

Aliva Nanda, Sumit Sen, James P McNamara. How spatiotemporal variation of soil moisture can explain hydrological connectivity of infiltration-excess dominated hillslope: Observations from lesser Himalayan landscape. Journal of Hydrology. 2019; 579 ():124146.

Chicago/Turabian Style

Aliva Nanda; Sumit Sen; James P McNamara. 2019. "How spatiotemporal variation of soil moisture can explain hydrological connectivity of infiltration-excess dominated hillslope: Observations from lesser Himalayan landscape." Journal of Hydrology 579, no. : 124146.

Journal article
Published: 03 June 2019 in Agricultural Water Management
Reads 0
Downloads 0

For efficient irrigation management practices, an accurate prediction of water uptake in the root zone and soil information are foremost important. The present study deals with the identification and estimation of root water uptake (RWU) and soil hydraulic parameters using inverse modeling. These parameters were estimated by minimizing the difference between observed and model simulated soil moisture and deep percolation during the crop growth period. The linked simulation optimization model is tested for three different objective functions using hypothetically generated observed data. Results indicate that the optimizer with objective function defined by soil moisture, failed to provide unique estimate of RWU and soil hydraulic parameters. Further, it has been observed that with the objective function defined by deep percolation, soil hydraulic parameters were uniquely estimated but RWU parameter was not estimated accurately. However, with the objective function, that includes both soil moisture and deep percolation, these parameters were uniquely estimated. A Lysimeter experiments were conducted with four crops i.e. berseem (Trifolium alexandrinum), wheat (Triticum aestivum), maize (Zea mays) and pearl millet (Pennisetum glaucum). Daily monitoring of soil moisture and deep percolation along with soil and crop parameter measurements were done for model validation. Inversely estimated soil hydraulic parameters were found to be in close agreement with laboratory obtained values. The results indicate that specifically for soils with high hydraulic conductivity, the information about deep percolation along with soil moisture is necessary for inverse estimation of root and soil parameters simultaneously. The moisture depletion pattern and deep percolation corresponding to optimized parameters for these crops were found to be in close agreement with observed values.

ACS Style

Ickkshaanshu Sonkar; Hari Prasad Kotnoor; Sumit Sen. Estimation of root water uptake and soil hydraulic parameters from root zone soil moisture and deep percolation. Agricultural Water Management 2019, 222, 38 -47.

AMA Style

Ickkshaanshu Sonkar, Hari Prasad Kotnoor, Sumit Sen. Estimation of root water uptake and soil hydraulic parameters from root zone soil moisture and deep percolation. Agricultural Water Management. 2019; 222 ():38-47.

Chicago/Turabian Style

Ickkshaanshu Sonkar; Hari Prasad Kotnoor; Sumit Sen. 2019. "Estimation of root water uptake and soil hydraulic parameters from root zone soil moisture and deep percolation." Agricultural Water Management 222, no. : 38-47.

Journal article
Published: 09 May 2019 in Remote Sensing of Environment
Reads 0
Downloads 0

Estimating regional evapotranspiration (ET) is challenging in data-limited regions where a lack of in situ observations constrain model calibration and implementation. Here we developed an ensemble mean surface energy balance (EnSEB) modeling framework that is independent of any ground calibration and applied it in India to understand the magnitude and variability of ET in this agriculturally important region. EnSEB uses daily land surface temperature (LST) and vegetation biophysical inputs from Moderate Resolution Imaging Spectroradiometer (MODIS) and climatic information from the National Aeronautics and Space Administration (NASA) Modern-Era Retrospective Analysis for Research and Applications, version 2 (Merra-2) products and runs seven surface energy balance (SEB) algorithms to estimate ensemble mean ET or latent heat (LE) fluxes at a spatial resolution of 1 km × 1 km. Due to limited access to observed flux data, we conducted three different types of model evaluation: i) instantaneous LE validation using observed SEB fluxes from Bowen ratio energy balance (BREB) measurements in four agroecosystems, ii) annual and seasonal ET comparison with six global products at the regional scale, and iii) by closing the basin-scale monthly water budget (WB) for five large river basins (87,900–312,812 km2) in India. Validation with the BREB measurements revealed hourly EnSEB LE estimates to be within 2% of the observed LE (R2 = 0.57 and RMSE = 59 W m−2) and EnSEB was more accurate than any of the individual SEB models. Annual ET from EnSEB was positively correlated with six widely-used global ET products (r = 0.52–0.83, p-value < 0.001), but EnSEB captured the magnitude of ET in intensively irrigated regions much better. Basin-scale monthly WB miscloures were found to be between −1 and 9 mm month−1 from EnSEB ET estimates, which were better than those from the six global ET products. The gap filling method based on the constant ETrF (ET/reference ET) approach introduced some uncertainties in EnSEB, which presents room for future improvements. Overall, our results suggest that the automated and calibration-free multi-model EnSEB framework, which uses only remote sensing and readily available reanalysis data, has the ability to estimate ET with reliable accuracy in Indian agroecosystems. Such a framework could help us better understand and monitor the water cycle in regions where ground data are limited or non-existent.

ACS Style

Nishan Bhattarai; Kaniska Mallick; Julia Stuart; Bramha Dutt Vishwakarma; Rewati Niraula; Sumit Sen; Meha Jain. An automated multi-model evapotranspiration mapping framework using remotely sensed and reanalysis data. Remote Sensing of Environment 2019, 229, 69 -92.

AMA Style

Nishan Bhattarai, Kaniska Mallick, Julia Stuart, Bramha Dutt Vishwakarma, Rewati Niraula, Sumit Sen, Meha Jain. An automated multi-model evapotranspiration mapping framework using remotely sensed and reanalysis data. Remote Sensing of Environment. 2019; 229 ():69-92.

Chicago/Turabian Style

Nishan Bhattarai; Kaniska Mallick; Julia Stuart; Bramha Dutt Vishwakarma; Rewati Niraula; Sumit Sen; Meha Jain. 2019. "An automated multi-model evapotranspiration mapping framework using remotely sensed and reanalysis data." Remote Sensing of Environment 229, no. : 69-92.

Article
Published: 16 April 2018 in Hydrological Processes
Reads 0
Downloads 0

Soil moisture dynamics have a significant effect on overland flow generation. Catchment aspect is one of the major controlling factors of overland flow and soil moisture behaviour. A few experimental studies have been carried out in the uneven topography of the Himalayas. This study presents plot-scale experiments using portable rainfall simulator at an altitude of 1230 m above mean sea level and modelling of overland flow using observed datasets. Two plots were selected in two different aspects of Aglar watershed of lesser Himalaya; the agro-forested plot was positioned at the north aspect whereas the degraded plot was located at the south aspect of the hillslope. HS flumes and rain gauges were installed to measure the runoff at the outlet of the plot and the rainfall depth during rainfall simulation experiments. Moreover, ten soil moisture sensors were installed at upslope and downslope locations of both the plots at 5, 15, 25, 35 and 45 cm depth from ground level to capture the soil moisture dynamics. The tests were conducted at intensities of 79.8 and 75 mm/hr in agroforested plot and 82.2 and 72 mm/hr in the degraded plot during Test 1 and Test 2, respectively. The observed data indicates the presence of re-infiltration process only in the agro-forested. The high water holding capacity and the presence of re-infiltration process results in less runoff volume in the agro-forested plot compared to the degraded plot. The Hortonian overland flow mechanism was found to be the dominant overland flow mechanism as only a few layers of top soil gets saturated during all of the rainfall-runoff experiments. The runoff, rainfall and soil moisture data were subsequently used to calibrate the parameters of HYDRUS-2D overland flow module to simulate the runoff hydrograph and soil moisture. The components of hydrograph were evaluated in terms of peak discharge, runoff volume and time of concentration, the results were found to be within the satisfactory range. The goodness of fit of simulated hydrographs were more than 0.85 and 0.95 for agro-forested and degraded plot, respectively. The model produced satisfactory simulation results of soil moisture for all of the rainfall-runoff experiments. The HYDRUS-2D overland flow module was found promising to simulate the runoff hydrograph and soil moisture in plot-scale research.

ACS Style

Aliva Nanda; Sumit Sen; Vijay Jirwan; Anupma Sharma; Vikram Kumar. Understanding plot-scale hydrology of Lesser Himalayan watershed-A field study and HYDRUS-2D modelling approach. Hydrological Processes 2018, 32, 1254 -1266.

AMA Style

Aliva Nanda, Sumit Sen, Vijay Jirwan, Anupma Sharma, Vikram Kumar. Understanding plot-scale hydrology of Lesser Himalayan watershed-A field study and HYDRUS-2D modelling approach. Hydrological Processes. 2018; 32 (9):1254-1266.

Chicago/Turabian Style

Aliva Nanda; Sumit Sen; Vijay Jirwan; Anupma Sharma; Vikram Kumar. 2018. "Understanding plot-scale hydrology of Lesser Himalayan watershed-A field study and HYDRUS-2D modelling approach." Hydrological Processes 32, no. 9: 1254-1266.

Original article
Published: 23 May 2017 in Sustainable Water Resources Management
Reads 0
Downloads 0

There is a huge concern that the springs originating naturally from unconfined aquifers which are the main sources of domestic water on mountainous regions are either drying up or becoming seasonal. To understand the behavior of these springs, an analysis of spring discharge recession curve based on Darcian theory is being employed. A fracture- and contact-type spring located in the Aglar watershed has been instrumented for continuous discharge data collection. Objectives of this study are (1) to understand recession curves for different rainfall events, (2) to develop a master recession curve (MRC) and gain integrated information during the lean period and (3) to analyze the flow duration curve (FDC) for estimation of sustainable drinking water supply from spring. Ten major recession events from continuous daily rainfall and discharge data has been selected to understand the flow behavior during recession using exponential, least square, hyperbola and to develop a combined power law and exponential method. This paper also presents the MRC using three recession components (α1, α2, and α3) as compared one recession coefficient. Domestic water requirement and availability is assessed by FDC analysis over the 2 years daily data. Analysis of ten events shows that, the combined power law and exponential relationship fits the recession curve, NSE (0.97–0.99) and RMSE (0.07–0.50) during the dry period in which depletion of flow occurs with low hydraulic conductivity and the exponential component represents its base flow, whereas the least square method fits the recession curve having NSE (0.90–0.99) and RMSE (0.07–0.22) during the wet period. The MRC supports the use of three exponential coefficients over a single exponential coefficient. The change in these ratio (α1/α2) from 5 to 8.76 and (α2/α3) from 9.21 to 2.9 explains the heterogeneity in the spring aquifer. The relationship between (−dQ/dt) and (Q) for recession events has different configuration which characterizes the dynamic behavior of spring. The flow duration curve indicates that there is water scarcity during dry seasons with around 30.6 liter per min could be taken as the characteristic value for the minimum spring flow.

ACS Style

Vikram Kumar; Sumit Sen. Evaluation of spring discharge dynamics using recession curve analysis: a case study in data-scarce region, Lesser Himalayas, India. Sustainable Water Resources Management 2017, 4, 539 -557.

AMA Style

Vikram Kumar, Sumit Sen. Evaluation of spring discharge dynamics using recession curve analysis: a case study in data-scarce region, Lesser Himalayas, India. Sustainable Water Resources Management. 2017; 4 (3):539-557.

Chicago/Turabian Style

Vikram Kumar; Sumit Sen. 2017. "Evaluation of spring discharge dynamics using recession curve analysis: a case study in data-scarce region, Lesser Himalayas, India." Sustainable Water Resources Management 4, no. 3: 539-557.

Journal article
Published: 11 February 2016 in Regional Environmental Change
Reads 0
Downloads 0

This paper explored the linkage between historic, current and future land use/land cover (LULC) conditions and peak flow and runoff volumes in a coastal community in Alabama in an effort to identify critical areas for downstream flooding. The study demonstrated that critical areas cannot be determined intuitively without conducting modeling studies. The study watershed, Eightmile Creek, experienced approximately 48 % forest loss between 1966 and 2011 largely due to urbanization. Residential development is expected to continue mostly in the central part of the watershed in the near future. Historic, current and future LULC maps were developed by processing aerial imagery, which were used in the HEC-HMS hydrologic model to study flood risk. An index method was applied to estimate the contribution of different parts of the watershed to downstream peak flows. The model showed a significant increase in peak flow and runoff volume from 1966 to 2011 and from 2011 to 2022 due to urbanization. The sensitivity of peak flows to LULC change decreased with increasing storm return periods, but the order of importance of different parts of the watershed, in terms of flooding, did not change significantly. Results of this study demonstrate the need for sustainable development by targeting areas that can have the least impacts on downstream flooding. The methodology presented in this paper can help decision makers propose land use alternatives to minimize adverse environmental impacts.

ACS Style

Navideh Noori; Latif Kalin; Sumit Sen; Puneet Srivastava; Charlene Lebleu. Identifying areas sensitive to land use/land cover change for downstream flooding in a coastal Alabama watershed. Regional Environmental Change 2016, 16, 1833 -1845.

AMA Style

Navideh Noori, Latif Kalin, Sumit Sen, Puneet Srivastava, Charlene Lebleu. Identifying areas sensitive to land use/land cover change for downstream flooding in a coastal Alabama watershed. Regional Environmental Change. 2016; 16 (6):1833-1845.

Chicago/Turabian Style

Navideh Noori; Latif Kalin; Sumit Sen; Puneet Srivastava; Charlene Lebleu. 2016. "Identifying areas sensitive to land use/land cover change for downstream flooding in a coastal Alabama watershed." Regional Environmental Change 16, no. 6: 1833-1845.

Journal article
Published: 01 September 2013 in Journal of Environmental Quality
Reads 0
Downloads 0

Subsurface band application of poultry litter has been shown to reduce the transport of nutrients from fields in surface runoff compared with conventional surface broadcast application. Little research has been conducted to determine the effects of surface broadcast application and subsurface banding of litter on nutrients in leachate. Therefore, a field experiment was conducted to determine the effects of subsurface band application and surface broadcast application of poultry litter on nutrient losses in leachate. Zero-tension pan and passive capillary fiberglass wick lysimeters were installed in situ 50 cm beneath the soil surface of an established tall fescue (Festuca arundinacea Schreb.) pasture on a sandy loam soil. The treatments were surface broadcast and subsurface-banded poultry litter at 5 Mg ha−1 and an unfertilized control. Results of the rainfall simulations showed that the concentrations of PO4–P and total phosphorus (TP) in leachate were reduced by 96 and 37%, respectively, in subsurface-banded litter treatment compared with the surface-applied litter treatment. There was no significant difference in PO4–P concentration between control and subsurface-banded litter treatment in leachate. The trend in the loading of nutrients in leachate was similar to the trend in concentration. Concentration and loading of the nutrients (TP, PO4–P, NH4–N, and NO3–N) in runoff from the subsurface-banded treatment were significantly less than for the surface-applied treatment and were similar to those from control plots. These results show that, compared with conventional surface broadcast application of litter, subsurface band application of litter can greatly reduce loss of P in surface runoff and leachate. Copyright © 2013. . Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

ACS Style

Jasmeet Lamba; Puneet Srivastava; Thomas R. Way; Sumit Sen; C. Wesley Wood; Kyung H. Yoo. Nutrient Loss in Leachate and Surface Runoff from Surface-Broadcast and Subsurface-Banded Broiler Litter. Journal of Environmental Quality 2013, 42, 1574 -1582.

AMA Style

Jasmeet Lamba, Puneet Srivastava, Thomas R. Way, Sumit Sen, C. Wesley Wood, Kyung H. Yoo. Nutrient Loss in Leachate and Surface Runoff from Surface-Broadcast and Subsurface-Banded Broiler Litter. Journal of Environmental Quality. 2013; 42 (5):1574-1582.

Chicago/Turabian Style

Jasmeet Lamba; Puneet Srivastava; Thomas R. Way; Sumit Sen; C. Wesley Wood; Kyung H. Yoo. 2013. "Nutrient Loss in Leachate and Surface Runoff from Surface-Broadcast and Subsurface-Banded Broiler Litter." Journal of Environmental Quality 42, no. 5: 1574-1582.

Comparative study
Published: 01 September 2012 in Journal of Environmental Quality
Reads 0
Downloads 0

Buildup of phosphorus (P) in agricultural soils and transport of P to nearby surface waters due to excessive, long-term application of poultry litter is an environmental concern in many poultry-producing states. Watershed models are often used to quantify soil and water quality impacts of poultry litter applications. However, depending on how P transport is simulated in watershed models, the anticipated impact could be quite different. The objective of this study was to determine the predictability and sensitivity of the Soil and Water Assessment Tool (SWAT) P model and a newly developed, state-of-the-art manure P model called SurPhos in a poultry litter–applied pasture watershed. A small, predominantly agricultural watershed in Randolph County, Alabama was used for this study. The SWAT model, calibrated for surface runoff and total stream flows (Nash-Sutcliffe coefficient of 0.70 for both), was used to provide runoff inputs to the SurPhos model. Total dissolved P (TDP) exports simulated by the SWAT P and SurPhos models from the hay hydrological response units of the watershed were compared for different poultry litter application rates and different initial soil Solution P levels. Both models showed sensitivity to poultry litter application rates, with SWAT simulating linear and SurPhos simulating nonlinear increases in TDP exports with increase in poultry litter application rates. SWAT showed greater sensitivity to initial soil Solution P levels, which can lead to overestimation of TDP exports, especially at low poultry litter application rates. As opposed to the SurPhos model simulations and contrary to recent studies, SWAT simulated excessive accumulation of Solution P in the top 10 mm of soil. Because SurPhos appears to simulate P transport and build-up processes from manure-applied areas more accurately, this study suggests that SWAT be replaced by SurPhos to more accurately determine watershed-level effectiveness of P management measures. Copyright © 2012. . Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

ACS Style

Sumit Sen; Puneet Srivastava; Peter A. Vadas; Latif Kalin. Watershed-level Comparison of Predictability and Sensitivity of Two Phosphorus Models. Journal of Environmental Quality 2012, 41, 1642 -1652.

AMA Style

Sumit Sen, Puneet Srivastava, Peter A. Vadas, Latif Kalin. Watershed-level Comparison of Predictability and Sensitivity of Two Phosphorus Models. Journal of Environmental Quality. 2012; 41 (5):1642-1652.

Chicago/Turabian Style

Sumit Sen; Puneet Srivastava; Peter A. Vadas; Latif Kalin. 2012. "Watershed-level Comparison of Predictability and Sensitivity of Two Phosphorus Models." Journal of Environmental Quality 41, no. 5: 1642-1652.

Journal article
Published: 01 January 2012 in Transactions of the ASABE
Reads 0
Downloads 0

Nutrient buildup, mainly phosphorus (P), and loss from fields fertilized with poultry (broiler) litter contribute to eutrophication of surface waters. In the U.S., broiler litter is typically surface-applied, but recently, to reduce surface transport of P and other nutrients, subsurface-banding of broiler litter has been promoted as a new manure application method. The objective of this study was to evaluate differences in nutrient transport between subsurface-banded and surface-applied broiler litter in a tall fescue pasture. Treatments were surface-applied and subsurface-banded broiler litter at a rate of 5.0 Mg ha-1, and no application of litter (control). Results showed that runoff concentrations and loadings of total P (TP), ortho-P (PO4-P), nitrate-nitrogen (NO3-N), and ammonium-N (NH4-N) were reduced by 83%, 88%, 74%, and 80%, respectively, for the subsurface-banded litter as compared to the surface-applied litter. Concentrations and loadings of all nutrients in surface runoff from the subsurface-banded treatment were similar to those from the control. This study showed that subsurface banding of broiler litter can substantially reduce nutrient losses in surface runoff. However, since less than 10% of the simulated rainfall contributed to surface runoff (more than 90% rainfall infiltrated), subsurface transport of nutrients from surface-applied and subsurface-banded litter needs to be studied in field research.

ACS Style

J. Lamba; T. R. Way; P. Srivastava; S. Sen; C. W. Wood; K. H. Yoo. Surface Transport of Nutrients from Surface-Broadcast and Subsurface-Banded Broiler Litter. Transactions of the ASABE 2012, 55, 995 -1002.

AMA Style

J. Lamba, T. R. Way, P. Srivastava, S. Sen, C. W. Wood, K. H. Yoo. Surface Transport of Nutrients from Surface-Broadcast and Subsurface-Banded Broiler Litter. Transactions of the ASABE. 2012; 55 (3):995-1002.

Chicago/Turabian Style

J. Lamba; T. R. Way; P. Srivastava; S. Sen; C. W. Wood; K. H. Yoo. 2012. "Surface Transport of Nutrients from Surface-Broadcast and Subsurface-Banded Broiler Litter." Transactions of the ASABE 55, no. 3: 995-1002.

Journal article
Published: 01 November 2011 in Journal of Soil and Water Conservation
Reads 0
Downloads 0

A physically based, fully distributed Hortonian Infiltration and Runoff/On hydrologic model was used to model infiltration excess as the dominant runoff generation mechanism on a pasture hillslope. The model was evaluated for its applicability to simulate spatial and temporal variability of runoff generation areas observed on a pasture hillslope in the Sand Mountain region of North Alabama, United States. Three rainfall events of varying intensity and duration were simulated for a highly instrumented pasture hillslope to study the dynamics of runoff generation and runon areas. Calibration and cross validation were performed on all three rainfall events. Performance of the Hortonian Infiltration and Runoff/On–simulated hydrographs was evaluated using root mean squared error, coefficient of determination and Nash-Sutcliffe coefficient of efficiency. The calibrated model for the first event resulted in a root mean squared error of 1.18 m3 (41.7 ft3) for runoff volume; the next two events resulted in root mean squared errors of less than 1 m3 (35.3 ft3). Similarly, the coefficient of determination and Nash-Sutcliffe coefficient of efficiency values for all three events were greater than 0.70 for the calibrated model. Results from cross validation showed that the Hortonian Infiltration and Runoff/On model-simulated runoffs were in agreement with the observed data. In addition, the model simulated spatial and temporal variations in runoff generation, and runon areas were in agreement with observed variations. Model results helped explain the interactions among hydrologic and climatic characteristics, such as topography, soil parameters, and rainfall variations, and their connections to surface runoff–generation processes. Although the model does not simulate subsurface lateral flow, it shows promise for identifying runoff generation and runon areas for controlling nonpoint source pollution from pasture hillslopes in this and similar regions.

ACS Style

Sumit Sen; P. Srivastava; T. P. Clement; J. H. Dane; Huan Meng. Simulating hydrologic response of a pasture hillslope in North Alabama using the Hortonian Infiltration and Runoff/On model. Journal of Soil and Water Conservation 2011, 66, 411 -422.

AMA Style

Sumit Sen, P. Srivastava, T. P. Clement, J. H. Dane, Huan Meng. Simulating hydrologic response of a pasture hillslope in North Alabama using the Hortonian Infiltration and Runoff/On model. Journal of Soil and Water Conservation. 2011; 66 (6):411-422.

Chicago/Turabian Style

Sumit Sen; P. Srivastava; T. P. Clement; J. H. Dane; Huan Meng. 2011. "Simulating hydrologic response of a pasture hillslope in North Alabama using the Hortonian Infiltration and Runoff/On model." Journal of Soil and Water Conservation 66, no. 6: 411-422.

Journal article
Published: 16 November 2009 in Hydrological Processes
Reads 0
Downloads 0

This study delineated spatially and temporally variable runoff generation areas in the Sand Mountain region pasture of North Alabama under natural rainfall conditions, and demonstrated that hydrologic connectivity is important for generating hillslope response when infiltration‐excess (IE) runoff mechanism dominates. Data from six rainfall events (13·7–32·3 mm) on an intensively instrumented pasture hillslope (0·12 ha) were analysed. Analysis of data from surface runoff sensors, tipping bucket rain gauge and HS‐flume demonstrated spatial and temporal variability in runoff generation areas. Results showed that the maximum runoff generation area, which contributed to runoff at the outlet of the hillslope, varied between 67 and 100%. Furthermore, because IE was the main runoff generation mechanism on the hillslope, the data showed that as the rainfall intensity changed during a rainfall event, the runoff generation areas expanded or contracted. During rainfall events with high‐intensity short‐ to medium‐duration, 4–8% of total rainfall was converted to runoff at the outlet. Rainfall events with medium‐ to low‐intensity, medium‐duration were found less likely to generate runoff at the outlet. In situ soil hydraulic conductivity (k) was measured across the hillslope, which confirmed its effect on hydrologic connectivity of runoff generation areas. Combined surface runoff sensor and k‐interpolated data clearly showed that during a rainfall event, lower k areas generate runoff first, and then, depending on rainfall intensity, runoff at the outlet is generated by hydrologically connected areas. It was concluded that in IE‐runoff‐dominated areas, rainfall intensity and k can explain hydrologic response. The study demonstrated that only connected areas of low k values generate surface runoff during high‐intensity rainfall events. Identification of these areas would serve as an important foundation for controlling nonpoint source pollutant transport, especially phosphorus. The best management practices can be developed and implemented to reduce transport of phosphorus from these hydrologically connected areas. Copyright © 2009 John Wiley & Sons, Ltd.

ACS Style

Sumit Sen; Puneet Srivastava; Jacob H. Dane; Kyung H. Yoo; Joey N. Shaw. Spatial-temporal variability and hydrologic connectivity of runoff generation areas in a North Alabama pasture-implications for phosphorus transport. Hydrological Processes 2009, 24, 342 -356.

AMA Style

Sumit Sen, Puneet Srivastava, Jacob H. Dane, Kyung H. Yoo, Joey N. Shaw. Spatial-temporal variability and hydrologic connectivity of runoff generation areas in a North Alabama pasture-implications for phosphorus transport. Hydrological Processes. 2009; 24 (3):342-356.

Chicago/Turabian Style

Sumit Sen; Puneet Srivastava; Jacob H. Dane; Kyung H. Yoo; Joey N. Shaw. 2009. "Spatial-temporal variability and hydrologic connectivity of runoff generation areas in a North Alabama pasture-implications for phosphorus transport." Hydrological Processes 24, no. 3: 342-356.

Journal article
Published: 15 October 2008 in Hydrological Processes
Reads 0
Downloads 0
ACS Style

Sumit Sen; Puneet Srivastava; Kyung H. Yoo; Jacob H. Dane; Joey N. Shaw; Moon S. Kang. Runoff generation mechanisms in pastures of the Sand Mountain region of Alabama-a field investigation. Hydrological Processes 2008, 22, 4222 -4232.

AMA Style

Sumit Sen, Puneet Srivastava, Kyung H. Yoo, Jacob H. Dane, Joey N. Shaw, Moon S. Kang. Runoff generation mechanisms in pastures of the Sand Mountain region of Alabama-a field investigation. Hydrological Processes. 2008; 22 (21):4222-4232.

Chicago/Turabian Style

Sumit Sen; Puneet Srivastava; Kyung H. Yoo; Jacob H. Dane; Joey N. Shaw; Moon S. Kang. 2008. "Runoff generation mechanisms in pastures of the Sand Mountain region of Alabama-a field investigation." Hydrological Processes 22, no. 21: 4222-4232.