Center for Environmental Sciences & Engineering

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Shiv Nadar University

India and Nepal not only share common borders and cultures, but also share precious freshwater sources, i.e., rivers. Rivers have been discussed often in the political corridors because they cross international borders, which transform water reserves into a competitive resource and lead to hydropolitical dynamics between riparian countries. Nepal and India are two of the major riparian nations that share the mighty and complex Ganges Basin. The objective here was to study the more-than-a-century-old hydro-diplomacy between India and Nepal, passing through tumultuous political scenarios to understand how water relations have been shaped and reshaped with time. For this, a database of historical individual events/actions of water cooperation and conflict from 1874 to 2014 was compiled. These events/actions were ranked by intensity, using precise definitions of conflict and cooperation as suggested by the Transboundary Freshwater Dispute Database under the Basins at Risk project formulated at Oregon State University. Statistical analyses indicated cooperative events greatly outnumbered conflictive events. Out of 351 events, only 4% were conflictive, 92% were cooperative, and the remaining 4% were neutral. The study revealed an abundance of cooperative events; however, when seen through the lens of conflict-cooperation levels, the findings indicated a moderately positive cooperation, without much concrete action. © IWA Publishing 2017.

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Water Policy

Hydropolitics and hydropolitical dynamics between India and Nepal: An event-based study

Studies of annual peak discharge and its temporal variations are widely used in the planning and decision making process of water resources management. Very recently, soft computing techniques are gaining ground for time series analysis of hydrological events such as rainfall and runoff. In this study Artificial Neural Network (ANN) has been used in combination with wavelet to model the annual maximum flow discharge of rivers. The results of ANN-Wavelet (WANN) model indicate overall low coherence (R2 = 0.39) better than ANN (R2 = 0.31) in isolation. In the present analysis, the authors also conceded a probabilistic distributional analysis of river flow time series which has greater potential to better reflect peak flow dynamics. The results highlight that the overall performance of probability distribution models is superior to WANN model. Instead of that WANN is better than probabilistic models to find the global maxima of the series. © 2015 Faculty of Engineering, Ain Shams University

Ain Shams Engineering Journal

Computational approaches for annual maximum river flow series

Turbulent phenomenon in braided rivers is much more complex as compared to the straight and meandering rivers. Turbulent flow characteristics around the braid bar are not thoroughly studied till now. The results of measurements of three-dimensional velocities carried out in a laboratory model of braided river are presented in this paper. Velocity is measured with the help of acoustic Doppler velocimeter. The main purpose of the study is the recognition of structure of Reynolds stresses in turbulent flow near the bar. Sweep quadrant event is considered to be the most important for entrainment of sediment particles as it exerts forces in the flow direction resulting in rolling and sliding of sediment particle. Similarly, the ejection event has been considered important for sediment transport since these events maintain the sediment particles in suspension. Special attention has been given to sweep and ejection bursting events due to their relation with the sediment entrainment and transport. The fractional Reynolds stresses are examined by a quadrant technique with an arbitrarily chosen hole size. It has been observed near the bed, the largest fractional Reynolds stress contribution comes from the second quadrant and the fourth quadrant. Angle of sweep and ejection events was plotted against the flow depth, in order to relate the sweep and ejection events with the scouring/depositional pattern around the bar. The maximum residence time of each event is also computed. From computation, it was found that the maximum residence time of the even events is much greater than for the odd events near the bed. In order to examine the depth-wise distribution of turbulent flow, Reynolds stress and higher moment Fku are plotted against the flow depth. These parameters assess the sediment characteristics in the vicinity of the bar. Results show that the Fku parameter better assesses the sediment characteristics of flow around the bar. © 2017 Indian Society for Hydraulics.

ISH Journal of Hydraulic Engineering

Analysis of turbulent flow characteristics in the vicinity of the bar in a braided river model

Rapid increases in demand for food and energy as a result of population growth and economic development is placing ever increasing demands on limited water resources in South Asia, and climate change is expected further complicate water resource management. In spite of important reductions in poverty levels in recent decades the region is still home to a very large number of poor whose quality of life is directly affected by the availability and quality of water and water services. A significant fraction of the water resources of the region and a significant fraction of the poor are associated with major Himalayan transboundary rivers, and given growing water demand it is likely that the already significant sensitivity around water cooperation amongst co-riparians will increase. Understanding the risks and opportunities for transboundary cooperation in the river systems in South Asia is thus important for guiding sustainable transboundary basin management in the region. This study refines a novel method for a rapid assessment of these cooperation risks and opportunities and applies it to the Brahmaputra, Ganges and Indus river basins to test its utility. The method employs a fuzzy synthetic evaluation technique that combines fuzzy logic and an analytical hierarchy process to assess cooperation risk and opportunity in terms of a Risk-Opportunity Index (ROI). The ROI is a function of four composite development variables and three hegemony variables that indicate the various pressures on the basin water resource and the different control strategies riparians could adopt given existing power asymmetries. In the absence of a clear rationale for differential weighting, equal weights were assigned to all seven variables for this application. A “defuzzification” scoring method is used to define compromising, risk-averse and risk-taking variants of ROI for riparian pairs within each basin. Overall, the results for the compromising ROI suggest that the opportunities for bilateral cooperation are highest (and risks the lowest) in the Brahmaputra Basin and the opportunities are lowest (and the risks highest) in the Indus Basin. This overall assessment is consistent with current common perception. Within the basins the compromising ROI values suggest a few instances of high risk and/or low opportunity, as well as an approximately equal number of instances of medium risk/opportunity and low risk/high opportunity. The study demonstrates that the fuzzy synthetic evaluation technique has utility for rapidly identifying potential opportunities for riparian cooperation in transboundary basins, in order to guide dialogue processes and more detailed analyzes. The study also however, reveals some aspects of the method where further refinement would likely yield more reliable assessments of cooperation risks and opportunities. Specifically, further refinements could consider the relative geographic position of co-riparians within a basin, and the relative resource access of different riparians. The method only considers bilateral riparian interactions and not more complex multi-lateral interactions. The results of study may contribute to various ongoing regional and basin dialogues on water cooperation in South Asia. © 2017, Springer Science+Business Media Dordrecht.

Water Resources Management

Risk and Opportunity Assessment for Water Cooperation in Transboundary River Basins in South Asia

23rd Canadian Hydrotechnical Conference, Held as part of the Canadian Society for Civil Engineering Annual Conference and General Meeting 2017

Development and field application of the RCC Jack Jetty for river training

To support the GPM mission which is homologous to its predecessor, the Tropical Rainfall Measuring Mission (TRMM), this study has been undertaken to evaluate the accuracy of Tropical Rainfall Measuring Mission multi-satellite precipitation analysis (TMPA) daily-accumulated precipitation products for 5 years (2008–2012) using the statistical methods and contingency table method. The analysis was performed on daily, monthly, seasonal and yearly basis. The TMPA precipitation estimates were also evaluated for each grid point i.e. 0.25° × 0.25° and for 18 rain gauge stations of the Betwa River basin, India. Results indicated that TMPA precipitation overestimates the daily and monthly precipitation in general, particularly for the middle sub-basin in the non-monsoon season. Furthermore, precision of TMPA precipitation estimates declines with the decrease of altitude at both grid and sub-basin scale. The study also revealed that TMPA precipitation estimates provide better accuracy in the upstream of the basin compared to downstream basin. Nevertheless, the detection capability of daily TMPA precipitation improves with increase in altitude for drizzle rain events. However, the detection capability decreases during non-monsoon and monsoon seasons when capturing moderate and heavy rain events, respectively. The veracity of TMPA precipitation estimates was improved during the rainy season than during the dry season at all scenarios investigated. The analyses suggest that there is a need for better precipitation estimation algorithm and extensive accuracy verification against terrestrial precipitation measurement to capture the different types of rain events more reliably over the sub-humid tropical regions of India. © 2016, Springer-Verlag Wien.

Theoretical and Applied Climatology

Evaluation of TRMM multi-satellite precipitation analysis (TMPA) against terrestrial measurement over a humid sub-tropical basin, India

A process-oriented hydrological model J2000 was employed on daily and monthly time steps for run-off simulation under Indian condition for the years 2003-2010.Further, a validated model was used for water balance assessment of the basin under both present scenario and hypothetical variations in precipitation and temperature. The regional sensitivity analysis (RSA) approach was employed for sensitivity analysis to determine the critical input parameter of the study area. It is inferred that recession coefficient for overland flow (soilConcRD1) is the most sensitive parameter, followed by recession coefficient for interflow (soilConcRD2) and linear reduction coefficient for AET (soilLinRed). Four evaluation criteria, i.e. coefficient of correlation (R), Nash-Sutcliffe efficiency (NSE), percent bias (PBIAS) and root-mean-square error (RMSE) observation standard deviation ratio (RSR), were adopted, for judging the model’s performance. For daily time steps, the PBIAS, R, NSE and RSR were found to be 4.73, 0.85, 0.67 and 0.45, respectively, during calibration and -1.50, 0.92, 0.85 and 0.29, respectively, during validation of the model. For monthly time steps, the PBIAS, R, NSE and RSR were found to be 4.73, 0.88, 0.7 and 0.43, respectively, during calibration and -1.50, 0.94, 0.89 and 0.26, respectively, during validation of the model. Further, model-simulated run-off components are overland flow (RD1), model’s interflow components (RD2 and RG1) and baseflow component (RG2), and the percent contribution was found to be 43.1%, 35.8% and 21.1%, respectively. The water balance analysis carried out in the study demonstrated that the annual average precipitation in the basin is about 1,388 mm, out of which about 21% flows out as run-off, 22% as groundwater and about 56% as evapotranspiration. The higher value of evaluation criteria indicates that the model is efficient in imitating the hydrological phenomenon of the Kopili River basin fairly well and can be cogitated as a promising tool to understand the constantly changing hydrological processes of Northeast (NE) India. Moreover, the hypothetical temperature increases due to the lowest emission scenario (1.1-2.9 °C), and the highest emission scenario (2.4-6.4 °C) of the IPCC (Climate change 2007: the physical science basis. Contribution of working group I. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller HL (eds) Fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, UK, 2007) indicates that the higher evapotranspiration is mainly resulting in low surface run-off and groundwater contribution. The run-off fluctuations resulting from ±10% variation in precipitation were also analysed and were found to be approx. ±18% deviation from simulated run-off. This analysis will be useful to understand the verge of hydrological processes in anticipation of global climate change (CC) and finally for sustainable water resource management in the NE region of India. © 2017 Springer Science+Business Media Singapore.

River System Analysis and Management

Distributed hydrological modelling under hypothetical climate change scenario for a sub-basin of the brahmaputra river

Environmental Policy and Law

Transboundary Water Sharing: Issues Involved

The present study describes the methods of bed shear stress estimation, numerical estimate of velocity distribution and quadrant events on different hydraulic roughness. Quadrant events of velocity signify the contribution of velocity to generate shear. Experimental data sets of velocities were collected over bed with different hydraulic roughness. In the present work, a turbulent kinetic energy method is anticipated as more reliable to describe the bed shear stress in open channels. These data analysis express that the quadrant events associated with flow is influenced inherently by the bed roughness. Percentage distribution of first and fourth quadrant looks like a wine cup which is wider in the case of hydraulically smooth conditions and getting narrower as the bed roughness increased. It is also a sign of increasing randomness throughout the depth with increased roughness. It is found that at same relative depth for three different roughness conditions, eddy motions are displaying more uncertainty for hydraulically rough condition. Increase in bed roughness augments randomness of Reynolds stress at relative depth 0.05-0.4. The analysis relies on relative depth, which can for imply the local phenomenon and this local phenomenon of velocity on different bed roughness condition was also investigated in this paper. © 2015 Indian Society for Hydraulics.

Interaction between flow hydrodynamics and bed roughness in alluvial channel

The Brahmaputra River in the Northeastern State of Assam in India is characterized by its exceedingly high discharge with enormous sediment load, spatio-temporal variation in channel morphology, substantially high bed aggradations, and severe bank line erosion. The river maintains almost continuous channel braiding in most of its segments in the alluvial floodplains of Assam. One-dimensional (1-D) flow models are insufficient to tackle problems of braided streams due to lack of information with regard to transverse flow field. Hence, for better and more realistic flow field assessment, two-dimensional (2-D) or three-dimensional (3-D) numerical models are to be used. 3-D models are numerically too expensive for macro scale river reaches. Hence, 2-D enhanced model with secondary flow corrections in governing equations may be used. After successful implementation of 1-D mathematical model for a braided stretch of Brahmaputra River, 2-D enhanced numerical model with boundary-fitted coordinate system for the same stretch has been developed and verified. A new planform index is proposed namely braid power. It increases with decrease in incoming discharge into the reach in a particular instance of time. The measured braiding indicator, namely, Plan Form Index (PFI) using high-resolution satellite data application, is found to be quite useful for the monitoring and analysis of persistent and complex braiding behavior of a large river like the Brahmaputra. The erosion study based on satellite data based analysis conclusively identifies three to four major geological channel nodal points present along the Brahmaputra River. The variability of stream power with bank erosion and braiding process is investigated. A distinct behavioral pattern between these is observed. For example, with low stream power, braiding appears to intensify which in result may reflect a higher possibility of bank erosion. © 2017 Springer Science+Business Media Singapore.