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The ship-generated waves in restricted waterways can influence the behavior of sediment resuspension and bank erosion. This paper explores the case study considering the effect of ship-generated waves in restricted channels. A fully nonlinear Boussinesq model (FUNWAVE-TVD) is used to simulate the ship-generated waves. The sediment transport model adopted in FUNWAVE has been changed to incorporate the modified diffusion coefficients, deposition flux, and an explicit equation for settling velocity and critical shield parameter. The sediment transport model was validated against the experimental results of solitary waves in a wave tank, and model performance in shoreline geometry was reported. The implementation of the moving vessel in the numerical model and its impact on suspended sediment concentration were evaluated against the field measurements in the Falta stretch of the Hooghly river in Indian National Waterway 1. The error value in predicting the depth-averaged suspended sediment concentration by the FUNWAVE module was 97.6%, which has been significantly reduced to 16.3% based on the present modification. The parametric study of the ship waves in a typical restricted waterway of India revealed that the concentration of the sediments gradually decreases from the navigation channel to the river banks due to dissipation in the ship waves. The change in wave height and depth-averaged sediment concentration increases with the increasing depth Froude number. Finally, the impact on sediment transport due to different scenarios, such as the movement of two vessels in close proximity, the passage of vehicles coming from the opposite direction on the navigation channel, the influence of small draft vessels, and the bed morphology changes due to the multiple vessel movements are analyzed and reported. [ABSTRACT FROM AUTHOR]

Sandy beaches generally are influenced by various coastal dynamic processes and undergo constant changes. The present study is an attempt to understand the hydromorphodynamic characteristics of a sandy pocket beach situated along the central west coast of India through field observation and numerical modeling. Multiple oceanographic instruments are deployed to capture the actual nearshore hydrodynamics, and sediment transport is measured using the streamer trap method suggested earlier during the premonsoon season. The observed vertical distribution of sediment fluxes showed a typical upward decrease from the seabed to the water surface. It is also noted that nearly 75% of the trap measurements showed that near-bed transport is higher than the depth-integrated values, confirming that the maximum sand remobilization is in the vicinity of the seabed rather than in suspension. The beach profiles of selected transects were measured during the pre- and postmonsoon seasons to understand the bed evolution. A one-dimensional numerical model, developed using XBeach and validated with field-observed values, demonstratively captured the effect of monsoon hydrodynamics on the beach profiles with fair accuracy. The various significant numerical parameters that govern the morphodynamics in the sandy beach are evaluated through a comprehensive analysis. In the end, the simulated beach profile that captures the effect of monsoon and storm are in good agreement with that obtained from field observations, with Brier Skill Scores (BSSs) of 0.69, 0.76, and 0.74 for Profiles 1, 2, and 3, respectively. [ABSTRACT FROM AUTHOR]

Watershed models supported by a geographic information system (GIS) and remote sensing data have proven to be vital research tools for the planning and management of land and water resources at watershed or river basin scales. The present study was undertaken with the objective of evaluating a watershed model for the simulation of streamflow and sediment yield in the Baitarani watershed of Eastern India. The watershed model was calibrated and validated using daily rainfall and streamflow data from 1998 to 2005 and sediment yield data from 2002 to 2005. Other input parameters of the watershed model such as digital elevation model, soil map, and land use/land cover map were generated using GIS. The performance of the model was evaluated using salient statistical and graphical indicators. The model calibration and validation results revealed that the watershed model simulated streamflow in the study watershed with a higher level of accuracy at daily [Nash-Sutcliffe efficiency (NSE) = 0.86 and 0.84] and monthly (NSE = 0.95 and 0.93) time steps during both calibration and validation periods. However, the model simulated sediment yields more accurately at the monthly time step (NSE = 0.91 and 0.90) than the daily time step (NSE = 0.62 and 0.59). During the entire period of sediment simulation (2002-2005), the total model-simulated sediment yield was 1,771 x 10³ tons against the observed sediment yield of 1,799 x 10³ tons with a deviation of approximately 1.6%. It is concluded that the watershed model is suitable for the simulation of streamflow and sediment transport in the study area, and it also has potential for adoption in other watersheds of the Baitarani River Basin as well as in other watersheds of India. [ABSTRACT FROM AUTHOR]

Due to an increase in deforestation and construction activities in the Himalayan region, there is an increase in sediment laden flow in many rivers, such as the Ganges, which originate from the Himalayan region. Many cities, located along these rivers, withdraw river water through abstraction wells located close to river banks and it is of growing interest to know how the sediment load increase in the source water may affect the turbidity, also a measure of sediment load, in the abstracted water. With this in mind, a study has been carried out to assess the variation of turbidity in the source water and the abstracted water at a river bank filtration site in Haridwar, located on the bank of the River Ganges and at the foothills of the Himalayas, for the period 2005-2006. It is found that the turbidity removal coefficient varies with the natural logarithm of influent concentration of the source water. A theoretical development, based on the use of the Sakthivadivel and Einstein model, is also provided to justify the removal coefficient's logarithmic variation with the influent concentration. [ABSTRACT FROM AUTHOR]