Organic micropollutants in the surface riverine sediment along the lower stretch of the transboundary river Ganga: Occurrences, sources and ecological risk assessment.

The Hooghly estuary located in the head Bay of Bengal region is a part of the highly dynamic deltaic environment Tidal variations are pre-dominant in this estuary, and tides propagate considerable distance through a complex network of various riverine systems, inlets, bays and creeks having vital implications on water mass exchange, reworking of deltaic sediments and the mixing process The Hooghly River houses two major ports of national importance, viz Kolkata Dock System and Haldia Dock Complex Tidal forcing is primarily semi-diurnal in nature and with the presence of complex riverine morphology, the tidal characteristics are substantially modified causing various tidal constituents of compound tides The present study performs location-specific tidal analysis and prediction utilizing one-hourly tide data with SLPR2 harmonic tidal analysis tool for Gangra situated upstream of the Hooghly River In a geomorphologic perspective, the water-level elevation at Gangra results from natural tidal flow, as well as refracted effects from cross-flow due to the presence of two natural island barriers, namely Sagar Island situated southward off Gangra and Nayachara in the east The Hooghly channel comprises of complex bathymetric features and tidal analysis at Gangra reveals the presence of Msf (luni-solar synodic fortnightly) tidal constituent Very few locations in India have reported on the existence of the Msf tides, and Gangra is one among them This study also performs a comprehensive validation between the computed monthly tidal prediction from SLPR2 and measured water level at Gangra The skill level of prediction exhibits a good match This study also investigates the influence of atmospheric effects on sea-level pressure variations and the resultant water-level elevation from extreme weather events such as depressions and severe cyclonic storms that occurred during 2013 The study signifies the importance of tidal analysis and prediction for operational needs

Tidal Analysis and Prediction for the Gangra Location, Hooghly Estuary in the Bay of Bengal

The present study presents regional algorithm to estimate suspended sediment concentration (SSC) from remote sensing reflectance (Rrs) and field observations for the Hooghly Estuary and coastal waters of West Bengal. The understanding of the suspended sediment concentration along the coastal waters is essential to estimate the environmental impact of erosion and depositional process. The water samples were collected onboard for cloud-free days along the Hooghly Estuary and along the open coast of West Bengal. The field synchronous OCM data are then processed for geometric corrections, and remote sensing reflectance at pixel level is retrieved. The SSC is observed to vary from 35 to 75 mg/l along coastal waters and 24 to 270 mg/l in Hooghly Estuary. The sum of Rrs at 555 and 620 nm is observed to have high correlation with the SSC observed by conventional method. An exponential relation is observed to show better comparison with an R2 value of around 0.74. From observations, it is evident that the reflectance values and SSC for Hooghly Estuary (particularly clay sediment) yielded good correlation than coastal waters for sand sediment concentration. As the regional algorithm developed for the West Bengal coastal area gives better results, this algorithm can used for further research and to estimate SSC in the study area.

Development of Regional Algorithm to Estimate Suspended Sediment Concentration (SSC) Based on the Remotely Sensed Reflectance and Field Observations for the Hooghly Estuary and West Bengal Coastal Waters

The head Bay of Bengal region that borders the North Indian Ocean is crisscrossed with numerous tidal creeks, riverine systems and channels that play an important role in storm surge studies. In pa...

River-tide-storm surge interaction characteristics for the Hooghly estuary, East coast of India

The navigational channel leading to Haldia Dock Complex suffers heavy sedimentation causing gradual reduction of water depth and posing inconvenience for marine traffic movements To overcome this 

Evaluation of dredging efficiency indices of TSHDs deployed in a navigational channel leading to Haldia Dock Complex

The present study reports on a systematic procedure and maintenance plan for conducting dredging activity at the Kolkata port located in the Head Bay region, east coast of India. It is one of the oldest riverine ports in the country constructed by the British East India Company. The port comprises two docks, viz. Kolkata Dock Complex and the Haldia Dock System under the administrative control of the Kolkata Port Trust. The navigation channel located in the Hooghly River accommodates sea-going vessels with 200 GRT with pilotage assistance cruising upstream almost 145 km from Sagar Islands located in Hooghly estuary. The navigation channel experiences high rates of sedimentation being a riverine port. This study investigates the sedimentation rate throughout the navigation channel, identifying zones of high sedimentation rate. The behavioural pattern of tides and currents is analysed using the state-of-the-art ADCIRC model, and wave conditions are simulated using SWAN model. The hydrodynamic information obtained from ADCIRC and SWAN is input to the SEDTRANS model. Based on the intensity of sedimentation, the maintenance plan is proposed for three dredging seasons. On the basis of this scientific rationale and seasonal dredging maintenance procedure, it is anticipated that huge investments involved in the maintenance dredging of this channel can be minimized.

Swetha Mangalagiri

Papers

Dredging Maintenance Plan for the Kolkata Port, India