Seasonal variability of physico-chemical characteristics of the Haldia channel of Hooghly estuary, India

Abstract

seasons have been studied. Salinity varied spatially and temporally and seasonally during ebb and flood tide conditions. Water temperature showed a difference of 10 • C in winter to summer. Temperature did not vary much vertically as it is a well-mixed estuary. Strong currents exceeding 100 cm s −1 were observed during peak ebb and flood tide conditions irrespective of the season. Longitudinal eddy diffusion coefficient (K x) was estimated as 757 m s −1 and 811 m 2 s −1 during summer and post-monsoon seasons, respectively. The vertical eddy diffusion coefficient (ε v) was estimated as 0.0337 m 2 s −1 during post-monsoon season. The salinity and current observations are compared with those obtained from models reported earlier. Values of pH, Dissolved Oxygen and Biological Oxygen Demand are within the threshold limits of the estuarine environment. Nutrients show seasonal variation in the estuarine environment. High values (160-2686 mg l −1) of total suspended matter were noticed both at surface and bottom in the study region showing the impact of fresh water and sediment transportation.

Dissolved inorganic carbon (DIC) and its δ13C in the Ganga (Hooghly) River estuary, India: Evidence of DIC generation via organic carbon degradation and carbonate dissolution

“…Thus, the presence of H 2 S in the pore water is not necessarily an indication of the prevalence of anoxic condition in the overlying water column. The observation that dissolved O 2 concentrations in the surface water of the estuary are not very different than those in the bottom water (Sadhuram et al, 2005) provides support to the contention that anoxic conditions do not prevail in the water column of the estuary. Ghosh et al (2013) also cite the occurrence of CH 4 reported by Biswas et al (2007), and contend that oxidation of this methane could be a source of the lower d 13 C DIC values observed in their study.…”

“…2) to $8 m (25 ft) at the mouth of the estuary (CIFRI, 2012). The Hooghly main channel is much deeper than its distributary, the Muriganga channel ($6 m; Sadhuram et al, 2005).The width of the river at the mouth of the estuary is $25 km (Mukhopadhyay et al, 2006). Annual rainfall over the last 5 years (2009)(2010)(2011)(2012)(2013) in and around the Hooghly River estuary varied from $1310 mm to $2300 mm (IMD, 2013).…”

“…The Hooghly River carries 328 Â 10 12 g of suspended sediment annually (Abbas and Subramanian, 1984). The Hooghly estuary receives approximately 13 m 3 /s of industrial effluent and urban wastewater (Sadhuram et al, 2005, and references therein) from densely populated and industrial cities such as Kolkata, Haldia and Howrah (Fig. 2).…”

“…III Based on the evaporation data Banerjee (2012). IV Based on the waste water discharge of 1154 million liters/day Sadhuram et al (2005). V Calculated based on Eq.…”

Sedimentation and trace metal distribution in selected locations of Sundarbans mangroves and Hooghly estuary, Northeast coast of India

“…The depth of the water column varies from 10 to 15 m (Mukhopadhyay et al 2006). Hooghly is a well-mixed estuary because of shallow depth (average 6 m) and intense tidal mixing (Sadhuram et al 2005). The estuary gets semidiurnal tides with a maximum range of 5.5 m at spring and minimum 1.8 m at neap.…”