Applicability of MIKE 21 to assess temporal and spatial variation in water quality of an estuary under the impact of effluent from an industrial estate

Abstract

This study aims at analysing the impact of wastewater load of industrial units in Haldia on the water quality of the Hoogly estuary using numerical modelling techniques. Modelling was never attempted in this region because it was generally felt that simulating such a complex system would not be easy with limited data availability but MIKE 21, a hydrodynamic and water quality model, was used to simulate BOD and DO profiles in the study area and simulation provided reasonably good predictions. A scenario assessment was also carried by increasing the flows from various sources to understand the site-specific relationships between pollution sources and water quality conditions and also to calculate the assimilative capacity of Hoogly with respect to waste discharged from the industrial units at Haldia. The results suggested that water quality of the canal towards closed Oil Jetty was highly deteriorated due to stagnant pond condition and discharges from a refinery. But large part of the canal was found to be well drained under tidal influence as a consequence of which both DO and BOD conform to the prescribed water quality standards most of the times. The impact of industrial waste load on the Hoogly was found to be negligible and the radius of influence was limited to about 200-300 m across the estuary and about 1.6 km along the shore during ebb conditions. Assimilative capacity of the region was estimated to be 837 kg/d as against the present load of 121 kg/d. The study suggested that the estuary had good dilution capacity and intense tidal mixing helped in rapidly diluting the pollutants.

Numeric Study on the Influence of Sluice-Gate Operation on Salinity, Nutrients and Organisms in the Jiaojiang River Estuary, China

“…For example, Le Thi Viet Hoa et al [24] used the numeric model to analyze the comprehensive impact of dams on the Mekong River and sea level rise on the hydrodynamic environment of the Mekong river estuary. At present, there are many two-dimensional models widely used in the world, among which MIKE 21, a useful and powerful tool based on two-dimensional free surface flow simulation for simulating hydrodynamics and environment, is widely used in the shallow estuary region [25][26][27]. This study demonstrated the practicality of the MIKE 21 model in hydrodynamic simulation and reflection of nutrient distribution and movement in the estuarine system.…”

“…Keeping the objective of the study in view, two modules of the MIKE 21 FM software (Danish Hydraulic Institute (DHI)-Water, Environment and Health, Denmark) were used in this study [26]. The flow regime was calculated by setting up the hydrodynamic (HD) module followed by the transfer and diffusion process of salinity, DIN and o-phosphate by the transmission (TM) module.…”

Spatiotemporal Dynamics of Ammonia Nitrogen and Its Response to Inflow River Based on Random Forest Model in Northwest Taihu Lake, China

“…An RF makes no any additional assumptions about either the dependent or independent variables and could describe nonlinear and linear relationships (Cutler et al, 2007). The final model predictions are the average of the forest predictions and this method has been successfully used in analysis of many fileds (Maraqa et al, 2007;Paliwal and Patra, 2011). Despite the optimise predictive performance and wide potential, the complex relationship between pollutant concentrations and ambient conditions couldn't be provided and satisfactory descripted in this model (Khan et al, 2017;Kaminska, 2019).…”

Analysis of the Water Quality Improvement in Urban Stream Using MIKE 21 FM

“…Among these models, the MIKE 21 FM model is universally utilized both in and outside South Korea. Its chief advantage is that it can quickly analyze the hydraulic and water quality of the complicated streamflow under the unsteady flow [29][30][31].…”

“…The MIKE 21 FM model is designed such that the hydraulic flow is analyzed using the continuity and momentum equations of the Hydrodynamic Module (HD) [31]. This HD module is the numerical analysis model that performs the water level and flow rate analyses in the stream and coastal areas.…”