Research on numerical modelling in lake dynamics

Abstract

Lakes are natural water bodies, where flow from single or various rivers is impounded by a natural impediment. Lake water environmental problem has severe effect on human health and the socio-economic sustainable development. So, it’s very important to find the more effective way of controlling the water pollution. Dynamics of lakes is the vast topic, which includes important concepts such as circulation of lakes, pollutant transport and interaction between lakes and hydrology. The hydrological dynamics of lake has been influenced by land cover modification, climate change, and increase in population and development activities within the catchment. Due to less velocity, lake impounds water for some time, and a significant characteristic of a lake is its retention time. Wind is the prevalent force in driving the circulation and in developing turbulent mixing in the lakes. Vertical mixing is caused by this turbulence. During circulation, summer and winter has different wind patterns. Strong wind would cause storm surge, which results in increased, mixing and transport in the surface water systems. Air temperature influence surface waters through heat flux and evaporation exchange between the air and the water. The Coriolis force is certain in large lakes due to earth rotation. Precipitation, tributaries inflow, runoffs, etc are lake water inputs. During numerical simulation of lakes, generally Boussinesq approximation and hydrostatic approximation are considered due to actual density distribution variations in water depth concepts respectively. It is essential to calibrate and verify the model before predictive applications anywhere. A simple numerical hydrodynamic model of a lake includes wind stress, bottom friction, Coriolis force, inflow, outflow, and the bottom topography of the lake. The hydrodynamic model has to be tested for stability, convergence, and sensitivity to parameters such as wind shear, wind direction, and vertical eddy viscosity effects. In this paper, the numerical simulation of lake dynamics has been discussed in detail.