Water Quality Model - Essay Example

The quantitative investigations on water quality are assessed on the physical, chemical and biological characteristics of water. The physical parameters refer to those assessed by physical means like visual appeal, odor and taste. The high turbidity, mixing with colored wastewater, high water temperature, odour generated from the dead and decayed matter are some of the changes that are noticed through physical means. But chemicals parameters are those that require detailed chemical analysis to understand the characteristics.

The dissolved oxygen that measures the number of oxygen molecules present in the dissolved state, biochemical oxygen demand to give the measure of organic impurities in water, nutrients like nitrates and phosphates are the major chemical parameters that must be monitored continuously. The bacteriological quality refers to the various biological organisms that are present in water like phytoplankton, bacteria, protozoa, and a variety of small plants. In the case of lakes and reservoirs, the high influx of nutrients into the water body results in the indiscriminate growth of green plants like phytoplankton and small-sized floating weeds termed as eutrophication.

Importance of Models In order to estimate the long term impact of the current pollution trends on the water quality, model and simulation studies become very essential. The models usually proposed are theoretical models, empirical models or statistical models. They are very essential to understand the changes in the water quality of streams and hence to propose appropriate means for the restoration methods. The mechanisms behind the fate and transport of contaminants/pollutants are mostly based on mass balance calculations that incorporate different processes like dispersion, adsorption/desorption, accumulation, biodegradation, and precipitation.

Different type of mathematical models has been proposed for undertaking the water quality simulation based on the above principles. WASP5 is one such model developed by US EPA for water quality simulation. These models are successfully used in understanding the impact of mining activity and hence to evolve the possible restoration initiatives at the mountain watershed of Upper Tenmile Creek, Montana (Caruso, 2003). Another important purpose for which models could be used is to assess the importance of any particular parameter.

The successful use of models to evaluate the significance of residence time in lakes and reservoirs on the quality of water has been established using suitable case studies (Jorgensen, 2003). In another attempt, a dynamic model built around the UNEP software called PAMOLARE1 gave reliable results to reduce the phytoplankton concentration and total phosphorus in the lakes using methods like aeration of hypolimnion and bio-manipulation (Gurkan, 2006). Various multivariate statistical models have also been found very useful in analyzing the quality of water and pollutions sources in lakes (Li, 2007).

Though the models are widely used in the water quality management for lakes and reservoirs, necessary care must be taken to adapt the chosen model to the specific requirements for the case considered.