Transfer Functions in Volume Rendering of Lake Water Quality Considering Frequency Distribution

To explore the distribution and diffusion of pollutants in lakes, the volume rendering technique was used to express the lake water quality model in three dimensions. Due to the narrow distribution ranges and small spatial differences of the scalar field of the lake water quality mode, the perspective expression of subtle differences in the volume rendering process becomes important but difficult. In view of the foregoing case, this paper proposed transfer functions (TFs) in volume rendering of lake water quality considering the frequency distribution. The frequency distribution of the lake water quality scalar field was counted, the voxel ratios and the coloring probabilities of the frequency ranges were calculated, and then the voxel values were effectively mapped to colors and transparencies according to the coloring probabilities, to realize the refined expression of the differences in the spatial distribution of lake water quality. Experiments showed that the perspective expression of the subtle differences of lake (especially shallow lakes) water quality was improved using this method, which is conducive to analyzing the characteristics and changing laws of lake water quality model.

Modeling Biological Oxygen Demand Load Capacity in a Data-Scarce Basin with Important Anthropogenic Interventions

Most water bodies are currently used as receptors for pollutants coming mainly from the industrial and domestic sectors. The Biobío river is subjected to multiple anthropogenic pressures such as industrial water supply, drinking water, hydroelectric power generation, agriculture, and the final receptor body of a large amount of industrial and urban waste, pressures that will intensify due to the decrease in water flow as a result of climate change. In this context, organic contamination has been found mainly from sewage discharges and oxidizable waste discharges generated by industrial processes. In this sense, the objective of this research is to determine the Biological Oxygen Demand Loading Capacity (LC) in a basin with a low density of water quality data subjected to strong anthropogenic pressures. To estimate the carrying capacity in a section of the Biobío River, the water quality model River and Stream Water Quality Model- Qual2K version 2.11b8, developed by Chapra, was used. This model solves the Streeter–Phelps equation, proposing an analytical expression to relate the dissolved oxygen (DO) and biochemical oxygen demand (BOD5) variables. These variables were modeled for different critical scenarios of minimum flows in return periods of 5, 50, and 100 years, determining that the studied section of the Biobío river would have a high carrying capacity to not be affected by its organic matter pollution.

Application of fuzzy logic in river water quality modelling for analysis of industrialization and climate change impact on Sabarmati river

Rivers are critical to human life because they are strategically significant in the world, providing primary water supplies for various purposes. Rivers are the prime importance of any country as most of the cities are settled near the river. Due to developmental activities and increase in population, it will results into huge waste generation. Surface water quality is affected because of increasing urbanization and industrialization. The aim of this research is to examine the effect of climate change and industrialization on the water quality of the Sabarmati river using a mathematical model. For this study four important town along the lower Sabarmati River have been considered and water quality data was considered from 2005 to 2015. In this study different water quality parameters were considered to derive water quality model. Results shows the water quality in downstream after Ahmedabad city is worst compare to the other location where the Maximum WQI is 0.71 at Rasikapur and average WQI is 0.50 for the same location for last 15 year. It has been observed that effect of monsoon and also by comparing time scale water quality model role of regulations for industrialization also plays important role in quality of Sabarmati river.