Presenter/Author Information

Gonzalez J. Holguin
Peter L. M. Goethals

Keywords

integrated ecological modelling, habitat suitability models

Start Date

1-7-2010 12:00 AM

Description

The Cauca river is one of most severe cases of pollution for domestic and industrial wastewater discharges in Colombia, principally when it crosses the industrial cities of Cali and Yumbo. The rapid urbanization and major economic development in the Cauca river´s geographical valley has led to dramatic degradation of the environment and increased health risks due to inefficient processing of the increased pollutant load effluents and solid wastes. The city of Cali which is the main urbanization center, with more than two million inhabitants and limitations of the treatment of its wastewaters, discharged in the year 2005, 75 tons of BOD5 per day. These discharges of wastewater are producing an increasing deterioration of the water quality of the Cauca river. This pollution problem is critical after the river crosses the city of Cali, especially during dry season (low flows), when pollution can reach values of 7.5 mg/l of BOD5 and concentrations of Dissolved Oxygen (DO) near to zero (0) mg/l. Low DO levels affect the ecosystem equilibrium and the functioning and survival of biological communities. For this reason, the main objective of this research was to contribute to the integrated water quality management of the Cauca river, developing a mathematical model to investigate the ecological quality of this river under actual conditions as well as after different restoration actions. The approach followed was to build habitat suitability models (statistical models) that allow predicting the presence and the abundance of macroinvertebrates in this river under different conditions. An integration of these ecological models with the hydrodynamic and physical-chemical water quality model MIKE11 was performed. The integrated ecological model allows to model and assess the ecological impact of wastewater discharges into the Cauca river and to calculate the needed reductions in discharges of organic matter to meet biological quality criteria in this river.

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Jul 1st, 12:00 AM

Modelling the ecological impact of discharged urban waters upon receiving aquatic ecosystems. A tropical lowland river case study: city Cali and the Cauca river in Colombia

The Cauca river is one of most severe cases of pollution for domestic and industrial wastewater discharges in Colombia, principally when it crosses the industrial cities of Cali and Yumbo. The rapid urbanization and major economic development in the Cauca river´s geographical valley has led to dramatic degradation of the environment and increased health risks due to inefficient processing of the increased pollutant load effluents and solid wastes. The city of Cali which is the main urbanization center, with more than two million inhabitants and limitations of the treatment of its wastewaters, discharged in the year 2005, 75 tons of BOD5 per day. These discharges of wastewater are producing an increasing deterioration of the water quality of the Cauca river. This pollution problem is critical after the river crosses the city of Cali, especially during dry season (low flows), when pollution can reach values of 7.5 mg/l of BOD5 and concentrations of Dissolved Oxygen (DO) near to zero (0) mg/l. Low DO levels affect the ecosystem equilibrium and the functioning and survival of biological communities. For this reason, the main objective of this research was to contribute to the integrated water quality management of the Cauca river, developing a mathematical model to investigate the ecological quality of this river under actual conditions as well as after different restoration actions. The approach followed was to build habitat suitability models (statistical models) that allow predicting the presence and the abundance of macroinvertebrates in this river under different conditions. An integration of these ecological models with the hydrodynamic and physical-chemical water quality model MIKE11 was performed. The integrated ecological model allows to model and assess the ecological impact of wastewater discharges into the Cauca river and to calculate the needed reductions in discharges of organic matter to meet biological quality criteria in this river.