Calibration of a Water Quality Model in a Semi-arid Basin of the Lurin River, Peru

Abstract:

Factors such as the increased demand for water as a result of population, industrial and agrarian increment; pollution of water resources and deforestation of forests leave fresh water availability in a critical situation in many regions of the planet. Peru is not the exception for this reality, the lower basin of Lurín River, which is one of the last great extensions of green areas in Lima, the capital of Peru, is strongly affected by the extraction of water resources, inadequate management of urban and industrial wastewater, agricultural drainage and inefficient solid waste management. For this situation and the absence of information for an appropriate management of the basin, the purpose of this research work was to formulate and parameterize water quality model in the lower section of Lurín River based on the GESCAL module of the AQUATOOL Decision Support System. With this objective, water quality of Lurín River lower section was evaluated, through 12 monitoring sessions with a network of 13 stations analyzing the behavior of Dissolved Oxygen (DO), Biological Oxygen Demand (BOD5) and microbiological parameters such as Total Coliforms (TC), Thermotolerant Coliforms (FC) and Escherichia coli (EC). Subsequently, deoxygenation and reaeration coefficients of river sections were determined. Finally, with the obtained information, water quality of the river was modeled. Adequate results were obtained in relation to the observed and simulated parameters, with values of 0.61 to 0.99 and 0.69 to 0.99 for Nash-Sutcliffe index and coefficient of determination, respectively. Consequently, it can be affirmed that the AQUATOOL software can be useful as support for decision-making in water resource management.