Integrated Urban Water Resources Model to Improve Water Quality Management in Data-Limited Cities with Application to Bogotá, Colombia

Abstract

Cities in developing countries frequently suffer from poor water quality. Thus, the ability to make informed decisions on the current state of urban water quality, as well as on rehabilitating or implementing new infrastructure, is necessary. Therefore, the authors present a stochastic and dynamic water quality model for cities by integrating existing models for surface water quality, wastewater generation, and drainage routing. The purpose is to assess the water quality state of urban systems and to explore suitability of treatment scenarios. The model can also be useful for urban water planners in developed countries, emphasizing how sustainability is central to assimilative capacity-based water quality modeling. The integrated model is implemented in the Bogotá River, Colombia, to analyze how wastewater discharges in the upper basin can affect the water treatability in a downstream drinking water treatment plant (DWTP) that serves approximately 3 million people. The authors also analyze how the lack of wastewater treatment in the city of Bogotá influences the water quality of the Bogotá River middle basin. The results indicate that pathogens, ammonium, and total suspended solids exceed national and international standards at the DWTP. Additionally, wastewater discharges from Bogotá into the river increase pollutant concentrations to significantly exceed standard limits. To explore solutions to these current problems, the authors model different scenarios consisting of wastewater treatment plants (WWTPs) for the urban rivers in the city and the Bogotá River. The analyses indicate that, in addition to regional controls, it would be necessary to implement other strategies, such as source control, to comply with regulatory standards. The application of the model demonstrates how it can be a useful tool for water management and planning in multiple settings, especially in data-limited scenarios.