Sustainable Integrated Water Management Model with Public Health Strategies

Water management is a global challenge. Important facts of current concern in the water sector are: water scarcity threatened by the increasing consumption, safe drinking water supply resources threatened by climate changes and pollutants discharged from anthropogenic activities; and the accelerated urbanisation demanding adequate water supply together with the increasing wastewater generated by the growing urban population. These issues are becoming an imperative need that could be effectively addressed through adaptive water management strategies for the sustainable development of the societies worldwide. Metropolitan areas exemplify the rapid increase of urban population within a relative small area, which consequently results in the overexploitation of water supplies. Together with this overexploitation, human health could be threatened due to the water-health nexus in terms of water quality and quantity. The specific case study of this research: the Metropolitan Area of Merida (MAM) in Yucatan, Mexico has been analysed in order to exemplify the use of a decision maker’s tool to improve public health through the identification of major water pollutants and correlate them with waterborne diseases documented in epidemiologic statistics. The focus of this research was on two indicator contaminants: Faecal coliforms as microbial indicator of water quality, representing the non-conservative pollutants, and nitrate as chemical indicator of water quality, an example of a conservative pollutant that may persists in the groundwater for decades. Seven engineering interventions have been tested to identify most suitable management strategies through the following steps: 1. Quantify pollutants in the aquifer with the Sustainable Integrated Water Management Model (SIWMM), using a system dynamics approach; 2. Outcomes of the model served to quantify a) Public health risks posed from faecal coliforms through Quantitative Microbial Risk Assessment (QMRA), and b) Economic savings associated with pollutants reduction, 3. Develop cost benefit analysis of selected interventions, and 4. Identify the most suitable intervention in order to assist decision makers to cope with a sustainable supply of safe water and an integrated water management. The model framework developed in this thesis identifies the installation of soil absorption systems into septic tanks at household level, and installation of treatment plants for livestock wastewater as the most cost-benefit interventions of substantial positive impacts on groundwater quality and public health and, in addition, economic benefits.