Total Urban Water Cycle Models in Semiarid Environments��Quantitative Scenario Analysis at the Area of San Luis Potosi, Mexico

Systems view thinking and holistic urban water cycle concepts are increasingly called upon for integrated analysis of urban water systems to mitigate water stress in large urban agglomerations. However, integrated analysis is frequently not applied due to the inherent complexity, limitations in data availability and especially the lack of guidelines and suitable software tools. The paper presents the application of the total urban water balance model UVQ to the City of San Luis Potosi (1.2 Mio inhabitants) under the arid conditions of Northern Mexico. UVQ is a lumped parameter model which describes water and contaminant flows from source to sink in urban areas and includes all water types such as rainwater, imported water, surface runoff, wastewater and groundwater. The results were especially useful for spatially explicit groundwater recharge calculation in urban areas. A range of urban water scenarios, including different supply strategies and the effect of externalities such as demand change, were simulated and compared to a calibrated baseline scenario. The analysis demonstrated that shallow urban groundwater resources can substantially mitigate problems of water scarcity and overexploitation of deep aquifers if appropriate water quality protection or fit-for-use paradigms are put into place. The modelling exercise delivers relevant information for the decision making process and identifies the most relevant shortcomings in current monitoring systems. This represents a key step on the path to water sensitive and sustainable urban development, including the urban aquifers which have been neglected in the management policy of most cities of the Mexican arid zone.     

Water Management in San Luis Potosí Metropolitan Area,Mexico

The San Luis Potosí Metropolitan Zone, one of the key urban centres of Mexico's semi-arid central region, has experienced remarkable socio-economic development in recent decades, but it confronts inadequate water services in a context of scarcity, inefficient management, and lack of planning, investment and technology. Strategies currently being undertaken include efforts to improve the efficiency of wells, reduce leakage, sanitize the area, and develop alternative water supplies from neighbouring catchments. The challenge today is to move from considerations that focus mainly on supply management, to an approach based on integrated water resources management. This represents an immense task, but innovative water technologies, management systems and institutional arrangements are necessary in order to meet the multiple objectives of equity, environmental integrity and economic efficiency.     

Development of a Protection Strategy of Karst Limestone Aquifers: The Merida Yucatan,Mexico Case Study

In many regions karstic aquifers constitute the only available source of drinking water. Due to the high risk of contamination in these aquifers, a comprehensive groundwater protection and control system must be designed and established. It has recentlybeen proposed that Hydrogeologic Reserve Zones (HRZ) can be established as a tool for the groundwater management in these aquifers. The following approach is proposed in order to establish the HRZ in karstic aquifers: including several generalstrategies for the protection of the ground waters within them, as well as the zoning of the land use and the development of acode of practice. A general procedure is proposed for the development of code of practice for ground water protection inkarst aquifers, which is applied as a case study in Merida, Yucatan, Mexico.