A System Dynamics Model to Evaluate Sustainability of Water Supply in a Watershed

摘要

A system dynamics model is developed with the purpose of analyzing scenarios of supply and demand of water in the hydrological basin around the city of Queretaro, Mexico. The model takes into account the main components of the social environment, together with their relations with the hydrological cycle. Population was estimated with the Cohort-Component method, domestic, industrial and livestock use was calculated with standard coefficients, while agricultural use was estimated with the Blaney-Criddle method. The hydrological model involved estimated monthly runoff with the Curve Number method. Precipitation was modeled in a disaggregate manner, first annual rainfall was modeled with spatially correlated lognormal random variables and these variables are used to generate monthly precipitations with the fragments method. Percolation coefficients were used to estimate aquifer's recharge. Water supply took into account the main reservoirs and aquifers in the region, together with water treatment and reuse. In the scenario construction phase, ten critical variables were selected and integrated in three basic scenarios. Results showed that in spite of a recent major inter-basin transfer, overexploitation of the main aquifer will continue in two of those scenarios, reinforcing the idea that demand administration measures are necessary to complement future supplies of water.