Evaluating the Current and Future Water Supply and Demands in the Apurimac River Basin, in Peru. Sensitivity Analysis of a Hydrologic and Water Planning Model

Abstract:

This research presents an analysis to estimate water availability and water supply for current and future water management policies in the Apurimac River Basin (ARB), in Peru. The objective of this research is to build a coupled hydrologic and water planning model to simulate the water availability and water supply in the ARB. This model is used to evaluate the average (synthetic) and historic conditions to test current and future water demands that include the construction of a reservoir. The hydrologic model is a two bucket model, where the processes of direct runoff, interflow and baseflow are represented in the top bucket and the process of groundwater storage is represented in the bottom bucket. The water planning model is a routing model that calculates the water balance between water supply, water demand and change in storage throughout the basin. The Water Evaluation and Planning (WEAP) platform is used in this research. Model inputs are climate data (precipitation, air temperature, relative humidity and wind velocity) and land use data (land use cover and crop coefficients). Streamflow at different control points and water budgets for all the sub-basin have been calculated to calibrate the model. A sensitivity analysis for the input data was performed to identify parameters that affect the most the water budget for each sub-basin. Precipitation is the most sensitive input data and root zone conductivity is the most sensitive parameter in the model. This research explains the implications of these conditions, and their impact in the analysis of the water availability and water supply for current and future water demands in the ARB.