Water scarcity and the planning of socioeconomic activities are challenges in the management of water resources. Therefore, the objective of this study was to use reliability indicators (RIs) to simulate management scenarios in the Lurin River Basin. First, flow rates for the period 1969–2019 were calculated using the EvalHid HBV hydrological model and SIMGES, both from the AQUATOOL decision support system, to simulate demands. The estimation of agricultural demand IRs was made under three conditions: that the deficits for 1, 2, and 10 years should not exceed 20–40, 40–60, and 80–100% of the annual demand. The goodness-of-fit indices obtained for flow calibration were 0.716, 0.89, and 0.901 for Nash indices (NSE), Nash natural logarithm (Ln NSE), and Pearson's correlation coefficient (R), representing the values of satisfactory, very good, and good, respectively. Agricultural demands present annual deficits of 59–96, 92–138, and 333–688% for 1, 2, and 10 years, so a 50 m3 reservoir is proposed to meet the IR. Thus, the information generated could be used to improve water resource management in the Lurin Basin
Improvements in the management of water resources are proposed to guarantee the supply of agricultural demands in terms of a reliability indicator (RI) according to legal guidelines in Peru and Spain.
Implementation of a calibrated and validated watershed management model, using the AQUATOOL system, which provides useful information for decision-making on effective public investment in water resource management.