Verificação do parâmetro de percentual de armazenamento de água no solo "parm" em modelo pra fins de balanço hídrico simplificado para irrigação

Abstract

The management of water resources aims at the proper use and availability of water for its various uses (BRASIL, 1997), therefore, management must be carried out by environmental agencies, as in the case of RS, through the Department of Resources (DRH), with support from the State Foundation for Environmental Protection (FEPAM). In order for management to comply with technical standards and limits, the use of decision support tools is essential. On the other hand, studies that result in a response in time for a decision-making process in an environmental licensing process or in granting the use of water can be complex, becoming a challenge for management. In this context, the present work evaluates the tool proposed by Maziero (2015) to parsimoniously estimate the water balance between water uses in a stretch of river, as well as the simplified water balance in the water demand of the plant to verify the need for irrigation, especially regarding the representation of the water storage process in the soil, through the Parm parameter. In the methodology proposed by Maziero (2015), a study of the management of water resources was developed in a stretch of river with multiple uses for hydroelectric generation and irrigation, considering a remaining flow that meets the environmental issues defined by the Operating License of the plant under study. of case. In the model, irrigation was defined as a function of rainfall, evaporation, the water requirement of the plant and losses in the irrigation system. In the present work, scenarios were simulated to evaluate the impact of the Parm parameter on the model results, with the irrigation demands considering different percentages of water storage in the Parm soil, in addition to the variation of the areas to be irrigated and the quotations of energy and soy . The values of average annual MWh lost with the generation versus the irrigated soybean crop were low, while the monetary gains with the irrigation were much higher than the losses of the generation. For variations in the percentage of water stored in the soil, the differences can be considered negligible, considering the water balance of that stretch of river. That is, the model does not need to quantify this percentage in a complex or exact way, as it had little impact on the simulated results. This demonstrates that the water balance proposed in a simplified form has the potential to support a discussion in the decision-making process.