Estimate of water demand and area irrigated by central pivot in the state of Espírito Santo

Abstract

The generation of information on the scenario of irrigated agriculture, represents an important primary source for inspection and planning of management of water resources. Thus, the present study aimed to quantify the number of central pivots in the State of Espírito Santo and their respective irrigated area, aiming to estimate the water volume (m3) required to supply water demand in these areas. A 1: 1,000 photointerpretation was performed to identify the equipment. With a historical series of data, potential monthly evapotranspiration (ETP) was estimated and then a water balance was elaborated. The data were spatialized by krigagem, forming twelve maps, guaranteeing the determination of the monthly value of water deficit or surplus (mm) for each coordinate, making it possible to estimate the volume of water required to meet demand. A total of 276 central pivot units were irrigated, irrigating an area close to 12,991.76 ha, requiring an annual irrigation of 33,694,344.50 m3. The Northern Macroregion concentrates 80.85% of this total irrigated area in the State and accounts for 89.52% of water demand, especially the municipality of Pinheiros. The Itaún River Interbank Basin corresponds to 80.42% of the water demand. In May and June water complementation needs were superior.