Abstract

INIGUEZ-COVARRUBIAS, Mauro; OJEDA-BUSTAMANTE, Waldo  and  ROJANO-AGUILAR, Abraham. Methodology for estimation of integrated evapotranspiration and canal capacity in an irrigation zone. Rev. Fac. Cienc. Agrar., Univ. Nac. Cuyo [online]. 2011, vol.43, n.2, pp.175-191. ISSN 1853-8665.

Capacity of irrigation networks needs to satisfy peak crop water demands. The methods to size canal capacity require the estimation of an agronomic variable: crop evapotranspiration. There is not an integrated procedure to estimate crop evapotranspiration for large irrigation zones with a diversified crop pattern, different planting dates, and several crop seasons. Not having this procedure generates uncertainty in methods for canal capacity estimations. This paper presents a methodological proposal to estimate the ET variable for large irrigation zones. The procedure starts with calculating the ET for each planting date per crop and season. Next, it integrates a general ET curve for the water year that finds the evapotranspiration for the irrigation zone (ET_zr). The methodology was applied to size the main canal that supplies the "Santa Rosa" Water Irrigation Association in the 075 Irrigation District located in the state of Sinaloa, Mexico. A value of 4.1 mm d-1 was estimated for ET_zr. The results indicate the proposed method’s accuracy to estimate the ET variable to size irrigation canals.

Keywords : Canal sizing; Crop water requirements; Irrigation districts.

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