Uniformity of water distribution by a sprinkler irrigation system on a soccer field

Abstract

Soccer field grass can be compared to highly sensitive crops regarding water deficit and must be irrigated throughout the year to provide decent conditions for use. For this, efficient irrigation systems are necessary to save water and energy, and this is possible, provided that they are evaluated. Therefore, this paper evaluated the water distribution uniformity, by different methodologies, for an irrigation system installed in a grass soccer field. Also, the influences of multiple spacings between sprinklers and meteorological factors on the final results were assessed. The irrigation system had Falcon 6504 sprinklers, operating at the pressure of 320 kPa. Six field essays were conducted considering overlaying water depths originated from the same irrigation system considering spacings between sprinklers varying from 6 m x 6 m, 6 m x 9 m, 9 m x 9 m, 9 m x 12 m, 12 m x 12 m, 12 m x 15 m, 15 m x 15 m, 15 m x 18 m, 18 m x 18 m, 18 m x 21 m, 21 m x 21 m, 21 m x 24 m, 24 m x 24 m, 24 m x 27 m, 27 m x 27 m, 27 m x 30 m and 30 m x 30 m. The uniformity coefficients used were: Christiansen uniformity coefficient (CU), distribution uniformity coefficient (DU), absolute uniformity coefficient (UA), statistical uniformity coefficient (US), Hart uniformity coefficient (UH) and HSPA standard efficiency (UHSPA). Meteorological data were obtained during the essays. Wind speed caused reduction in the length of the water jet applied by the sprinkler and also caused a bigger effect on the water distribution uniformity. Both CU and UH showed higher values compared to the other coefficients. The increase in the spacing between the sprinklers resulted in reduced water distribution coefficients. To comply with technical and economic criteria, an arrangement of 12 m x 15 m between the Falcon 6504 sprinklers, operating at a 320 kPa pressure, is recommended.