Surface‐Slope Effects on Sprinkler Uniformity

Abstract

The slope of the soil surface has a significant effect on water distribution from sprinklers. Field tests were conducted to quantify the effects. A ballistic trajectory model was developed to simulate precipitation data for a sprinkler working on different ground slopes and at different sprinkler riser angles. The model uses precipitation data from a single sprinkler working on a zero slope plane under no wind conditions. The model is verified against measured data for a sprinkler operating on a slope. A study is made of the influence of sprinkler riser angle, nozzle angle, and soil surface slope on the uniformity of water distribution. Two different precipitation patterns, similar to Christiansen's sprinkler patterns B and E, are studied in detail. The results show that the sprinkler risers should be kept perpendicular to the soil surface to maximize the uniformity of water application and to minimize the erosion risk. Higher nozzle angles are preferable to lower nozzle angles when working on steep slopes, but higher nozzle angles increase sensitivity to wind. With higher nozzle angles, surface slope is less critical.