Improving Flow Conditions in Irrigation Splitter Boxes

A study was conducted to identify methods of achieving uniform flow distribution in compact irrigation splitter boxes over a wide range of flows but specifically operating at high flow rates. The hydraulic issues resulting from high flow rates in the boxes and their potential implications are discussed to provide a basis for the study. Two splitter boxes, one square and one rectangular in layout, were constructed for testing. Numerous improvement designs were developed, built, and installed in the boxes to inspect and measure their performance. Vertical perforated plates with varying hole diameter, perforated area porosity, and plate thickness succeeded in distributing the flow uniformly across the length of the weir. Data presented show the effectiveness of the various designs in improving the distribution and splitting the flow entering into the box. Vertical removable perforated plates are recommended to be installed in splitter boxes where uniform distribution is not currently achieved. Details for the designs that improved flow performance are discussed and the successful application of the designs into prototype splitter boxes is demonstrated.