Dissertation
OPTIMIZING AND MODELING THE PERFORMANCE OF MOVING SPRINKLER IRRIGATION SYSTEMS
Doctor of Philosophy (PhD), Washington State University
01/2019
Handle:
https://hdl.handle.net/2376/118231
Abstract
The goal of this work was to develop new methods of calculating irrigation uniformities and to create a model of the intermittent movement of moving sprinkler irrigation systems that can affect irrigation uniformity. A detailed literature review of low energy, high-efficiency alternatives for center pivot was presented to provide a meta-analysis of the research findings on their irrigation efficiencies. A suggested method of estimating the distance of the optimal containers was introduced to improve the accuracy of distribution uniformity (DU) tests with respect to the sprinkler distance under two different irrigation systems: mid elevation spray application (MESA), and low elevation spray application (LESA). The results showed that the distances between containers under MESA must not exceed twice the sprinkler spacing, 6m (20 ft.), and it should be set equivalent to the spacing of sprinkler 1.5m (5 ft.) under LESA. Moreover, a new method was suggested to measure and adjust distribution uniformity (DU) and coefficient of uniformity (CU) for the less important irrigation application variability on a small scale (i.e. less than 30 cm). The results showed that the absolute value of DU and CU might be adjusted up 6 to 8% and 3 to 6%, respectively. If gross irrigation depth is being corrected for poor DU or CU, then using this method would result in 9 to 12.5% less water being applied to compensate for poor DU. A model for simulating the varying depths of water applied to the ground with different sprinkler application patterns (elliptical, triangular, rectangular and donut) under a moving center pivot was developed. The model was developed to specifically test how the stop-go, intermittent movements of a typical center pivot affect irrigation uniformity. The simulated scenarios showed that irrigation uniformities are a function of wetted radius, cycle time, and travel speed. How these affect DU and CU was essentially due to the move distance as a % of the wetted radius. These results can have a significant impact on water savings not only on a field scale but on the total water use at the watershed scale as well.
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Details
- Title
- OPTIMIZING AND MODELING THE PERFORMANCE OF MOVING SPRINKLER IRRIGATION SYSTEMS
- Creators
- Abdelmoneim Zakaria Mohamed
- Contributors
- Troy Peters (Advisor)Claudio Stockle (Committee Member)Jennifer Adam (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Systems Engineering, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 115
- Identifiers
- 99900581705301842
- Language
- English
- Resource Type
- Dissertation