2 research outputs found
Performance analysis of pressurized irrigation systems operating on-demand using flow-driven simulation models
On-demand pressurized irrigation systems are designed to deliver water with the flow rate
and pressure required by the farm irrigation systems, sprinkling or micro-irrigation, and
respecting the time, duration and frequency decided by the farmers. Due to the variation in
farm demand along the season and the day, a large spatial and temporal variability of flow
regimes occurs in these systems, which may affect the performance of the farm systems
and the yields of the irrigated crops. Therefore, there is a need to analyse those systems to
identify and solve performance problems. In this research, two simulation models for the
analysis of irrigation systems operating on-demand, ICARE and AKLA, are used and
compared to assess the hydraulic performance of the irrigation network of the Lucefecit
Irrigation System, in Southern Portugal. ICARE assesses the global performance of the
irrigation system through the indexed characteristic curves, while AKLA provides for the
identification of the relative pressure deficit and reliability at every hydrant. Both models
adopt a flow-driven analysis approach, performing the analysis for multiple flow regimes.
To support the hydraulic characterization of the system and for calibration of the steadystate
hydraulic model, field measurements were performed at selected nodes of the network,
including four hydrants. The analysis with ICARE does not provide for a sufficient
identification of problems. In fact, poor performance is indicated when a few hydrants
operate below the minimum pressure set at design. Differently, the analysis with AKLA,
applied at the hydrant level, shows that the performance of the Lucefecit system is generally
acceptable. AKLA identifies which hydrants operate below the required pressure and,
therefore, allows to support any eventual related improvement. Results show that the
performance of the system highly improved when changing the piezometric elevation from
260 to 265m a.s.l. However, this improvement is not sufficient because three hydrants still
have high relative pressure deficit and low reliability. Solutions for those hydrants require
increasing diameters of network pipes supplying them