Assessing Pressure Changes in an On-Demand Water Distribution System on Drip Irrigation Performance—Case Study in Italy

• Published in: Journal of irrigation and drainage engineering Vol. 136; no. 4; pp. 261 - 270
• Main Authors: Daccache, A, Lamaddalena, N, Fratino, U
• Format: Journal Article
• Language: English
• Published: Reston, VA American Society of Civil Engineers 01.04.2010
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agronomy. Soil science and plant productions; Biological and medical sciences; calibration; CASE STUDIES; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; hydrologic models; irrigation management; Irrigation. Drainage; Italy; microirrigation; pressure; Italy; Southern Europe; Europe; Water distribution systems; Hydraulics; Water supply; Flow regulator; Network characteristic curve; Water distribution; Water flow; Regulator; Case study; Hydrant pressure variation; Irrigation performance; Network analysis; Trickle irrigation; Network; Water engineering; Water requirement; Hydraulic networks; Hydraulic pressure
• ISSN: 0733-9437; 1943-4774
• DOI: 10.1061/(ASCE)IR.1943-4774.0000170

The hydrant pressure head in an on-demand water distribution system can be subject to high fluctuation depending on the discharge flowing inside the pipes, with consequent impacts on the performance of on-farm irrigation systems. In this work, an Italian water distribution system was analyzed using the AKLA model at upstream discharges of 1,200 and 600 L⋅ s−1 to estimate the range of hydrant pressure variation. A computer model was developed, calibrated, and used to evaluate the performance of a drip irrigation system by relating the on-farm network with the hydrant characteristic curve at a certain operating status. The flow regulator within the hydrant played an important role in stabilizing the performance of the network at hydrant pressures higher than 27 m. At lower hydrant pressures, to apply the same amount of water, irrigation time must be extended by 17 and 95% for pressure heads of 20 and 12 m, respectively. These approaches described have great utility to ensure adequate irrigation management when water is delivered by pressurized on-demand systems.