Skip to main content
ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Soil and Water Management Research » Research » Publications at this Location » Publication #343642

Research Project: Precipitation and Irrigation Management to Optimize Profits from Crop Production

Location: Soil and Water Management Research

Title: Simplified Equations to Estimate Flushline Diameter for Subsurface Drip Irrigation Systems

item Lamm, Freddie - Kansas State University
item Puig-bargues, Jaume - Kansas State University

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2016
Publication Date: 1/1/2017
Citation: Lamm, F.R., Puig-Bargues, J. 2017. Simplified Equations to Estimate Flushline Diameter for Subsurface Drip Irrigation Systems. Transactions of the ASABE. 60:185-192.

Interpretive Summary: As water availability from the Ogallala Aquifer for irrigation decreases, farmers are looking at installing the most water efficient irrigation systems. Water use efficiency by plants growing over sub-surface drip irrigation (SDI) tends to be highest among irrigation systems. However, SDI is a relatively new irrigation technology and design features are still evolving. Therefore, scientists in the ARS Ogallala Aquifer Program from Kansas State University examined the applicability of fluid equations to the design of flushlines. The authors recommend that these modified equations be used with a standard fluid model to ensure reliability of improved flushline design for SDI systems.

Technical Abstract: A formulation of the Hazen-Williams equation is typically used to determine the diameter of the common flushline that is often used at the distal end of subsurface drip irrigation systems to aid in joint flushing of a group of driplines. Although this method is accurate, its usage is not intuitive and can be confusing since designers must only consider the portion of flows reaching the flushline. Earlier alternative methods provided simple flushline diameter guidelines related to the cross-sectional areas of the flushline and the driplines contributing flow to it. Improvements to these alternative guidelines and their accuracy with respect to the full Hazen-Williams formulation are reported here in both SI and English units to aid in their usage. The improved equations are accurate and tend to self-regulate their accuracy over the range of typical SDI system design parameters. The authors recommend that these equations be used in concert with the full Hazen-Williams formulation for improved quality assurance in flushline design for SDI systems.