For many very sound and sensible reasons, we are seeing the increasing use of drip irrigation for ornamental landscape planting areas. I hope the following observations and thoughts will be helpful to those embarking upon the use of this method of irrigation.

1. There is no mystery. This is simply a different method of doing what we have been doing providing adequate moisture for healthy plant growth. True, closer attention to the hydraulic aspects of design, filtration requirements, and actual plant water requirements is required. These systems tend to be less forgiving of design errors or oversight, and are much less forgiving of sloppy installation procedures.


2. A drip system must be thought of as a permanent installation; the same as a conventional spray system. Generally, any system larger than residential should employ traditional methods of assembly, materials, and pipe burial depths. Traditional methods of assembly include the use of threaded connections, solvent weld joints (using rigid or flexible PVC pipe) and the use of iron pipe size (IPS) pipe and fittings ONLY.


3. Drip irrigation was developed for agricultural applications, and some in the industry would have us use many of the same components for drip in the ornamental landscape. Often, this requires the use of various sized adapters, transition fittings and bushings, hose thread equipment and fittings, and tubing of assorted sizes. This is confusing and can lead to design problems and haphazard installations. Again, we should make an effort to use only IPS pipe and fittings.


4. As with all other types of systems, but more so with drip, potential vandalism must be considered. With the possible exception of distribution tubing, it is possible for drip systems to be completely concealed from view. This goes a long way toward ease of landscape maintenance.


5. With drip irrigation there is always the possibility that the system will require adding on, particularly for maturing trees with an increasing water demand. This must be taken into account by the designer. The designer should not prejudge whether the work of adding-on will actually ever be done, but must instead build this capability into the system.

Jack R. Donis, a graduate of the University of Oregon School of Landscape Architecture, is a Certified irrigation Designer, based in Tucson, Arizona. A designer of sprinkler irrigation systems since 1962, he is currently 1st Vice President of the A.S.I.C. Call him @ 602-297-9794.