Ways to Reduce Irrigation Installation Costs Through the Landscape Design

Disclaimer:  The following is in no way an attempt to suggest how to design a landscape.  I am not a landscape architect or designer.  Not even close.  The following will illustrate how landscape design decisions affect the installation costs of an irrigation system.

There are several ways a landscape architect can help reduce the installation costs of the irrigation system:

1. Using only one type of plant material (perennials, annuals, or turf) in all of the parking lot islands on the site.  Each of these plant materials have different water requirements.  What this means is when the islands are designed with more than one type of plant material, the irrigation system will need to have a separate valve/zone for each.  When a valve/zone is added additional wire and a larger controller will also be required.  There will also need to be two or three different laterals run to each island, which increases the total pipe and fittings quantities.  Because of the additional pipe running between the islands, the sleeving size would also need to be increased.
2. Limit the frequent transitions between turf and plantbeds to the more focal areas.  Breaking up the landscape undoubtedly adds beauty to the project.  However as the landscape transitions so does the irrigation system.  These transitions ultimately results in requiring a higher total station count, more sprinklers, valves, wire, pipe and a larger controller.
3. Limiting the width of turf areas.  The most economical type of irrigation to install in turf areas is pop-up type sprinklers.  There are two primary types of pop-up type sprinklers.  The spray head type sprinkler, which is typically used for any areas that do not require a radius of more than 17’, and the rotor type sprinkler to treat larger areas.  The minimum pressure requirement for the spray type sprinkler is 30 psi at the base of the sprinkler.  The rotor type requires at least 40 psi, but we usually like to see a little more.  I have seen many sites were and additional 10 psi requirement has made it necessary to have a booster pump station installed.
4. Space plants further apart in less focal areas.  This can be a very effective way to decrease the total quantity of drip tubing, lateral piping, and valves, as well as minimizing the total station count required by the controller.
5. When the rear of a building is rarely seen by customers, leave it undisturbed.  Not to sell myself out of a job, but areas left undisturbed with existing trees and “rough mowed”, usually can go un-irrigated in our area.

Please note that utilizing these methods only decreases the installation costs.  Maintenance and operation costs would be a whole other entry.