Our plant materials selection contains mostly native species and those that are not are drought resistant species that require no supplemental watering after the establishment period of two years. During the establishment period a standard irrigation system will be installed in all shrub areas and 8.4% of lawn area as is required by the City of Beaverton until plant materials are established. Considering the cost of labor, water conservation and human error factor in water management monitoring in providing watering with a temporary/portable system, the system selected is a timed underground system with pop up spray heads, which is intended to be used only until establishment of plant materials, at the end of which establishment period the system will be disconnected. Both a drip system and a temporary/portable system were considered for use but rejected because of the vulnerability of these systems to vandalism in a school environment. We believe that the system we have selected for temporary establishment support is the more cost effective system and when the system is disconnected and abandoned in place, it will have achieved the intent of WE Credit 1.2 by providing an indigenous drought resistant landscape that will use no potable water for irrigation from that point on. Will the use of this irrigation system prevent us from receiving WE credit 1.1. and WE credit 1.2?
The temporary pop-up strategy you describe here is not an acceptable one to meet WEc1 for a number of reasons, but primarily because there is no way to ensure that the system will be disconnected at the end of the establishment period. A pop-up requires substantial piping since it is a pressurized system, as well as deep piping below frost. USGBC\'s concern is that once a system like this is in place, it will be too easy to use on a regular basis. Hand watering and/or a drip irrigation system as you suggest are recommended for this application as they are less expensive upfront and much simpler to install and remove. The drip piping can be installed a bit below the surface so it is not visible, or covered with mulch to hide the pipe and thus give less opportunity for vandalizing. Also, there is less waste than installing PVC piping and pop-up heads and discontinuing use after a couple of years. Applicable internationally.