Rating System

LEED BD+C: New Construction

Rating System Version

v2 - LEED 2.2

Inquiry

Our project includes a college dormitory in eastern Washington, a climate with summer droughts. Significant areas will be densely planted with drought tolerant native plants, and a the project includes a small lawn. Reclaimed roof water will be used to irrigate the lawn. At the native planting areas most likely to be impacted by humans, larger installation sizes are planned, requiring more than one year of irrigation, so a permanent but seldom used system will be installed, mostly just to establish plants. At several other areas, plants will be installed at small enough sizes to allow establishment using temporary irrigation for one year. We have reviewed relevant CIRs related to temporary irrigation and have the following questions: QUESTION #1: Do the following meet the requirements for removal of temporary irrigation after one year?  Contractor will be required as part of the contract to remove all temporary irrigation zones at end of one year, including all pipes, valves and sprinklers.  Owner will also certify in writing that temporary system will be removed. QUESTION #2: Do the following installation techniques meet the requirements for temporary irrigation?  All PVC pipes and valves will be pinned directly to the surface of soil.  Sprinkler bodies will be buried, but immediately attached to pipes on the surface. RATIONALE FOR THE ABOVE PROPOSED TEMPORARY IRRIGATION SYTEM:  System will be drained during winter (November to April), thus no soil cover is needed.  Surface piping is less likely to be retained after establishment than underground systems, because of undesirable appearance.  Surface piping causes less disturbance to remove than drip tubing because there are so few pipes involved.  Large radius spray heads/rotors will be used, because they can be spaced widely, resulting in a bare minimum of piping and quantity of sprinkler heads.  Due to high density of our plantings, drip irrigation would require much more total material to irrigate all plants, would be more difficult to remove, and would cause more disturbance to planting areas at removal. For example, one large planting area will contain native plants spaced 16" apart, with seed applied between. A large quantity of dripline would be required to irrigate this, and disturbance would be significant at removal.  Pop-ups will be used (vs. fixed, rigid risers), to protect from vandalism -- heads will be tucked into soil, disappearing from sight when not in operation, even though attached immediately to surface mounted pipes. Vandalism is a significant problem on this college campus. The university does not want the liability of above ground spray heads attached to stakes and the danger that can pose to careless students. QUESTION #3: Would any of the options below also meet the requirements for temporary irrigation?  Covering mainline and lateral lines with mulch to help prevent vandalism.  OR Painting surface mounted pipes a dark color, to help prevent vandalism.  Burying mainlines but not laterals lines. At end of one year, laterals would be removed, but mainlines remain so that quick couplers may be used later for hand watering during periods of extended drought.