LEED was originally developed with noble intentions. Over the years a few weaknesses or holes have been exposed. However, it has caused many engineers and architects to stop and think about how their decisions or recommendations affect the environment. For this reason, you may say that it has been a success. It is a work in progress, so I think we can all see that its heart is in the right place, and where weaknesses have been exposed, corrections have been made. Looking at it from an irrigation viewpoint, there is so much to discuss. However, discussing everything in one post would not be very productive unless I am using this blog to help those of you with insomnia. What I feel would be most beneficial would be to provide personal experiences on projects where LEED accomplished its intentions, or how it fell short, in multiple postings.
The most common LEED points earned in our area for irrigation are the 2 points awarded for a 50% reduction in landscape water use when compared to a baseline system. The 50% reduction is accomplished through two common practices.
The first is using technology that our industry typically refers to as “smart” or “high efficiency.” This is a combination of ET based controllers, soil moisture sensors, pressure-regulators, flow sensors, etc. These are technologies that I always recommend, regardless of an owner’s desire to seek LEED accreditation. When properly used, these items typically pay for themselves within a couple of years.
The second method we use to accomplish this 50% reductions is to increase the amount of drip irrigation and decrease the amount of pop-up sprinkler irrigation. Drip irrigation is significantly more efficient than pop-up sprinkler type irrigation. There are methods that help us narrow the gap between the two, but few are recognized by the U.S. Green Building Council. Increasing the percentage of drip irrigation on a project results in more landscaped areas and less turf areas. Drip irrigation can also be used in turf areas, but it is not very common in our area. Established mulched landscaped plantbeds have a lower water requirement then turf.
I recently completed construction documents on a project which is seeking the two points for 50% landscape water reduction. Because of the criteria set by the U.S. Green Building Council, the landscape architect reduced the amount of turf that they would have typically used so that we could utilize more drip irrigation. As a result of the reduced percentage of turf, we were able to reduce the water requirement of the landscape by more than 50% and apply for two points towards LEED Certification.
