Meeting Date: September 16th, 2010`
WUCOLS Discussion – David Shaw from the UC Coop Extension Service presented his take on WUCOLS discussing issues with utilizing the program.
- New plants are not on the list
Horticulturalists are finding and creating new plant types all the time. What are these new plant factors?
- Plant Factors (PF) are Guidelines and do not tell the designer EXACTLY what the plant needs.
If the PF is Medium= 0.4-0.6 that is a large percent change between the low end and high end of the PF spectrum.
- What about California Native Plants?
WOCULS shows a PF that is constant all year. Then the designers must multiple that by an ETo that is always lower in the winter and higher than the summer. Therefore, the equation always shows a higher water demand in summer. But that is not the case with Natives.
Mr. Shaw informed us that 79 plants have been studied to-date. Only 30% of the plants matched the recommend WUCOLS number and maintained good plant health. 30% of plants were a partial match to the WUCOLS number, showing some plant stress. 40% of plants studied completed disagreed with the WUCOLS number, either needing more or less water than recommended.
- WUCOLS is only a guideline.
Mr. Shaw made it very clear that then PFs in WUCOLS III are not set in stone, and a lot of assumption were, and still need, to be made when using PFs. Everyone at the meeting was very shocked to hear how a set of guidelines, that never passed a peer review, found their way into a State Ordinance.
Thank you again David for your time and valuable information. More info from David and his colleagues can be found at;
www.ucanr.org/plantfactors
AB1881 – 9 months into it, and what we are seeing from Agencies and their interpretation of the bill.
- City’s/Counties that are enforcing AB 1881 at the design level.
Members have submitted plans to: City of Riverside, County of Riverside, Huntington Beach, Santa Monica. These agencies are requesting the Hydrozone Map. Some members suggest the Landscape Architect should create the map instead of the Irrigation Consultant. After all it would be beneficial the LA to know if want they are proposing will pass AB1881 before the design Planting Construction Documents.
- Who is enforcing the Turnover Items of the Bill?
No member has been asked to submit Turnover Items. Members do have concerns about the Certification of Completion. Does the Contractor, LA, or Irrigation consultant sign? Who should really be the liable party?
- Have we noticed changes in design due to the constraints of the Bill?
Most of the Membership has seen a change in planting designs and irrigation designs. There is a lot less turf, and a lot more drip being use.
- What about the irrigation maintenance?
Most of the Membership believes that the weakest link is maintenance. Members stated that our designs alone cannot save water. The most efficient irrigation design is only as good as the maintenance personnel. Irrigation Consultants should not sign anything stating that their design will use x amount of water, because we do not maintain the system.
