We would like to gain credit through option 2. Some parts of our landscape area are irrigated regularly by drip system connected to the rainwater cistern. Another part of the area is covered by trees and shrubs that are not irrigated regularly but only ocasionally during periods of drought. These periods are very rare in our country. For this situation, the hose bib connected to the rainwater cistern will be installed.
Do I have to put he area irrigated only ocassionally into the calculations? If this is the right method, can I decrease the species coefficeint Ks to very low number (for example to 0,05 – lower then indicates table 1 in LEED Reference Guide)? The landscape engineer does not give me any estimation because the number of drought periods is impossible to predict.
Or is it the right method to neglect this hose bib in calculations? In LEED Reference Guide, pg. 183, it is said: „Hose bibs are not considered permanent irrigation and can be used for temporary irrigation during periods of drought.“ Does it mean that this kind of temporary irrigation does not have to be removed within 1 year of installation (option 2 – path 2)?
Thanks for any help!
Douglas Ross
Project ManagerGray Construction
9 thumbs up
June 27, 2012 - 10:30 am
Lucie:
It looks to me that you should be able to follow Option 2-Path1 without any problems since you are utilizing captured rainwater from the cistern for your water source during drought periods. The key is the demonstrated use of non-potable water.
Hope that helps.
Lucie Cervena
Ekowatt CZ13 thumbs up
June 27, 2012 - 11:18 am
Douglas, thanks a lot. Does it mean that when I follow Option 2-Path 1, even the water source for temporary irrigation for drought periods can´t use potable water?
Please does anyone have any experience if it is necessary to involve the landscape irrigated only during drought periods into the calculations? If I use the lowest possible numbers for species coefficient Ks, the calculated TWA is too high and does not reflect the real water demand of these plants. According to TWA result I will design the rainwater cistern size in order to meet Option 2-path 1 and involving temporary irrigated area has very high impact on the final result. Do you have any suggestion if and how to involve temporary irrigation in calculations?
Susann Geithner
PrincipalEmerald Built Environments
1297 thumbs up
July 5, 2012 - 11:39 am
Lucie, include all areas in your calculation. The area with drip irrigation would be enter just as you where planning on doing it. The other area (no permanent irrigation, hose only is still considered not irrigated. So you just enter 0 for the water demand of those area. Your baseline case for this area could be a different type of vegetation such as turf. However I would recommend to be a little more conservative and also show the same area in the baseline case to be not irrigated.