Hi Timothy,

I would caution that a potable waterline attached to the permanent nonpotable irrigation system for an emergency-use-only type condition is not an acceptable strategy for achievement of this credit (unless there is a LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. I missed that states otherwise), primarily because there is no way to ensure that the potable water system will be disconnected at the end of the emergency-use-only period. As outlined in the LEED BD+C RG, hose bibs are an acceptable strategy that can be used for temporary irrigation during periods of drought. Refer to LEED Interpretations 2207, 5766 and 5962 for similar strategies that are acceptable as a temporary irrigation strategy for this credit.

Thanks for your reply Carlie - very helpful. And thank you for the LEED interpretations references - I'm going to check them out. If I have any more questions I'll head back this way.

1.0 is not controller at all. If a controller saves 10% of the water then your controller efficiency (CE) is 90%, 0.90.

It seems the certification reviewers have turned CE into a math game. It may not longer be safe to use an average savings like Rainbird provides.

http://www.rainbird.com/documents/turf/LEED_QuickGuide.pdf

Determining the actual CE for a specific project is not something the equipment providers seem to know how to do. Yet, it is sometimes demanded by the reviewers, possibly every time it is claimed based on current review requirements.

I have a method I came up with myself for how to meet the reviewer demand for rain sensors. It requires an annual water use calculation using ETo for an entire year. Here is an example of an annual calculation:

http://www.graywatergardening.com/ETo.html

You do not have to do monthly calculations. You will get the same answer using annual ETo and average annual rainfall.

In the calculations provided the assumption is that the rain sensor stops with any amount of rain. This is not the way the sensors work. The stop after a specific amount of water is collected. Stop irrigating values could range from 1/8" to 1".

Assume you set the stop point to 1/4". You need to determine the frequency of rain events under 1/4". For those you do not stop irrigating. For events greater than 1/4" the rainfall greater than 1/4" is saved water. If you determined that 50% of the rain that fell was for events over the 1/4" stop point then you annual water savings is 50% times the average annual rainfall.

I still haven't figured out how to take math-wise credit for soil moisture sensors, or plant-wise smart controllers that can manage per irrigation point.

http://www.rainbird.com/documents/turf/LEED_Products_WaterEfficient.pdf

Thanks Hernando. I am really in the dark on this one so I appreciate your fast reply.

Judging by your link, the ETEvapotranspiration (ET) is the loss of water by evaporation from the soil and by transpiration from plants. It is expressed in millimeters per unit of time. Manager (or like Smart Controller Technologies) give a baseline of 40% water savings... citing case studies having been done in CA. This is my first time trying to procure this sort of data so excuse me if I ask a dumb question, but... the project I am currently working on is in NYC so:
A- Will this data even apply here?
and
B- How would I begin to use it?

Again, many thanks.

Thank you for your comments, they are very helpful.

Just to clarify, do you use manufacture's documentation or do your own calculation to determine CE?

I have the understanding that LEED instructions focus on a single month for mathematical calculations, the month of July. The example I was sent looks at 10 years of daily ET and rainfall data for the 31 days of July. They assume that the controller will be programmed to deliver sufficient water to handle the hottest week of the month. They then compare that amount of water in inches applied to a smart controller that adjusts the watering times daily to whatever the daily ET demand requires.

Thank you again for your help!

You might get through with this strategy, but if I were the reviewer I'd say that is easy to reconnect and not enough to be seen as a permanent disabled system. You might want to argue with destroying the landscape while removing it all or take out more of it to proof this isn't easily reversible.

Christine, there are many changes for LEED 2009 that don't apply to v2.2—apparently, this is one of them.

I would do what's best for the project, though. If you need 18 months, take it, and try to explain in a narrative why—maybe it will fly.

You can do that. I have actually done it on one of our projects. However we also used a different mix of seeds for the turf, so it's more drought resistant to begin with. We also had no other permanent irrigation in place. If it's extremely dry, which at that location rarely happens, the turf just turns yellow. However you will need at least a letter from the landscape architect explaining that your turf can handle it. If you are planning on doing this in Arizona, when I doubt the reviewer will accept that.

Stephen, I believe that USGBC specifically rules out use of well water in the Reference Guide. I believe that for the purposes of LEED this would supersede the city definition. As Emily suggests it may be possible, though.

You may be able to account for the additional reduction. Potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. is defined as water that "...meets or exceeds EPA's drinking water quality standards..." Other users here on LEEDuser posted that they showed non compliance with EPA's standards in order to account for it.

Depending of the reduction of the potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. demand you can get 1 or 2 points under the LEED NC v2 system and 2or 4 under LEED NC v3. Your irrigation system can not achieve full points without using non-potable water for the irrigation.
For the time period, the reduction is base of a midsummer baseline. So a snap shut of the time with highest demand.
If you want to show the savings of your system than a study of savings based on midsummer conditions is probably most appropriate. I hope that helps.

Hi Susann, on our project we can demonstrate that in mid summer (July) we have enough (+50%) non potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. (condensate + greywater) to sustain for irrigation need. But in winter we will have to use potable water since we are short of condensate water surplus, and greywater alone won't be enough. In this case scenario, can we still pass the credit?

July is representative for the month this the biggest irrigation water demand. As long as you are using the month with the largest irrigation water demand in your location, you should be fine. This is not exactly what the credit was intended to do, but I think you kinda found a loophole here.
The question is doesn't your irrigation water demand decrease in the winter months, just like the amount of condensate?

Correct, in winter we have less condensate water and irrigation demand decreases, but we're still short. So we can use potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. whenever needed as long as the biggest month is covered with non potable water?! So basically we need to prove that we're saving 50% potable water for 1 month of the year only?

You are meeting the credit requirements of LEED v2.2 by doing that.
LEED v2.1 is less specific, which can be interpreted differently.
Anyhow if you are saving more than 50% of the water looking at the whole year, you will be fine for sure. I hope that helps.

Brett, my understanding is that you don't need to do that at all. The temporary irrigation is pretty much ignored since you are on a path to no irrigation.

Thanks Tristin. Most of the site landscape areaThe landscape area is the total site area less the building footprint, paved surfaces, water bodies, and patios. will be irrigated, but there is a substantial portion that will be natural restoration with tmeporary irrgation. We would like that area to be included in the calculations to meet the 50% irrigation reduction. Is the area still ignore in this instance?

I would count that natural restored area as not irrigated at all, since it's permanent systems that you're modeling for the credit. Make sense?

Thanks Tristan. I think I am confused as to how this can be expressed in the calculation spreadsheet or if it should at all. If the baseline design would have ground cover with average plants, density and micro-climate, how do include this square footage zero TWA thus reducing my percentage compared to the baseline? Thanks for your help.

Brett, can you be more specific about where you're getting hung up?

I am suggesting that the temporary irrigation should be ignored in your calculations. The baseline and design cases should highlight the reduced irrigation needs for the native landscape.

OK. This specific area, of several areas, is being restored with temporary irrigation and would otherwise be spray irrigated and have shrubs and ground cover that need regular water. We have reduced the need for irrigation to a temporary situation. Why would we not then receive credit to our irrigation reduction calculations to achieve the total site irrigation reduction of 50%? It would seem that we are not being credited for eliminating irrigation in this planting area because it doesn't fit in to the calculation spreadsheet. Maybe I am looking at this the wrong way.

Brett, I don't see any reason you shouldn't get credit for it, or any reason it shouldn't be reflected in the calcs. So I think I would need to see whatever you're seeing to understand your predicament. If you want to email me specifics, you can do so at tristan (at) leeduser.com.

Hi Kath,
Since the baseline case is really a theoretical landscape plan using "average values representative of conventional equipment and design practices" (Ref guide pg 121) it doesn't really matter what plantings or irrigation system was there before. I understand the credit is intended to compare your design case to what would "normally" be built, not to what actually was there before. Otherwise, you might be penalized for having a water conserving existing design.

Thus, the baseline irrigation system would not necessarily be an efficient rainbird system, but probably more of a guzzler, so you should be able to take credit for the better system in the design case.

It's left up to the design team's judgement to define what would be "conventional" plantings to list in the baseline case, which might be a combination of turf and other plantings. As for the prior parking spaces being demo'd and planted, this is an odd situation: since the baseline case needs to have the same total planted area as the design case, you probably have to assume those parking areas are also "planted" in the baseline case, which might reasonably be assumed to be turf grass.
Hope that helps!

Yongmei, the credit requirements here are twofold: use native/adapted landscaping, AND use no permanent irrigation. According to the LEED Reference Guide, any monoculture is not considered native/adapted. So whether or not turfgrass can survive without irrigation, it won't meet the credit requirements. You'll need to talk to your landscape designer about a more diverse landscape.

Tristan, thanks for your response. Hmm, the project already built, unfortunately the people who designed landscape for this project didnt pay attention... Now we have to fix it.

Anyway, we did design lots of native trees shrubs near our building. Are you sure that all the landscape have to be native, adapted? we have a project which has some turf grass and no irrigation system, ( but area of turf is not as big as our project) and it got 2 points. Does it depend on the type of turf?

yongmei - while Tristan's intent was correct from an ideal stand point - ie: native planting typically equates to a higher likelihood for compliance for no irrigation needs, the WEc1 does not "require" native/adapted planting. (note: native/adaptive could help with SSc5) With that said, the fact that you have turf grass means you will need to assess, given the rainfall for the site/local climate, whether the grass will survive without water. Aesthetics may come in to play too... we have had clients accept that grass at peak summer/heat may die off/turn brown, and they are ok with this... you may need to explain this to the reviewer, if questioned.

Since the lawn has been installed, and if you (or your client) determine irrigation is now "needed", then the fix can be to install a water efficient irrigation system... and accept only 1 point (or 2 points if you are using 2009). Or you could also add a stormwater collection system sized to irrigate the lawn based on appropriate calculations accounting for annual rainfall. My guess is this is too much added cost and/or site disruption, and you may need to forgo this credit.

Gunnar, thanks for your suggetion. Your guess is right, the client will not add irrigation system/ extra cost for this credit...

I am still wondering we might be able to explain somehow to reviewer because WE 1.2 in the V2.2 version requirement says "install landscaping that is not require permanent irrigation". We do have native trees/ shrubs, and this big SOD grass. If the SOD grass is drought-resistant type, and the client is ok if the grass turn brown at peak summer, then it is a ' landscaping that is not require permanent irrigation, right?

Is there anyone who did get the WE1.2 point with no irrigation on turf grass area?

Thanks

If you do not have irrigation, you meet the intent of the credit.

Mark, a lot of buildings use non-irrigated plantings for green roofs so the company you are keeping is a bit sparse. Your question is kind of tough to answer because so much depends on site and climate specifics. And then on the site, a roof is often more exposed to drying conditions (wind and direct sun) so the irrigation needs may be higher, but a higher baseline may also be justifiable. I would work with your landscape architect and use everyone's best knowledge and common sense. Tough to give more specific advice than that, at least for now.

No, calculations would not be necessary to document the credit in this situation.

Do you know what MasterFormat section they fall under? As far as I know, it would be Section 32, and included in the materials budget.

The project was bid and constructed under Masterformat 1995 (Divs 2-16). this was a renovation and the irrigation system serves a larger area outside of the LEED boundary. The modifications that were made to accommodate some site changes were contracted by the Owner and were not bid. We are tracking our material costs as actual construction costs and following MF 2004 divisions. The irrigation repairs fall under 32 80 00. I had assumed that we would include all of the plantings, paving, and other Div 32 items, but exclude soils and excavation along with other Div 31 items.

Zarah, I'd suggest a landscape plan, with the legend and a written narrative that explains the design approach and your rational.

Also, please insure that you've met the requirements for WE 1.1. Some folks are missing the fact that TWO strategies are required by 1.1 and getting 1.1 is required to get 1.2

Rick, do you mean that it's a requirement to use at least  two things to earn WEc1.1, from the list of Plant species factorSpecies factor (ks) is a constant used to adjust the evapotranspiration rate to reflect the biological features of a specific plant species., Irrigation efficienc, Use of captured rainwater, etc.? Not sure I was aware of that.

Tristan,
From what we have determined, under 2.2, the "any combination" means that at least TWO of the methods must be utilized. This is a change from prior versions, where plant species alone would get you the credit. If it said "one or more" or "two or more" it would be more clear, but "any combination" is pretty clear in it's intent.

Still, the credit isn't terribly difficult, as we usually always install a high efficiency sprinkler system. However, if this system is only used for establishment (AND is then disabled) , the reviewer many not consider that as a valid claim.

As I read it, the intent is to encourage the use of alternate irrigation in an effort to encourage others to start to shift from potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. to rain water or other alternate sources.

The text of the credit follows:

Reductions shall be attributed to any combination of the following items:
❑ Plant species factorSpecies factor (ks) is a constant used to adjust the evapotranspiration rate to reflect the biological features of a specific plant species.
❑ Irrigation efficiency
❑ Use of captured rainwater
❑ Use of recycled waste water
❑ Use of water treated and conveyed by a public agency specifically for non-potable uses

Rick,

I actually disagree with your interpretation as requiring at least 2 of the reduction methods, although I am not sure it makes a difference since a combination is the easiest way to achieve a 50% reduction of calculated water budget.

To clarify your other point, you must show a 50% reduction in total water needs before applying non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. sources in order to achieve WEc1.2.

I'm confused - please tell me if I'm reading the above comments correctly: if we are not providing a permanent irrigation system under 1.2, we still need to complete the calculations to earn 1.1? Yet, the template (V2.2) simply lists the 4 options, and under Option #4 (no irrigation), there are no calcs listed. Aside from selecting the option, there isn't anything else to fill out, except describing the documents being uploaded.

So, what else are we supposed to complete for Option #4?

Roxanne, I don't think there is anything else for Option 4. The comments above are for a reduction in irrigation water, which is a different option.

Does that make sense?

Thanks for responding, Tristan.
You are correct, if no irrigation will be provided a water budget is not required.

Only "softscape" areas (classified by vegetation type) are included in the credit calculations. Non-irrigated rock gardens will reduce your water use, but are not part of the calculation.

Thanks Allison! Is there any specific credit language in the Reference Guide or elsewhere that I can point to that states this?

It's interesting that this is not more explicit in the Reference Guide, and it should be, I think. But, I think it's pretty clear, for two reasons.

1) The credit language gives the allowable ways to show water reduction, and not using plants is not one of them. This omission is continued through the Reference Guide on this credit and is intentional (although could be explicit).

2) If you were allowed to do this for rock gardens, where would it stop? Artificial turf, artfully designed concrete or asphalt, etc.? If you take it to the logical extreme it seems clear that not using vegetation is not within the credit intent.

Projects cannot take credit for non-irrigated areas. See NCv2.1 CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide Ruling dated 3/23/2004 and v2.2 CIR Ruling 4/08/2009. Excerpts from these CIRs: “The strategy proposed could be achieved by virtually any project simply by manipulating the area for irrigation and is not acceptable to earn this credit.” AND “A project may not include planted areas in the irrigation calculations if these areas are intended to be left in a natural state, and not therefore require irrigation. Only landscaped areas can be included in the calculations for this project.”

Hope helpful!

Carlie,

Very helpful indeed. Our intent is not manipulation of the numbers, but rather to assure that our basis for calculations is internally consistent. We are renovating the principal structure in a multi-building office campus setting and the timing and program for subsequent renovations is not finalized so we are addressing those areas under the existing contract limits while anticipating future requirements and strategies to maintain the standards established in our initial renovation.

Thanks!

Same project, different question. We have created a pond on site that is around 27,000 sf to capture rainwater for irrigation use. Using the EPA Water Budget Tool, we haven't classified this as a "hydrozone" as it is not factored into the Evapotranspiration figures (evaporation yes, transpiration no....) What's the proper way to classify this area so we can get rid of the error message telling us our Base and Design case areas don't match?

You are correct in excluding the pond as a hydrozone. The pond area should also be removed from the landscaped area total. If I am understanding you correctly, this should result in landscaped areas that match in the basecase and design case.

The 0.7 acre pond is new and located within a five acre area that was primarily irrigated turf grass in the base case. My dilemma is we have to include the pond surface if the areas for the Base and Design cases are to match. We are replacing a large area of irrigated turf with non-irrigated native meadow, so the water reduction requirement is met, the puzzle is how to characterize it.

For the purposes of calculating this credit, the baseline is not the site prior to construction, but rather convential landscaping practices. This applies to the project site assuming that the landscaped areas improved as part of your project would be landscaped even if this wasn't a LEED project, but would be done so in a less than ideal way.

Essentially, you don't get credit for removing irrigated turf if you aren't replacing with lower water using species and/or irrigation equipment, just like you don't get credit for removing turf to replace it with a parking lot. The pond area doesn't count for or against you and should not be included in either the baseline or design case.

Bueno. I've been trying to fit the problem into the limits of the EPA Water Sense universe. I can see this will take a clean spreadsheet for the comparison.

Thanks....

Are you trying to figure out the evapotranspiration rate, which is the basis for many of the credit calculations? If so, depending on which version of LEED NC 2.2 you are using, there was first an errata sheet and then two resources listed in the Resources section of the credit (in the Reference Guide) to find evapotranspiration data for your region: Rain Bird ET Manager Scheduler software and the Texas Water Development Board Web Site. The Rain Bird link listed in the Reference Guide no longer works but you can google "Rain Bird" and find the correct link. It is not obvious to me where the free version of the software exists, so you may need to get in touch with someone at Rain Bird. If your project is in Texas, presumably you can find the regional data on the Texas website. I have not completed this calculation myself but this is where I would start.

I'm having difficulty finding the calculator at the LEED online site. We're using v. 2.2

Thanks