Option 2 with the theoretical calculation can still be used by teams that have an irrigation meter. The only caution is that you can't compare the metered irrigation use to the theoretical baseline calculation. Instead the comparison has to be between the theoretical calculations for both the baseline and installed cases.

Lyle - That's a tough one. The answer to the first part is fairly clear to me - you should definitely include the area of any landscaped area that does not require irrigation due to the nature of the vegetation. In a perfect world, everyone replaces their turf grass with native/adapted vegetationAdapted (or introduced) plants reliably grow well in a given habitat with minimal winter protection, pest control, fertilization, or irrigation once their root systems are established. Adapted plants are considered low maintenance and not invasive. that doesn't need irrigation - the credit certainly should reward instances where that is the case. A detailed site plan showing the various vegetation types would be key to that submittal.

That being said, I'm not sure how to go about documenting an irrigation approach that involves a hose and sprinkler. Assuming there's no water meter data, you'd need to really help the reviewer feel confident that you know exactly how much water you're using with that equipment.

Hope that helps at least a little,

Dan

Thanks for your insight, Dan. I’m assuming that Option 2 (theoretical calculations) can be used successfully in this case to demonstrate the usage of irrigation water. I am planning on listing the shaded landscaped areas that do not receive irrigation separately from the irrigated areas in the LOL form. For the non-irrigated areas, I have set IE=0. This is the only way that I have found that I can get zero Total Water Applied (0 TWA) for those areas. Do you think that this approach (described in a narrative) will be acceptable?
As always, thank you for your time, Dan.

Vincent, in my opinion, this could meet the definition of nonpotable waterNonpotable water: does not meet EPA's drinking water quality standards and is not approved for human consumption by the state or local authorities having jurisdiction. Water that is unsafe or unpalatable to drink because it contains pollutants, contaminants, minerals, or infective agents. use. You are making use of a nonpotable water source, and treating it to the standards needed in the building. Other more common nonpotable sources, like graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area., would require similar treatment.

The energy required to desalinate the water will count against you in the EA category, of course.

Tristan, thank you for your elucidating clarification. On energy, we are thinking about wind turbines to keep our head above water in the EA category.

Just to follow Tristan's comment here - the credit language is more broad than just 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.. It includes " . . . other natural surface or subsurface resource consumption . . . " which would seem to encompass seawater or a beachwell. I'm actually struggling with how this relates to the fundamental intent of the credit - its a really interesting question ecologically, as using desalinated seawater could theoretically be better for 'the environment' than using potable water, even with the associated climate impacts. (It could just as easily be worse, of course.) But it gets very complicated very quickly, and if I were making a decision with LEED in mind, I think the much safer assumption is that the language around other natural surface water would apply and the desal approach would not be approved.

And I agree with Tristan completely - even with wind turbines associated, that energy penalty is going to be an albatross . . .

Dan

Hi Jiri - I think the language of the credit would preclude that approach. The targeted water includes both 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. and 'other natural surface or subsurface resource.' A river sounds like natural surface water to me.

Hope that helps clarify,

Dan

That's an interesting question and I dare say the answer won't be entirely black & white. I think it fundamentally requires you to ask yourself what the intent of the specific area is. A gravel parking lot, for example, is not landscaped area, nor would it be irrigated in a 'conventional' scenario. On the other hand, if the gravel area is part of the functional landscaping (I'm thinking here of something akin to xeriscapingXeriscaping is a landscaping method that makes routine irrigation unnecessary. It uses drought-adaptable and low-water plants as well as soil amendments such as compost and mulches to reduce evaporation.) and the gravel ostensibly replaces what might otherwise be turf grass on a more conventional site, then yes, I would include it. It really comes down to what purpose the gravel area serves.

Hope that helps,

Dan

Absolutely include the non-irrigated natural vegetation Michael. In a perfect world, EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. would inspire all building owners to keep their vegetated areas with natural vegetation that does not require irrigation. The fact that it is not actively maintained or 'landscaped' is a positive, not a negative.

Hope that helps,

Dan

Thanks, Dan.

I just wanted to make sure since the pulldown menu did not include "No Irrigation" as an option.

Just to update, I submitted using the natural vegetation and the credit was denied. We received the following comment:

"...only landscaped areas may be included in the calculation. Natural areas that are not irrigated must be excluded."

Yikes - I dare say the folks at LEEDuser should retract my expert status given a review comment like that one. My apologies Mike. I spoke to someone at GBCI about this topic recently and I think I failed to consider the various scenarios by which 'natural vegetation' might be present on site. If an area has been in a natural vegetative state for an extended period of time, GBCI doesn't believe that simply preserving the status quo merits credit in terms of irrigation water use. On the other hand, if that area were restored to a natural state from an alternative use, particularly a conventional landscaping scheme, it would be eligible for consideration. There's obviously some gray area there for case-by-case evaluation and the question of when things took place becomes relevant, but I hope this sheds a bit more light both on GBCI's reasoning around the issue and my unhelpful response.

Dan

I think we'll just replace your photo with a grain of salt, Dan.

Jiri, you can choose whichever of the three credit options is most suitable for the project.

Hi Meryl,
It sounds like your project may not be eligible to pursue the credit. Vegetated space equal to at least 5% of the total site area is required, regardless of the project location or constraints.

Kevin, the credit is about reducing 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. use, so manual irrigation is not a way to earn the credit. In fact, manual irrigation can be less efficient than some permanent systems.

The artificial turf won't help you earn the credit, because LEED does not want to incentivize reducing landscaped area as a way to earn the credit. The baseline and actual case here use the same landscaped area.

I agree with Tristan on everything above, although I do pause at the artificial turf issue. Certainly LEED would not want to provide an incentive for replacing landscaped area with say, a concrete patio or parking (thereby reducing irrigated area). But the use of artificial turf is effectively a zero-water method of providing nearly the exact same functionality. Here in Northern California artificial turf fields are becoming more and more common and the water savings are substantial. I'm not entirely convinced that LEED shouldn't support the switch from grass to artificial turf in WEc3. I suspect Tristan is right as to how a reviewer will respond, but its an interesting one for debate.

Dan

Hi Linh, I'm no review expert, but I don't see how this would fly since during the performance period you need to demonstrate that the strategy is in place. In this credit specifically you must show 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. use and reclaim or reuse water use % and back it up with meter readings in order to achieve. Hope this helps!

My take on this is its an example of a situation where its important not to let the LOL template divert you from describing the situation in the most intuitive and clear manner. I think GBCI agrees that shifting turf grass to xeriscapingXeriscaping is a landscaping method that makes routine irrigation unnecessary. It uses drought-adaptable and low-water plants as well as soil amendments such as compost and mulches to reduce evaporation., for example, is an irrigation water use savings that should be reflected in this credit even if it technically means you have reduced the irrigated area at hand. Your situation is no different. I would consider taking two steps: 1. In the template, keep your irrigated area consistent between the baseline and design cases, but account for the water used to irrigate that specific zone as 0 (or some diminishingly small number like 0.001 to make the template work). 2. Use the special circumstances box to explain exactly what you've done and how you've done it. Make it transparent to the reviewer so they can follow your logic and the template work-around. That way, even if they prefer you document your savings in a different manner, they will understand your intent and achievements fully.

Hope that helps,

Dan

I believe that term in the reference guide has a typo and is meant to be gal/sf/min. The value that you ultimately need is the gallons of water used over performance period for a conventional system. That value, for the baseline case, is a function of the gallons per minute applied to a given area, like 1 gallon per minute per square foot while the irrigation system is running. From there, take the total amount of time the irrigation system is expected to run over the performance period and your total irrigated site area multiplied by the rate (gal/sf/min) to determine the baseline water applied.

Yes, I interpret the rating system language to imply that roof gardens have to be included. Also the total vegetated area needs to equal at least 5% of the building site area to be eligible for the credit.

The reference guide has some specific information about how to classify the density factorDensity factor (kd) is a coefficient used in calculating the landscape coefficient. It modifies the evapotranspiration rate to reflect the water use of a plant or group of plants, particularly with reference to the density of the plant material. and microclimate factorMicroclimate factor (kmc) is a constant used in calculating the landscape coefficient. It adjusts the evapotranspiration rate to reflect the climate of the immediate area.. Those values are site specific.

For species factorSpecies factor (ks) is a constant used to adjust the evapotranspiration rate to reflect the biological features of a specific plant species., I don't know of a one-stop shop to look up the water needs of specific plants. But there are a few good resources here on LEED User and then also the local "Extension" is a good place to track down information or local government or water utilities may have information as well. Here are a few links to what I'm talking about. http://www.coopext.colostate.edu/jefferson/natural/native.htm

http://qcode.us/codes/sacramentocounty/view.php?topic=14-14_10-14_10_120...

The reference guide shows in table 1 some landscape factors for trees, shrubs, groundcover, etc. but in our project located in Mexico City a big part of our green areas are vegetation (Geranium, euphorbia pulcherrima, African lily, etc) which factor should we use? thank you in advance for your help.

Because you only have three months of data, it might be best to pursue the credit through Option 2, which is the theoretical calculation. The baseline water use is calculated for July accordingly. If you do it this way, you can't use the metered data to compare to the theoretical baseline and instead you have to use the theoretical methodology to calculate the "design" case for comparison to the baseline.

Yes, you should be eligible for all available points and need to provide a letter from the owner or property manager verifying that 100% of the water is reclaimed. It is also good to provide context about where the reclaimed water is coming from, meaning if it's a "purple pipe" or some other reclaimed water source.

Marie, when you say "footprint" of the trees, do you mean the plan view that includes their canopy?

I think that the measurement of the actual footprint of the planters is what meets the intent, since we are talking about irrigated area, not shaded area or some other measure.

John, this approach should work. You need plantings to be 5% of site area, and planters and internal gardens can make this possible.

Yes to the latter - If I were in your shoes, I would actually document both ways. Your primary documentation path should be the Option 2 path that is based on your inability to show metered water consumption for July. But you can provide full transparency and really give the reviewer reason to feel confident about your approach by also providing your meter data to date and indicating what you think it tells you about likely consumption rates. But your situation is definitely not uncommon and I wouldn't be concerned about the disconnect between credits being problematic.

That sounds a lot like a rainwater retention system to me Paul. You're taking rainwater that otherwise would have run off your property into the storm sewer, storing it, and then using it in lieu of 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 irrigate the property. If that is your sole source of irrigation water, I'd say you qualify for the 100% reduction for this credit, and may want to look into SSc6 as well. Nice work!

I recently learned our ponds also tap into wells (a natural subsurface source) incase the water line needs to be brought up. I am able to calculate the baseline irrigation amount but how would I go about calculating the amount of water harvested by the retention pond vs. how much is supplied by the well unless I metered the well? I also had a question as to if the same pond provides for other surrounding building irrigation systems, would this be impacted by the project boundaries as they cannot overlap one another or is there a way to allow this if I were to pursue LEED EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. on the other buildings in the future?

Paul, with the multiple-building question I would check out the new campus guidance just out from USGBC. Check LEED Resources on their site.

I would agree, you need to have some way of knowing what comes out of the well.

You might have to cast a slightly wider net in terms of recruiting some expert help, as this is a tough thing to get reliable figures on. Perhaps a landscape architect could help you identify a rough sketch of conventional landscaping for the region, and then your landscaper could help estimate how much water per SF they would recommend for that type of landscaping? You might also touch base with local water conservation and/or xeriscapingXeriscaping is a landscaping method that makes routine irrigation unnecessary. It uses drought-adaptable and low-water plants as well as soil amendments such as compost and mulches to reduce evaporation.-type organizations. There are a number in the South BayA bay is a component of a standard, rectilinear building design. It is the open area defined by a building element such as columns or a window. Typically, there are multiple identical bays in succession. - the Central Coast GraywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area. Alliance comes to mind as a starting point that might help you get there eventually. Hope that helps at least a tiny bit.

I'd suggest a middle ground of sorts. By carefully explaining that the system has been shut down (completely I assume) for X years and that shutdown was a strategic decision rather than simple convenience due to abundant rainfall, I think you're halfway there. But to really convince the reviewer that you are committed to zero irrigation water use going forward, you might consider some physical interruption to the system that would render its use more difficult than opening a valve. Perhaps there is a main line that could be cut or removed while the remainder of the system stays in place? That would ensure that there was no reactivation of the system by a new facility manager or landscape contractor without some kind of formal approval, and mitigate costs by leaving 99% of the system undisturbed.

can we resort to alternative compliance path since 100% of irrigation is coming from treated gray water? - this has been in place for the past 2-1/2 years.

In your situation with 100% of your irrigation water coming from a non-potable, non-natural source (reclaimed water), your compliance with the credit is basically automatic. Using an alternative compliance path to document this is the right way to go.

I'm 99.9% sure the above answered my questioned but I wanted to confirm that if the project site uses 100% reclaimed water from the municipal irrigation system, we should take the alternative compliance path. I am only doubting my judgement because the above scenarios sounded like the reclaim systems were on site and our situation is not within project boundary but in the immediate area. Thank you

Consider it confirmed Jeff - the reclaimed water does not have to come exclusively (or even partially) from your project site, nor does the reclamation system need to be on your site. No requirement of that nature exists in the credit language.

Dan

I think your question illustrates exactly the reason the USGBC hasn't established clear guidance as to what is conventional or typical in various regions or settings. Practices may differ widely based on applications, context, etc... and there simply aren't hard and fast rules out there that anticipate all these variables. I think your best bet is to do some legwork to establish what common practice in your neighborhood, in similar applications/buildings/settings is and document your conclusions for the reviewer. That being said, though I can't speak to roof gardens, I would think that turf grass is considered a typical/conventional landscaping practice pretty much anywhere in the US. Hope that helps a little. . .

David,

Page 106 of the v2009 RG explicitly calls out the need to include July in the analysis, so reviewers may well be on the look out for its inclusion. You could include data from 2009 if you wanted/it's available, because the performance period can be up to two years long.

"Turf" or "turf grass" generally refers to "grass" in the conventional sense of mowed Kentucky bluegrass monoculture lawn. "Vegetation" implies a broader array of plants.

"Grass" is of course a type of vegetation and native, mixed grasses may be a low-irrigation solution in some climates.