EBOM 2009 WEc3: Water Efficient Landscaping

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...

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 Graywater1. Defined by the Uniform Plumbing Code (UPC) in its Appendix G, titled "Gray water Systems for Single-Family Dwellings," as "untreated household wastewater which has not come into contact with toilet waste. Grey water includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs. It shall not include wastewater from kitchen sinks or dishwashers." 2. The International Plumbing Code (IPC) defines graywater in its Appendix C, titled "Graywater Recycling Systems," as "wastewater discharged from lavatories, bathtubs, showers, clothes washers, and laundry sinks." Some states and local authorities allow kitchen sink wastewater to be included in graywater. Other differences with the UPC and IPC definitions can probably be found in state and local codes. Project teams should comply with the graywater definitions as established by the authority having jurisdiction in their areas. 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.

Without metering irrigation water use you're almost certainly going to be working on an Option 2 approach. In this approach, you basically model your current irrigation regime vs a conventional regime, applying actual vs conventional filters for each variable (vegetation, irrigation system, topography, etc...). I believe the Reference Guide discusses integrating factors like schedules and weather-based controls as well, but there is ample room for documenting technologies that influence water use and adjusting the modeling accordingly. I'll say that having a knowledgeable landscape architect involved in this process is probably very worthwhile. . .

I don't feel like the above response answers the question of how to document 'weather-based controls'-there is no where to put it in the template. do you submit an alternative compliance path?

Version 3 of the credit form has a column (CE) in the design case table to input controller efficiency. Input the controller efficiency there and then I would also supply manufacturer documentation or other documentation confirming the controller efficiency value you've input in the for.

For example, if the weather based control is expected to save 20% of the irrigation water, you would input 0.8 for the controller efficiency in the form and then upload manufacturer documentation confirming the assumption of a 20% savings.

Rashid, there is no path associated with this credit for not having an irrigation system. Perhaps you are thinking of the NC version?

I think you may be able to earn several points here but you will have to follow one of the three options given for the credit.

Thanks for the replies,

We are not in the version of NC as our facility was built few years ago. We do not have any mechanical systems and as i have mentioned we only use manual watering then and there only in the times of dry days.

Tristan and Rashid -

There is no path outlined in the Reference Guide for buildings without a permanent irrigation system; however, there is such a path listed on the Template (both v2008 and v2009). As documentation, you must upload a signed statement "from the facility manager, property manager, or property owner stating that there is no permanent irrigation system installed on the grounds and that temporary or hand-watering occurs only on an as-needed basis and only during periods of drought or for the establishment of new plantings."

The key for you, Rashid, will be proving that watering only occurs on rare occasions, during periods of drought or for the establishment of new plantings. If you water by hand regularly (say weekly or bi-weekly), then this would definitely not be considered "only on an as-needed basis".

My situation is similar to Rashid, except my building does not even do the "as needed" irrigation. There is no permanent system, and no water of any kind is used to irrigate the landscaping. Does this qualify as a 100% reduction, and 5 points? How do I document this for my building?

Jordan, the credit is very simple to document in this situation. In the LEED Online credit form, you will need to check a few boxes, and upload the following: (quoting here from the LEED Online form)

"Provide a signed statement from the facility manager, property manager, or property owner stating that there is no permanent irrigation system installed on the grounds and that temporary or hand-watering occurs only on an as-needed basis and only during periods of drought or for the establishment of new plantings."

Tristan, thanks for your reply. I apologize if I've missed this, but should I then expect to earn all 5 points for this credit?

Yes, sorry I didn't say that explicitly. You should earn 5 points via this path.

As Corinna mentioned, LEED does mention "natural surface" or other "subsurface" resources. Many such sources are potable. Well water for example is often very brackish (hard, full of calcium), but technically still fit for human consumption. I don't think LEED is refering to using non-potable subsurface or surface water. The intent is to reduce the demand on our 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. supply infrastructure as well as reducing the loads on our aquifers.

There are several 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's from past projects that clearly state using well water is against the credit intent.

Jeff -

Unfortunately, I don't think your well system will comply with this credit under Option 4.

If you look at the intent of the credit, it says "To limit or eliminate the use 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. or other natural surface or subsurface resources available on or near the project site for landscape irrigation." Your well system would certainly fall under "natural surface or subsurface resources available on or near the project site." This is further reinforced on the v2008 Template, as Option 4 requires you to certify that your irrigation system does not use "natural surface or subsurface water."

Unfortunately, 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. is not clearly defined in the "Definitions" section of this credit, but p. 103 of the LEED Reference Guide for Green Building Operations and Maintenance describes it as "rainwater, graywater1. Defined by the Uniform Plumbing Code (UPC) in its Appendix G, titled "Gray water Systems for Single-Family Dwellings," as "untreated household wastewater which has not come into contact with toilet waste. Grey water includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs. It shall not include wastewater from kitchen sinks or dishwashers." 2. The International Plumbing Code (IPC) defines graywater in its Appendix C, titled "Graywater Recycling Systems," as "wastewater discharged from lavatories, bathtubs, showers, clothes washers, and laundry sinks." Some states and local authorities allow kitchen sink wastewater to be included in graywater. Other differences with the UPC and IPC definitions can probably be found in state and local codes. Project teams should comply with the graywater definitions as established by the authority having jurisdiction in their areas., or reclaimed water", and some examples are given in the text.

Good news, Kathy. There's a compliance path for just this type of situation. As long as the property's landscaped area is equal to at least 5% of the total site area, the Rating System and other documents state you are eligible for the credit. If the project is registered, check out the form in LEED Online for how to document compliance based on zero use of irrigation (and if it's not registered yet, it's a good idea to do so and always look at the submittal forms early on to get a full sense of the compliance and documentation options).

Another thing to note - you'll need to make sure there's no regular hand watering going on, as sometimes even if there's not a permanent irrigation system the grounds are still regularly watered.

Patrick, good question. You can find information about the eligibility requirements in the Rating System language (see p. 101 of the Reference Guide). Basically, it states that your site has to contain some vegetation (at least 5% of the building site area) in order to be eligible.