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Can be either simple or complex—it's up to you
You can earn this credit simply by eliminating turf grass, planting native and adaptive species, and not installing an irrigation system. If those measures go too far for your project, you can still achieve the credit as long as you have some flexibility with plant species selection, and irrigation system design and controls. You may need a landscape designer to identify local or adaptive plant species that require little irrigation, to design water-efficient irrigation systems, to address the potential use of 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., and to reduce irrigation needs through zoning, grouping, and grading of the landscape.
If you install irrigation
If you do install irrigation, you must perform calculations to show the savings of the project design versus a baseline. Usually done by the landscape architect or architect, these calculations determine the percent reduction of total water applied and total potable water applied. Projects with landscaping on less than 5% of their site area cannot earn points here, so consider planters or small gardens to meet that threshold.
FAQs for WEc1
Can non-potable well water that is used for irrigation contribute to potable water reduction?
No, non-potable groundwater used for irrigation (other than nuisance groundwater, i.e. water pumped away from a foundation) is considered a potential potable source and would not count towards earning this credit. GBCI has upheld this rule even in cases where the local groundwater has mineral or other content that requires treatment before it can be potable.
Can surface water, such as water from an irrigation ditch or a local creek, be used as nonpotable water?
No. This approach has been rejected by LEED reviewers, who state that these are potential sources of potable water and their use does not meet the credit intent. The LEED Reference Guide makes reference to groundwater in specifically allowing use of nuisance water that needs to be pumped away from the building—but other groundwater is not mentioned as compliant.
Is the area of the baseline case the same as the design case?
The baseline and design cases are the same, and they are based on the total landscaped area in the design case.
What is the minimum required irrigated area that will achieve the credit?
There is no minimum required irrigated area to achieve the credit. Projects without vegetation on the grounds must have vegetated areas such as courtyards, planters, or vegetated roofs equal to at least 5% of the total site area to pursue the credit. Projects with no landscaping are ineligible for the credit.
Does existing landscaping have to be included in the calculations?
Yes, all landscaping (existing and new) must be included in the documentation.
Do vegetated roofs count in the calculation?
Yes.
Does installing artificial turf, pavers, or hardscape in place of landscape plantings improve your chances of getting the credit?
Although this may contribute to reducing irrigation demand, this does not help with achieving the credit, as landscaped area in both the baseline and design case has to be the same (see the LEED Reference Guide for acceptable methods to earn the credit, and LEED Interpretations #6039 and #731—which have not been applied officially to LEED 2009). Although decreasing vegetated space may be a sensible option for some projects, it is not allowed to contribute to this credit. It would not match the intent of this and other credits for LEED to include an incentive to reduce vegetated area.
How long can a temporary irrigation system for plants to be established remain on site and have the project still be able to achieve the credit?
According to a LEED Reference Guide addendum from 7/19/2010, the time period has been increased from 12 months to 18 months.
How is "temporary" irrigation system defined? What do I have to do to show that a system is temporary?
LEED does not distinguish what characteristics make an irrigation system "temporary." However, teams have had success by installing irrigation systems with plans to disable them in some way, such as removing sprinkler heads, cutting up pipe, or causing some other severe, if not unalterable, damage to the system.
We will be using a municipal non-potable water source for irrigation. For extreme drought conditions, the project will also be tied to the city's potable water source for backup. Does this backup supply negate our credit achievement?
Yes, it does. A potable waterline attached to the permanent nonpotable irrigation system for an emergency-use-only type condition is not acceptable, because there is no way to ensure that the potable water system will be disconnected at the end of the emergency-use-only period.
Legend
- Best Practices
- Gotcha
- Action Steps
- Cost Tip
Pre-Design
Expand All
Lawn as the default landscape planting doesn't make sense in dry climates, where its lushness can only be maintained at the cost of frequent watering. Xeriscaping such as shown here, using native and drought-resistant plants, is a better choice. Las Vegas Valley Water DistrictEvaluate the project’s landscaping needs and develop water savings goals. Consider opportunities to use native or 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. to reduce irrigation needs. Look for all water sources on the site, such as stormwater, 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., treated wastewater, and note opportunities for using that water for irrigation. Include water savings goals in the Owner’s Project Requirements (OPROwner's project requirements (OPR) is a written document that details the ideas, concepts, and criteria that are determined by the owner to be important to the success of the project.) for EAp1: Fundamental Commissioning.
Design Development
Expand All
If irrigation is necessary, drip irrigation is a water-efficient way to deliver it where it is needed, with minimal evaporative losses. City of San Luis Obisbo Utilities DepartmentDesign landscape and irrigation systems to maximize native and adapted species, use efficient irrigation technology, and reuse water where possible. Evaluate the different irrigation technologies for their efficiency and suitability to the project. These include subsurface, bubbler, drip, and rotor sprinkler. Installing weather controls or soil moisture sensors can greatly reduce unnecessary irrigation. Consider directing rainwater to planting beds to reduce the need for potable irrigation water.
Use of drip irrigation helps to conserve water. BuildingGreen ImageThe design cost of a drip irrigation system is generally comparable to a standard system. However, installation might be more expensive for drip irrigation, particularly as plant density increases.
USGBC
Excerpted from LEED 2009 for New Construction and Major Renovations
WE Credit 1: Water efficient landscaping
2–4 Points
Intent
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 water resources available on or near the project site for landscape irrigation.
Requirements
OPTION 1: Reduce by 50% (2 points)
Reduce 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. consumption for irrigation by 50% from a calculated midsummer baseline case or using the month with the highest irrigation demand.
Reductions must be attributed to any combination of the following items:- Plant species, density 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.
- Irrigation efficiency
- Use of captured rainwater
- Use of recycled wastewater
- Use of water treated and conveyed by a public agency specifically for nonpotable uses
Groundwater seepage that is pumped away from the immediate vicinity of building slabs and foundations may be used for landscape irrigation to meet the intent of this credit. However, the project team must demonstrate that doing so does not affect site stormwater management systems.
OR
Option 2: No potable water use or irrigation1 (4 points)
Meet the requirements for Option 1.
AND
PATH 1
Use only captured rainwater, recycled wastewater, recycled 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. or water treated and conveyed by a public agency specifically for nonpotable uses for irrigation.
OR
PATH 2
Install landscaping that does not require permanent irrigation systems. Temporary irrigation systems used for plant establishment are allowed only if removed within a period not to exceed 18 months of installation.
Potential Technologies & Strategies
Perform a soil/climate analysis to determine appropriate plant material and design the landscape with native or adapted plants to reduce or eliminate irrigation requirements. Where irrigation is required, use high-efficiency equipment and/or climate-based controllers.
Additionally the credit can be met when landscape irrigation is provided by raw water (excluding naturally occurring surface bodies of water, streams, or rivers, and ground water) that would otherwise be treated specifically for nonpotable uses. Only ponds designed solely for the purposes of stormwater retention or detention can be used for this credit.
Organizations
American Rainwater Catchment Systems Association
ARCSA was founded to promote rainwater catchment systems in the United States. The ARCSA website provides regional resources, publications, suppliers, and membership information.
Center for Irrigation Technology
CIT is an independent research and testing facility that provides information to designers, manufacturers, and users of irrigation equipment.
Irrigation Association
This nonprofit organization focuses on promoting products that efficiently use water in irrigation applications.
Articles
American Water Works Association, Water Wiser: The Water Efficiency Clearinghouse
The clearinghouse includes articles, reference materials, and papers on all forms of water efficiency.
Web Tools
National Oceanic and Atmospheric Administration, National Climatic Data Center
The NCDC site is useful for researching local climate information such as data for rainwater harvesting calculations, and it also includes links to state climate offices.
World Water and Climate Atlas
Enter your project latitude and longitude—easily taken from Google Earth—and you will get the ETo for pretty much anywhere on earth. A note of caution: spot checking reveals that data may not be reliable in all locations. Make sure that data such as precipitation and temperatures checks out before using the ETo values proposed by the model.
Software Tools
Rain Bird® ET Manager™
This free software provides sufficient local evapotranspiration data for the United States and Canada. Access data from the closest or most climate-appropriate location.
Technical Guides
Texas Water Development Board website
This website provides data from the state of Texas regarding water resources and services such as groundwater mapping and water availability modeling. The site also provides brochures on indoor and outdoor water efficiency strategies.
Performance and Water Conservation Potential of Multi-Stream, Multi-Trajectory Rotating Sprinklers for Landscape Irrigation
This study provides expected water conservation percentages derived from measured data, which can be used to support water efficiency calculations for this credit.
Publications
U.S. EPA, Water Efficient Landscaping: Prevening Pollution and Using Resources Wisely
This manual provides information about reducing water consumption through creative landscaping techniques.
Landscape Plan and Narrative
All Options
Use a site plan and narrative to approach and document credit compliance, like these examples from the Denver School of Science and Technology Landscape Design.
Narrative – Water Use Reduction
Option 1
Use a narrative like this to demonstrate a 50% reduction in 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.
Narrative – No Water Use
Option 2
Use a narrative like one of these to demonstrate no 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 for irrigation, or no irrigation.
LEED Online Forms: NC-2009 WE
The following links take you to the public, informational versions of the dynamic LEED Online forms for each NC-2009 WE credit. You'll need to fill out the live versions of these forms on LEED Online for each credit you hope to earn.
Version 4 forms (newest):
Version 3 forms:
- WEp1: Water Use Reduction
- WEc1: Water Efficient Landscaping
- WEc2: Innovative Wastewater Tech.
- WEc3: Water Use Reduction
These links are posted by LEEDuser with USGBC's permission. USGBC has certain usage restrictions on these forms; for more information, visit LEED Online and click "Sample Forms Download."
Design Submittal
Documentation for this credit can be part of a Design Phase submittal.
LEEDuser is produced by BuildingGreen, Inc., with YR&G authoring most of the original content. LEEDuser enjoys ongoing collaboration with USGBC.
239 Comments
different irrigation system between landscape and green roof
Hi,
If we have a project that will have landscape and a green roof which will have different irrigation system whereas no permanent irrigation system will be installed on the landscape and the install permanent one on the green roof, can we still get 4 points for Option 2? How to describe this on the leedonline form?
water use reduction calculation
How to calculate the baseline building performanceBaseline building performance is the annual energy cost for a building design, used as a baseline for comparison with above-standard design. with compare to my building performance in water use reduction?
WE C1, Option 2, Path 2 submittal requirements
If a site will have no irrigation installed (permanent or temporary) is one still required to complete the baseline and design case information as part of the submittal requirements (tables WE c1-1 and 1-2)? Or is the narrative under "No Permanent Irrigation" the only required data upload (in addition to drawings)?
You do not need to complete the calculator you just need to upload the plan and get the owner to sign the form committing to no 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.
If you meet the "no potable water" goal by using non-potable water for irrigation you do have to complete the calculator.
Municipal tertiary treated water transported in on tankers?
Hi, is anyone aware if USGBC will accept municipal tertiary treated water that is not piped in for irrigation but occasionally conveyed to site via owner's tankers and stored in water storage tanks?
Water Efficient Landscaping
Am working with a project on LEED NC version 2009 which is located in Melaka, Malaysia..........
I have a doubt in species factorSpecies factor (ks) is a constant used to adjust the evapotranspiration rate to reflect the biological features of a specific plant species. for Axonopus compressus....
Whether i can consider Cow grass ( Axonopus compressus) as zero species factor?
Or kindly help me to find the species factor for Axonopus compressus...............
WEc1 Water Efficient Landscaping
We are doing a renovation on a hospital in Las Vegas NV. The hospital has two very small patches of landscape that use what we believe to be an efficient irrigation system. To fill out the form on LEEDonline.com, we need to fill in an 'irrigation baseline case' and an 'irrigation design case'. I've been told to fill out what exists at the hospital for the design case, and what "conventional practice" for the area is in the baseline case. How do I figure out what the exact numbers would be for 'conventional practice'?
Efficienty of permanent hose irrigation
We've posted this question here a few times before but no response...
Does anyone know which efficiency should we consider for landscape that will be irrigated manually, by hose? Reference Guide only provides efficiency for sprinklers (0.625) and drip (0.90), and neither fit our case. We know a hose is not a very efficent irrigation system but we are using native/adapted plants and they require little water. But even so, sometimes they will require some water and to do so the project will use a hose.
Any thoughts on how to approach that? Any numbers for the hose irrigation efficieny? Thanks!
The reference guide says "hose bibs are not considered permanent irrigation and can be used for temporary irrigation during periods of drought" (pg 183)
You may want to search the LEED Interpretations database for the word "hose" to make sure there isn't anything specifically disallowing the way you plan to water. Theoretically, if your plants are native/adapted and well suited for the environment they shouldn't need watering unless there is a drought. It's a bit tricky. Maybe you could supply this limited amount of water using harvested rainwater. That would be a more clear cut way to meet the intent of the credit. Also, maybe look at amending the soil so that you only need to water under drought conditions.
Cistern doesn't fulfull need, but there is no-potable backup
If you can't prove that your cistern will satisfy the irrigation need every month, but the client has agreed to not have a potable backup (ie the cistern gets drained, and then the plants just live without water until it rains again), how do you explain this? It seems like LEED wants us to prove that the cistern supplies enough water, but if we aren't using potable as a backup (meaning no matter what we are 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 for irrigation by 100%) why would we need to prove that the cistern supplies enough rain water?
Buried Tiles
How feasible is it to provide a way to use storm water from the buried tiles (or ahead of them) for grass and garden watering. I am thinking of a pump there to feed sprinklers, for example, from the other end (i.e. not from the city water supply connection end). Any advice? Thanks!
Without some form of storage such as a cistern system, it will be difficult to utilize stormwater directly from buried tiles. The main reason for that is because it will be difficult for one to determine if the water level within the tiles are enough to support gardening activities when watering is needed. Most cisterns are designed to be buried, but there are above-grade cisterns available commercially as well.
Note: You can consider using tiles as a gigantic cistern system. But such approach is not advisable as the extensive amount of joints would be difficult to maintain over the building's life-cycle.
Thank you for your feedback, Issac!
Interior vegetation
Hi!!
Should we include interior vegetation on the calculations of this credit? This a building with several interior plants, including trees that need irrigation. In case that we considerer this plants, how could we create the baseline? Or should we justify this interior plants by an alternative compliance?
Sorting Cactus
I have two questions,
Should I categorize Cactus as a tree or as a shrub?
Can I set all base-case to sprinkler, then the design case is to be dripping?
I would expect in most instances the base-case can be set to sprinklers except where local codes / council requirements prevent. i.e. above ground sprinklers are restricted in some areas of Australia due to water restrictions.
Evapotranspiration rate units?
What is the evapotranspiration rate unit? Inches per day?
Open grid pavement
Does open grid pavement (at least 50% pervious) count as vegetated area in this credit?
Can you be more specific? Some open-grid paving has vegetation in it; some doesn't.
The credit is looking at landscape areaThe landscape area is the total site area less the building footprint, paved surfaces, water bodies, and patios.. Paved area is excluded. I think open-grid paving could go either way, depending, again, on specifics.
The open-grid pavement is in the parking lot.
Alicia, since you didn't mention vegetation, I'm going to assume that it is not vegetated, and should not be counted as vegetated area.
Hi Alicia,
based on some reviewer comments I've had in the past, I'd say that open grid pavement would count towards this particular credit (I imagine is "adopasto"), since it does have vegetation that will need to be irrigated, but it doesn't account for vegetated area in the Protect and restore habitat credit for sure.
Plants grow naturally in "adopasto", but the area is not seeded. We will provide pictures in order to argue this.
Thanks for your help.
Filling out the credit form for Option 2 Path 1
I have a project that is using captured rainwater only, no 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 supply the irrigation system. However, the credit form does not seem to have this option. This is considered and alternative compliance path? (We are use the v3 form, but the v4 form has the same options).
E H, there is a line for 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. used toward the bottom of Table WEc1-2.
Ah, yes. I missed that. Thanks!
Controller efficiency factor (CE)
During a certification process I have found an electronic irrigation controller (model Hunter Pro-C) that is equipped also with a rain sensor (model Hunter Rain-Click).
I need to prove the efficiency of this controller (CE), but I can't get this information directly from the manufacturer. However, there is a general document from Hunter (http://www.hunterindustries.com/sites/default/files/Hunter_LEED_Guide.pdf) where some efficiencies are available, for example:
- Automatic controllers (including Hunter Pro-C): water savings up to 10%;
- Rain sensors (including Hunter Rain-Click): water savings up to 20%.
My question: is this information enough for LEED? In that scenario, which values shall I use for CE?
Many thanks!
Baseline estimate for an exterior Green Wall?
Hi all,
We have a tight urban condition with a large expanse of exterior green wall. Any thoughts on what to use for a baseline for this? Can we use an equivalent area of lawn? There is no "conventional" version of a green wall so not sure what to compare it to. It's going to be irrigated with harvested rainwater and condensate but we still need to demonstrate the 50% reduction in irrigation. Thoughts appreciated!
Janika, is the green wall built onsite, or a product specified from a manufacturer? If the latter, perhaps you could ask the manufacturer what plantings most of their customers use. Lawn doesn't seem quite right.
Hi Tristan,
Thanks for your reply. It's a custom green wall built on site. I received comment back from GBCI that we'll have to baseline it with a narrative approach in showing how the strategy meets the intent of the credit and compares to a "conventional" planting plan, whatever that means. We'll probably see if we can find a manufactured system we can compare to and see how that goes. Thanks, Janika
Rainfall contribution to TWA??
Hi All,
My general question is - can direct rainfall to landscaped areas that soaks in through the soil contribute to the irrigation demand in the WEc1?
Our project is in Australia and using the bureau of meteorology (BOM) data for ETo - our site is showing a total water applied (TWA) of 29.5 kGal for Jan (month with highest ETo rate). Looking at rainfall data for the month, we can expect around 6 kGal of direct rainfall over the landscaped area that would be soaked into the soil. My interpretation is that the supplied irrigation demand would then be 23.5 kGal.. However looking at the LEED worked example in the reference manual they don't seem to consider the rainfall contribution (only potable / recycled water contribution)??
I think my confusion revolves around how ETo is calculated. The LEED referenced ETo is the amount of water required in a region to grow a reference plant (not clear if this is water in addition to natural rainfall?) - whereas in Australia it is the amount of water that is expected to be evaporated from moist soil - so in our case; total water applied (TWA) minus rainfall = irrigation demand.
I think I can explain this clearly enough to the assessors, just wondering if anybody has done something similar before?
Note that i'm only including rainfall directly to the irrigated areas that is soaked in through the soil.. I'm no including rainfall to rooftops etc. which is diverted to the storage tanks (not double counting).
Thanks.
.. I think I've managed to find the answer I've been looking for...
Reductions in irrigation demand due to natural rainfall should be accounted for using the controller efficiency factor (CE) - provided you have the suitable systems.
Drawing the baseline case
I find this credit extremely subjective. Or maybe we don't quite understand it... Our landscape architects have a hardtime in assuming what is the baseline case for "conventional landscape practices". Is there any sort of more accurate criteria to determine the baseline? How do you folks work on that?
And the other thing is that many projects here (Brazil) are manually irrigated with hose during the lifetime of the project. However the reference guide doesn't provide the efficiency for hose irrigation only for sprinklers and drip. So what's the efficiency to assumefor our hose irrigation? Ive submitted this question a few times before in this forum but no responses at all...
Any thought?
Thanks!
Yes developing the baseline is subjective. Most LA's I've worked with use plantings and irrigation system that are "typical" for the building type. In this, experience will be your best guide. It can be a bit of guesswork, and I'm not aware of a resource for this. Maybe others know of one?
In terms of hand watering, there is no assumption for manual irrigation, which in some cases would probably be the most efficient! The calculation assumes timed or sensored automatic sprinkler systems in all cases. If the landscaping plan relies on hand watering, then the project is likely not able to get the credit.
Water Efficient landscaping - finding the ETo
How can I find the evapotranspirtaion rate, ETo, for various plants in various regions, and can this be found on LEEDuser's website?
Yes, LEEDuser lists Resources within the tab above that provide that data.
there were no references indicated
"Evapotranspiration (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.) rates vary greatly regionally and seasonally. There is no comprehensive single reference point for national ET data. "
This website will rock your world: http://www.iwmi.cgiar.org/WAtlas/
If you enter in the project latitude and longitude-easily taken from Google Earth--it will give you the ETo for pretty much anywhere on earth.
A note of caution: I just checked the online model from the website above for a few locations in Morocco, and the data on precipitation and temperatures is significantly off. I'd make sure the rest of the data (precipitation, temperatures etc.) checks out before I used the ETo values proposed by the model.
Daniel is correct in his caution. The website does not contain long-term averages & is based on the last year of actual data only & is intended for real-time agriculture use.
Sorry for the bum steer.
Non Potable Ground Water
Our project is located in an semi-arid climate area with low precipitation and high evapotranspiration rates, where the rain water will be captured and used in water closets.
The subsurface groundwater is unsuitable for human use because it has high levels of nitrates due to sewage contamination. The 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. test analisys was conducted according to the local law requirements and every year it must be retested. Furthermore, since the nitrates are dissolved, they can not be removed with conventional treatment, only with high-cost reverse osmosis membrane treatment.
We will use only draught resistant and native plants for landscape which reduced considerably our water demand for irrigation.
But a backup irrigation system is still needed and we consider using groundwater, because it is not a potable source, not suitable for human use even after treatment and it is highly recommended for plants since nitrate is a natural fertilizer.
The irrigation water would then naturally infiltrate back into the soil, the nitrates are absorbed by the plants helping cleaning the groundwater and closing the cycle.
Would this strategy be acceptable for achieving Water Efficient Landscaping, WEc1?
Disclaimer: about one year ago we did exactly this same question throught the leed online feedback an the answer that we had was the following:
Thank you for contacting the Green Building Certification Institute. Note that in this forum we cannot approve project teams' strategies, only offer guidance. The LEED reference guide, as well as multiple LEED Interpretations (LIs), suggest that your strategy would not be accepted by the review team. For example one LI, which can be reviewed by searching our LI database (available through this link https://www.usgbc.org/LeedInterpretations/LILanding.aspx) for entry number 456, discusses that "Although the local groundwater at the project may not be suitable for drinking straight out of the ground, it still represents an important source of potable water. Using groundwater as an irrigation source does not achieve this credit."
This being said, it may be possible that your strategy would be accepted as an Innovation in Design (ID) credit. This is because, as you mentioned, the nitrates would be a good fertilizer and the process to make the water potable would be excessive. Also the 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 mentioned above was written for NCv2.0, not for NCv2009. Therefore, we recommend you submit a CIR to have your strategy pre-approved as an ID credit. A CIR ruling is guaranteed to be accepted by the review team. For more information regarding CIRs refer to this website http://www.gbci.org/Certification/Resources/cirs.aspx. When submitting your CIR we recommend mentioning the elaborate process for making the water potable, the benefit of the water to the vegetation, etc.
However, the reference guide states that potable 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.
Before submitting a CIR dont you think we still can follow by this way once is proven that our ground water is not potable?
Marcio, I think that USGBC is blurring the line between "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 "well water" and basically assuming that any well water could be considered potable water. This approach seems a bit arbitrary, but it is the approach that they have consistently taken, as far as I know. I think you need a 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.
Many Thanks Tristan!
This was my last try before submitting a 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!
WEc1 Option 1
We have a project located in Vienna. More than %80 of the landscaped areas has been designed for no irrigation including green roof. Drip irrigationDrip irrigation delivers water at low pressure through buried mains and submains. From the submains, water is distributed to the soil through a network of perforated tubes or emitters. Drip irrigation is a high-efficiency type of microirrigation. system (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.) will be used for the groundcover of courtyard and shrubs. In this case is it possible to follow Option 2 Path 2 since the courtyard which is irrigated with potable water corresponds less than %20, contains low water need species and uses a water efficient irrigation system (drip irrigation system)? In case we need to choose option 1, then the question arises; is there a way to include no irrigation to the water consumption reduction calculations ?
I have already tried to include no irrigated areas to calculations by assigning the value 0 (zero) to the ks (species factorSpecies factor (ks) is a constant used to adjust the evapotranspiration rate to reflect the biological features of a specific plant species.), the value 1 (one) to IE (irrigation efficiency) and 'other' to irrigation type.
It calculates, but at the end when I check compliance, it forces me to choose either sprinkler irrigation or drip irrigation, does not accept 'other'.
I have also another question regarding to Reference evapotranspiration rate (ETo). I have checked the World Water and Climate Atlas of International Water Management Institute, but could not provide the information because of a server error. Is there any other source that I can use for a project in Austria?
Any help would be appreciated!
Best
Irrigation by hose
Hi,
my project will use non-potable irrigation by hose, but the template of LEED online don't show this option.
How can I calculate the efficiency of this method?
Thanks in advance
Hi Marcio, I don't have personal experience with the situation you're describing, but the reference manual does say that hose bibs are not considered permanent irrigation. To me, that means you could say that the area in question does not use any water for the purpose of the calculations, but I'm not 100% sure.
Measuring the landscaped area
We are trying to reach the 5% landscaped area in a project.
The question is: how do we measure it? The shaded area or the tree well area?
Thank you!
There is no hard and fast rule on how to measure, but I'd argue that it would vary depending on context. For example, for a tree in the ground (no hard scape), I will typically use the tree's drip line as my tree area. However, in a more urban or plaza context in which the tree is in a specific tree well, then I would use the well area. Hope that helps.
Evapotransportation Units
What unit is ETo expressed in? And what time period does the Total 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. Allied (gal) refer to? The CI reference guide states that ETo is expressed in millimeters or inches. My research into ETo indicates that ETo is actually expressed in units of volume/time, and that units of mm/day or in/day are common. The form does not provide any guidance on the units for ETo or the TPWA, although the tables are labeled "July" which suggests that the calculation should produce total consumption for the month of July. The translation of the information provided for our building in Tel Aviv does not provide any units - but the calculation appears to be incorrect as the TPWA is 6,003 and the non-potable water used is 408,970.
Michael. you may find your answer here:
The new guidance for international projects also includes a resource for evapotranspiration data worldwide. Here is the link http://bit.ly/sp275F
Also find the guideline for international projects here. http://bit.ly/tYhrtV
WEc1 Option 2 Path 1
Hi,
I have a project planning to use 100% 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. for irrigation.They are planning on doing this through collecting rain water. It rains a good bit in the area of the project but sometimes there will be 1 dry month in the summer. Would they be able to use potable water that month (I told them probably not, then not 100%). Is the only option here to get water that month from a public agency in the area that supplies treated non-potable water for irrigation?
Hi Don,
There may be other sources of non-potable you can tap for those dry months. Cooling system condensate is an option, especially if humidity is high. 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. from sinks might also work, if health codes allow it. But you definitely cannot plan on using 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. if you're claiming the 100% reduction.
Efficiency for hose irrgation?
Doe anyone knows which efficiency to consider for landscape to be irrigated manually by a hose?
Thanks
Marcio, if you scroll back through earlier forum posts you'll see some discussion of this, but none of it conclusive. It would help to answer the question if you shared why you were looking for that value.
The template asks for the efficiency of the irrigation type, but the Reference Guide only give values for sprinklers and drip irrigationDrip irrigation delivers water at low pressure through buried mains and submains. From the submains, water is distributed to the soil through a network of perforated tubes or emitters. Drip irrigation is a high-efficiency type of microirrigation.. We will be using a hose, so not sure which value to input there.
Hi folks, any thoughts on that issue about which irrigation efficiency to consider in the calculations when we are using simple hose irrigation?
Grass only, no irrigation
Hello
Our client is using only grass in the landscaping and this is not going to be irrigated.
Are we elegible for credit WEc1?
Hi Marcio,
It is my understanding that turf is considered to require irrigation. Electing not to water something that requires irrigation doesn't meet the intent. The challenge with vegetation that requires irrigation is to reduce 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 through the use of reclaimed water (rainwater, gray water) and/or through the use of efficient irrigation design and controls.
Thanks William.
My fault, I guess I miselaborated the question: it is going to be irrigated but not by a permanent infrastructure, they will use only a hose - no sprinklers, drip irrigationDrip irrigation delivers water at low pressure through buried mains and submains. From the submains, water is distributed to the soil through a network of perforated tubes or emitters. Drip irrigation is a high-efficiency type of microirrigation. or similars.
Are we elegible for this credit and in case this is a yes, will we need to provide the evapotranspiration calculations?
Marcio, I had projects with grass and it was not irrigated and is not going to. Hard to believe for Americans, but very common in Europe. If it is dry in summer the grass will turn yellow and that is perfectly fine. We did however feel that this would be cheating to have the baseline case irrigated and the actual grass not. However we also had other landscaped areas with drought resistant plants, which also did not required irrigation. So this is how we got full credit.
In your case you do indeed have irrigation with a hose (that's a pretty inefficient way of irrigation). You will need to do the calculation and it will probably not look good regarding your consumption. My suggestion is to get a really good sprinkler, which you can connect the hose to and maybe a smart controller if that's in the budget (depending on size $500-1500). Do the calculation and make sure you are reducing your consumption enough to gain credit points.
Good luck!
Hi Susann,
In your case, did you include these species of grass as "turf" or as "groundcover"? it is not clear to me where is the line between these categories.
Grass is turf. Ground cover are plants overgrowing the ground and covering is other than grass Here is a link to a picture of ground cover: http://gogardennow.blogspot.com/2009/05/tips-for-planting-ground-cover-j...
Thanks. I have a similar project. Did you then insert "0" for the species factorSpecies factor (ks) is a constant used to adjust the evapotranspiration rate to reflect the biological features of a specific plant species. for the non-irrigated grass?
Yes. You can enter 0, so it will show 0 in the last column. Keep in mind we did enter the turf as having no consumption in baseline and proposed design.
Oct 05 2012: We did however feel that this would be cheating to have the baseline case irrigated and the actual grass not. However we also had other landscaped areas with drought resistant plants, which also did not required irrigation. So this is how we got full credit.
Oct 08 2012 : Keep in mind we did enter the turf as having no consumption in baseline and proposed design.
Hi Susann, I am just slightly consfuse from your above replies. So does that mean you included grass to be irrigated in baseline and in proposed design, no water cosumption, giving your project high percentage of water saving that resulted in full credit.
I am working on project which has football ground that will be using turf grass and need assistance. I would truly appreciate your reply,thank you!!
For the not irrigated turf grass, we claimed no savings, since we entered both baseline and design case with 0 water use.
As for a football ground, there are exception for such areas. You will find more under LEED for Schools regarding this credit. It has been heavily discussed there.
Permanent Irrigation System, Temporary Use of Potable Water
Hello,
I am working on a project where there will be a permanent irrigation system. This system will be fed by a combination of harvested rainwater, greywater treated on-site and municipal treated wastewater. These various recycled waters will serve 100% of the irrigation demand as soon as that is technically feasible.
However, there is concern that we may not have enough of these various recycled waters to meet all the irrigation needs on Day 1. We are considering the option of feeding the permanent irrigation system with 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. until the recycled waters are sufficient (there has been some rain, and some greywater has been harvested, and the municipal plant has come online) for a period not to exceed the 18 months allowable under Option 2, path 2.
Does anyone have experience with a comparable strategy, and do you know if this would be acceptable in a review?
Daniel, I haven't heard this discussed before, but I imagine a lot of projects with this kind of system must face such a question. It seems to me that it falls squarely under the allowance of temporary irrigation for establishment of plants, and can be ignored, as it's not part of the design conditions of the facility.
Tristan, thanks for your reply. I tend to agree, but as it melds Path 1 and 2 of Option 2 and I have not been able to find any CIRs that conclusively address the issue, I'm hesitant to recommend this to my project designer.
I don't know of any 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 either. However LEED NC is certifying the buildings design as it relates to use over the life span of the building. That's why you have to use a calculation of determining the irrigation demand for the average month. So it really doesn't matter what happens in the first year after completion. It's the building and its systems operation after that.
So as long as your system is design to meet the 100% 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. requirements per the calculation, you should be fine. I think there are very few zero-potable-water-system, which don't use potable water in the first year. If for plant establishment, while the system is still being installed, for testing, for maintenance, or if it simply hasn't rained yet since the system has been completed or the building is not yet fully occupied. So even thought there is no written ruling in that regards. I would be surprised if using potable water within the first year or 18 months is an issue for the reviewer.
Another way for getting around it, is to use a hose to fill the irrigation water tank, if needed during that time. That's not a permanent system but would address shortfalls during the start-up period. That I actually would even mention for LEED review purposes.
Besides a potable water connection is often installed just for maintenance purposes.
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