Oman Botanic Garden is a broad scale botanic reserve in Muscat, Oman. We are preparing a design submission for our 3 LEED nominated buildings and associated landscape areas. The LEED project footprint is within a much larger general project area of some 550 hectares. The total project area includes large natural landscapes comprising wadis or dry river beds. We have calculated the specified pre and post runoff volumes (SS6.1) and storm event volumes using the Arid Watershed specifications (SS6.2) as per the LEED requirements and have designed detention facilities to meet these requirements. We are proposing to use a traditional water capture and treatment process implemented in Oman known as a recharge dam. Surface water is detained behind a small dam constructed of natural materials in the existing wadi bed. It is then allowed to infiltrate back into the groundwater aquifers. This practice is widely used in arid areas of the Middle East and allows effective recharging of valuable groundwater resources. In order to minimize impact to the landscape the current drainage lines will be used, those being the existing wadis. These wadi areas are located nearby the proposed LEED footprint but not within them. All surface water flowing from the LEED Project will flow to one of two proposed recharge dams within the wadis where infiltration will occur. All detention and infiltration will occur completely within the project site. We are requesting whether the proposed treatment dams can be located outside of the specified LEED footprint but still within the project boundary and requesting confirmation that our assumption of 100% treatment for on site infiltration through this process is correct?
The project is seeking clarification on whether required stormwater management systems can be located outside of the LEED site boundary, and whether 100% infiltration meets the credit requirements. If the project cannot meet the credit requirements based on the LEED site boundary (referred to as "LEED project footprint" in the CIR), which needs to be applied consistently across all credits, there may be the option to achieve this credit on a campus level as described in the LEED-NC Application Guide for Multiple Buildings & On-Campus Building Projects. As supported by the LEED-NC v2.2 CIR Rulings dated 8/22/08 and 5/23/08, "the requirements for credit SSc6.1 can be met by demonstrating that the existing stormwater management systems that serve the LEED Site Boundary meet the LEED requirements for all areas within the site serviced by those systems." In the case of 100% infiltration, both the requirements for SSc6.1 and SSc6.2 are met.Update April 15, 2011: Please note that all 2009 projects in multiple building situations must follow the 2010 Application Guide for Multiple Buildings and On-Campus Building Projects, located here: https://www.usgbc.org/ShowFile.aspx?DocumentID=7987. 2009 project teams should check this document for up to date guidance on all multiple building issues. Applicable Internationally; Middle East; Oman.