Rating System

LEED BD+C: New Construction, LEED BD+C: Core and Shell, LEED BD+C: Schools

Rating System Version

v3 - LEED 2009, v2 - Schools 2007, v2 - LEED 2.2, v2 - LEED 2.0

Inquiry

Focus of Interpretation: Location of Treatment Facilities\nThe site is located in an expansive urban context (City of Chicago) and is served by a municipal stormwater system that filters run-off to levels that exceed the credit requirements. Based on the following discussion, we would like to use the municipal stormwater filtration system as the basis for earning this point.\nA whole systems approach was used in assessing the specific aspects of this project and it\'s relationship to existing stormwater infrastructure. Below is the rational for considering existing off-site treatment for this site as a preferred option to constructing new on-site treatment:\n1) City owned and operated filtration facilities are already constructed and in place to treat the stormwater.\nThe City of Chicago requires that all stormwater be funneled to the public right of way. In this case, the public right of way consists of a street (a public right of way in the form of open water such as a creek, river or lake is not available). Therefore all run-off from the site must be funneled to the street (municipal stormwater system) and must pass through the municipal water treatment plant serving the system.\nTherefore, on-site filtration would not allow for a reduction in the municipal infrastructure demand by diverting storm water to a natural water course.\n2) On-site in-filtration to re-charge the aquifer or to provide natural treatment of run-off is not feasible because the sub-soils have a low peculation rate.\n3) Since adequate treatment already exists, adding an on-site filtration system unnecessarily increases the demand on resources and creates excessive redundancy.\nThe new design decreases the impact on the municipal system by reducing the quantity of run-off by almost 20% (through evapo-transpiration). The new site use will decrease levels of pollutants and sediment required to be filtered. The new use is much cleaner (Retail) than the previous use (Automotive repair and Trucking).\nTherefore, on-site filtration would not be an improvement over the life cycle of the stormwater filtration provided by the municipality. In fact the life cycle impact may actually be worse for on-site filtration due to decreased efficiencies:\na) On-site filtration will require the use of additional material and embodied energy for tanks and piping.\nb) This site, which is very flat, will also require a pump, electricity to run the pump and on-site infrastructure to support the pump (wiring, conduit, switch and controls).\nc) Regular maintenance and cleaning of the filters will require transportation and energy that is likely to exceed that required for the maintenance of the existing centralized system.\n4) We are dramatically reducing the rate of run-off from the site.\nTherefore, we are helping to spread out concentrated storm loads impacting the City\'s treatment system and reducing the potential that water from the site would bi-pass city filtration due to overload of the system.\n5) Precedent has been established defining that existing infrastructure beyond the immediate scope of a project must be considered as part of a LEED Certification:\nExample -- For new buildings utilizing an existing central chiller, existing CFC refrigerants must be replaced for the project(s) to achieve Certification due to non-compliance with pre-requisites.\nIf existing non-compliant infrastructure systems serving a project are taken into consideration as part of certification, can existing compliant infrastructure systems be taken into consideration for certification as well?\nThank you for your consideration.