The Pentagon lies immediately adjacent to a lagoon off of and fed by the Potomac River, which is itself "receiving" water body containing non-potable water, all of which is also inherently fed by rainwater. Previous Credit Rulings have stated that water drawn from a source (such as a river) "that provides the municipality access to water that is treatable and ultimately potable". Our desired irrigation strategy would involve pumping water directly from the lagoon off of the Potomac River, a lagoon which is currently providing some of the irrigation water used elsewhere on the Pentagon site and which is also currently used for cooling central plant equipment. We do not intend any interim treatment of this water other than on-site filtration for large contaminants, and do not intend any additional "catch basin". We feel that the very direct access that the facility has to the water source from the lagoon, which is itself is something of a large-scale catch basin, should be considered equivalent to providing an intermediate catchment source that would overflow into and be supplemented by the receiving waters themselves, as proposed by the project Inquiry dated 6/28/04. In terms of the net environmental benefit, we do not see any functional difference between the previously proposed strategy and our proposed strategy, and believe that this water should at least allow us to earn Water Credit 1.1 as long as back-up water used in addition to the lagoon water amounted to a minimum of 50% total non-potable water, and possibly Water Credit 1.1 as long as back-up water used in addition to the lagoon water amounted to 100% non-potable water.
The man-made lagoon you describe does not appear to be completely equivalent to the rainwater catchment basin described in the 6/28/04 CIR. From your description, there is no segregation of your site rainwater and the Potomac River water. Per the 1/20/04 Ruling under WEc1.2, irrigation water drawn from a receiving water does not qualify as nonpotable water under this credit. However, if the project’s certification submittal demonstrates that the quantity of anticipated rainfall flowing from the site to the Potomac River is equal to 50% of the site’s irrigation needs, WE Credit 1.1 will be awarded. This is because the net effect of drawing that amount of water from the lagoon is the same as if the rainwater was captured on site.