HomeMy WebLinkAboutRentonApronA_SEPA_Ecy_Comments_Response.pdfRenton Apron A SEPA Comments from Ecology dated June 30, 2020
The report Ecology attached to their SEPA comments was from the 2016 A9/A10
Construction Stormwater General Permit Application. This location is about 100 yards
north and cross gradient from this project. That data is also from 2016 and recent
monitoring data shows much lower levels. This Ecology reviewer did not have the
recent site specific data.
Two groundwater monitoring wells were installed at the project location and
groundwater sampled by Galloway Environmental at April/May 2020. VOC results were
either ND (Non-Detect) or “J” flagged by the lab. A “J” flag means estimated
concentration value detected below the reporting limit. Vinyl chloride was ND. TPH
was also ND. Metals were within typical background levels. These levels typically do
not warrant WAC 296-843 requirements. However, the contractor will evaluate and
determine the health & safety requirements for their workers.
Soil will be direct shipped to Waste Management for disposal at subtitle D landfill.
Groundwater from dewatering will be discharged to sanitary sewer under a KCDNR
Discharge Authorization and will pass through settling tanks prior to discharge. No
planned discharge to surface water.
Construction impacts are not considered to be an issue due to distance from the
Ecology referenced area and site specific sampling data.
As part of Due Diligence, all known information regarding the specific project area is
provided to the contractors.