Agenda - Council - 09/25/1990 - Laserfiche WebLink

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I ! I I I I ! I I I I I I I I I I I I the contact cannot be clearly defined due to physical similarities between the two formations .... the two formations are interpreted as one bedrock unit for Site P (p. P-II6)." Hence, the authors have elected to combine the St. Lawrence which is typically an aquitard, with the Franconia which is typically an aquifer, but is sometimes considered an aquitard. In the Site Hydrogeology section there is no discussion of the site-specific hydrogeologic characteristics of these combined formations -- it is unclear whether the combined formations are expected to act as-a .... confining layer or aquifer. Given that most of the drilling logs describe the uppermost bedrock as a sandstone, it is expected that the combined St. Lawrence- Franconia acts as an aquifer. Section G: Summary On page p. P-146, It states that '"oackground water quality results will be discussed in the EIS." The backgrou, nd groundwater quality results discussion was not addressed. Depth to groundwater is relatively shallow (less than 10 feet) beneath portions of the site, and wetlands southwest and east of the site reflect the water table elevation (p. P-148). Hence if a release were to occur from the facility, the potential for impacts to groundwater is high. Page P-149 discusses possible contaminant migration pathways for Site P. The bedrock aquifer should also be considered at risk to contamination since it is in direct hydraulic connection with the overlying buried outwash and tunnel valley deposits. Page P-149 it states that "designing a monitoring system which will address conditions prior to, during and possibly after remediation [of existing contamination] may be difficult." This is very true -- since potential contaminants from Site P 7