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I -- <br /> i <br /> E PO NS E ALTERNATIVES p�.,r„!ME f� S NST CARRIED FORWARD <br /> for Alternative 102 was 4.5 MGD greater than <br /> Alternative 101 Alternative C1, which has similar plume <br /> capture). <br /> Alternative 101 was Alternative C with S in-plume <br /> wells distributed throughout the footprint of the ■ The impact of the in-plume extraction well <br /> P <br /> lume. Tpurpose�he ose of the in-plume wells was to fences on the duration of plume cleanup is <br /> provide capture of portions of the plume upgradient unknown at this time. <br /> of the extraction well fences located along the ■ This well configuration results in significantifcant <br /> leading edge of the plume and along Sandwich <br /> mounding(from the reinjection wells), <br /> Road. <br /> ■ The plume response alternative ecological <br /> Considerations: screening goals would likely not be attained. <br />�'r ■ The total extraction rate for this alternative was <br /> approximately 13 million gallons per day <br /> pp �' Alternative 103 <br /> (MGD), approximately 4.5 MGD greater than <br /> Alternative C1. which has similar plume Alternative 103 utilizes axial well fences within the <br /> capture. footprint of the plume. Reinjection of the treated <br />., <br /> water is in well fences that run along the outside of <br /> Y This well configuration results in significant the plume footprint. The well configurations are <br /> ' to the regional groundwater flow field p p g <br /> impacts g g referred to as axial because they are oriented <br /> adjacent and downgradient of the CS-10 plume, <br /> approximately parallel with the long axis ofportions <br /> as well as impacts to Ashumet Pond. <br /> of the plume and are roughly parallel with the <br /> • The contaminant capture that results from the direction of groundwater flow. <br /> in-plume wells is incomplete and inefficient. <br /> Consi , <br /> (Many more wells and increased total extraction <br /> derations. <br />' rate would be required to provide complete and This alternative would result in significant <br /> f <br /> accelerated capture.) impact to the regional groundwater flow field <br /> • The impact of the in--plume extraction wells on <br /> due to limited locations or reinjection. <br /> the duration of plume cleanup is unknown at * Capture is incomplete and inefficient. In spite <br /> p p <br /> this time. of high pumping rates(I I MGD), only a portion <br /> ■ Significant drawdown from the extraction of the plume is captured. <br /> wells and mounding the reinjection ■ The alternative results in significant drawdown, <br /> ) g J <br /> wells)result from this well configuration. mounding, and disruption of the groundwater <br /> • The plume response alternative ecological <br /> flow field in the vicinity of the LF--1 and SD-5 <br /> plumes. <br /> screening goals would likely not be attained. <br /> f * The leading edges of the plume are not <br /> 3S <br /> contained. Leading edge plume containment <br /> Alternative 1 (capture of MCL exceedance) would require <br /> Alternate in-plume pumping downgradient of the plume; pumping <br /> Alternative 1�2 was Alternative B with p <br /> extraction well fences in the central portions of the clean water for same duration and pulling the <br /> plume a roximatel perpendicular to the direction plume outside its current footprint. <br /> a pp Y p � <br /> of groundwater flow. The purpose of the in-plume ■ The plume response alternative ecological <br /> wells was to provide capture of portions of the screening goals would not be attained. <br /> Plume upgradient of the extraction well fences <br /> located along the leading edge of the plume. <br /> Considerations: <br /> The total extraction rate for this alternative was <br /> estimated at approximately 13 MGD with little <br /> additional plume capture (e.g., the pumping rate <br /> 7 <br />