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Technical Comments Regarding Site Conditions September 7, 2011 <br />Western Gravel Disposal Facility CD Application Page 3 <br />the cell, and thereby inhibit fluid movement vertically. In addition the bedrock dip is to the south - southwest, away <br />from the White River, and any leak through the secondary liner system should have a preferred flow path down dip. <br />With this design wet/dry wells installed along the southerly edge of the facility and screened across the top of the <br />bedrock will be utilized to identify leakage through the secondary liner. The Green River Formation (Oil shale) <br />overlies the Wasatch Formation. It has been eroded away across the proposed facility but it is present on the hills <br />and higher elevations south of the site. The lowest member of the Green River Formation is the Garden Gulch oil <br />shale member which lies directly above the Wasatch Formation. One of the two more prolific aquifers (in the <br />Green River Formation) is situated above the Garden Gulch and is known as the Anvil Points member. This <br />potential aquifer is situated stratigraphically, structurally and physically above the site such that there is no <br />likelihood that seepage from the facility can enter this interval. <br />With regards to monitoring for potential impact to the White River, the applicant proposes to conduct seep surveys <br />along the steep slope as part of their annual monitoring. The White River alluvium contains a lot of groundwater <br />hydraulically connected to the river itself such that any release of contaminants from this facility would be difficult <br />to identify (due to dilution). Therefore, rather than installing a groundwater monitoring well at the base of the <br />steep slope in the White River alluvium and outside the CD boundary, the applicant may propose to annually <br />collect a surface water sample from the river both up and down stream of the facility during low flow for <br />contaminant testing specific to the proposed facility. <br />Overall -.the -site conditions- and - the - proposed robust- liner- system - design -meet and -even exceed- the requirements of <br />the Regulations, and yet the applicant appears to be amenable to the requested revisions that provide additional <br />protection of the White River. In the next week or so the Division will provide technical comments on the <br />application and then the applicant will submit a final proposal, which will also be reviewed. Assuming detrimental <br />information on the site stability is NOT identified during the additional requested investigation and the revised <br />Application provides the requested information, the Division will publish a public notice in local newspapers and a <br />30 -day written public comment period will follow. The Division's final recommendation to the County will not be <br />made until we have reviewed the public comments. <br />Please contact Robert Peterson at 970 - 248 -7151 if you have questions regarding this correspondence or if you <br />would like to discuss anything concerning the Application, solid waste regulation or the permitting process. <br />Sincerely, <br />Ydb-e-j1 <br />Robert Peterson, Environmental Protection Specialist <br />Solid Waste and Materials 1'vianagement Program <br />Hazardous Materials and Waste Management Division <br />cc: Rio Blanco Co BOCC <br />D. Valentine, Western Gravel LLC <br />B. Len, NWCC Inc. <br />T. Marshal, Division of Reclamation Mining and Safety <br />SW RBL WGR 2.1 <br />GJ file <br />