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<br />Requests modified configuration for underdrain pipe trench in upstream one-half of valley leach <br />facility - in areas of drain rock with widths less than 20 feet, excavate trench beneath grade and <br />place drain pipe into trench, covering pipe in trench with bedding material and placing large <br />rock on top and off to sides of bedded pipes rather than placing pipes at grade and building up <br />drain rock on either side (because of limited maneuvering room for construction equipment in <br />narrower parts of Arequa Gulch). <br />Q(5) CC&V letter dated July 14, 1994 -Adds another grain size for use of granite in finger <br />drain which does not flow but which is, on occasion, damp. <br />Letter Reference: Fineer Underdrain Material -Addition of Specification For Underdrain <br />Material In Small-Flow Channels -Commitment Number 32. Request <br />to Add To Specifications For Underdrain. <br />After field discussions held during one of Dr. Pendleton's visits, the nature (size distribution) <br />of finger drain material in a small valley which has not evidenced flowing water but which is <br />only damp was agreed to as an additional specification for "finger drains." The letter served <br />to add the specifications for these areas and to ensure that our understanding of the measures <br />agreed upon during Dr. Pendleton's July 14, 1994 site inspection were correctly understood. <br />We also asked that the specifications, if acceptable to the Office, be formally approved. The <br />additional specification provided for use of a slightly coarser, and therefore more permeable, <br />material. <br />Q(6) CC&V letter dated July 22, 1994 -Soil Liner size gradation modified to 2" minus and <br /><_ 10% 3/4 inch. <br />Letter Reference: Cresson Project: Permit Number M-80-244: Commitment Number "33" <br />(Specifications) -Gradation Specification Modification of the Soil Liner <br />Fill Material (Ironclad Material). <br />Request modification of size gradation specification for treated Ironclad soil liner to 2 inch minus <br />with the oversize picked out upon placement. Request based on permeability tests using the <br />slightly larger material and liner puncture test also using the slightly larger material, deliberately <br />placed, in both cases, in the tested materials. <br />Q(7) CC&V letter faxed July 22, 1994 -Removes stacking limit on stockpiled Geotextile and <br />retains specification to remove damaged geotextile material. <br />Letter Reference: Cresson Project: Permit Number M-80-244: Commitment Number "33" <br />(Specifications) -Modification of Specifications for Stacking Geotextile. <br />Requests deletion of stacking height limit for geotextile; retains requirement to cut out damaged <br />geotextile material in accordance with existing specification. <br />3 <br />