Laserfiche WebLink
<br />. <br />.~ <br /> <br />" <br /> <br />NORTHWEST, INC. Consulting Engineers and Scientists <br /> <br />October 28, 1993 <br /> <br />Santa Maria Reservoir Company <br />P.O. Box 288 <br />Monte Vista, CO 81144 <br /> <br />FIle: N931198P <br />Ser: 93-0595 <br /> <br />Attention: Mr. Bany Nelson <br /> <br />Subject: Evaluation and Proposal <br />Continental Dam Seepage <br />Hinsdale County, Colorado <br /> <br />Dear Sir: <br /> <br />As requested, Harza has reviewed the information provided by Mr. Bill Paddock <br />regarding Continental Dam. This information includes early repons of seepage along the <br />downstream face of the dam, extension of the bottom outlet with addition to the <br />downstream embankment, addition of a geotextile membrane and the survey of the <br />renewed seepage during 1993. <br /> <br />Summary <br /> <br />You have requested an evaluation of conditions and a means to resolve the seepage <br />problems in order to return to full storage in the reservoir. The accompanying evaluation <br />and proposal provides a portion of this request. We feel that there is insufficient <br />information available in the provided literl1ture to determine if the dam embankment is <br />unstable because of the high water levels, there are questions regarding the perfonnance of <br />the downstream core filter section and the penneability parameters of the downstream <br />embankment section. <br /> <br />The data indicates that there is a likelihood that seepage enters the downstream dam <br />section through both abutments. The prilIlary cause of the seepage is the open jointing <br />visible in the adjacent bedrock. Only one zone in the core section is suspect That is the <br />IS-foot zone between the bottom of piezometer CE-2 and the abutment rock. This zone <br />should be examined. <br /> <br />In order to obtain the necessary information we are proposing to drill and test five <br />cored borings as indicated in our text and on the accompanying drawing. The cost <br />estimate for these boring and following analyses is provided. The data obtained is <br /> <br />2353 130th Avenue N.E., Suite 200 Bellevue. Washington 98005 <br />Tel: (206) 882-2455 Fax: (206) 883-7555 <br /> <br />Page 5 of 15 <br />