Laserfiche WebLink
-13- <br />of sediment and soft material requiring extensive subgrade preparation. An added advantage <br />of performing downstream rehabilitation is the minimal effect on the storage capacity within <br />the reservoir. <br />Flattening of the upstream slopes on Dams 2 and 3 would require removal of the existing <br />concrete slope protection and subgrade preparation for new slope protection on the upstream <br />slope. <br />5.0 BORROW AREA <br />Generally, the material found in the areas near the downstream ,portion of the embankment <br />should be suitable for the construction of new or rehabilitation .!,of the existing embankments. <br />The overburden soil generally consists of very sandy to silty clays which have been used in <br />the construction of existing dams. However; im areas .where siltstone bedrock is exposed or <br />is otherwise available, it can also be used in the downstream zone of the embankment. If <br />siltstone is used, the downstream face of the embankment - should be protected by vegetation <br />to prevent erosion. <br />Sand for materials was previously obtained from local sources such as existing sand and gravel <br />pits and from the Harmony Ditch near the river intake. We assume that sand and gravel can <br />be obtained from alluvial deposits.of <P,latte River. It is anticipated that a new sand and gravel <br />mining pit would be developed to produce the material required for these rehabilitation and <br />enlargement alternatives. Regulatory permits would be obtained prior to mining these deposits. <br />6.0 SLOPE PROTECTION <br />Slope protection is a major issue for Julesburg Reservoir rehabilitation and enlargement. The <br />types of slope protection considered include riprap, concrete facing and soil cement. <br />No credible source of good quality riprap is known within the vicinity of the reservoir. Rock <br />outcrops and local quarries will have to be further evaluated to determine if they can produce <br />riprap quality material.. Most probably, the riprap will have to be imported from the front <br />Zreports \97 -1 -500. nk <br />