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Hazeltine/Road Runners Rest IIlBrinkmann-Woodward Gravel Pits Lining Project -Design Technical Memorandum <br />Denver Water <br />August 2003 <br />TABLE 4.2 <br />SUMMARY OF SELECTED ROCK <br />MASS HYDRAULIC CONDUCTIVITIES <br /> De th Below To of Bedrock Feet <br />Section 0-2 2-4 4-6 6-8 6-10 10-12 12.14 1416 16-18 18-20 20-22 22-24 24-60 <br />1 5.Ox10~' 5.0x10"B 2.0x10"B <br />2 S.Ox10~' 4.4z10~5 1.Ox10~' 2.Oz10~8 <br />3 5.0x10° 2.Ox10~0 <br />4 S.Ox10~5 2.Ox10~B <br />5 4.4x10"' 4.1 z10~5 2.0x10"` <br />6 5.0x10° 4.1x10' 5.0x10° 2.0x10° <br />Notes: <br />1. All conductivities are in cm/sec <br />2. Cutoff wall conductivity = 1.00x10"' <br />3. Alluvium conductivity = 3.OOx10~' <br />The upper portion of bedrock identified in the borings consists of intensely weathered and <br />intensely fractured claystone. Although this zone of intensely weathered and intensely <br />fractured bedrock ranged from 2 to 24 feet, it was generally identified to be between 2 to 4 feet <br />thick. Packer permeability tests could not be conducted in this intensely weathered and <br />intensely fractured zone. Therefore, we considered this zone to have a hydraulic conductivity <br />greater than the hydraulic conductivity of the intensely to moderately weathered and fractured <br />bedrock that could be tested. We assigned a hydraulic conductivity of 5 x 10"5 cm/sec to this <br />upper intensely weathered and intensely fractured zone of bedrock. <br />We used a hydraulic conductivity of 1.0 x 10-7 cm/sec to model the soil-bentonite cutoff wall <br />and a hydraulic conductivity of 3.0 x 102 cm/sec to model the alluvium above the bedrock. <br />4.5 Parametric Study <br />GEI performed a parametric study using the seepage analyses for each representative cross <br />section to evaluate the change in estimated seepage into the reservoir for various depths of <br />penetration ofasod-bentonite cutoff wall into the underlying bedrock. The seepage analyses <br />were performed for each representative section by varying the depth that the modeled soil- <br />bentonite cutoff wall extended into the bedrock layers for the hydraulic conductivity values <br />presented in Table 4.2. The depth the cutoff wall extended into bedrock was increased by 2- <br />foot intervals based on the stratigraphy of the section for each subsequent seepage analysis. <br />The results of the parametric study are summarized in Table 4.3. <br />GE[ Consultants, Inc. 19 0205003-07dI lA-Hazd~ine Design TN <br />