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<br />Reporting Period August 18, 1997 -August 29, 1997 <br />Main Crossing (Wall F-1 and F-2) In Progress Complete 9/12 <br />Wall G Begun 8/20 Complete 9/19 <br />Pond SG-1 and Main Drainage In Progress Complete 9/15 <br />Wall H Begun 8/22 Complete 9/5 <br />Water Tank Extension Indefinite Hold <br />Lower Sylvester Gulch Road Begun 8/27 Complete 10/3 <br />Field Observations, Data Collection, and Ongoing Evaluations <br />2 <br />A field inspection of specific areas of concern was conducted with CDMG staff in attendance on <br />Wednesday 8/20/97. A complete inspection was performed by MCC on 8/25/97 to visually <br />observe and evaluate the stability of slopes within the project azea. Data collection efforts and <br />evaluation or re-evaluation of specific azeas of concern continues. Individual azeas are discussed <br />in detail in the following sections. Supporting documentation is attached for your review. <br />RPE: No movement, slumping, or cracking has been observed on any finished or in- <br />progress slope at the RPE since the beginning of the project in late May, and no groundwater <br />has been encountered. Based on the last three months of observations, MCC is discontinuing <br />weekly monitoring and reporting for this area, however, reporting for this area will be <br />resumed should conditions warrant. <br />Lower Sylvester Gulch Road: Observation of the cut slopes and other disturbed slopes <br />adjacent to widened sections of the lower Sylvester Gulch road showed no failures or <br />slumping on 8/25. A fifth reading at inclinometer I-2 was taken, and movement remains <br />slower than anticipated. Monitoring and evaluation of I-2 will continue. Back analysis of the <br />slopes near I-2, and re-design efforts for slopes neaz I-2 (approximately Station 17+00) will <br />begin after the next reading, in approximately two weeks. Golder Associates completed <br />sensitivity analyses of the existing slopes at and around inclinometer I-4 using data from the <br />inclinometer readings, back calculated soil strength values, additional laboratory data, and <br />various groundwater levels assumptions. [t is readily apparent that water is the major <br />contributor to slope instability, and that by removing the water, global stability results at any <br />of the assumed friction angles. However, the back calculated friction angles do indicate the <br />current design cut slopes of 1.5:1 (33.7 degrees) may be subject to slumping and localized <br />failures. Based on these analyses, major redesign of the lower road appears unneccessary. <br />MCC has therefore elected to flatten the cut slopes to 2:1 to remove additional mass (driving <br />force), and install additional french drains on and above these slopes. Concurrently, MCC <br />will also field fit the alignment of the lower road approximately 20 feet to the west from <br />Station 20 through Station 47 in order to reduce fill heights and avoid potential fill slope <br />failures similar to that experienced at Station 62 to 68. This will also eliminate MSE Walls B <br />and C, partially eliminate MSE Wall D, and minimize impacts to riparian wetlands. As built <br />drawings of the final road configuration will be forwarded to CDMG when the road is <br />