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2002 Coal Basin Watershed Non-Point Source Grant Report <br /> March 15, 2004 through September 15, 2004 <br /> Activities accomplished at Coal Basin during the reporting period involved the evaluation <br /> of a demonstration surface particle retention system, evaluation of gully activity and of <br /> tree survival on the Mine 1 outslope, and bidding of the slope stabilization project. <br /> Surface Particle Retention System <br /> In the spring of 2003, the Division proposed to install an experimental slope stabilization <br /> device at Mine Number 1. The device had the potential to slow the downward migration <br /> of near surface soil particles on the severe slopes of Coal Basin. <br /> In August 2003, the barrier system was installed on the Mine 1 outslope. Approximately <br /> one hundred twenty five feet of the system was installed about one third down the Mine 1 <br /> outslope. The cones were configured so they were spaced at six inches, center to center, <br /> horizontally. The entire system was dug about ten inches into the outslope, so that the <br /> upper most two inches of the upper cones protruded from the slope surface. The two <br /> inches of the cones was left exposed in order to trap coarse rock debris that will cascade <br /> down from upslope. <br /> Slope monitoring points were established to help determine whether the system is <br /> effective. Initial measurements were made at the time of installation. Unfortunately, <br /> winter avalanche activity destroyed the monitoring installations, therefore, only visual <br /> observations of the effectiveness of the system could be made. <br /> Visual assessment of the system did not reveal that the system was particularly effective <br /> at inhibiting soil creep on the slopes. Some larger particles were slowed and trapped at <br /> the installation area, as a result of the cones protruding above the ground surface. <br /> However, an estimation of the long term effectiveness of the ability of this material to <br /> inhibit near-surface soil creep could not be made with a great degree of confidence. <br /> Therefore, due to the expense of obtaining and installing additional materials, a decision <br /> to abandon further installation of this material has been made. <br /> Installation of the initial retainage system for assessment purposes fulfilled Objective 1, <br /> Task 1 of the Non-Point Source Grant. The decision to abandon use of the system at the <br /> remaining outslopes fulfills Objective 1, Task 2 of the Grant. <br /> Evaluation of Gully Activity and Tree Survival <br /> An evaluation of gully activity was conducted at the Mine 1 outslope gully monitoring <br /> points in August 2004. Observations and measurements indicate that the gullies have not <br /> changed or degraded in any substantial manner since August 2003. The monitored <br /> gullies appear to be fairly stable. The side slopes of each are broad and exhibit moderate <br /> slope angles. No active channel was observed within either gully. Fairly significant <br />