Laserfiche WebLink
it <br />~i <br />blockage extends upstream 60'-80' and varies in width Prom 20' to 40'. There <br />' is an area oP active siltation upstream of the pool oP water for about 75 feet <br />to a sheer vertical limestone wall. All of the trees and vegetation in the area <br />of inundation are dead. <br />t It was evident that the area of contact between the active slide and <br />native vegetation resulted in a small outlet ditch. This ditch contained both <br />live and dead vegetation, loose rocks and boulders, but there was evidence <br />that water had flowed out oP the inundation area when the level rose high <br />enough from rainstorms. <br />' An examination of the downstream area did not indicate any eviden~:e of <br />seepage of the ponded water through the blockage material. The slide has <br />effectively blocked the natural stream in a very permanent fashion resu~.ting <br />in a significant permanent pool of water. It is the author's opinion, however <br />' that due to the nature of the composition of the blockage material iextre.nely <br />large well packed boulders) and the length of the blockage, that there would <br />likely not be a "failure" or "dam break" and flooding downstream in the event <br />' of a large storm. <br />The area upstream is also acting as a settling basin for silt from the <br />1 quarry operation and this siltation will likely continue to encroach into the <br />pond area reducing its size. The rate and reliability of this siltation is <br />unpredictable and shouldn't be relied upon to solve the water impoundment <br />problem, although over a period of time this eventually will likely occur. <br />' The stability of the slope is difficult to predict, however there was <br />virtually no surface cracking observed near the top of the slope, so little or <br />' no movement has likely occurred recently. <br />A schematic sketch illustrating the general field observations is included <br />at the end of the discussion - as is a copy of a portion of the referenced <br />topographic mapping. <br />RECOMMENDED SOLUTIONS <br />The solutionts) to this slope stability problem have been discussed with <br />Castle Concrete, Mr. Heffner, and the OWA staff. It is apparent that the <br />number one priority is to reduce and/or eliminate the impoundment of water <br />above the blockage. A secondary consideration is the mitigation of the <br />' movement of the slide area if reasonable and practical. Each of these will be <br />discussed separately. <br />' The elimination of the water impoundment can likely be done in one (~r a <br />combination) of the following ways. <br />' 1. Fill the impoundment area with available or imported material. <br /> <br />2 <br />1 <br />