2018-05-30_REVISION - M1983035 (3)

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Second,there are the areas within the pit where vegetation is in excellent condition and they should not be disturbed. Damaging these very good to excellent growths will require the damaged area be reclaimed and that will increase the cost of reclamation and will be a setback of the reclamation that has occurred. No need to fix what is already fixed if it works as needed. Reclamation Unit: Southeast corner of mined area. This is the location that exhibits the most severe erosion. A very deep gully has developed where water from mainly the undisturbed land to the east has flowed into the pit. That occurred by virtue of the lowest point of the land to the east is at this corner. Of course,there are other erosion areas that need treatment but this is the most critical of all. Without correction this area will continue to erode eastward for quite some distance and expand in width. As it does the mouth of the gully could cut into the north side of the South Berm causing it to slowly collapse into the cavity until an opening is created through the berm which would allow water to flow directly into the development to the south. This is already happening to a small extent although it is far from connecting at this time. Granted, that will take a while, but stopping it now is 1)the best action to protect undisturbed land to the east and northeast; 2)reduce the possibility of a berm being breached in the event of a huge thunderstorm, and 3)the only way the site is ever going to be released from bond. Corrective action will include marking off the full functional boundary of the erosion. Then the area will be shaped into a cove like form. The final slope here must be much less gradual than 3:1. More on the order of 5:1 or even less steep. The face of the cove where the underlying native material is exposed will be topsoiled, using soil from the east end of the North Berm and any native soils excavated in the process of creating the cove. Silt fences or other suitable material, even a row of staked straw bales,that eliminate rapid flows down the fresh slope will be placed around the top of the slope about 5 feet or so back of the top of the slope. The object of using a silt fence or other feature is not to stop silt but to reduce the rate of water flow and disperse it across a wider area so it enters the repaired area in a much less vigorous flow that increases the possibility of erosion. This treatment will extend all the way to the toe of the new drainage outslope. Otherwise, headward erosion from the bottom could still create new erosion damage. In other words, no matter what happens in the south basin, the transition from this drainage inlet into the basin must be gradual as well as strong and not subject to easily being eroded away creating another deep erosion area. It is also required to fill the gap the would connect this area with the entrance to the street in the development just to the south. It appears that a piece of the original South Berm in this area has partially Vollmer Pit Technical Revision June 2018 Updated Reclamation Plan Page 9 of 26