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property located according to best management practices in determining the progress of lowering <br /> the groundwater table. These wells should be subject to removal upon request of the landowner <br /> and at the sole expense of Al. <br /> B. Tetra Tech Memo, Page 1, Paragraph 2 <br /> The memo repeatedly makes the false conclusion that the purpose of the project is to <br /> reduce surface water when the groundwater is the issue. State law requires Al to "[m]inimize the <br /> impact to the prevailing Hydrologic Balance." Removing the surface water does nothing to <br /> remove the root cause, which was the drastic increase in the groundwater table. While it may not <br /> be feasible to lower groundwater levels to match the historic table, any proposal that does not <br /> return the Orr Property to its pre-existing condition is insufficient. A viable solution would be to <br /> lower the top of the slurry wall to the lowest groundwater elevation shown in AI's records prior <br /> to installation of the slurry wall in 2005. This would be done from the Northeast corner of the <br /> Henderson Property to a point equal to the southwest corner of the Orr Property. <br /> Also, according to the State Engineer, all groundwater that is exposed and covered must <br /> have at least a two-foot cover during high groundwater cycles. AI's plan to provide an <br /> maximum of 2.0 feet below the surface does not account for the nearly 2.5 feet fluctuations <br /> commonly seen along the South Platte River that would result in a violation of the State <br /> Engineer's groundwater cover requirements. <br /> C. Tetra Tech Memo, Page 1, Parag_raph 3 <br /> Although Al focuses improperly on surface water, returning Bull Seep to its historic <br /> condition is a legitimate objective. Bull Seep currently is choked with cattails that reduce the <br /> flows below historic levels. Al should, therefore, maintain the seep to improve the quantity of <br /> the flow on a consistent basis and during storm events. <br /> But for AI's relocation of Bull Seep, the Orr Property would not be inundated with water. <br /> Al may not attempt to shift the causal relationship to other mining operations. <br /> After installation of the 2 - 18 inch drain pipes in 2014-2015, Al succeeded in draining <br /> two feet of"surface water" on their permitted land without measurably lowering the groundwater <br /> on the Orr Property. Without some means of tracking the ground water elevation on the Orr <br /> Property, the success of AI's new design will be unknown. We request monitoring on a monthly <br /> basis until the ground water elevations are at least 2.5 feet below the ground surface at its highest <br /> point. Copies of the data collected should be provided every three months to all affected parties <br /> including the owner of the Orr Property. Once the water reaches the 2.5 feet level then <br /> monitoring could be reduced to quarterly unless it rises above the 2.5 foot mark. <br /> D. Tetra Tech Memo, Page 1, Paragraph 4 <br /> Al offers no reasonable assurances that the City of Thornton will not block the drain and <br /> the outlet pipes or allow them to be blocked once they assume operation of the reservoir. Rather, <br /> Al states only that it will "reduce flooding on the Orr Property" which provides little confidence <br /> Page 3 of 5 <br />