2016-01-26_REVISION - C1981014 - Laserfiche WebLink

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amount of sediment. The sediment report describes the reclamation in terms of erosion and vegetation growth as problem free, self -healing areas that produce less erosion than the adjacent non -mined lands while failing to observe obvious erosion, signs of concentrated runoff, and great amounts of sediment yield. The sediment report has failed to demonstrate any true sediment analyses, failed to adequately compare reclaimed and non -mined lands (or pre and post mine conditions), failed to use the best available information, incorrectly and selectively applied vegetation cover in the model demonstrations, failed to provide, discuss, or demonstrate RUSLE model assumptions, or violations of these assumptions, which resulted in a conclusion that cannot be defended based on the data and the explanation provided in the report. Statements like "Specific to the LS factor, it is not appropriate to use different slope values for the non -mined area as compared to the reclaimed area" (from DRMS adequacy review response) are in great error and cannot be supported or defended. In addition, no model uncertainty, validation of the RUSLE model were discussed in the January 13, 2016 sediment report. The two objectives in the January 13, 2016 sediment report state the reason for the report were to: 1. Develop a model to determine if the sediment yield from the existing reclaimed condition is comparable or better than the non -mined condition (or pre and post mine conditions—these are two different situations—which one is it or is it both?), and 2. Demonstrate that the reclaimed area does not contribute excess suspended solids to streamflow as compared to a similar non - mined area. None of the sediment reports satisfy either of these two objectives nor does it provide evidence as stated in the conclusion that the requirements of Rule 3.03.1(3)(b), as included in Mr. Gorham's January 13, 2016 revised sediment report, were adequately satisfied. In addition, there is little mention of the RUSLE model assumptions, each variable in the model listed lacks adequate citations (which RUSLE version is being used?), and explanations for selecting certain values (R -factor, K -factor, and P -factor) were lacking, other than referencing these values were used in the original Permit Application. Just because these values were in the Permit Application does not justify their use then nor today. In addition, the Addendum included two demonstrations that selected specific portions of the permit area with the greatest vegetation cover. Included in the Addendum were additional assumptions without any accompanying support material, such as mention of sediment ponds (which should not be considered long- term), that vegetation will continue to improve (the south -facing slope of the RDA may already be in decline in terms of vegetation cover), observations of no sign of erosion beyond what is occurring in adjacent areas and even extend this unsupported generalization that there is less erosion in many places (now claimed a fact) and does not provide evidence of self -healing. As an example, the Addendum states it is a supporting analysis specific to the length slope (LS) factor and the sediment demonstration for the mine site. The demonstration only examines the RDA and surrounding area, not the mine site as a whole (46% of the reclaimed area). By specifically selecting the RDA, Mr. Gorham chose a best case scenario in which to demonstrate LS. The reclaimed RDA happens to have the greatest recorded vegetation cover compared to any other reclaimed land or to any of the three reference areas. In addition, averaging the gentle slope of the top of the RDA and the steep slopes of the RDA also provides best model results for this area, as does averaging all model output values.