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• Sediment Load Standards for all Reclaimed Areas <br />In order to develop a standard for sediment erosion from the <br />reclaimed areas, a number of methods are potentially usable. <br />First, sampling of the reclaimed areas and pre-mining baseline <br />data could be compared for a particular storm event or number of <br />storm events. This cannot be done, however since there are no <br />data in the permit for the pre-mining slopes. Total suspended <br />solids data and total settleable solids data does exist for <br />Curtis Creek but for no other area. Also, the Rienau site was a <br />pre-law mine that had no sediment control features. <br />Second, sampling of the reclaimed area and the adjacent <br />undisturbed area could be made for a particular storm event or <br />number of storm events. After reviewing the sites, maps, etc., we <br />feel that it is not possible to pick locations on the reclaimed <br />areas and on adjacent areas that are equivalent in slope, length <br />of slope and control practices. For example, the Rienau #2 site <br />contains a permanent diversion immediately above the reclaimed <br />area. The surrounding undisturbed slopes have no such diversion. <br />At the Northern #1 site, no sample can be located in an area to <br />sole]y measure the reclaimed area. All locations will have some <br />• mixing of runoff from the reclaimed and the undisturbed areas. <br />Also, there are some serious questions about the mechanics of <br />collecting valid samples on the ground. For these reasons, this <br />alternative has been abandoned. <br />Third, computer modelling techniques such as the SEDcad model <br />could be used to predict sediment loads for a particular storm. <br />This technique is also flawed because the modelling requires <br />actual drainage basin parameters as input, and as described <br />above, the drainage basins are far from identical. There are no <br />points on the reclaimed and disturbed areas which are truly <br />comparable. Also, this model predicts the sediment concentration <br />for one design storm only. <br />Fourth, an estimate of the annual sediment loss can 6e made for <br />the undisturbed areas using the Universal Soil Loss Equation and <br />the baseline soil, vegetation and topographic information. This <br />calculation has a number of advantages. Hydrologically, it is <br />much better to compare sediment volumes on an annual basis than <br />for one particular storm. Many sources of error can be eliminated <br />in this way. The Soil Conservation Service office in Meeker also <br />agrees that this method is better suited for the reclaimed areas. <br />• <br />Z~~~43 <br />~~a <br />