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~, • II. METHODS SEDIMENTOLOGY DEMONSTRATION The reclaimed azeas and the undisturbed adjacent pinyon juniper and oakbrush communities are shown on Figure 1 of the vegetation report. The reclaimed areas must be shown to contribute equal or less sediment to the receiving waters downstream in order to satisfy the requirements for Phase II bond release. This is done by identifying equal areas from the two sites, and through the use of computer modeling (SEDCAD+), determining the amount of sediment eroded from each of the azeas for a given storm. Based on discussions with CDMG, an undisturbed adjacent pinyon- juniper community was identified for comparison to the reclaimed area. CDMG felt that this community better reflected the condition of the reclaimed areas prior to disturbance. SEDCAD+ computer modelling was undertaken for the reclaimed area and the undisturbed adjacent pinyon juniper community. Areas of 1.0 acre were selected at the reclaimed area and the undisturbed adjacent pinyon-juniper community. Each of these areas has approximately the same slope, elevation, aspect, and geomorphic condition. There are no drainages present in the sub-areas and sheet flow will occur during the model storm event. The sub-areas have • been carefully selected so that they allow a fair comparison for sedimentology purposes. The input parameters for the SEDCAD+ computer modelling azea discussed below. STORM EVENT In this case, the storm event used for comparison is the 10 yeaz-24 hour storm for this area of the state. The SCS Type II event comprising 2.25 inches of rain (Miller, et al., 1973). PARTICLE SIZING A composite sample of material at and neaz the surface (up to three inches deep) of the reclaimed area was collected to establish the particle size distribution of the reclaimed area soil material subject to surface water erosion. The composite sample was analyzed by the Colorado State University Soil, Water and Plant Testing Laboratory with the following results. • -2-