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Dave Zehner <br />Milner Pit No. 2 Expansion <br />Floodplain Evaluation <br />Page 6 of 7 <br />February 3, 2009 <br />6. Site specific evidence. The plant communities and soils at the existing pit and <br />the proposed expansion both show no evidence of historical flooding, such as <br />sand bars, drift wood, heavy willow growth, cottonwoods, etc. Instead, the plants <br />tend to be upland sagebrush species. Soils tend to be silty-sandy topsoil, or <br />gravels. Field observations are consistent with upland areas that are not prone <br />to flooding. <br />7. Site Information <br />It is my understanding that the expansion will not require locating permanent facilities <br />such as fuel storage tanks within the proposed expansion area. Currently, an above <br />grade fueling area exists outside of the existing pit near the scale house (Map 2). The <br />storage tanks are contained in a sealed concrete enclosure (see attached photo). A <br />check on elevations of the enclosure shows the base of the enclosure is higher than <br />FEMA's mapped floodplain by at least two (2.0) feet. <br />Conclusions <br />There are approximately 79.4 +- acres in the proposed pit area. Of this, 30.8 acres <br />(39%) are mapped outside of FEMA's floodplain, and 48.6 acres (61%) are mapped <br />within FEMA's floodplain. The depth of inundation is literally a judgment call. Practically <br />speaking, for reasons enumerated above, it will likely be nothing, or at most, a few <br />inches. The accuracy of FEMA's map data is simply not precise enough to be able to <br />make that determination <br />Additionally, the entirety of the proposed pit expansion lays completely outside of <br />FEMA's regulatory floodway, and only a portion of the expansion lays within the <br />regulatory flood fringe. <br />WA-MR RESOURCE CONSULTANTS, LLC