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The Leadville Mill M 1990 -057 INTRODUCTION & BACKGROUND Page 1 -3 The structures are identified on Figure 6 -2 and Structure Compensation agreements and an engineering report are presented in Sec. 13.0, Exhibit L. There are two distinct topographical features describing the Mill property. The northern portion of the property consists of a moderately steep, south facing slope which drains to the south. The average grade of this slope is 25% and ranges in elevation from 9,760ft to 9,730ft. The southern portion of the property consists of a gently sloping area that drains toward the west - southwest. The average grade of the southern slope is 3% and the slope on the southern portion of the property ranges from 9,730ft to 9,700ft at the southwest property corner. An unnamed 1 -3ft wide drainage channel enters the property on the eastern boundary, adjacent to the northwest corner of the Leadville Sanitation District polishing pond. This channel generally flows to the southwest across the property, crossing under two access roads. The channel flows into what appears to be an old soil conservation drainage ditch in the southwest corner of the property and the water then flows along the contour to the northwest, exiting the property on the western boundary. Undisturbed area runoff water to the north of the unnamed drainage channel reports to the channel. The flows are limited and the culverts under the road are 12in culverts, with no evidence of overtopping or washouts. The water exits the property into an existing road drainage network, flowing to the Highway 24 drainage network and then to California Gulch. Undisturbed area runoff water south of the unnamed drainage channel does not report to a drainage channel, and overland flows through trees and vegetative cover, leaving the property along the southern boundary. Runoff water in the construction area reports to either the TSF or is filtered through silt fences and vegetative filters prior to continuing its overland flow to a downslope channel. According to the Lake County Soil Survey, Leadville sandy loam (LeE) is the only soil type that exists within the property's drainage basin. This is a woodland soil. The predominant tree species on the property is Lodgepole Pine. 1.2 REFERENCES Apodaca, L.E., et al., 1996 Environmental Setting and implications on water quality upper Colorado River Basin, Colorado and Utah: U.S. Geological Survey Water Resources Investigation Report 95 -4263, 33p. Version 1.0 April 2013