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I . . I I f f , I I . I I I I I I I I I I I Simons, Li and Associates, Inc. Job. No. 6143J002 Project Portland Flume Reconstruction It is our understanding that the proposed reconstruction will consist of widening and deepening the existing flume with some minor realignments in several areas. The new channel will be concrete lined with a V-shaped bottom and vertical sides. No information was available as to the type of roadway crossings to be placed along the alignment, but is is assumed that con- crete box culverts will be used. It is anticipated that the flow line along the alignment will be lowered 4 to 5 feet. The existing Portland Flume runs generally east to west between 4th and 5th Avenues at an average slope of approximately 10 percent near the southern end of Ouray, Colorado. The flume channels runoff from Portland Creek through the developed area of town. The total length of the portion of the flume being studied is approximately 2400 feet and extends from 300 feet east of Sixth Street to the Uncompahgre River. The existing flume is a concrete lined box section an average of 10 feet wide and 3 feet deep. The concrete is in generally poor condition with numerous distressed areas. The existing flume has eight roadway crossings and runs adjacent to several existing structures. More detailed descriptions of structures which may be adversely affected by the proposed construction are included hereinafter. Two test pits were excavated along the portion of the flume covered in this report at the locations shown on the accom- panying site plan with a Case 580C backhoe. Locations were selected by the client and city personnel. Access for explor- ation was limited in some areas, particularly between 2nd and 4th Streets, due to previous development. During test pit ex- cavation, subsoils were visually examined and sampled at selec- ted intervals. Materials encountered in all of the test pits consisted primarily of varying percentages of silty sand, -2-