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C- 1981 -019 PR -03 Eng /Geotech PAR No. 2 22- Jun -2011 Page 3 of 5 Rule 2.05.3(4) Ponds and Impoundments Two sedimentation ponds have been proposed with PR -03: the Little Collom Pond and the Little Collom Sump. Specific information is provided in application sections 2.05.3(4); 4.05.6; Exhibit 7, Item 23; Exhibit 7, Item 26 — Collom Pond Design Maps; and Exhibit 23, Item 1 Shannon & Wilson Geotechnical Study (S &W). Text in 2.05.3(4) of the application directs the reader to Vol. 1, Section 2.05 of the permit for pond construction and maintenance details and to permit Section 4.05.6 for a discussion of quarterly inspections. 1. 2.05.3(4)(ii) Detailed Design Plan Detailed designs are provided in Exhibit 7 Item 23 (Figures 1 and 2). Geotechnical analysis and stability evaluation for the Pond Embankment are found in S &W pp. 14 -15 and Fig. 11. (A) The designs have been certified by a registered P.E. No response required. (B) The Division notes several discrepancies between the notes on S &W Fig. 11 and the notes provided with Exh. 7 Item 26 Fig. 1, as follows: Fill Materials: S &W lists soil types SM, SC, GM, GC and CL as "acceptable ", while Fig. 1 lists SC, CC, SL and CH. S &W states that high plasticity clay and silts (CH and ML) are "unacceptable ". Fig. 1 does not exclude these materials, and in fact lists CH as "acceptable ". Fill Placement and Compaction: S &W recommends that the moisture content be within 0 to +3% of optimum moisture content. Fig. 1 requires OMC +/- 2 %. Monitoring and Inspections: S &W recommends that a monitoring point be set at the crest of the embankment, and measured quarterly for the first year after construction. Fig. 1 does not mention a monitoring point. Please revise Exhibit 7 Item 26 Figure 1 to be consistent with the recommendations presented in the S& W Stability Evaluation. Figure 1 of Exhibit 7 Item 26 uses the word "should" when referring to site preparation and fill placement. Please replace "should" with "will" or "shall". (C) Operation and maintenance requirements are described in Collom Rule 4 Section 4.05.6. No response required. (D) Timetable and plans for removal were not found in the application. Please revise Section 2.05.3(4) to address the removal of the Sump and Pond. 2.05.3(4) — Applicability - Little Collom Pond — Embankment Height is 20 feet; surface area is 2.61 acres; capacity is 19.85 acre -feet. The State Engineer requirements of 2.05.3(4)(iii) (C.R.S. 37 -87 -105) are applicable to the Little Collom Pond.