2018-09-17_PERMIT FILE - C1981025 (4)

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(c) Wildlife should have no problem with safety and access to the impounded water. The pond embankment slopes are 2.5h:1 V. (d) The issue of water rights is discussed above. (e) The U. S. Soil Conservation Service Public Standard 378, "Ponds", Colorado, January, 1989 provides information on the design of permanent impoundments. Nearly all of the requirements of Standard 378 are duplicated in DRMS Rule 4.05.6 Sedimentation Ponds. There are a few requirements of Standard 378 that are not specifically addressed in Rule 4.05.6 as follows: Foundation cutoff. A cutoff of relatively impervious material shall be provided under the dam. Appendix 4-C in Volume III contains a Geotechnical Investigation at the Refuse Disposal area. The report recommended a liner or cutoff trench to control seepage (pages 12 & 13). According to the drawing D-4-10, a clay liner was installed in the pond. Seepage control. There is no documentation anti -seep collars were installed on the primary spillway. However, it is believed good construction practices were used during pond construction so there is a reason to assume anti -seep collars were installed on the primary spillway. (f) The pond spillway system is a combination of principle and emergency spillways. The single open channel spillway has a capacity of 15 cfs (ref. drawing D-4-10). The pond was designed to handle the 25 -year precipitation event (ref. page 4-17). Standard 378, Table 4, Page 378-6, specifies the spillway must handle the 25 year event. Therefore the pond spillway meets the requirements of Standard 378. Refuse Pile The reclamation of the refuse pile was completed during 1986. The area was contoured, seeded and mulched during the fall of 1986. The area exhibited good plant growth during the ensuing years. The refuse area was included in the vegetation study and demonstration mentioned above so no sedimentation control was required for the refuse Permit Renewal 4-v (Rev. 03/13)