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Maintenance Required: <br />Uncover burrows and re-compact in•situ backtill to dam construction specifications to maintain [he <br />integrity of the dam. Reseed disturbed areas. At the present degree of burrowing activity, the burrows <br />can probably be uncovered by hand spade work, and the materials tamped back in place by hand tamping. <br />In the event burrows are coo deep or extensive, backhoes and mechanical tampers might be required. This <br />maintenance work should be accomplished before the next high water season. <br />Replace emergency spillway riprap with durable rock to protect the integrity of the dam. The potential <br />(or a rapid failure of the dam due to erosion a[ the emergency spillway is low. This conclusion is based <br />on the observation that the spillway is located at the north limi[ of the embankment, and the north <br />abutment is a gradual slope. Mechanism o(failure would likely be a slow, progressive erosion of the dam <br />embankment to the south, slowly lowering the pond pool. This maintenance work should be accomplished <br />prior to the next high water season and period of higher probability of record storms (late summer). As <br />light equipmen[ will be required to make these repairs (haul riprap), and a catastrophic failure is not <br />likely, this work could be scheduled during relative dry periods so that equipment access would not <br />significantly disrupt other land reclamation accomplishments. <br />Clear the principal spillway of the plastic sheeting and the outfall of excessive vegetation growth to avoid <br />restrictions of Mows. This work should be accomplished prior to the next anticipated discharge of water <br />from the primary spillway (high water season). <br />Revegeta[ion of the upstream slupe is not a high priority maintenance item. Erosion in the bare area is <br />not likely, nor is it threatening to the dam embankment. Reseeding is recommended at the next optimum <br />plantine season. <br />Recommend: <br />Additional inspection at a time of high water is recommended. The area of accelera[ed vegetation growth <br />and areas of burrow activity need to be probed to determine if seepage is occurring (no seepage or signs <br />of prior seepage were noted during this inspection). <br />Monitoring of the erosion to the north upstream face of the dam at the high water level is recommended. <br />Stakes might be placed at the limits of current activity during the next quarterly inspection. If erosion is <br />persistent and progressive, stabilize with vegetation or riprap facing will be required eventually. Dam <br />integrity is not threatened at the present degree of erosion, nor is it anticipated to become so during the <br />next high water season. <br />Monitoring of rodent activity during quarterly inspections is recommended. Should burrows continue [o <br />be a problem, implementation of additional rodent control procedures to halt the burrowing activity on <br />the dam may be required. <br />f1y~r~G. Wilke- <br />Colcr~do ^C Nu!.;bcr 15378 <br />Canadian Mine Pond # 1 Inspection Report, 1.1 October 1993, Page 3 of 3 <br />