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Environmental Effects <br /> Proposed Action <br /> Direct and Indirect Impacts: Work under the modified Poo is not planned within the <br /> riparian area,however due to the steep slopes in the area of planned work it will be difficult to <br /> keep excavated material from tumbling down onto the streamside riparian margin and entering <br /> the Arkansas River. During extreme flows,materials entering the riparian area are prone to <br /> erosion. In addition,as shown in this document's photographs and related to existing operations <br /> at this location at some point in time,cast material has entered flood prone areas and some <br /> material has washed. Modern activity generated spoils still remain as shown in photos. Historic <br /> activity, slightly upstream created similar dumping,however that activity is abandoned and <br /> unrelated to this action but would be cumulative to this disturbance. Due to the length of time <br /> since the upstream disturbance,wetland species have grown through dumped materials. Similar <br /> activity is not planned for the downstream mining. Under the new PoO,native material <br /> excavated upslope of the riparian zone will leave more volume than geologic sorting did. Given <br /> the larger exposed volumes of material,planed altered slope angles, and reduced site vegetation, <br /> increased erosion during primarily high precipitation events in the May through September rain <br /> seasons is possible. Isolated thunderstorms produce heavy rains in short periods of time and <br /> naturally create overland flow. Very short duration overland flow carrying silts which would <br /> enter the riparian vegetation and the Arkansas River as turbidity will be difficult to control. If <br /> eroded materials reach the stream banks or river unnecessary impact would occur. <br /> Protective/Mitigation Measures: <br /> • The Poo states plans to plant vegetation in the riparian area as mitigation to offset <br /> recently cast material from previous activity. However, if cast material is planned <br /> for removal from flood prone areas, the proponent is responsible to coordinate <br /> these activities with the ACOE, as applicable. <br /> • If the planned constructed settling basins do not contain all pumped waters <br /> allowing it to soak in,then the mine proponent would need to consult with the <br /> State of Colorado as to the possible need for a NPDES discharge permit. <br /> Cumulative Impacts: Recent rise in gold prices and interest in both recreational mineral <br /> specimen collection and mining activity under the Mining Law has increased on the Arkansas <br /> River creating additional disturbances to obligate riparian wildlife species and stream-banks. <br /> Activities proposed here are cumulative to those other disturbances and activities, such as <br /> fishing,park development and rafting activities, and the other activities along the Arkansas River <br /> corridor. <br /> No Action Alternative <br /> Direct and Indirect Impacts: Current mining taking place under the approved Plan of <br /> Operations with associated impacts,will continue, irrespective of the proposed modification <br /> approval. <br /> Protective/Mitigation Measures:None <br /> Finding on the Public Land Health Standard for Riparian Systems: Following the Modified Poo <br /> with the protective mitigations measures documented in this analysis will insure that this Public <br /> Land Standard is achieved during the life of the mine, but with all functions returning after <br />