2014-06-20_REVISION - M1981207 (10)

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Blue Pit Exhibit G - Water Information Surface Water General Discussion 112 Permit Amendment The Blue Pit is separated from the Roaring Fork River Valley by an 80' tall natural slope which remains after removing the gravel from an elevated alluvial terrace. The pre -mine site was used for irrigated pasture and the western portion of the site still serves this use. This irrigation water enters the site from the south in the Basin Ditch. Hydrology and Sediment Control for during Mining Almost the entire site drains to the bottom of the pit with the exception of the East Topsoil Stockpile. This Stockpile will have a ditch and berm to prevent runoff from leaving the site, therefore, no discharge permit is needed for the site. The pit is approximately 6o feet deep and will become deeper in the western portion of the mine, therefore, it is more than adequate to handle an event larger than the loo year event with no discharge. No water from south of the permit area enters the site since it flows south to Highway 82. No water from the east enters the site due to a berm placed around the eastern portion of the site adjacent to the east Topsoil Stockpile. No water from the North enters the site, since it is intercepted by the Spring Ditch in the eastern part of the permit and the berm with trees for the north portion of Mining Area a. This berm will be 2.0 feet high and will have 3:1 sidelsopes and will be vegetated upon construction. The berm is shown on Maps C -213 and Map F. No disturbance will take place south of this area until the berm is installed. No water can enter the site from the west since this area drains to the west and is now part of the Cerise Pit for United Companies. One of the challenges that Western Slope Aggregates, Inc. faces at this site is mining the reserves under the Basin Ditch. Recovering these resources needs to happen in a way that will not disrupt the functionality of the ditch since this ditch supplies water to users downstream. This will be accomplished by creating an irrigation berm with a 3H:iV grade with an open ditch to move the water, as shown on Maps C -2A and C -213. This will be done in the winter when the ditch is non- functional. All plans and details have been evaluated and approved with the Ditch Company prior to making the changes. All documentation pertaining to this are found located in Appendix C. The Spring Ditch also enters the permit area in the southeast corner and then enters a holding pond from which the water goes in a 4" HDPE pipe along the eastern edge of the permit area as shown on Map C -1 and C -aB. Once the northeast corner of the permit area is reached, the water re- enters an open ditch which is north of the permit area and moves water to the west. Hydrology for after Mining (long term) Blue Pit May 2014 G -1