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The excavation will be confined to an area well above the normal high-water levels from the river. <br />There are no wetland areas within the project area and no mining will take place along the river. <br />Mining will not affect the historic drainage pattern across the property nor will it affect the flood <br />plain of the Colorado River. <br />2.1 Pit 1 <br />Pit 1 will be mined first. Initially, a berm will be maintained on the downslope of the pit. All <br />stormwater runoff will be held within the pit. The berm is over 20 feet in height. A natural visual <br />berm will be left in place at the western edge of the pit in order to prevent stonnwater from leaving <br />the disturbed areas. Alternate sediment control (straw bale, silt fence, or other) will also be <br />constructed and maintained for all areas of disturbance at this stage as needed. All of Pit 1 will <br />drain internally. <br />2.2 Pit 2 <br />Pit 2 will most likely be mined second. Initially, a berm will be maintained on the downslope of the <br />pit. All stormwater runoff will be held within the pit. The berm is around 30 feet in height. A <br />natural visual berm will be left in place at the western edge of the pit in order to prevent stormwater <br />from leaving the disturbed areas. Alternate sediment control (straw bale, silt fence, or other) will <br />also be constructed and maintained for all areas of disturbance at this stage as needed. All of Pit 2 <br />will drain internally. <br />2.3 Pit 3 <br />Pit 3 will most likely be mined last. Initially, like with the other pits, a berm will be maintained on <br />the downslope of the pit. All stormwater runoff will be held within the pit. The berm is around 16 <br />feet in height. A natural visual berm will be left in place at the western edge of the pit in order to <br />prevent stormwater from leaving the disturbed areas. Alternate sediment control (straw bale, silt <br />fence, or other) will also be constructed and maintained for all areas of disturbance at this stage as <br />needed. All of Pit 3 will drain internally. <br />2_4 Stormwater Runoff and Sump Retention Capacity <br />During mining activities, each of the pits will have act as a sump for area stormwater runoff. An at <br />least two foot tall berm will be maintained at the perimeter of each mining pit and the facilities area. <br />Rincon Materials G-3 <br />Greg Lewicki and AsvociaLLK, ITIA <br />February 2020 <br />