Laserfiche WebLink
• Appendix Exh 7-14C - Taylor Tributary Ditch <br />Taylor Tributary Ditch and its several tributaries are located in Sections 4, 8, 9, 16 and 17 <br />of T3N, R93 W. Because it is the source of flow into the East Taylor Sediment Pond, it is <br />presented here including all of its tributary ditches, some of which have also been <br />individually modeled and reported separately. Specifically, the East Taylor Ditch and the <br />Taylor Ditch, which also appear in this Exhibit 7, Item 14, are included within the Taylor <br />Tributary Ditch system. In addition, the East Taylor West Tributary Ditch and the East <br />Taylor East Tributary Ditch, which are discussed in detail in Volume 13, Exhibit 7, Item <br />20, Part E, feed into the Taylor Tributary Ditch at its upstream end. These upstream <br />ditches were designed pursuant to the revised post- mining topography described in TR- <br />81. Because they lie over out -of -pit spoil areas, they must be designed for the 100 year, <br />24 hour event. All ditch dimensions, design parameters, and calculated flows that are <br />included here as sub - components of the Taylor Tributary Ditch are identical to the <br />corresponding parameters separately described in TR -81 for East Taylor West Tributary <br />and East Taylor East Tributary ditches and the two ditches described elsewhere in this <br />Exhibit 7, Item 14 (East Taylor Ditch and Taylor Ditch) . <br />The alignment of the Taylor Tributary Ditch is shown on Map 41 and on two figures <br />Exhibit 7, Item 20, Figure 14C -1 and Figure 14C -2 in this section. The design profile of <br />the Taylor Tributary Ditch is provided on Map 33A. The entire channel was redesigned <br />following a revision to the post- mining topography for the upper reaches of the watershed <br />submitted under TR -81. <br />• The West Pit Ditch previously described in this section is no longer required due to other <br />mine plan changes and has been deleted. However, its drainage area is still included <br />within one of the sub - watersheds of the Taylor Tributary Ditch. <br />The total drainage area reporting to the ditch is 1,163.1 acres. Although portions of <br />Taylor Tributary Ditch could be designed for the 10 year, 24 hour event, the uppermost <br />portions that overlie out -of -pit spoil areas and the lower most reach which has a <br />watershed larger than 1 square mile after the confluence wit Eat Taylor Ditch require <br />design for the 100 year event. For simplicity, the entire Taylor Tributary Ditch has been <br />designed for the 100 year, 24 hour event. The East Taylor Ditch and Taylor Ditch, both <br />of which are tributary to Taylor Tributary Ditch, are designed separately for the 10 year, <br />24 hour event (See Sections Exh. 7 -14I, and Exh. 7 -14L). However, where they <br />contribute flow to the Taylor Tributary Ditch in this section, their contributory flows have <br />been determined using the 100 year, 24 hour event. <br />As shown on the profile, the steepest portion of the main stem of Taylor Tributary Ditch <br />is the lower portion, which has a slope of 7.4 percent. However, there are steeper <br />sections within the tributaries, including a 22 percent segment within East Taylor Ditch <br />and 25 percent slopes in both groin ditches adjacent to the East Taylor valley fill <br />described in TR -81. The overall length of the main stem of Taylor Tributary Ditch is <br />7,989 feet, from its base at East Taylor Sediment Pond, to its head at the toe of the East <br />is Taylor Valley Fill. <br />Exh.7 -14C -2 Revision Date: 12/31/10 <br />Revision No.: TR -81 <br />