Laserfiche WebLink
• The other type of gully which may form on sideslopes is from sheet wash. Occasionally sheet wash <br />may form concentrated flows because of the irregularities in the retopsoiled topography. These types <br />of gullies should not be confused with gullies which occur in drainageways. (See Section 4.8.1.3 for <br />definition of permanent drainageways and their tributaries and how they differ from sideslope gullies.) <br />Erosion control designed to prevent the formation of sideslope gullies will commence with the final <br />grading, which will be done along the contour 'rf it does not present a safety hazard to the operator or <br />equipment. Similarly, seedbed preparation and drill seeding will be conducted on the contour if it can <br />be done safety. <br />Runoff diversion ditches or other similar structures will be placed on all reclaimed rangeland sideslopes <br />where potential for excessive sideslope gullying exists by the end of the first fall following topsoil <br />replacement. These structures may be established with any of several pieces of equipment including, <br />but not limited to, a plow, a dozer, a rear -mounted tractor blade, or a specialty built contour furrower. <br />During the year of diversion ditch installation, if the vertical distance between diversion ditches is <br />greater than 75 feet, contour furrows may be installed between the diversion ditches. Further, if the first <br />• season of runoff after retopsoiling and seeding produces significant gully development, then contour <br />furrows or additional diversion ditches or other preventative measures may be installed. Where contour <br />furrows are installed, they may have cross dikes, as appropriate, to prevent water from concentrating at <br />a low section and causing a failure. Spacing between furrows will depend on the slope and the prox- <br />imity to the top of the reclaimed sideslope. <br />Table 3.6-13 shows the typical minimum standards to be used in designing diversion ditches for <br />reclaimed areas only. There are other ditch design standards in the permit for other areas, such as <br />roads. Diversion ditch configuration will not inhibit wildlife or livestock travel. Moreover, diversion <br />ditches will be stabilized by seeding a CMLRD-approved perennial seed mix. Table 3.6-13 shows <br />25 -toot, 50 -foot, and 100 -foot vertical spacing design criteria. In using this table, two points need <br />clarification. The designs are examples of minimum standards. Trapper may choose to over -design to <br />compensate for effects of snow, for example. Also, 25 -foot, 50 -foot and 100 -foot spacing may not <br />always be appropriate. However, revised designs will employ the same general criteria as was used to <br />construct Table 3.6-13. Thus, we would not resubmit changes caused by altering vertical spacing. <br />However, other changes would require your approval. <br />3-150a REVISION APPROVED <br />I' DATE <br />