1991-03-25_GENERAL DOCUMENTS - C1981017

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Recommendations Allowing the cut banks to naturally slough-in to narrow the road width and stabilize themselves is a long-term process and not by itself compatible with the short term objectives of controlling erosion and sediment production. The MLRD permit should be amended to change this prac- tice. Consensus is needed on appropriate widths of all haul roads and the type of construction required for ditches. Moving the ditch into the road 10 feet appears arbitrary and requires further study.In the case of 50-60 foot wide roads with 100 foot cut slopes, it may be necessary to move J� the ditch into the road 20-30 feet to permanently accommodate the sloughing. In other cases, �+ the existing stabilized cut slope and ditch should remain undisturbed and the road narrowed I� 4 by pulling back the outside edge of the road, lessening the fill slope gradient and thereby t� enhancing its revegetation. Independent of the ditch construction techniques used, all the eroding ditches should be stabilized by lining them with cobble size rock to reduce water velocities during periods of runoff and to prevent unnecessary erosion of outer slopes. Haul Road Berms (Photos 9-10) Mid-Continent has constructed berms of varying heights and widths on the outer edge of the 7y haul roads. There is some confusion regarding this practice. Mid-Continent contends that this is a safety feature required by the Department of Labor, Mine Health and Saftey Administration on all haul roads. However, according to Lee Smith, (MHSA field representative, pers. comm.), Mid-Continent has not been required to have these berms due to the issuance of a variance by U� his agency which allows them to haul on the inside of the roadway. 1 These constructed berms have several problems associated with them. As the roads are generally crowned in the middle, drainage from the road flows along the berm. This drainage (.t concentrates along the berms and its velocity is increased causing the berms and and road surface to erode. Since no outlets have been included in the berm design, erosion occurs until L,ir a natural outlet is found or the berm is eroded through. In addition, from Mid-Continent's efforts to narrow the roads by leaving several feet of road surface on the outer edge of berms have S resulted in surface erosion. Mid-Continent has failed to revegetate either the berms or the road surface outside of the berms due to the existing road maintenance practices that continually add new soil material which covers and enlarges the berms. Recommendations As in the case of the haul road ditches,a consensus is needed on road standards.Berms should be eliminated, unless required for safety under state or federal permits.The berms should then be designed and constructed as a permanent feature.Under this scenario,the number,size and type of outlets needed for individual berms should be specified for roads which are administered under special use permits and federal lease by the Forest Service. Design specifications should be based on the number of outlets needed to prevent erosion of berms.In addition,the selection of material needed to line culvert and berm outlets draining onto the fill slopes should be specified. Existing well-vegetated areas that are located on the outer edges of existing fill slopes and which could serve as natural sediment filters should also be identified. Revegetation of berms should be required if existing road maintenance practices can be changed to relocate disposal of sediment and snow from the berms to an off-site location. Any section of road on the outside of the berms should be scarified and revegetated. B. Non-utilized Haul Roads The issue of what should be done with haul roads that are no longer in use must be addressed. The current understanding between Mid-Continent and the Forest Service is that roads not