1994-01-07_REVISION - C1981017 - Laserfiche WebLink

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significantly different in suspended solids to that of the undisturbed areas for most runoff events . It should also be noted that on these road fill slopes , of 1 . OH : 1 . OV grade , total equilibrium will never be reached . It is also not reached on the natural slopes of the area. 2 ) After reviewing the permitting record , it is seen that Mid- Continent has done considerable work on erosion control on the roads over the years , some of it on its own initiative and some of it at the recommendation or demand of the Division . In 1991 , Dan Mathews of the Division conducted a three week long investigation that resulted in some specific corrective actions . Ail of the corrective measures . such as rip-rap , culvert outlet troug'r;s or downspouts , water bars , regrading road ditches , etc. were completed by Mid-Continent . in fact , it is my understanding that all specific requests made of Mid-Continent by the Division throughout the time of the permit have been performed . The record also shows that Mid-Continent has planted trees in many road slope areas and has applied seed and mulch to most other areas . I have seer; some general statements in the correspondence such as "erosion must be controlled over all road areas" . I realize that the reality o' the ground makes it extremely difficult to take action based on unspecific statements such as these . From site inspections and review of the permitting record , I believe that Ni-id-Continent has made an effort to control erosion on these pre- law roads to the extent reasonable and practicI . The effort to the extent reasonable and practical must be emphasized for these pre- law roads in the type of terrain and soil conditions in which they exist . 3) In certain areas , the gullies on the fill slopes have not reached relative equilibrium. These areas are not very widespread , but they do exist . In these areas , the fill material is usually comprised of a durable type of Marcos Shale as a result of past geologic intrusives . This material generally breaks up into granular and gravelly textured material but does not form clay or loam. Therefore , it has no cohesive strength . The fill slopes were able to be placed at a steep angle simply due to the fact that the angular nature of the material gives it a high angle of friction . The gravelly nature of the material causes two problems : a) it erodes easily with any appreciable surface flow and b) it is difficult to establish vegetation in the material because roots cannot anchor themselves without appreciable fine material . The enclosed photos show an area from the Mine #3 road that represents a problem area of this type .