GENERAL39214 - Laserfiche WebLink

Home Browse Search

some areas, was clearly evident beginning at the eastern one- third of your property and continuing upgradient past the J & J Pit and approaching the edge of Bwing Mesa. It was also evident that significant cutting of the immediate channel side embankments occurred as storm runoff scoured out the channel bottom. Although the drainage channel passes immediately adjacent to the affected area comprising the J & J Pit, there was little or no evidence that runoff from the mine carried any significant quantity of cobble material down into the drainage and onto your property. A portion of the access road to the pit which is immediately adjacent to and forms a part of oae of the side embankments of the drainage showed some evidence of cutting, however it was apparent from observations of the drainage channel as a whole that such a high quantity of runoff would probably have caused the same degree of embankment cutting regardless of whether there was a man-made road embankment adjacent to the. channel. Portions of-the-. natural drainage channel both above and below the road embankment area showed as much side embankment cutting es that occurring along the base of the road embankment. Other parts of the gravel pit which contribute runoff to the drainage showed no signs that storm runoff had washed any significant quantities of cobble material into the natural drainage. The operator has installed a berm along the outside portion of the - acres road beginning at the switchback where the road passes immediately below the pit. This berm appears to have been effective in preventing any significant quantities of cobble material from leaving the disturbed area. 2) The Carbon Junction Mine is located just to the south of the watershed which feeds the drainage in question and as such would not have had any effect on the channel. It should be noted that the Carbon Junction Mine has ea elaborate drainage control system as required by the Coal Regulations (different than the Regulations for gravel mines) that is designed to completely contain all of the disturbed area runoff from a 10 year, 24 hour storm event. 3) Apparently, the late August storm event was unusually severe end caused damage in many parts of the county that had not experienced such damage for a number of years, perhaps 20 or more. From talking to individuals who have lived in Durango fora long time, it is probable that the storm event occurring last August greatly exceeded the calculated runoff from a 10 year, 24 hour storm event. 4) Although it was difficult to determine due to the extent of landform changes that have occurred as a result of commercial development in areas within and surrounding your property, it is probable that the natural course of the drainage in this area has been altered over the years in order to eccomodate building sites situated on both sides of the highway. Such an 2