2009-06-09_INSPECTION - M1999120

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(Page 2) MINE ID # OR PROSPECTING ID #: M-1999-120 INSPECTION DATE: 6/04/09 INSPECTOR'S INITIALS: ECS OBSERVATIONS This was an inspection in response to a citizen complaint received by the Division on May 28, 2009. Mr. Russ Bachofer sent a letter to DRMS alleging that activity associated with the Ft. Lupton Sand and Gravel site (M 1999-120) or other mining activity in the vicinity had impacted the flood plain morphology sufficiently to cause flooding on his property that would not be otherwise occurring. Mr. Bachofer also made the same compliant previously, in the spring of 2008. At that time DRMS representatives Peter Hays and Erica Crosby inspected the site, the surrounding area, and reviewed the site files for M1999-120. It was determined that the mine needed to move some soil stockpiles that were located in the flood plain, and conduct a flood plain analysis to comply with Weld County's Flood Hazard Development Plan requirements. The mine complied and the soil stockpiles were removed entirely from the flood plain, and a floodplain analysis was conducted and submitted to Weld County for review and approval. On December 31, 2008, Weld County approved the flood hazard analysis and stated that Ft Lupton Sand and Gravel had adequately demonstrated that the operation does not negatively impact the flood plain, and was in compliance with their approved flood hazard development plan. At that time DRMS considered the matter to be resolved and Ft Lupton Sand and Gravel to be in compliance. No increases were shown by the flood plain analysis modeling that were even near the one-foot allowable increase, and for currently existing conditions over most of the site, the 100 year water surface profile is equal to or even less than the pre-mining condition. On June 4, 2009, DRMS representatives Eric Scott, Peter Hays, and David Bird met with Mr. Bachofer at 9:00 on his property to respond to this latest complaint and examine the situation. It was apparent that water had indeed risen to the level of the walk-out basement of the home. Upon inspection of the property, and contour mapping taken from 2008 aerial photography, it was apparent that the home and associated garage were constructed on top of an approximately three to four foot high bench along the east bank of the river in that location. It appears that in this area this bench is functionally the eastern limit of the floodplain. It also corresponds with the delineation of the eastern 100 yr floodplain boundary in the area as depicted on the FEMA floodplain map. There is minimal elevation change in the area between the base of the bench and the top of the riverbank. This bench was removed along the west side of the home to create the entrance to the walk-out basement. The basement exit as constructed is at the base of this three to four foot bench, and therefore "walks- out" onto the level of the local floodplain. Because of this configuration, any time the river tops its banks, very little additional increase in water level is necessary to impact the basement of the home. Also note that the 100 year flood plain, by definition, contains many areas that are flooded much more frequently. The area behind the house may, in fact, also be within the annual or 5 year floodplain. DRMS then inspected the west side of the river in that area to determine if any recent changes have occurred associated with mining that may contribute to the reported flooding. None were observed. During the inspection of the western riverbank it was noted that the river had also left its banks on the west side in several areas and has encroached onto the mine property and other properties on the west side of the river. This would seem to indicate that the river is not being significantly constrained by activities associated with the mine, and is in fact leaving its banks on both sides during flood events. Until such time that it can be demonstrated that there is a direct correlation between the mining activities and adverse off site flooding impacts, or that flood plain development compliance requirements are no longer being met, DRMS has no authority and therefore considers this matter closed.