2016-04-15_PERMIT FILE - M2016010 (8)

Home Browse Search

period of 1978 to 1988. Calculated flows at the LTC-1 station are similar to the historic flows at USGS 7099220, with higher flows during the spring runoff and summer months and mostly dry conditions during the fall and winter months." Questions: Given that the LTC-1 station only collected three data points, how can the statement even be made that the flows at the station are"similar to historic flows"? Were no sources available that included the significant floods of 1921, 1935, 1965, 1995,1997, 2013 and 2015? Without considering the precipitation levels of these flood years in the design of the water management plan, the planned structures may be undersized for the conditions of the canyon. G-10 36. "It is likely that storms larger than this will be controlled to some extent, but sediment loads and volumes from larger storms will probably exceed the capability of the system to provide full control. Questions: What 24 hour rain amount was used for this"maximum storm"estimate? What damage is expected to occur to Little Turkey Creek Road or property below the quarry if these structures do NOT provide full control of the flood event? What plans does Transit Mix have to compensate landowners for damage if the water management system is overwhelmed by a flood because they have improperly sized the ca acity of the water management structures to deal with flood events? G-10 37. "Table G-2 shows the 24-hour storm event data developed based on calculations performed by the National Oceanic and Atmospheric Administration (NOAA, 2013)." Questions: Is this table based on rain figures for the Colorado Springs airport? If so, why were no adjustments were made for the higher rain rates that the canyon experiences,compared to the airport? G-15 38. Comment: Table G-6 seems to have the columns incorrectly labeled. The column labeled"100 Yr. 24 hr peak flow appears to be the culvert diameter for a 10 year event. There is therefore NO column for culvert diameter for the 100 year event. G-16 39. "In addition to the primary water management structures, secondary sediment control measures should be installed to reduce water and sediment loads on the primary ponds. "Sediment levels should be examined annually following the highest runoff season(i.e. summer), and sediment removal should be undertaken in the fall to prepare the sediment pond for the next rainy season. " Question: The wording in the document says"SHOULD BE". Will these measures be included in the Transit Mix plan or not? G-17 40. "No acid-forming or toxic materials were identified during the exploratory drilling and sampling program; therefore,no release of pollutants to groundwater is expected" Question: The exploratory drilling collected samples from a VERY small portion of the overall quarry area. Will there be an ongoing testing of excavated material during future quarry operations to determine if acid- forming or toxic producing materials are found during future excavation? If so, what plans do Transit Mix have if these materials are found? SECAD 4 Hitch 41. 100 year, 24 hour event