2022-05-10_GENERAL DOCUMENTS - M1993041

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Dowe Flats Quarry Site Description and Future Mining Impact Analysis Z9 Wetlands No jurisdictional wetlands are located within the Dowe Flats permit area. Three wetland areas that were once thought to be present within the permit area were associated with the Saint Vrain Supply Canal liner leakage and are primarily within the Partition Lease Agreement buffer area. The canal was relined in 1994 and in 1997, CEMEX, Inc. hired a wetland consultant to conduct an additional study of these three areas. The study results were sent to the U.S. Army Corps of Engineers (ACOE). On July 22, 1997, the ACOE replied verifying that the three subject wetlands were no longer considered to be wetlands or waters of the United States (Corps File# 199580789).No activities proposed in the permit amendment application will have an impact on wetland areas. Field inspections conducted in summer 2021 found no potential wetland areas within Dowe Flats. However, there is a wet area of just north of the mining boundary on the buffer land owned by Boulder County. This wet area was first identified in 2010 and was reported in both the 10- Year Review and the 15-Year Review of the Boulder County Special Use Permit for Dowe Flats. The wet area has expanded over the past 21 years. CEMEX, Inc. requested more than once since the 15-Year Review that the ditch be relined to prevent potential for future artificial wetland development. 2.10 Climatology The climate at Dowe Flats is typical of the Front Range foothills of Colorado. While no climatological data are collected onsite at Dowe Flats,precipitation data have been collected at the Flatiron Reservoir located approximately 9 miles north of Dowe Flats at an elevation of 5,470 feet since 1997 (Western Regional Climate Center 2021a). Average annual precipitation is 16.6 inches the majority of which falls at rain in May through September. Average annual snowfall is approximately 44 inches with the greatest snowfall experienced in December through March. No temperature data are recorded at Flatiron Reservoir. The closest weather station with temperature data is the Loveland 2N station located 13 miles northeast of Dowe Flats at an elevation of 5040 feet(Western Regional Climate Center 2021b). The average high and low temperatures in July are 88°F and 56°F,respectively, while the average high and low temperatures in December are 43°F and 14°F,respectively. The average frost-free period lasts from mid-May through September(Plant Maps 2021). 3 Wildlife The Colorado Parks and Wildlife Department(CPW)has an extensive habitat and range data for over 200 species of mammals, birds, amphibians,reptiles, and fish throughout Colorado. GIS range data from CPW(CPW 2021) suggest that 57 of these species have ranges that overlap with the Dowe Flats permit boundary including 21 bird species, 20 mammals, and 16 reptiles (Table 1). The wildlife species and habitats of the Dowe Flats area were extensively studied and evaluated in the 1980s and 1990s as a part of the original Dowe Flats SUP application and several species were monitored for the first few years of mining. The relatively undisturbed habitats surrounding Dowe Flats support rich wildlife communities. Daily and seasonal wildlife movements across Dowe Flats connecting Rabbit Mountain, Indian Mountain, and the St. Vrain Creek Corridor are common and will not be further hindered by continued mining. No activities proposed in the permit amendment application will have new impacts on wildlife. Habitat Management, Inc. 7 May 2, 2022