2023-10-03_REVISION - M1977344 (31)

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Bear Creek Quarry (M-1977-344) Permit Amendment Holcim US Inc, 3500 Highway 120, Florence, CO 81226 Phone (719) 288-1443 www.holcim.us 63 2.7 Exhibit G: Water Information (Rule 6.4.7) 2.7.1 Existing Conditions The RCQ lies within the Great Plains physiographic region of Colorado and consists of Cretaceous Seaway Sedimentary rocks (Barkmann 2021). The Cretaceous sedimentary rocks of the region were deposited from an inland sea that divided the North American continent into two landmasses approximately 100 million years ago. The shifting coastal seashore line resulted in the varying marine environment responsible for the deposition with shallow water deposition represented by the sandstone units and deep water deposits represented by limestone and shales (Pinel, 1977). The topography at the Site is generally flat with some local relief along surface water drainages with shale, limestone, and sandstone outcrops. The overall gradient slopes downward to the northeast towards Red Creek and the Arkansas River. Within the Red Creek drainage, sequences of erosion and deposition resulted in multiple alluvial stream terraces covered to varying degree in vegetation. Within the Red Creek drainage are seeps and springs flowing from fractures within the rock outcrop. Minimal water flow was observed in alluvial sediments above the seep location indicating minor flow within Red Creek independent of the identified seeps. The surface water flow disappears into the creek sediments and Red Creek is dry at the boundary of the Site. Drainages south and east of Red Creek show signs of intermittent to no surface water flow. Upland areas on the site are grasslands with gentle slopes, few outcrops, and sparse shrubs and trees compared to the Red Creek drainage. Another feature on the Site is the Minnequa canal, owned by R ocky Mountain Steel Mills. The canal flows across the RCQ property along the northeast corner, diverting water from the Arkansas River at Florence for irrigation purposes and municipal/domestic use. The canal is fully fenced and is siphoned under Red Creek, just north of the Site property boundary. 2.7.2 U.S. Army Corp of Engineers Holcim engaged BC to begin the preliminary jurisdictional determination (PJD) for the Red Creek Quarry parcel in Fall 2019. BC personnel conducted a field reconnaissance at the Site on May 28, 2019 to observe and document conditions of the property, specifically related to the surface water drainages on the Site. The location of the sites visited are shown in Figure 2.7.2 -1. A second field visit was conducted on October 1, 2019 with Joshua Carpenter, regulatory staff with the United States Army Corps of Engineers (USACE), Albuquerque District, Pueblo Regulatory office to review the site conditions and discuss potential jurisdictional resources. Based on these two field visits, BC submitted a preliminary jurisdictional determination (PJD) request to the USACE; on May 21, 202 the USACE issued the initial PJD letter stating they concurred with the BC assessment. The USACE-approved PJD provided Holcim with the information necessary to start planning for mining operations and the disturbance footprint given the locations of jurisdictional resources. Based on the need for better defining the limits of ephemeral tributaries to Red Creek on the site, a second field reconnaissance was conducted by BC on December 3, 2020. Initially, the first limits between upland non-jurisdictional drainages and ephemeral tributaries were delineated using the dirt road that runs east-west across the property as the basis for the distinction between jurisdictional and non-jurisdictional resources. As such, a second, initial PJD form was submitted to U.S. Army Corps of Engineers (USACE) on January 8, 2021 with the revised stream field review. The revised USACE PJD approval from the USACE was received on November 10, 2022 (BC 2021, Appendix 4.2). A figure of the delineated stream and wetland resources are provided in Appendix 4.2 (BC 2021).