The URL can be used to link to this page

Home My WebLink About5.03 Geologic_Hazard_Report_N23CDP Geologic Hazards Assessment Caerus Piceance LLC BJU N23‐496 Central Delivery Point Garfield County, Colorado Administrative Review Project Number 021‐173 March 1, 2022 Entrada Consulting Group 330 Grand Ave, Suite C Grand Junction, CO 81501 P a g e | 2 Email: rjohnson@entradainc.com www.entradainc.com BJU N23‐496 Central Delivery Point Geological Hazards Assessment Table of Contents 1.0 INTRODUCTION ............................................................................................................................. 3 2.0 SITE GEOLOGY – LUDC Section 4‐203 (G).4. .................................................................................. 3 2.1 SITE OVERVIEW .......................................................................................................................... 3 2.2 STRUCTURAL GEOLOGY ............................................................................................................. 3 2.3 BEDROCK GEOLOGY ................................................................................................................... 3 2.4 SOILS .......................................................................................................................................... 4 3.0 GEOLOGIC HAZARDS ..................................................................................................................... 4 3.1 UTILITIES – LUDC Section 7‐207.A. ............................................................................................. 4 3.2 AVALANCHE HAZARD – LUDC Section 7‐207.B. ......................................................................... 5 3.3 LANDSLIDE HAZARD – LUDC Section 7‐207.C. ............................................................................ 5 3.4 ROCKFALL HAZARD– LUDC Section 7‐207.D............................................................................... 5 3.5 ALLUVIAL FAN HAZARD – LUDC Section 7‐207.E. ....................................................................... 5 3.6 SLOPE DEVELOPMENT – LUDC Section 7‐207.F. ........................................................................ 5 3.7 CORROSIVE OR EXPANSIVE SOILS OR ROCK – LUDC Section 7‐207.G. ....................................... 5 3.8 MUDFLOW OR DEBRIS FLOW HAZARD – LUDC Section 7‐207.H. ............................................... 5 3.9 DEVELOPMENT OVER FAULTS – LUDC Section 7‐207.I. ............................................................. 6 3.10 RADIOACTIVE HAZARDS – LUDC Section 4‐203(G)6.d. ............................................................. 6 4.0 CONCLUSIONS AND SUMMARY ............................................................................................ 6 5.0 REFERENCES ......................................................................................................................... 6 Entrada Consulting Group 330 Grand Ave, Suite C Grand Junction, CO 81501 P a g e | 3 Email: rjohnson@entradainc.com www.entradainc.com BJU N23‐496 Central Delivery Point Geological Hazards Assessment 1.0 INTRODUCTION Caerus Piceance LLC (Caerus) retained Entrada Consulting Group, Inc. (Entrada) to develop a Geological Hazards Report for submittal to the Garfield County Community Development Department for the proposed BJU N23‐496 Central Delivery Point (N23 CDP). The following assessment addresses the requirements for the Article 4 Section 203.G. 4 Geology and Hazard, Section 4‐203(G)6.d., and Section 7‐207. Natural and Geological Hazards of the Garfield County Land Use and Development Code (LUDC). 2.0 SITE GEOLOGY – LUDC Section 4‐203 (G).4. 2.1 SITE OVERVIEW The Site is located on the Roan Plateau which lies within the Piceance Creek Basin and the Colorado Plateau physiographic region. The topography of the area consists of rolling hills atop a plateau that is bounded by cliffs and cut by deeply incised, steep walled canyons. The Site is located on topographic high‐ground approximately 15.25 miles north of Parachute, Colorado at an approximate elevation of 8,169 feet above mean sea level. The Site is located in the SESW Section 23, Township 4 South, Range 96 West, 6th P.M. Latitude and Longitude for the Site are 39.680578° and ‐108.138397° respectively. Due to wildlife timeframe stipulations set forth by CPW, COGCC, and the BLM, Caerus obtained a grading permit from Garfield County prior to the submittal of the land use change application. Grading activities were completed in the 3rd quarter of 2021. 2.2 STRUCTURAL GEOLOGY The Piceance Creek Basin is a large structural and depositional basin that is bounded by the Yampa Plateau, Axial Basin Arch, White River Uplift, Gunnison Uplift, Uncompagre Uplift, and Douglas Creek Arch. The Piceance Creek Basin was formed during the Laramide Orogeny and structural formation of the basin lasted from Late Cretaceous through the Tertiary. The sediments within the basin were sourced from surrounding highlands and were subsequently lithified and structurally deformed. There are no major faults in the area, however there are a series of grabens (normal faults) located 0.85 miles northeast of the Site and another series located 1.25 miles southwest of the Site. 2.3 BEDROCK GEOLOGY The bedrock geology underlying the Site is composed of the Uinta Formation which is underlain by the Green River Formation. The Green River formation can be subdivided into the lower Green River and the Parachute Creek Member. The Lower Green River can be further subdivided into Anvil Points, Garden Gulch, and Douglas Creek Members. Both the Uinta and Green River formations are Eocene in age. The Uinta formation consists of tuffaceaous sandstones and siltstones, marlstones, oil shale, conglomeratic sandstones, and limestones. The underlying Green River formation is approximately 2,100 feet thick and consists of oil shale, dolomitic shale, clay shale, limestone, siltstone, sandstone, Entrada Consulting Group 330 Grand Ave, Suite C Grand Junction, CO 81501 P a g e | 4 Email: rjohnson@entradainc.com www.entradainc.com BJU N23‐496 Central Delivery Point Geological Hazards Assessment and tuff. Intertounging between the Green River and Uinta formations is common in this area. 2.4 SOILS A soils report from the Natural Resource Conservation Service (NRCS) indicates that within the area of disturbance three soil types are present. NRCS Soils Report is provided in the Impact Analysis tab. Table 1: Map Units Present within BJU N23‐496 CDP Perimeter Map Unit Soil Type Percent Slope Description 38 Irigul‐Starman channery loams 5 to 50 Percent Slopes Occurs on ridges and mountain sides from 7,800 to 9,000 feet. Parent material is marl and/or residuum weathered from sandstone. Not Prime Farmland 53 Parachute‐ Rhone loams 5 to 30 Percent Slopes Occurs on mountains slopes at an elevation of 7,600 to 8,600 feet. Parent material is colluvium over residuum weathered from sandstone and shale. Not Prime Farmland. 61 Rhone loam 30 to 70 Percent Slopes Occurs on ridges and mountain sides from 7,600 to 8,600 feet. Parent material is marl and/or residuum weathered from sandstone. Not Prime Farmland Table 2: Profile of Soil Types Present Map Unit Soil Composition Typical Profile 38 Irigul (55%) H1 – 0 to 6 inches: channery loam H2 ‐6 to 17 inches: extremely channery sandy clay loam H3 ‐ 17 to 21 inches: unweathered bedrock Starman (30%) H1 ‐ 0 to 3 inches: channery loam H2 ‐ 3 to 13 inches: very channery loam, extremely channery loam H2 ‐ 3 to 13 inches: unweathered bedrock 53 Parachute (55 %) A ‐ 0 to 5 inches: loam Bw1 ‐ 5 to 18 inches: loam Bw2 ‐ 18 to 29 inches: extremely cobbly loam R ‐ 29 to 59 inches: bedrock Rhone (30%) A1 ‐ 0 to 8 inches: loam A2 ‐ 8 to 28 inches: sandy clay loam C ‐ 28 to 52 inches: very channery sandy clay loam R ‐ 52 to 60 inches: bedrock Irigul (15%) A1 ‐ 0 to 6 inches: channery loam A2 ‐ 6 to 13 inches: very channery loam R ‐ 13 to 60 inches: bedrock 61 Rhone (85%) H1 ‐ 0 to 8 inches: loam H2 ‐ 8 to 28 inches: sandy clay loam H3 ‐ 28 to 52 inches: very channery sandy clay loam H4 ‐ 52 to 56 inches: unweathered bedrock 3.0 GEOLOGIC HAZARDS 3.1 UTILITIES – LUDC Section 7‐207.A. Caerus is proposing overhead electrical power for this Site. This report did not find any Geologic Hazards that would pose a threat to the proposed power source. Entrada Consulting Group 330 Grand Ave, Suite C Grand Junction, CO 81501 P a g e | 5 Email: rjohnson@entradainc.com www.entradainc.com BJU N23‐496 Central Delivery Point Geological Hazards Assessment 3.2 AVALANCHE HAZARD – LUDC Section 7‐207.B. The Site is not located in a known Avalanche Hazard Area. Furthermore, the Site is not within the higher precipitation areas of Garfield County where avalanches tend to occur. The site is located on a topographic high within a greater plateau. 3.3 LANDSLIDE HAZARD – LUDC Section 7‐207.C. The Site is not located in a known Landslide Hazard area. However, removal of lateral support, altering drainage, or the addition of moisture can increase the risk for landslides. Landslide deposits have been mapped in nearby Garden Gulch, Cascade Canyon, Conn Creek Canyon, and other unnamed canyons in the area. 3.4 ROCKFALL HAZARD– LUDC Section 7‐207.D. The Site is not located in a known Rockfall Hazard area. The site is located on a ridge with no upslope rock exposures. 3.5 ALLUVIAL FAN HAZARD – LUDC Section 7‐207.E. The Site is not located in a known Alluvial Fan Hazard area. The Site is located on a topographic high within a greater plateau. 3.6 SLOPE DEVELOPMENT – LUDC Section 7‐207.F. The Site has been previously graded and is located on a relatively broad topographic high within a greater plateau. Within the site perimeter the grade is less than 20%. 3.7 CORROSIVE OR EXPANSIVE SOILS OR ROCK – LUDC Section 7‐207.G. The Irigul‐Starman channery loams (Map Unit 38) has a high corrosiveness rating for uncoated steel and a low corrosiveness rating for concrete per the USDA Natural Resources Conservation Service. The Parachute‐Rhone loams (Map Unit 53) and the Rhone loam (Map Unit 61) has a moderate corrosiveness rating for uncoated steel and a low corrosiveness rating for concrete per the USDA Natural Resources Conservation Service. According to the USDA Natural Resource Conservation Service, the Irigul‐Starman channery loams (Map Unit 38) has a value for linear extensibility percent (LEP) of 1.5, the Parachute‐Rhone loams (Map Unit 53) has a value for LEP of 2.5, and the Rhone loam (Map Unit 61) has a value for LEP of 1.5. According to the USDA Natural Resource Conservation Service values of LEP less than 3.0 are considered within the “Low” shrink‐swell class. 3.8 MUDFLOW OR DEBRIS FLOW HAZARD – LUDC Section 7‐207.H. The Site is not located in a known Mudflow or Debris Flow Hazard area. The Site is located on a topographic high within a greater plateau. Entrada Consulting Group 330 Grand Ave, Suite C Grand Junction, CO 81501 P a g e | 6 Email: rjohnson@entradainc.com www.entradainc.com BJU N23‐496 Central Delivery Point Geological Hazards Assessment 3.9 DEVELOPMENT OVER FAULTS – LUDC Section 7‐207.I. The Site is not located immediately above any known mapped faults. However, small normal faults exist nearby (See Section 2.2). The closest faults known to have shown surface deformation due to large earthquakes in the last 1.6 million years are the Redlands Fault complex near Grand Junction and the Grand Hogback Fault complex near Glenwood Springs. Earthquakes in Garfield County are likely to measure 5.0 or less on the Richter Scale (Garfield County Hazard Mitigation Plan, 2017). The United States Geological Survey (USGS) Earthquake Hazards Program online records were researched for seismic activity dating back to 1867. Six earthquakes with magnitudes greater than 2.5 exist in the dataset within a 20 mile radius of the Site. The largest earthquake in the dataset was from an Atomic Energy Commission Project Rio Blanco nuclear detonation (magnitude 5.4) in 1973, fourteen miles northwest of the Site. The largest natural earthquake was a magnitude 4.3 that occurred fourteen miles west‐northwest of the Site in 2018. The closest earthquake in the dataset was a magnitude 2.6 that occurred in 2018 and was located 1.77 miles southwest of the Site. Earthquake hazards at this Site are relatively low. 3.10 RADIOACTIVE HAZARDS – LUDC Section 4‐203(G)6.d. Review of the Colorado Department of Public Health and Environment website for Radon information indicates that Garfield County has high radon potential. It is anticipated that based on the proposed project for the Site, that limited structures and buildings will be developed, and workers will predominantly be outside during the normal work shifts; therefore, radon is not expected to represent a significant geologic or worker exposure health hazard. Naturally occurring radioactive minerals are common Garfield County. However, they are not anticipated in the geologic section exposed at the surface at this Site. 4.0 CONCLUSIONS AND SUMMARY Based on this Limited Desktop Geological Hazards Assessment of publicly available information, there are no known Geological Hazards within or to the BJU N23‐496 Central Delivery Point Site. 5.0 REFERENCES Coffin, D.L., Welder, F.A., and Glanzman, R.K., 1971, Geohydrology of the Piceance Creek Structural Basin Between the White and Colorado Rivers, Northwestern Colorado, U.S.G.S., Atlas HA‐370, 2 sheets Hail, W.J., 1975, Preliminary Geologic Map of the Cutoff Gulch Quadrangle, Rio Blanco and Garfield Counties, Colorado, U.S.G.S., Map MF‐691; scale 1:24,000, 2 plates. Hail, W.J., Jr., 1992, U.S.G.S. Bulletin 1787‐R, Geology of the Central Roan Plateau Area, Northwestern, Colorado, 26 p., Hail, W.J., O’Sullivan, R.B., Smith, M.C., 1989, U.S.G.S. Miscellaneous Investigations Series, Map 1‐1797‐C, Geologic Map of The Roan Plateau Area, Northwestern Colorado, 1 map sheet Entrada Consulting Group 330 Grand Ave, Suite C Grand Junction, CO 81501 P a g e | 7 Email: rjohnson@entradainc.com www.entradainc.com BJU N23‐496 Central Delivery Point Geological Hazards Assessment Nelson‐Moore, J.L., Bishop C.D., and Hornbaker, A.L., 2005, Colorado Geologic Survey, Bulletin 40, Radioactive Mineral Occurrences of Colorado, 1054 p. White, J. L., and Greenman, C., 2008, EG‐14 Collapsible Soils in Colorado, Colorado Geological Survey, Department of Natural Resources, 108p, 1 map sheet Colorado Abandoned Mine Land Information Map https://erams.com/aml Colorado Department of Public Health and Environment – Radon https://cdphe.colorado.gov/understanding‐radon Colorado Oil and Gas Conservation Comission GIS Online https://cogccmap.state.co.us/cogcc_gis_online/ Garfield County Land Use and Development Code https://www.garfield‐county.com/community‐development/land‐use‐code/ Garfield County Natural Hazard Mitigation Plan, 2017 https://www.garfield‐county.com/emergency‐management/natural‐hazard‐mitigation‐plan/ Oregon State University ‐ Prism Climate Group https://prism.oregonstate.edu/ USDA Natural Resources Conservation Service, Web Soil Survey https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx USGS Earthquake Hazards Program https://earthquake.usgs.gov/ Sincerely, S. Reed Johnson Senior Project Geologist Entrada Consulting Group Phone: 720‐253‐2940 Email: rjohnson@entradainc.com