NEWCREST JARBIDGE 2020 EXPLORATION PROJECT DRAINAGE PLAN Prepared for USDA Forest Service Mountain City, Ruby Mountains, and Jarbidge Ranger District Elko County, Nevada c/o Joshua Nicholes c/o Robin Wignall Prepared by SWCA Environmental Consultants 295 Interlocken Boulevard, Suite 300 Broomfield, Colorado 80021 303.487.1183 www.swca.com February 2020 Newcrest Jarbidge Exploration Project: Soils and Hydrology Specialist Report CONTENTS Executive Summary ................................................................................................................................... iii 1 Introduction .......................................................................................................................................... 1 1.1 Report Objectives ......................................................................................................................... 1 1.2 Purpose and Need ......................................................................................................................... 2 2 Proposed Action and Alternatives ...................................................................................................... 2 2.1 Proposed Action ........................................................................................................................... 2 2.1.1 Project Location .................................................................................................................. 3 2.1.2 Construction ........................................................................................................................ 5 2.1.3 Water Supply and Usage ..................................................................................................... 6 2.1.4 Stormwater and Drill Return Fluids Management .............................................................. 6 2.1.5 Hydrocarbons and Chemicals ............................................................................................. 7 2.2 Reclamation .................................................................................................................................. 7 2.2.1 Interim Reclamation and Site Stabilization ........................................................................ 8 2.2.2 Concurrent Reclamation ..................................................................................................... 8 2.2.3 Final Reclamation ............................................................................................................... 9 2.3 Drainage Plan ............................................................................................................................... 9 2.4 Best Management Practices and Design Features ...................................................................... 10 3 No Action Alternative ........................................................................................................................ 12 4 Current Conditions ............................................................................................................................ 12 4.1 Existing Disturbance ................................................................................................................... 12 4.2 Soils ............................................................................................................................................ 13 4.3 Surface Water Quality and Quantity ........................................................................................... 16 4.3.1 Designated Uses and Identified Impairments ................................................................... 18 4.3.2 Water Quality Data Assessment ....................................................................................... 20 4.3.3 Water Quantity .................................................................................................................. 22 5 Mitigation Measures ........................................................................................................................... 25 6 Effects Analysis of Proposed Action ................................................................................................. 25 6.1 Phase 1 and Overall Project Impact Areas.................................................................................. 25 6.1.1 Phase 1 Project Impacts .................................................................................................... 25 6.1.2 Overall Project Impacts .................................................................................................... 29 6.2 Direct Effects – Here and Now ................................................................................................... 33 6.2.1 Surface Disturbance .......................................................................................................... 33 6.2.2 Erosion and Sedimentation ............................................................................................... 34 6.2.3 Water Quality .................................................................................................................... 34 6.2.4 Water Quantity .................................................................................................................. 35 6.3 Indirect Effects – Separated in Space and/or Time..................................................................... 35 6.3.1 Water Quality and Quantity .............................................................................................. 35 6.4 Cumulative Effects – Additive Impacts to the CWE .................................................................. 36 6.4.1 Soils/Surface Disturbance ................................................................................................. 36 6.4.2 Water Quality .................................................................................................................... 36 7 Laws, Regulations, and Forest Plan Compliance ............................................................................ 37 8 Literature Cited and/or Reviewed .................................................................................................... 38 i Newcrest Jarbidge Exploration Project: Soils and Hydrology Specialist Report Appendices Appendix A. Proposed Action • Attachment 1 – Best Management Practices Appendix B. Drainage Plan • Attachment 1 – Project Maps and Drainage Evaluation • Attachment 2 – Hydrological Calculations • Attachment 3 – Typical Best Management Practices • Attachment 4 – Project Design Typicals Appendix C. Water Quality and Water Quantity Tables and Charts • Attachment 1 – Surface Water Temperature Data • Attachment 2 – Surface Water Quality Statistics • Attachment 3 – Surface Water Quality Hydrographs Appendix D. McGinley and Associates Water Quality Data Appendix E. Mapping of Existing and Proposed Disturbance Appendix F. Land and Resource Management Plan Standards, Guidance, and Direction Checklist Appendix G. Legal Compliance Checklist Figures Figure 1. Project Area overview. .................................................................................................................. 4 Figure 2. Soil types in the Project Area. ..................................................................................................... 15 Figure 3. Histograms of soil depth (in centimeters) according to generalized slope descriptions. ............. 16 Figure 4. Surface water cumulative effects study area and water quality and quantity monitoring locations................................................................................................................................................ 17 Figure 5. Daily average discharge trends for the Bruneau River at Rowland. ............................................ 23 Figure 6. Daily average discharge trends for the Jarbidge River Below Jarbidge. ..................................... 24 Tables Table 1. Existing Disturbance within the Project Area ............................................................................... 13 Table 2. Existing Disturbance within the CESA ......................................................................................... 13 Table 3. Soil Types within the Project Area ............................................................................................... 14 Table 4. NDEP Profile I Constituents and Reference Values ..................................................................... 20 Table 5. NDEP MRBU for Waterbodies in the CESA ............................................................................... 21 Table 6. Phase 1 Project Impacts on Subcatchment Basis .......................................................................... 27 Table 7. Phase 1 Surface Disturbance within HUC 12 Basins.................................................................... 28 Table 8. Phase 1 Surface Disturbance within HUC 10 Basins.................................................................... 28 Table 9. Overall Project Impacts on Subcatchment Basis .......................................................................... 30 Table 10. Overall Project Impact Ranges to HUC 12 Basins ..................................................................... 31 Table 11. Overall Project Impact Ranges to HUC 10 Basins ..................................................................... 32 ii Newcrest Jarbidge Exploration Project: Soils and Hydrology Specialist Report EXECUTIVE SUMMARY Newcrest Resources, Inc., proposes to conduct a 12-year phased exploration drilling