Geotechnical and Hydrotechnical Overview Assessment
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DISTRICT OF KITIMAT LAND CONSTRAINT AND SUITABILITY STUD Y Geotechnical and Hydrotechnical Overview Assessment FOR: Westland Resources Limited, and District of Kitimat BY: Roberta Adams, M.Sc., G.I.T. Gordon Butt, M.Sc., P.Geo. Madrone Environmental Services Ltd. February 16, 2018 (updated August 24, 2018) MADRONE ENVIRONMENTA L SERVICES LTD. #202 -2790 GLADWIN ROAD • ABBOTSFORD • BC • V2 T 4S7 TEL 604.504.1972 • F AX 604.504.1912 • WW W.MADRONE.CA DOSSIER: 17.0357 TABLE OF CONTENTS 1 INTRODUCTION ................................................................................ 1 1.1 BACKGROUND INFORMATION ......................................................................................... 4 2 METHODOLOGY ............................................................................... 5 2.1 LIDAR ANALYSIS ............................................................................................................... 5 2.2 AIR PHOTO ANALYSIS ...................................................................................................... 5 2.3 TERRAIN CLASSIFICATION SYSTEM ................................................................................. 8 2.3.1 SURFICIAL MATERIAL ................................................................................................. 9 2.3.2 GEOMORPHOLOGICAL PROCESSES ........................................................................11 2.4 TERRAIN STABILITY CLASSIFICATION ............................................................................ 12 2.5 HYDROTECHNICAL ANALYSIS .........................................................................................13 3 GEOMORPHIC SETTING ................................................................... 14 3.1 BEDROCK GEOLOGY ....................................................................................................... 14 3.2 SURFICIAL GEOLOGY AND QUATERNARY HISTORY ..................................................... 14 3.3 CLIMATE .......................................................................................................................... 18 3.4 HYDROLOGY ................................................................................................................... 18 3.5 RESOURCES .................................................................................................................... 20 3.5.1 MINERAL POTENTIAL............................................................................................... 21 4 GEOTECHNICAL IMPLICATIONS ...................................................... 23 4.1 NATURAL HAZARDS ....................................................................................................... 23 DOSSIER: 17.0357 MADRONE ENVIRONMENTA L SERVICES LTD. FILE: \\FS4\ACTIVEDOSS \PROJECTS\17. 0357 \FINAL REPORT \17.0357 TERRAIN ASSE SS MENT DOK LCSS_FINAL TO CL IENT.DOCX LAST SAVED: 9/4/2018 10:16:00 AM DISTRIC T OF KITIMAT PAGE TOC-II GEOTECHNICAL AND HYD ROTECHNICAL OVERVIEW ASSESSMENT FEBRUARY 14, 2018 4.1.1 FLOODING ................................................................................................................ 23 4.1.2 STREAM EROSION AND AVULSION ......................................................................... 26 4.1.3 LANDSLIDES ............................................................................................................. 30 4.1.4 SNOW AVALANCHES ............................................................................................... 36 4.2 SEISMIC CONSIDERATIONS ............................................................................................ 36 4.3 SENSITIVE CLAYS ............................................................................................................. 37 5 CONCLUSION AND RECOMMENDATIONS ....................................... 40 5.1 HAZARD ACCEPTABILITY THRESHOLDS ........................................................................ 40 5.2 DEVELOPMENT PERMIT AREAS ..................................................................................... 41 5.2.1 FLOOD HAZARD ....................................................................................................... 44 5.2.2 STREAM EROSION HAZARD .................................................................................... 44 5.2.3 HILLSLOPES AND UPLANDS HAZARD ..................................................................... 47 6 CLOSURE ........................................................................................ 49 7 REFERENCES .................................................................................. 50 8 LIMITATIONS .................................................................................. 52 8.1 LIMITATIONS ON LIABILITY ............................................................................................ 53 8.2 INTELLECTUAL PROPERTY ............................................................................................. 53 DOSSIER: 17.0357 MADRONE ENVIRONMENTA L SERVICES LTD. DISTRIC T OF KITIMAT PAGE TOC-III GEOTECHNICAL AND HYD ROTECHNICAL OVERVIEW ASSESSMENT FEBRUARY 14, 2018 L I S T O F FIGURES FIGURE 1: LAND CONSTRAINT AND SUITABILITY STUDY PROJECT AREA MAP. .......................... 3 FIGURE 2: DIGITAL ELEVATION MODEL OF THE STUDY AREA FROM LIDAR DATASET OF 1 M RESOLUTION PROVIDED BY DOK. ..................................................................................... 6 FIGURE 3: AIR PHOTO COVERAGE FROM DOK (BLUE) AND GEOBC (RED LINES, 2003). ............... 8 FIGURE 4: DOMINANT SURFICIAL MATERIAL OF THE STUDY AREA, AS DETERMINED BY DESKTOP ANALYSIS OF LIDAR AND AIR PHOTO ANALYSIS. ....................................................... 17 FIGURE 5: MINERAL POTENTIAL IN THE DOK REGION. ............................................................... 22 FIGURE 6: FLUVIAL FANS (ORANGE) AND FLUVIAL PLAINS (YELLOW) WITHIN THE STUDY AREA. .................................................................................................................................... 28 FIGURE 7: WATERCOURSE DISTRIBUTION AS MAPPED BY FRESHWATER ATLAS WITHIN THE STUDY AREA. ........................................................................................................... 29 FIGURE 8: OBSERVED LANDSLIDES AND OTHER EVIDENCE OF INSTABILITY IN THE STUDY AREA, AS DISCOVERED THROUGH DESKTOP ANALYSIS OF LIDAR DATA. .....................31 FIGURE 9: DOMINANT GEOMORPHOLOGICAL PROCESSES WITHIN THE STUDY AREA. ........... 34 FIGURE 10: RECONNAISSANCE TERRAIN STABILITY MAPPING (RTSM). ..................................... 35 FIGURE 11: MAPPED GLACIOMARINE SEDIMENTS (PURPLE) AND FIELD CONFIRMED LOCATIONS OF SENSITIVE CLAYS FROM LITERATURE (PINK DOTS). ......................................... 39 FIGURE 12: HAZARD ACCEPTABILITY DEVELOPMENT, FROM CAVE (1993). ............................... 40 FIGURE 13: GENERAL GEO-HAZARD DPA MAP FOR THE STUDY AREA. ...................................... 42 FIGURE 14: AREAS POTENTIALLY SUSCEPTIBLE TO FLOODING. ................................................ 46 FIGURE 15: POTENTIAL EXTENT OF HILLSLOPE AND UPLANDS HAZARD AREA WITHIN THE STUDY AREA. ........................................................................................................................ 48 DOSSIER: 17.0357 MADRONE ENVIRONMENTA L SERVICES LTD. DISTRIC T OF KITIMAT PAGE TOC-IV GEOTECHNICAL AND HYD ROTECHNICAL OVERVIEW ASSESSMENT FEBRUARY 14, 2018 LIST OF TABLES TABLE 1: DESCRIPTION OF TERRAIN MAPPING PROJECT DATA, ADAPTED FROM STANDARDS FOR DIGITAL TERRAIN DATA CAPTURE ................................................................... 8 TABLE 2: DOMINANT SURFICIAL MATERIAL WITHIN THE STUDY AREA WITH APPROXIMATE AREA COVERAGE. ............................................................................................... 16 TABLE 3: CLIMATIC CONDITIONS OF THE STUDY AREA DURING THE PERIOD 1981 TO 2010. ......................................................................................................................................... 18 TABLE 4. WATERSHED CHARACTERISTICS .................................................................................. 20 TABLE 5. ESTIMATED 200-YEAR MAXIMUM DAILY MEAN DISCHARGE ...................................... 24 TABLE 6: GEOLOGICAL PROCESSES THAT OCCUR IN THE STUDY AS OBSERVED THROUGH DESKTOP ANALYSIS OF LIDAR .................................................................................. 32 TABLE 7: SLOPE STABILITY CLASS OF THE STUDY AREA, AS DETERMINED FROM DESKTOP ANALYSIS OF LIDAR. ................................................................................................... 33 TABLE 8. PEAK GROUND ACCELERATION AND SPECTRAL ACCELERATIONS AT ........................ 37 TABLE 9: HAZARD ACCEPTABILITY THRESHOLDS FOR A NEW BUILDING, AS PER CAVE (1993). ......................................................................................................................................... 41 DOSSIER: 17.0357 MADRONE ENVIRONMENTA L SERVICES LTD. DISTRICT OF KITIMAT LAND CONSTRAINT AND SUITABILITY STUD Y Geotechnical and Hydrotechnical Overview Assessment 1 Introduction Madrone Environmental Services Ltd has been contracted by Westland Resources Limited to provide a geotechnical and hydrotechnical overview as part of a Land Constraint and Suitability Study for the District of Kitimat. The Land Constraint and Suitability Study Project Area (LCSS Project Area or Study Area) focuses on an undeveloped portion of the District of Kitimat located on the west side of the Douglas Channel. The boundary extends from the old Eurocan