FL A ADAMS LAKE. KAMLOOPS AND CLEARWATER FOREST DISTRl 'TS TSILD RECONNAISSANCE SLOPE T ABILITY FINALREPOR. Submitted

Transcription

1 FL A ADAMS LAKE I KAMLOOPS AND CLEARWATER FOREST DISTRl 'TS TSILD RECONNAISSANCE SLOPE T ABILITY FINALREPOR Submitted to INTERNATIONAL FOREST PRODUCTS LTD. Adams Lake Divisibn Terratech Consulting Ltd. Salmon Arm, B.C. A.S. Jones, E.I.T. Project Mapper Date: 31 March 1998 File: R.T. Pack, PEng, PGeo Revie 'Y-.Q.~Qs~enti s t,. Of: '01--:~'" l 'f( -" l f'r N... ~ - T PACK ~.. ~ -.1~ 5 H ~. co '" '",t '\... Q e;,,,' ~.. ~~OSC\EN-<' I' ~" ~" " -"" ~'~ ~h CONSUL T/NG ito.

2 I! lnterfor - Adams Lake Division TSIL D Mapping 2 31 March 1998 File: TABLE OF CONTE~TS! INTRODUCTION ~ Scope... ~ Limitations of the Study t... 3 LOCATION AND PHYSIOGRAPHY I SURFICIAL GEOLOGY Bedrock Moraine (Till) Colluvium Glaciofluvial Deposits...! Lacustrine Deposits Fluvial Deposits SLOPE PROCESSES Debris Slides... J Debris Flows (Debris Torrents) Slumps... ~ r Gullying Rockfall and Rockslide... 1' Creep METHODOLOGY Aerial Photograph and Slope Map Interpretation... J Field Checks... I RELIABILITY APPEND IX A I LIST OF FIGURES, TABLES AND MAPS Figure 1 - Location Plan... (following page)... 4 Figure 2 - Gcology Map... J (following page).. S Table I - Field Checking Statistics... l... (following page) II Slope Stability Maps..., under separate cover I ~h CONSlIlTlNGLTD.

3 Interfor - Adams Lake Division TSIL D Mapping 3 31 March 1998 File: INTRODUCTION! This report is prepared as an accompaniment to 2tl 1 :20,000 scale map sheets covering Forest License Al8693 in the area surrounding Adams Lake entitled "TSIL D RECONNAISSANCE SLOPE STABILITY MAP, FL Al8 93, ADAMS LAKE." The study area is located within the Kamloops I d Clearwater Forest Districts and is generally defined on all sides by height-of-land (watershl boundaries for Adams Lake and the Adams River. This area covers an estimated 174,250 hectjes. This report provides a general description of the modifying geological processes that affect the slopes of the study area and an interpretation or the slope stability. In addition, the mapping methodology is presented along with a discussio~ of the applicability and reliability of this information as it relates to proposed forest engineering Scope The scope of this work is defined in Minis~ry of Forests, Kamloops Region, Contract dated 17 January The work itlitially involved the preparation of preliminary reconnaissance-level slope stability maps at I a scale of 1 :20,000 (TSIL D), and preparation of an interim report. This work was completfd in March Work completed subsequent to this interim report has included field checkmg of the slope stability polygons by aerial reconnaissance, limited ground checking in easily acdessible areas, and preparation of final maps. Terratech Consulting Ltd. has also conducted a lim!ited amount of aerial reconnaissance and ground checking in parts of the study area during other Investigations. 1.2 Limitations of the Study The methodology ~ed in this study is appropriate for use in forestry development applications only. The ratings presented should not be coniidered appropriate for any other land use applications. The slope stability maps produced by thi study represent a level of reliability commonly associated with TSIL D reconnaissance studies. I The identification and classification of geological landforms within the study areas, as identified on the aerial photographs, are based on commonly accepted methods of interpretation employ~d by professional terrain mappers. 1 However, the interpretations are still judgmental in naturer Accordingly, Terratech Consulting cannot warrant or guarantee the exactness of the descriptio~s and/or boundaries of the polygons shown on the maps. It is highly recommended that more getailed assessments be carried out as part of forest development planning. I I Howes & Kenk, Terrain Classification System for British Colu bia, MOE Manual 10. ~h CONSIII.T1NGI.TD.

4 Interfor - Adams Lake Division TSIL D Mapping 4 31 March 1998 File: LOCATION AND PHYSIOGRAPHY The location of the study area is shown on the location plan (Figure 1). The study area is centered on Adams Lake in the Shuswap Highlands subdivision of the Interior Plateau physiographic region of British Columbia. The Shuswap Highlands are approximately 225 kin long by 80 km wide and lie between the Thompson Plateau to the west and the Monashee Mountains to the east. The study area is generhliy defined on all sides by height-ofland (watershed) boundaries for Adams Lake. The study area extends to the north as far as Christie Creek, east of Vavenby; south to Highway 1 near the western end of Little Shuswap Lake; east as far as Cayenne Creek; and )Vest as far as Dixon Ridge, near the western limit of Sinmax Creek. I The physiography of the Shuswap Highlands as described by Holland 2 consists of a gentle to moderately sloping plateau rising to over 2100 m in elevation. The plateau is dissected by the Clearwater, North Thompson, Adams, and Shuswap Rivers and their tributaries into large upland tracts. These valleys are typically steep and rounded due to glacial erosion. The mountains within the study area typically reach up to 1700 m elevation and are rounded. All drainages in the study area flow into Adams Lake or the Adams River. There are numerous rock groups and formations in the study area ranging in age from Cretaceous (granitic intrusions) to Paleozoic (Shuswap Metamorphic Complex). Common rock types in the area include phyllites, quartzites and biotite schists of the Eagle Bay Formation; paragneiss, schist and granitic intrusions of the Shuswap Metamorphic Complex; as well as several other formations which include greenstone, argillite, limestone, granite, granodiorite and quartz monzonite. The bedrock geology is discussed in more detail in Section SURFICIAL GEOLOGY Information on the bedrock and surficial geology of this area was derived from Holland, , Kowal , & , Fulton (1974)6, Fulton (1983)7, Okulitch (1978)8, Campbell, , B.C. Ministry of Environment, , and Dobson Engineering (1992)11. 2 Holland, J.S., Landforms of British Columbia. B.C. Dept. of Mines and Petroleum Resources Bulletin Kowal, R.C., Soil and Terrain of the Seymour Ann Area (82M). B.C. Ministry of Environment RAB Bulletin 19, August Kowal, R.C., Soils of the Vernon Map Area, Chase 82L/13. B.C. Ministry of Environment. 1:50,000. S Kowal, R.C., Soils of the Vernon Map Area, Sorrento, 82L/14.B.C. Ministry of Environment. 1:50, Fulton, RJ., Surficial Geology, Shuswap Lake, British Columbia. G.S.C. Map 1391A. 1:125, Fulton, RJ., Surficial Geology, Seymour Ann, British Columbia. G.S.C. Map 1609A. 1:250, OkuIitch, A.V. and Campbell, R.B., Bedrock Geology of the Thompson-Shuswap-Okanagan, Maps A, B and C: Lithology, Structure & Stratigraphy, Mineral Occurrences. G.S.C. Open File :250, Campbell, R.B., Geology Adams Lake (Seymour Arm, West Half), B.C. G.S.C. Map 48, B.C. Ministry of Environment, Landforms and Slopes. 1 :50, M13 Alibis, 82M14 Adams Plateau, 82M/5 Barriere Lakes, 82M/6 Cayenne Creek, 82M/II Adams River, 82M112 Vavenby II Dobson Engineering and Foxview Management, Terrain Stability and Hydrology of the Nikwik~aia Creek Watershed. Report prepared for Ministry of Forests, Kamloop~ Forest District, January ~IJ CONSIJLTlNG LTD.

5 Reference Map: Ministry of Environment, Lands and Parks, 1992 South-Eastern British Columbia, 4th Edition Client ntlo INTERFOR - ADAMS LAKE DIV. LOCATION PLAN FL A18693 ADAMS LAKE ~~ Scale 1:600,000 Lterratech -II--JOb_No...::. 49;:.;:;6-=.-9..l...-,;~:...=.=.L.._F_I_G_U_RE 1 "'" CONSlJI.T1NG LTD.

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