APPENDIX 3 - PHYSICAL SHORE-ZONE MAPPING EXAMPLE

This section has been reproduced from Howes et al. (1994: Section 5.0). Minor changes have been made to section, figure and table numbers and the text.

The following example shows the mapping and coding procedures along with appropriate reference within the text. The example is taken from the recently completed coastal physical mapping project of Gwaii Haanas National Marine Park in the southern Queen Charlotte Islands (Harper et al. 1994). The example shows East Copper and Jeffery Island from the Skincuttle Inlet area, bordering on Hecate Strait (Fig. A3.1).

FIGURE A3.1 - Location of the Queen Charlotte Islands (inset) and the Copper Islands

A3.1 Project Data

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Information related to the entire project is included in the Project Data Fields (Table A3.1).

A3.2 Exposure Information

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Once the resource materials are collected (in this project this included: aerial video imagery, vertical air photos, topographic maps, charts and oblique aerial photos), the Exposure Units were defined (Fig. A3.2). Three Exposure Units were defined in this case:

Exposure Unit 7/7 -- a general southerly orientation with limited fetches to the south within Skincuttle Inlet, but with maximum fetches exposed to the open Hecate Strait

Exposure Unit 7/8 -- mostly east-facing shore units and exposed to the extensive fetch window of Hecate Strait

Exposure Unit 7/9 -- generally north-facing shoreline with a fetch window open to northern Hecate Strait

Although there are small indentations and islets along the coast that have slightly different wave exposures, these exposure units provide a reasonable first approximation of the wave climate around the Copper Islands.

More detailed fetch measurements are then made for each exposure unit. The measurements made for Exposure Unit 7/7 are schematically shown in Figure A3.3 and summarized in Table A3.2.

The data show that the maximum fetch direction is to the east-southeast and extends across Hecate Strait for over 200km. The shoreline within the Exposure Unit is approximately south-facing; the shore perpendicular is just to the west of south at 192o. Fetches within Skincuttle Inlet are limited and all of the measured distances are less than 6km. The computed Effective Fetch is 3.8km , but the high Maximum Fetch Distance (219.6km) results in a Semi-Exposed categorization for the unit.

The wave fetch measurements provide a general indication of the wave climate for the unit. Under moderate wind conditions, the shoreline is relatively protected by islands to the south and west; however, extensive open water to the east can result in large waves being generated, especially during southeast storms.

Figure A3.2 - Wave Exposure Units of East Copper and Jeffrey Islands

A3.3 Shore Unit Information

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The Exposure Unit is then subdivided into Shore Units which have more or less uniform geomorphology and substrate. Figure A3.4 shows the air photo of the island (scale approximately 1:20,000) and the base map (in this case, a photocopy of the nautical chart) used for recording the unit boundaries.

Four Shore Units are defined within the Exposure Unit and data for one (Shore Unit 7/7/01) are summarized in Table A3.3. The Unit type is linear (L) and is classified as a wide rock platform with a gravel beach (Class 7). An associated note (#277) is included in a separate database.

Unit Location and Unit Length information are normally computed by the GIS program but were manually measured in this case. The mean Intertidal Width is estimated at 80m.

There is no external Sediment Source to the unit or an indication of Sediment Transport Direction, so these fields have been left blank. Sediment Abundance is sparse (S).

The morphology of the unit (eroding cliff) indicates the shoreline is erosional (E) but the rate is unknown (?).

Data sources include: air photos, topgraphic maps, charts and aerial video imagery. No ground-truthing was conducted in the unit.

Figure A3.3 - Wave fetch measurements for Exposure Units 7/7 showing direction of Maximum Wave Fetch (110 degrees at 219 km) and the Shore Normal(192 degrees) with associated fetch measurements.

TABLE A3.1 - Data entry fields - project information

TABLE A3.2 - Shore-zone data entry fields - wave exposure information

A3.4 Across-Shore Component Information

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Each Shore Unit has associated across-shore components that provide a detailed characterization of morphology within the unit in an onshore to offshore progression. The Across-shore Component data are summarized in Table A3.4 and schematically represented in a sketch (Fig. A3.5).

The first Zone characterized is the supra-tidal zone (indicated by A). There is only one component (A1), a low ("l" indicates less than 5m high), inclined ("i" indicates a slope of 20-35o cliff (C)); the cliff includes anthropogenic or cut logs (At) over rock, sedimentary (Rs).

The next component (B1), located in the upper intertidal zone, is a beach, inclined (Bi) comprised of logs (At) over clastic cobbles (Cc) over rock, sedimentary (Rs); this beach is approximately 10m in width.

The second component (B2) lies seaward of the beach and consists of rock platform (P) which is a high-tide platform ("h") and has an irregular ("i") surface; it is comprised of sedimentary bedrock and is estimated at 70m in width.

The third component (B3) lies seaward of the platform and consists of two types of morphologies: offshore islet chains (Oc) and detached reefs with an irregular surface (Fi). Both the reefs and islets are comprised of sedimentary bedrock.

Figure A3.4 - Vertical aerial photo of the Copper Islands and the working copy of associated Shore Units on East Copper Island.

TABLE A3.3 - Shore-zone data entry fields - shore unit information

TABLE A3.4 - Shore-zone data entry fields - shore component information

FIGURE A3.5 - Sketch of Shore Unit 7/7/01 illusrating across-shore components of the Shore Unit. See Table A3.4 for detailed coding of across-shore components.

iv B.C. Biological Shore-zone Mapping System

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18 B.C. Biological Shore-zone Mapping System

B.C. Biological Shore-zone Mapping System 1

32 B.C. Biological Shore-zone Mapping System • Appendix 1

B.C. Biological Shore-zone Mapping System • Appendix 1 33

38 B.C. Biological Shore-zone Mapping System • Appendix 2

B.C. Biological Shore-zone Mapping System • Appendix 2 39

46 B.C. Biological Shore-zone Mapping System • Appendix 3

B.C. Biological Shore-zone Mapping System • Appendix 3 45


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