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Width: The intertidal zone width is the sum of the widths of the B zone components (B1+B2+B3…) and is very important in assigning the BC Class. The intertidal width must be classified as “narrow” (<30 m) or wide (>30 m), thus a width of “30” is not used. Widths of “29” or “31” are occasionally used to express that the width is very close to 30 m.

Rock (BC Classes 1-5): Rock substrate dominates the intertidal zone of the unit, with little or no unconsolidated sediment or organics (<10% of the overall unit area).  [Example (1-5)]

Rock and Sediment (BC Classes 6-20) vs. Sediment-Dominated (BC Classes 21- 31): When a unit consists of a beach with rock outcrops/platforms, the BC Class should be coded to emphasize the beach sediment (BC Class 21 to 30) unless the rock outcrops/platforms make up 25% or more of the total area of the unit. When the rock outcrops are 25% or more, the BC Class should be coded to reflect the influence that the rock has on the unit (BC Class 6 to 20).  [Example (6-20)]  [Example (21-30)]  [Example (31)]

Supratidal rock with intertidal beaches: When a unit consists of a supratidal cliff/ramp with an intertidal beach, the BC Class should be coded to reflect the importance of the beach (BC Classes 21 to 30) even if the cliff/ramp slightly infringes (<3 m) on the high intertidal zone. When the cliff/ramp significantly infringes on the intertidal zone (>3 m), a “Rock and Sediment” classification should be applied (BC Classes 6 to 20).

BC Class 11: When a unit consists of a prominent cliff in the supratidal and > 3 meters in the intertidal, in conjunction with a beach face containing sand and gravel (>25% of unit) and an intertidal zone wider than 30 meters, slope is ignored and BC Class 11 is used.  [Example (6-20)]

BC Class 13: When a unit consists of a significant cliff in the supratidal and > 3 meters in the intertidal, in conjunction with a beach face containing sand and gravel (>25% of unit) and an intertidal zone < 30 meters, slope is observed and BC Class 13 is used.  [Example (6-20)]

Sand Rule: To include sand in BC Class assignment, particles that are 2 mm and finer must be observed as 10% or more of the sediment type, or when a patch of sand is 10 m or more in diameter.

Sand Veneer: When a boulder/cobble/pebble beach is observed in a protected or semi-protected area, it should be noted that these materials are almost always a veneer overlying sand. This should be taken into consideration when coding the materials and choosing a BC Class. If the geologist’s commentary mentions sand in nearby units with similar wave exposures, apply the presence of sand to the unit. Close examination of the lower intertidal in the digital still photos will often reveal the presence of sand, even if the commentary lacks mention of it. If there is no evidence or commentary regarding sand, do not assume it is present.

BC Class 31 (Organic Shorelines): Organics and vegetation dominate the unit; may characterize units with large marshes in the supratidal (A) zone (if the marsh represents >50% of the combined supratidal and intertidal area of the unit), even if the unit has another dominant intertidal feature such as a wide tidal flat or sand beach. This “50% rule” may be ignored and a BC Class 31 applied if a significant amount of marsh (25% or more) infringes on the intertidal (B) zone.  [Example (31)]

BC Class 32 and 33 (Anthropogenically-Altered): Units exhibit >50% human alteration the area of the intertidal (B) zone to be classified as anthropogenically altered. Shore modifications may be mapped in the XShr Forms and Materials, and in the SHORE_MOD fields of the Unit table, without applying a BC Class 32 or 33 to the entire unit.  [Example (32-33)]

Current-dominated (BC Class 34): Usually occur in channels between islands or at constricted entrances to large lagoons, bays, or inlets. Water movement will be visible within the channel but not outside the channel. The biota tends to be lush within these channels. This BC Class does not occur in estuaries.  [Example (34)]