Upper Intertidal Substrate (section observations)
Beach Name	Cobble	Gravel	Mixed Coarse	Mixed Fine	Mud Silt	No Data	Grand Total
Birch Bay	7	20	9				36
Drayton Harbor	11	34	1	21	3	8	78
Semi-ah-moo		6	0				6
Whatcom County	18	60	10	21	3	8	120

Upper Intertidal Substrate (% of observations by beach)
Beach Name	Cobble	Gravel	Mixed Coarse	Mixed Fine	Mud Silt	No Data
Birch Bay	19%	56%	25%	0%	0%	0%
Drayton Harbor	14%	44%	1%	27%	4%	10%
Semi-ah-moo	0%	100%	0%	0%	0%	0%
Whatcom County	15%	50%	8%	18%	3%	7%

 

Lower Intertidal Substrate

Experts identify the tidal 'break' for each section, which separates the tidaly influenced beach into an 'upper intertidal' and 'lower intertidal' area. Observers are then asked to assess the beach substrate composition for the lower intertidal and report the dominant substrate. Following scientific convention, substrate composition is defined by the size of the materials. Observers categorized substrate into the following categories (from largest to smallest substrate size): cobble, gravel, mixed coarse materials, mixed fine materials, sand, and mud/silt. If observers were unable to identify substrate type or data reports are conflicting the data is reported as 'no data.'

Note: Reports of no data in this table represent disputes between data reported on data sheets that resulted from multiple tidal breaks along a portion of Drayton Harbor's beach line. These data are in the process of being classified appropriately.

 

Lower Intertidal Substrate (section observations)
Beach Name	Cobble	Gravel	Mixed Coarse	Mixed Fine	Mud Silt	No Data	Sand	Grand Total
Birch Bay	16	7	3	2	2	1	5	36
Drayton Harbor		1	1	2	8	33	33	78
Semi-ah-moo		1			1		4	6
Whatcom County	18	9	4	4	11	34	42	120

 

Lower Intertidal Substrate (% of observations by beach)
Beach Name	Cobble	Gravel	Mixed Coarse	Mixed Fine	Mud Silt	No Data	Sand
Birch Bay	44%	19%	8%	6%	6%	3%	14%
Drayton Harbor	0%	1%	1%	3%	10%	42%	42%
Semi-ah-moo	0%	17%	0%	0%	17%	0%	67%
Whatcom County	13%	8%	3%	3%	9%	28%	35%