Many shorelines can be divided into discrete littoral, or drift, cells, which are independent of one another and for which distinct sediment sources and sinks can be identified. This coverage denotes the extent of individual littoral cells and the direction of net shore-drift within each.
Skagit County - Keuler, 1979 Whatcom County - Jacobsen, 1980 King County - Chrzastowski, 1982 Thurston County - Hatfield, 1983 Mason County - Blankenship, 1983 Pierce County - Harp, 1983 Kitsap County - Taggart, 1984 Grays Harbor and Pacific Counties - Bronson, 1984 Jefferson and Clallam Counties (ocean coast) - Mahala, 1984 Clallam County (Strait of Juan de Fuca) - Bubnick, 1986 Parts of San Juan, Snohomish, Island, and Jefferson Counties - Johannessen, 1993 Grays Harbor, Willapa Bay, and the Columbia Estuary -Thomas, 1995
and a USGS publication: Map showing coastal erosion, sediment supply, and longshore transport in the Port Townsend 30- by 60-minute quadrangle, Puget Sound Region, Washington [Keuler, R.F., 1988, United States Geological Survey; Map 1198-E]
These reports have subsequently been compiled and republished as the Ecology reports cited below. Source materials for drift cells were done a different times. Each report in the series covers a different area.
Volume 1: Pacific Ocean and Strait of Juan de Fuca (Pacific, Grays Harbor, Jefferson, and Clallam Counties) [Schwartz et al., 1991, Ecology Report #00-06-30]
Volume 2: South Puget Sound (Mason, Thurston, and Pierce Counties) [Schwartz et al., 1991, Ecology Report #00-06-31]
Volume 3: Central Puget Sound (Kitsap, Pierce, and King Counties) [Schwartz et al., 1991, Ecology Report #00-06-32]
Volume 4: Hood Canal (Mason and Kitsap Counties) [Schwartz et al., 1991, Ecology Report #00-06-33]
Volume 5: Northern Bays and Straits (Whatcom and Skagit Counties) [Schwartz et al., 1991, Ecology Report #00-06-34]
Net Shore-Drive of San Juan, and parts of Jefferson, Island, and Snohomish Counties [Johannessen, 1992, Report 00-06-35]
Net Shore-Drift within Grays Harbor, Willapa Bay, and the Mouth of the Columbia River, Washington [Thomas, 1995, Report #00-06-36]
Volume 1: Pacific Ocean and Strait of Juan de Fuca (Pacific, Grays Harbor, Jefferson, and Clallam Counties); Volume 2: South Puget Sound (Mason, Thurston, and Pierce Counties); Volume 3: Central Puget Sound (Kitsap, Pierce, and King Counties); Volume 4: Hood Canal (Mason and Kitsap Counties); Volume 5: Northern Bays and Straits (Whatcom and Skagit Counties); Net Shore-Drive of San Juan, and parts of Jefferson, Island, and Snohomish Counties Net Shore-Drift within Grays Harbor, Willapa Bay, and the Mouth of the Columbia River, Washington Clallam County, Washington, Strait of Juan de Fuca, Net Shore-Drift
Skagit County - Keuler, 1979 Whatcom County - Jacobsen, 1980 King County - Chrzastowski, 1982 Thurston County - Hatfield, 1983 Mason County - Blankenship, 1983 Pierce County - Harp, 1983 Kitsap County - Taggart, 1984 Grays Harbor and Pacific Counties - Bronson, 1984 Jefferson and Clallam Counties (ocean coast) - Mahala, 1984 Clallam County (Strait of Juan de Fuca) - Bubnick, 1986 Parts of San Juan, Snohomish, Island, and Jefferson Counties - Johannessen, 1993 Grays Harbor, Willapa Bay, and the Columbia Estuary -Thomas, 1995
and a USGS publication: Map showing coastal erosion, sediment supply, and longshore transport in the Port Townsend 30- by 60-minute quadrangle, Puget Sound Region, Washington [Keuler, R.F., 1988, United States Geological Survey; Map 1198-E]
These reports have subsequently been compiled and republished as the Ecology reports cited below. Source materials for drift cells were done a different times. Each report in the series covers a different area.
Volume 1: Pacific Ocean and Strait of Juan de Fuca (Pacific, Grays Harbor, Jefferson, and Clallam Counties) [Schwartz et al., 1991, Ecology Report #00-06-30]
Volume 2: South Puget Sound (Mason, Thurston, and Pierce Counties) [Schwartz et al., 1991, Ecology Report #00-06-31]
Volume 3: Central Puget Sound (Kitsap, Pierce, and King Counties) [Schwartz et al., 1991, Ecology Report #00-06-32]
Volume 4: Hood Canal (Mason and Kitsap Counties) [Schwartz et al., 1991, Ecology Report #00-06-33]
Volume 5: Northern Bays and Straits (Whatcom and Skagit Counties) [Schwartz et al., 1991, Ecology Report #00-06-34]
Net Shore-Drive of San Juan, and parts of Jefferson, Island, and Snohomish Counties [Johannessen, 1992, Report 00-06-35]
Net Shore-Drift within Grays Harbor, Willapa Bay, and the Mouth of the Columbia River, Washington [Thomas, 1995, Report #00-06-36]
Drift cells were digitized as a single point, the point being the end of the drift cell with the largest measure on the underlying shoreline route. The end with the largest measure as a rule will be: * on marine islands, the counter clockwise most point of the cell on the island shoreline * on the main marine shoreline, the point closest to Oregon if one were walking the shoreline from Canada to Oregon.
After digitizing of the points and entry of point attributes, the points were converted into linear events via point2driftcell.aml. The logic of the AML is: * get the route measure for each drift cell point * assign the route measure at the point as the to measure of the event * assign the route measure of the nearest clockwise point on the shoreline as the from measure of the event. * assign the drift cell identifier as the unique event identifier * assign the drift cell type as an event attribute * If the event is the first one on the route, assign 0.000 as the from measure. * (For islands only) for the last event on the route, assume it is a part of the first event on the route (as shorelines are continuous around an island). Assign the identifier and type from the first event and assign the route highmeasure as the to measure.
All segments of the shoreline were covered by one and only one drift cell event (no gaps, no overlaps).
For each drift cell, two attributes were recorded: * The drift cell identifier * The drift cell type Drift cell identifiers and types were taken from the drift cell maps in the books.
Drift cells were categorized as one of 5 types: * Clockwise drift cell (right to left when looking at the shore) * Counter clockwise drift cell (left to right when looking at the shore) * No appreciable net shore drift (NANSD) * Divergence zone * Undefined
For the first two types of drift cells, the identifiers were used as defined on the maps. For the others, the identifier is composed by the identifiers of the upshore and downshore drift cells separated by a slash (the identifier with the lower number in it is entered first).
Ex. A NANSD cell between cells BL-1 and BL-2 will be identified as BL-1/BL-2.
PROCEDURE
Tiling: For the digitizing effort, the project was tiled by county as that is how the data was originally gathered and published. After all of the counties were digitized and edited, the county data was merged into a single statewide event table.
Source Materials: The source materials were the Net Shore Drift volumes and the USGS 1:24,000 quadrangle maps plus any other supporting material available to the cartographer.
Shoreline coverage: The drift cell points were aligned with a 24k scale marine shoreline coverage.
Attributes: For each drift cell point, two attributes were entered: * The unique driftcell identifier into a 20 character field named DRIFTCELL_NR and is taken or derived from the identifiers in the booklets. * The driftcell type code into a 2 character field named DRIFTCELL_TY_CD and must be one of five codes.
The driftcell type codes are:
Code Definition
LtoR - Left to Right Drift Cell (counter clockwise)
RtoL - Right to Left Drift Cell (clockwise)
DZ - Zone of Divergence
NAD - No Appreciable Net Shore Drift (NANSD)
UN - Undefined drift cell type
Placement: For consistency, the drift cell points were located as close as possible to the beginning and end of the drift cell arrows on the paper maps.