Finkl, C.W. and Makowski, C., 2021. Alongshore classification and morphometric analysis of coastal belts: The state of Oregon, USA. Journal of Coastal Research, 37(2), 238–271. Coconut Creek (Florida), ISSN 0749-0208.
Classification of the state of Oregon coastal belt (western United States) was based on the interpretation of satellite imagery using the Biophysical Cross-shore Classification System (BCCS). This seven-county, 480-km stretch was subdivided based on coastal archetypes that formed distinct bio-geomorphological and ecological sequences on both alongshore and cross-shore axes. Shore-parallel and shore-perpendicular units were concomitantly determined by cognitive inspection of satellite images, in which cross-shore archetypical sequences were observed in the first instance to have alongshore spread that could be secondarily codified in terms of alongshore catenas. Because shore-normal transects encompass marine, coastal, and terrestrial environments that have a shore-parallel width, it was possible to extrapolate cross-shore classificatory units into alongshore stretches called domains. Characterization of alongshore domains was based on conjoining archetypes into catenary sequences that typify coastal belts both alongshore and cross-shore from adjacent offshore areas to several kilometers inland. Compilation of coastal belt catenas showed that promontories and headlands, which are composed of resistant igneous and metamorphic rocks, function as anchor points along the shore and are interspersed by sedimentary (littoral) coastal belts that contain mainland and barrier beaches backed by dune, wetland, flat (estuaries), or upland archetypes. A consizement of several alongshore domain catenary sequences within a particular coastal segment thus formed an overarching super domain. Typical alongshore super domains consisted of the following sequences: Barrier-Beach-Dune (Ba-Be-Du), Barrier-Beach-Dune-Wetland (Ba-Be-Du-W), Beach-Dune-Upland (Be-Du-U), Beach-Dune-Wetland (Be-Du-W), Beach-Cliff-Upland (Be-Cl-U), Beach-Wetland-Flat (Be-W-F), and Rock-Cliff-Upland (R-Cl-U). Morphometric analysis of each county allowed the determination of specific characteristics for each super domain (e.g., alongshore length, percentage of the county coastal belt, and percentage of the Oregon coastal belt). Furthermore, archetype morphometrics were calculated to show which cross-shore archetypical features were most prevalent along the state's coastal belt. This examination of the Oregon coast showed that the alongshore classification of coastal belts on a regional scale, which is based on cross-shore biophysical interpretations, offers the opportunity to characterize offshore, inshore, and onshore eco-geomorphological features through the use of super domains and morphometric analysis. This approach to coastal classification thus serves as a blueprint for the comprehensive characterization of coastal belts worldwide.
The Oregon coast is renowned for its scenic vistas and diverse coastal seascapes that attract tourists and researchers alike. Much of the coast is photogenic, because the basaltic headlands that jut out into the Pacific Ocean provide a natural platform for observation of sea cliffs, skerries, sea stacks, sedimentary barriers, beaches, dunes, wetlands, and tidal flats, all of which are backed landward by temperate conifer forests. This picturesque middle-latitude coast, which occurs adjacent to the Central Pacific Northwest Coast Forests Ecoregion (ER351; Dinerstein et al., 2017), is characteristic of the U.S. Pacific Northwest coastal region. This area is referred to as a Mediterranean climate—with a hot, dry summer [Csa] or cool, dry summer [Csb], as classified in the Köppen climate system (e.g., Kottek et al., 2006)—or a Marine West Coast climate (e.g., Peel, Finlayson, and McMahon, 2007), which occur on the western continental coastal margins between 30 and 45° latitude. Affected by the polar front region in winter, these coastal zones are characterized by moderate temperatures and changeable, rainy weather. Dominated by subtropical high-pressure systems, summers are hot and dry (Csa) except in coastal areas, where summers are milder because of ocean currents, such as the California Current, Davidson Current, and the Oregon Coastal Current (e.g., Mazzini et al., 2014). These currents ameliorate the summer heat to form cooler (Csb) coastal climates (e.g., Kottek et al., 2006).
Because the coastal margins of this terrestrial ecoregion (ER) contain various eco-geomorphological units within relatively short alongshore distances, the entire state of Oregon coastal belt (Figure 1) was selected as a study site to apply the Biophysical Cross-shore Classification System (BCCS) (Finkl and Makowski, 2020a,b,c). The adjacent Large Marine Ecosystem (LME) offshore of this study area was the California Current (LME3). The Coastal Belt Linked Classification (CBLC) system (Finkl and Makowski, 2020d), which incorporates both offshore LMEs (e.g., IOC-UNESCO, 2011; Sherman, Aquarone, and Adams, 2009; Sherman and Hempel, 2008) and terrestrial ERs (Dinerstein et al., 2017) into the BCCS classification, was not used in this analysis, because the California Current (LME3) and Central Pacific Northwest Coast Forests Ecoregion (ER351) remained static along the entire coastal belt study area. This general location, lying between the states of Washington to the north and California to the south, is shown in Figure 1 for regional reference. For geographical orientation, the seven coastal counties are indicated, as well as LME3 and ER351. This annotated satellite image thus sets the scene for the Oregon coastal belt study area in a Marine West Coast climatic environment.
Purpose and Goals
The Biophysical Cross-shore Classification System (BCCS) (Finkl and Makowski, 2020a,b,c) was developed on the foundation that cross-shore classificatory units had alongshore spread. When preliminary investigations showed that the concept of cross-shore and alongshore catenas was viable from equatorial to polar latitudes (Finkl and Makowski, 2020a,b,c,d), it seemed reasonable to explore the potential of alongshore classification based on spatial distributions of cross-shore eco-geomoprhological units that extend some kilometers inland while at the same time manifesting alongshore catenary associations in the form of domains (Finkl and Makowski, 2021). The goal of such an endeavor would culminate in codified descriptions of cross-shore coastal environments that have alongshore extents. Finkl and Makowski (2021) showed that such a study was possible through the establishment of alongshore super domain classification sequences for coastal belts at varying latitudes. However, the current study combined several alongshore super domain codified sequences throughout the entire Oregon coastal belt in order to classify the biophysical ecological features on a regional scale and interpret the eco-geomorphological diversity through morphometric unit analysis.
Background Research and Coastal Characterization
Because of the geographical proximity of Oregon State University (OSU) in Corvallis, some 74 km inland from the coast in the Willamette Valley, and the local presence of the OSU Hatfield Marine Science Center and the Oregon Coast Aquarium in the Yaquina Bay estuary, this coastal region has a long history of being studied from many different points of view (e.g., Allan, Gabel, and O'Brien, 2018; Allan and Komar, 2006; Baldwin, 1950; Buijsman et al., 2003; Byrne, 1964; Connolly, 1995; Cooper, 1958; Hunter, Clifton, and Phillips, 1979; Hunter and Richmond, 1983; Knight, 2002; Komar, 1992; Komar, Allan, and Ruggiero, 2011; Komar, Lizarraga-Arciniega, and Terich, 1976; Komar, McManus, and Styllas, 2004; Komar et al., 1999; Komar and Shih, 1993; Lund, 1971, 1972a,b, 1973, 1974a,b, 1975; Mazzini et al., 2014; Oceana Staff, 2020; OCS Staff, 2016; Peterson et al., 2010, 2013, 2019; Ruggiero et al., 2005, 2012; Rumrill and Sowers, 2008; Schlicker et al., 1972, 1973; Shih and Komar, 1994; Smith, 1975; Snavely and MacLeod, 1971; Snavely, Macleod, and Rau, 1969). Studies of this kind, which focused on a myriad of biophysical topics, provided much needed background information and useful guidance on the subdivision of coastal environments along the Oregon coast. In this paper, previous studies involving the specifics of marsh biology, ecology, and intertidal zone ecological systems were not included, because they were not relevant to the methods of biophysical classification of coasts discussed here.
The Oregon coast has already been conveniently classified in the Oregon Territorial Sea Plan (TSP Staff, 1994) into ecoregions, regions, provinces, and segments. In the TSP, the overarching marine ecoregion is the Northern California Current Ecoregion, which is equivalent to LME3 in the IOC-UNESCO (2011) system. Two TSP regions unequally bifurcate the coast into the southern Cape Blanco/Coos Bay Region and the northern Tillamook Bay/Columbia River Region. The two regions are further subdivided in provinces that include, from the south moving northward, the Klamath Mountains, Ump-qua Dunes, and Alsea-Nehalem provinces. Six segments in this system are recognized as containing a mixture of geomorphological features, with the Ferrelo, Orford, and Seven Devils segments in the Klamath Mountain Province and the Yachats, Yaquina, Kwanda, and Neahkahnie segments in the Alsea-Nehalem Province. Finally, 29 promontories and headlands fill out the TSP classification of the Oregon coast, providing a comprehensive overview of the major environmental features. Estuaries, which mostly occur in drowned river valleys, have been described from varying points of view that emphasize their ecological and biophysical importance along the Oregon coast (e.g., Bottom et al., 1979; Hayslip et al., 2006). The main 29 basaltic headlands function as permanent anchor points along the coast and separate intervening coastal segments into littoral cells or sedimentary compartments. Rocky shores tend to be clustered about these erosionally resistant headlands, with long stretches of sandy beaches that extend up to 25 km between rocky anchor points.
The TSP (1994) classification provides a good overview of the Oregon coast, and it is succinctly recapitulated here as a reference guide to the overall character of the shore. It serves as a reference point for comparison of eco-geomorphological units in the BCCS that are identified from interpretation of satellite imagery. The alongshore classification of the TSP system, which is a remarkable achievement, differs from the BCCS in that it does not include consecutive sequences of cross-shore environments.
Classification of Coastal Belts Using Satellite Imagery
The complexity of regional coastal belts leads to many difficulties for small-scale (large area) studies based on fieldwork alone. To this end, most researchers find that access to either aerial photography or satellite imagery assists in the cognitive interpretation of biogeographical elements, because their spatial distributions are readily discerned in the imagery and then substantiated by ground-truthing or collateral data. In the case of the Marine West Coast climatic zone of western Oregon, primary eco-geomorphological features have already been identified in the TCP (1994) hierarchical classification, which was used as background information and guidance in the collection of collateral data.
The classification units that make up the Biophysical Cross-shore Classification System (BCCS) for this study are listed in Table 1, identifying shore-parallel (alongshore) coastal belt configurational terms and cross-shore archetype descriptors. These terms are a simplified version of a more complex categorization derived from the original presentation of the conceptual BCCS, providing a satellite-based framework for cross-shore classification (Finkl and Makowski, 2020a). Effective use of the cross-shore classificatory approach was provided in a series of studies in various coastal climatic zones from equatorial to polar regions (Finkl and Makowski, 2020a,b,c,d, 2021). These previous papers showed that it is possible to classify coastal belts in terms of archetypical units by recognizing repetitious cross-shore sequences (catenas) that repeat the world over. These classificatory efforts were made through the Google Earth Pro platform, which made available satellite imagery for the world. Characterizing coastal belts based on cognitive interpretation of major archetypes and sub archetypes demonstrated that the BCCS is a viable means of identifying both cross-shore (Finkl and Makowski, 2020a,b,c) and alongshore (Finkl and Makowski, 2020c,d, 2021) catenas in individual satellite image scenes. The current study tests this approach on a regional scale. The Oregon seaboard was thus selected for the bio-geomorphological complexity and the plethora of prior works that classify this coastal belt for different purposes.
The basic procedure was the application of the Biophysical Cross-shore Classification System (BCCS) (Finkl and Makowski, 2020a) to determine cross-shore catenary sequences and their alongshore extents. Satellite imagery was obtained from the Google Earth Pro interactive Internet platform and imported into the GNU Image Manipulation Program (GIMP) to access scale and image enhancement parameters. Then, modified images were imported into Microsoft PowerPoint for annotation and symbolization.
Derivation of useful spatial information from the satellite images includes visual detection of the bio-geomorphological and ecological units indicated in the cross-section. This identification procedure requires zooming capabilities to fully detect the extent of certain features at a multiplicity of scales. The higher the spatial or spectral resolution of an image, the more detail that can be derived from the image; thus, the highest resolution available in Google Earth Pro (e.g., 4800 × 4800 pixels) was selected, and then the image was scaled in another program (GIMP) to obtain publication quality (e.g., 23 pixels/mm). Combined identification and delineation were then used to demarcate the cross-shore and alongshore extents of archetypes in each satellite scene.
The success of the image interpretation stage depends on the ability of the human analyst or interpreter to extract pertinent information by visual inspection (cognition) from an image. That is, the image interpretation depends on the analyst effectively exploiting the spatial, spectral, and temporal elements present in the composed image product. For example, spatial information is present in the qualities of shape, size, orientation, and texture. Coastlines, shorelines, beaches, dunes, wetlands and estuarine systems, rock outcrops, ecotonal boundaries between archetypes, and so on, are usually readily identified by their spatial disposition. Spectral clues are also used based on the analyst's foreknowledge of, and experience with, the spectral reflectance characteristics of typical ground-cover types and knowledge of how those characteristics are sampled by the sensor of the satellite used to acquire the image data (e.g., Finkl and Makowski, 2019a,b; Richards and Jia, 1999).
For ease of manipulation and accommodation of scaler issues, the imagery was broken into manageable coastal stretches defined by county boundaries. Although variable scales exist due to the length of the county stretch, each coastal belt image contains a 20-km scale bar, north arrow, and Google Earth Pro acquisition information. The images also contain some limited geographical information, such as place names, roads, and county boundary lines, for locational purposes. Coastal belts that make up the entire 480-km-long stretch were thus interpreted by county from north to south as follows: Clatsop, Tillamook, Lincoln, Lane, Douglas, Coos, and Curry counties. Boundaries between cross-shore catenary sequences were demarcated by shore-perpendicular red lines. The catenas between the red lines were deemed to represent that section of coast that had landward penetration and alongshore length. The lengths of the red shore-normal demarcation lines broadly represented the distance inland for the identified catena. The catenas were identified by the codifications listed in Table 1. The zone between the red demarcation lines (the alongshore length of the coast) was identified as a domain. Each domain is thus represented by one cross-shore catena that has a specified alongshore length. The term “super domain” was used to represent simplified longer stretches of coastal belts containing one or more domains. This concept was adopted from principles established in Finkl and Makowski (2021).
Color-coded vertical lines in the offshore zone were used to identify the alongshore extents of super domains. To accommodate graphical limitations when annotating the satellite images by county, triangles with the apex pointing seaward were used to indicate the presence of smaller (compared with headlands) onshore and offshore rocks. Rock units were not further subdivided but were instead indicated within domains without further reference in the catena because of their limited spatial, extent notwithstanding their prominent appearance. Some transitional zones on the margins of rocky headlands and promontories that contained nearshore submarine rocks and skerries (boilers) were depicted on the satellite imagery by translucent red boxes to indicate the complicated combinational transition from rock to sandy beach in these special domain interfaces.
Visual interpretation, cognition, and manual collation of collateral and geographical information are all required to complete the task of laterally extrapolating the cross-section catenas and converting them into alongshore domains. Although there is a general tendency for researchers to attempt various aspects of computer image processing, human cognition and interpretation procedures remain indispensable for certain tasks, such as those identified in the delineation of archetypes in the Oregon coastal belt.
Visual analysis procedures were thus applied to the seven satellite image scenes, one scene per county, to obtain the results shown in each figure (Figures 2–8), with annotated cross-shore transectal catenas and alongshore super domains for each county. Domain numbers were assigned and organized in a manner that corresponded with the figure numbers; for example, the first digit corresponds to the figure number (i.e. Domain 2, which corresponds to Figure 2), and the second, hyphenated digit refers to the individual domain within the county (i.e. Domain 2-1 corresponds to the first domain in Figure 2). The following domain and figure numbers are as follows: Clatsop County (represented by Domains 2-1 through 2-9 in Figure 2), Tillamook County (represented by Domains 3-1 through 3-13 in Figure 3), Lincoln County (represented by Domains 4-1 through 4-9 in Figure 4), Lane County (represented by Domains 5-1 through 5-5 in Figure 5), Douglas County (represented by Domains 6-1 through 6-4 in Figure 6), Coos County (represented by Domains 7-1 through 7-11 in Figure 7), and Curry County (represented by Domains 8-1 through 8-13 in Figure 8).
Alongshore distances where measured using straight-line segments from the beginning to the end of a classification unit, regardless of curvatures within the segment. The ruler tool was used in the Google Earth Pro platform to record map length using a mouse function. These measurements, which were arbitrary and approximate for scoliomorphic coastal segments compared with leiomorphic stretches (cf. Finkl, 2004), were used to gain an overall impression of length in individual coastal belts. For simplicity, and in an effort not to imply greater precision, the coastal lengths were rounded to the nearest whole number kilometer when less than or greater than 0.5 km, except when the measurement included an exact half kilometer (e.g., 8.5 km).
The results of alongshore classification for each county are presented in the form of annotated satellite images starting in the northwesternmost corner of the Oregon coastal belt at the mouth of the Columbia River. The states of Oregon and Washington are separated by this river, which is the largest in the North American Pacific Northwest and rises in the Rocky Mountains of British Columbia, Canada. Cross-shore and alongshore codifications according to the Biophysical Cross-shore Classification System (BCCS) (Finkl and Makowski, 2020a) are summarized by county in Tables 2–8 that complement the annotations in Figures 2–8. The 30 super domains (and associated domanial transition zones) recognized along the Oregon coastal belt are subdivided into 64 domains that include the following archetypical cross-shore catenas; these have alongshore extents and are composed of barrier and mainland beach archetypes and rock archetypes that break down into the following seven consociations that replicate along the coast: Barrier-Beach-Dune, Barrier-Beach-Dune-Wetland, Beach-Cliff-Upland, Beach-Dune-Upland, Beach-Dune-Wetland, Beach-Wetland-Flat, and Rock-Cliff-Upland. Counties that make up the Oregon coastal belt contain the following number of super domains, from north to south: Clatsop (three super domains; Figure 2 and Table 2), Tillamook (seven super domains; Figure 3 and Table 3), Lincoln (five super domains; Figure 4 and Table 4), Lane (three super domains; Figure 5 and Table 5), Douglas (one super domain; Figure 6 and Table 6), Coos (four super domains; Figure 7 and Table 7), and Curry (five super domains; Figure 8 and Table 8). Four alongshore domanial transition zones are composed of two Rock-Beach-Cliff-Upland (R-Be-Cl-U) consociations (Bird Rock in Clatsop County and Sebastian in Curry County) and two Rock-Beach-Dune-Upland (R-Be-Du-U) consociations (Gull Rock in Lincoln County and Utter in Coos County), and together account for about 15 km of alongshore coast. For ease of reference and comparison of printed Figures 2–8 in this paper with interactive online imagery in Google Earth Pro, the super domains are given geographical place names and the domains are consecutively numbered from north to south in each county coastal belt.
Oregon's northernmost county, Clatsop County, is characterized by the Seaside Barrier-Beach-Dune (Ba-Be-Du), Tillamook Rock-Cliff-Upland (R-CL-U), and Cannon Beach-Dune-Upland (Be-Du-U) Super Domains that together comprise a 52-km-long coastal belt (Table 2) stretching from the mouth of the Columbia River in the north to the latitude of county line in the south (Figure 2). The Bird Rock Transition Zone (Domain 2-6) is a complicated 3-km alongshore stretch that is a transmutation between the Seaside and the Tillamook super domains. The overall characterization of the Clatsop County coastal belt is broadly characterized by rocky headlands with cliffs and skerries that are interspersed by littoral cells composed of barrier beach systems, with attendant beach ridges and wetlands, and mainland beach-dune systems, which are backed by uplands with interceding cliffs or wetlands.
Seaside Barrier-Beach-Dune Super Domain
The Seaside Super Domain is characterized by a 29-km-long Barrier-Beach-Dune (Ba-Be-Du) trisequent archetypical catena (Table 2). The barrier beach is backed by dunes and wetlands with remnants of beach ridges and shore-parallel lakes and ponds, which are most dramatic and evident in the northern part of this alongshore segment but persist to the northern flanks of the rocky headland 2 km south of Seaside. The Seaside Super Domain is composed of four smaller domains (Domains 2-1 through 2-4), the cross-shore codifications of which are initiated by the trisequent Barrier-Beach-Dune archetypical sequence that in turn is followed by other ecogeomorphological units, such as beach ridges (Br), flats (F), wetlands (W), and uplands (U) (cf. Table 1). The northern Domain 2-1 on the southern banks of the Columbia River is defined as a cross-shore Barrier-Beach-Dune-Flat (Ba-Be-Du-F) tetrasequent catena with an alongshore distance of about 4 km, which is followed southward by a hexasequent catena in Domain 2-2 that is codified as Ba-Be-Du-Br-W-F for a coastal belt that is about 6 km long. Domain 2-3, which occurs in about the center of the Seaside Super Domain, is about 15 km long and classified as a Ba-Be-Du-Br-W-U hexasequent catena. Domain 2-4 is classified as a Ba-Be-Du-W-U pentasequent catena where the beach ridges, although faintly and partially visible in the imagery, have been mostly disrupted by urban development. The sedimentary compartment that makes up this domain, which measures about 4 km long, is abruptly terminated by a rocky headland to the south.
Tillamook Rock-Cliff-Upland Super Domain
The 6-km-long Tillamook Super Domain is composed of a cross-shore Rock-Cliff-Upland (R-Cl-U) trisequent catena (Domain 2-5). This forested upland extends about 4 km inland from the 270-m high cliffs that drop directly into the Pacific Ocean. Some footslope areas contain small gravel beaches up to 25 m wide, rock benches, or boulder ramparts. Most steep cliff faces are unvegetated and exhibit active mass wasting, with materials sliding downslope because of gravity. There are some basaltic rock outcrops in the nearshore zone.
Bird Rock Rock-Beach-Cliff-Upland Transition Zone
The 3-km-long Bird Rock R-Be-Cl-U Transition Zone (Domain 2-6) occurs on the southern margin of Domain 2-5, where there is a complicated mixture of rock outcrops in the nearshore zone, small isolated rocky headlands, and sedimentary compartments containing narrow sandy or gravelly beaches. These eco-geomorphological features are easily recognized in the satellite image, by zooming in and out, but are too complicated spatially to separate at a coastal county scale. Therefore, the zone is simply marked as transitional or mutational between a rocky headland (Domain 2-5) and beach systems (Domain 2-7) and graphically denoted in Figure 2 by a translucent red rectangle that indicates the approximate offshore and onshore extent of these coastal features, as also noted in Table 2.
Canon Beach-Dune-Upland Super Domain
The Canon Super Domain is distilled to an average alongshore Beach-Dune-Upland (Be-Du-U) trisequent catena, in which the beach-dune system is directly backed by cliffs (Cl), uplands (U), or wetlands (W). The widths (alongshore extents) of cross-shore catenary sequences make up the domains identified in the Canon Super Domain. That is, in all cases, the beach-dune system is ultimately backed cross-shore by uplands with interpositions of cliff or wetland segments. The Canon Super Domain is derived from a cross-shore Beach-Dune-Upland (Be-Du-U) trisequent catena and composed of Domains 2-7 to 2-9. The length of this super domain is about 14 km, extending from Bird Rocks north of Cannon Beach to the southern border of Clatsop County. It contains three alongshore domains that are based on cross-shore catenas from north to south, a Be-Du-U trisequent catena (Domain 2-7), a Be-Du-Cl-U tetrasequent catena (Domain 2-8), and a Be-Du-WU tetrasequent catena (Domain 2-9), that have alongshore extends of 6, 5, and 3 km, respectively.
The Tillamook County coastal belt stretches about 82 km along the coast and is dominated by littoral cells that are interspersed by rocky headlands (Figure 3 and Table 3). A general or overall description of this coastal belt refers to littoral cell super domains that are bounded at the northern and southern ends of the county by Rock-Cliff-Upland (R-Cl-U) trisequent catenary sequences in the Flacon and Three Rocks super domains. The intervening super domains are characterized by the Rockaway and Netarts Beach-Dune-Wetland (Be-Du-W) super domains, the Meares and Tierra Del Mar Beach-Dune-Upland (Be-Du-U) super domains, and the Nestuca Barrier-Beach-Dune-Wetland (Ba-Be-Du-W) super domain. The Rockaway, Netarts, and Nestuca super domains encompass major stretches of barrier and non-barrier beaches backed by dunes, wetlands, and uplands that occur in the vicinity of estuarine eco-geomorphological environments. Cross-shore mainland Beach-Dune-Wetland (Be-Du-W) trisequent catenas with alongshore extents are also included in this super domain category. The locations of smaller isolated headlands, which are too small to call out as alongshore mapping units at a county scale, are symbolized by orange-colored arrows with the apex pointing seaward (cf. Figure 3). These large-scale (small areal distribution) features mainly occur south of Rockaway Beach, west of Tillamook, and north of Pacific City. The primary characteristics of the 13 domains in Tillamook County are summarized in the next sections.
Falcon Rock-Cliff-Upland Super Domain
The Falcon Super Domain contains one cross-shore Rock-Cliff-Upland (R-Cl-U) trisequent catena with rock outcrops and skerries in the offshore zone. This alongshore section, denoted as Domain 3-1, is a major rocky headland that has an alongshore extent of about 5 km and includes a short headland bay beach that is about 750 m long. Domain 3-1 predominantly contains sea cliffs that rise to a maximum of 170 m above sea level, where some footslopes fall directly into the Pacific Ocean, whereas other cliff bases are accompanied by steep-faced, coarse-grained beaches that are backed by driftwood and colluvial scree deposits sliding from the cliff face.
Rockaway Beach-Dune-Wetland Super Domain
The Rockaway Super Domain, which is based on a cross-shore Beach-Dune-Wetland (Be-Du-W) trisequent catena, features alongshore sedimentary compartments that contain beaches, dunes, wetlands, and flats (i.e. Domains 3-2 through 3-5) that occur south of the rocky headland in the Falcon Super Domain (Domain 3-1), and it centers on Rockaway Beach. Measuring about 26 km in alongshore length between rocky headlands, the Rockaway Super Domain contains two mainland beach domains (Domains 3-2 and 3-4) and two barrier beach domains (Domains 3-3 and 3-5). These four domains, subsumed under the aegis of the Beach-Dune-Wetland (Be-Du-W) super domain, make up the longest littoral cell in Tillamook County. The mainland beach Domains 3-2 and 3-4 are characterized by Beach-Dune-Wetland-Upland (Be-Du-W-U) tetrasequent catenas that are 2 and 10 km long, respectively, from north to south. Northern barrier beach Domain 3-3 is about 6 km long and composed mainly of a long spit that fronts an estuarine environment with tidal flats, the cross-shore sequence of which keys out to a Barrier-Beach-Dune-Wetland-Flat (Ba-Be-Du-W-F) pentasequent catena. The barrier beach Domain 3-5, which makes up the southern portion of the Rockaway Super Domain, occupies about 8 km of this coastal belt section and is backed by extensive tidal flat archetypes that extend more than 15 km inland, as measured from the inlet mouth to the western margin of the Tillamook township.
Meares Beach-Dune-Upland Super Domain
The Meares Super Domain is characterized by a cross-shore Beach-Dune-Upland (Be-Du-U) trisequent catena that has an alongshore length of about 6 km, making up Domain 3-6. Some cliff crests reach 120 m above sea level, with bare cliff faces that are steep-to, whereas others have footslopes that contain benches and platforms with an occasional sea cave. Rock archetypes occur as outcrops in the offshore zone but are most prevalent along the inshore zone near cliff bases. Narrow beach archetypes ranging up to 30 m in dry beach width occur on the southern margins of this domain.
Netarts Beach-Dune-Wetland Super Domain
The Netarts Super Domain contains a cross-shore Beach-Dune-Wetland (Be-Du-W) basic trisequent catena with an alongshore extent of about 22 km. This super domain is composed of one barrier beach cross-shore catena in Domain 3-7 that keys out to a cross-shore Barrier-Beach-Dune-Wetland-Flat (Ba-Be-Du-W-F) pentasequent catena. Domains 3-8 and 3-9 key out to Beach-Dune-Wetland (Be-Du-W) and Beach-Dune-Wetland-Flat (Be-Du-W-F) tri- and tetrasequent catenas that have respective alongshore extents of 9 and 3 km, including short barrier spits at the inlet. Cross-shore rock archetypes that have an approximate 5-km alongshore extent around a rocky headland (marked by a yellow arrow on Figure 3) separate the barrier beaches in Domain 3-7 from mainland beaches and barrier spits in Domain 3-8. The 3-km-long alongshore stretch of Domain 3-9 is characterized by a cross-shore Beach-Dune-Wetland-Flat (Be-Du-W-F) tetrasequent catena.
Tierra Del Mar Beach-Dune-Upland Super Domain
Spanning a distance of about 4 km alongshore, the Tierra Del Mar Super Domain embraces Domain 3-10 with a cross-shore Beach-Dune-Upland (Be-Du-U) trisequent catena. The mainland beaches in the northern part of this segment range from about 60 to 100 m in dry beach width, whereas those in the southern part range up to about 100 m in width. Some dunes on a point of land heading out into the Pacific Ocean reach 30 m or more in height, whereas those in the backbeach area to the north are incipient and those in the south may reach several meters in height. The uplands range in height from about 20 to 60 m in elevation about 100 to 300 m inland from the shore.
Nestuca Barrier-Beach-Dune-Wetland Super Domain
The Nestuca Super Domain is characterized by a basic cross-shore Barrier-Beach-Dune-Wetland (Ba-Be-Du-W) tetrasequent catena that has an alongshore extent of 14 km. The two domains comprising this super domain are Domain 3-11, which has an alongshore length of about 6 km and is made up of a cross-shore Barrier-Beach-Dune-Wetland-Flat (Ba-Be-Du-W-F) pentasequent catena, and Domain 3-12, which instead of having an onshore flat archetype, has a wetland backed landward by an upland archetype that spans an alongshore distance of about 8 km. The dry beach widths of the barrier beach range between 20 and 100 m, with backbeach dunes rising about 10 to 14 m above sea level. The northern section of Domain 3-11 is partly urbanized on the northwestern margins of Pacific City. Tidal wetland archetypes extend about 6 km inland, whereas the flats are more restricted and reach about 3 km inland south of Pacific City. Wetland archetypes in Domain 3-12, which is about 8 km long, extend about 300 to 700 m inland from the inland margin of the coastal dunes. Peaks on the uplands reach about 170 m in elevation but slope gradually seaward to where they terminate the wetlands, with bluffs up to around 20 m in height. Thus, the main difference between Domain 3-11 and Domain 3-12 is that the archetype following the cross-shore Barrier-Beach-Dune-Wetland tetrasequent catena falls to a flat archetype in the former and an upland archetype in the latter.
Three Rocks Rock-Cliff-Upland Super Domain
The Three Rocks Rock-Cliff-Upland Super Domain occurs on the SW margin of Tillamook County and consists of Domain 3-13, which is classified by a cross-shore Rock-Cliff-Upland (RCL-U) trisequent catena that has an alongshore extent of about 5 km. Cliff crests max out around 320 m in elevation about 500 m inland from footslopes that plunge directly into the sea or merge with rock archetypes such as platforms, benches, beach sub archetypes (Table 1) such as ramparts, or the occasional narrow beach archetype that might range up to 50 m in width. Cliff faces are unvegetated in areas of active mass wasting where talus and scree deposits move downslope to the cliff base, whereas other less steep faces are partially covered by vegetative growths. Some isolated offshore rock outcrops rise 10 to 20 m above sea level in the form of sea stacks.
The 86-km-long coastal stretch of Lincoln County (Figure 4 and Table 4) is composed of four super domains and one transition zone. Coastal classifications, in terms of cross-shore catenas and alongshore domains, and unit lengths are tabulated in Table 4 as an adjunct to Figure 4. The Lincoln Beach-Dune-Upland (Be-Du-U) and Newport Beach-Cliff-Upland (Be-Cl-U) Super Domains are dominated by two littoral cells that are characterized by mainland beaches with and without backbeach dunes, respectively. The Depoe Bay and Yachats Rock-Cliff-Upland (R-CL-U) Super Domains are constituted by rocky promontories that separate littoral cells. The Gull Rock Transition Zone (Domain 4-5) is a combination of rock and beach archetypes backed by cliff and upland archetypes that is identified by the tetrasequent concatenation R-Be-Cl-U.
Lincoln Beach-Dune-Upland Super Domain
The northern littoral cell making up the Lincoln Beach-Dune-Upland (Be-Du-U) Super Domain spans an alongshore distance of about 23 km and contains two Beach-Dune-Upland (Be-Du-U) trisequent catenas (Domains 4-1 and 4-3) that are separated by a Beach-Dune-Flat-Upland (Be-Du-F-U) tetrasequent catena (Domain 4-2) in the vicinity of an eco-geomorphological estuarine environment south of Lincoln City. Domain 4-1, which is classified as a cross-shore trisequent catena with an alongshore extent of 12 km, extends from the county line in the north to the inlet south of Lincoln City (Figure 4). The 100-m-wide beaches are backed by incipient dunes that average less than 1 m in height above a berm that is frequently overwashed. Seaward margins of upland archetypes rise from a few meters up to 20 m higher than the back-beach area. These uplands are mostly urbanized. The cross-shore catenary sequence in Domain 4-2 is similar to that in Domain 4-1 except that the beach-dune couplet is backed by flat archetypes before terminating in uplands. The cross-shore Beach-Dune-Flat-Upland (Be-Du-F-U) tetrasequent catena of Domain 4-2 has an alongshore extent of about 6 km, part of which is composed of a spit that separates the Pacific Ocean from Siletz Bay. The spit has a low elevation, generally less than 10 m above the beach berm and less than about 5 m above the tidal mud flats. The 5-km-long stretch of Domain 4-3 is characterized by a cross-shore Beach-Dune-Upland (Be-Du-U) trisequent catena that is similar to Domain 4-1. The beaches in Domain 4-3 average about 50 to 60 m in width and are backed by incipient dunes; both archetypes are frequently overwashed during storms. The developed upland, which is commonly fronted by riprap to protect from the erosive effects of wave uprush, stands 5 to 10 m above the back-beach area.
Depoe Bay Rock-Cliff-Upland Super Domain
The Depoe Bay Rock-Cliff-Upland Super Domain is composed of Domain 4-4, a cross-shore Rock-Cliff-Upland (R-Cl-U) trisequent catena that has an alongshore length of about 11 km and is centered on Depoe Bay. Offshore rock outcrops are generally a few meters above the water surface, but some may reach 8 or 10 m above sea level. Most sea cliffs are about 10 to 20 m above sea level, although some may reach 80 to 100 m in elevation. The higher and steeper cliffs tend to be steep-to, whereas the remaining cliff archetypes with a lower crest elevation tend to be fronted by rock platforms and benches that range up to 40 or 50 m in width. Coves, reentrants, and small headlands occur in this domain, along with infrequently occurring narrow beaches up to 25 m in dry beach width. Ramparts tend to be narrow, perhaps extending several meters seaward from the cliff base. Steep cliff faces tend to be unvegetated, because active mass wasting occurs there, but upper slopes landward of the false crest are vegetated. Some forested uplands may reach 150 m in elevation within 500 m of cliff bases. These cliff archetypes merge southward into the Gull Rock Transition Zone (Domain 4-5).
Gull Rock Rock-Beach-Cliff-Upland Transition Zone
The Gull Rock Rock-Beach-Cliff-Upland Transition Zone is composed of Domain 4-5, which is a cross-shore Rock-Beach-Cliff-Upland (R-Be-Cl-U) tetrasequent catena that has an alongshore length of 5 km. This zone is similar to Domain 4-4 except that beach archetypes occur more frequently, with up to five or six along this coastal stretch; the longest occurs on the southern margin of the domain and stretches about 380 m. A headland bay beach occurs on the northern margin of Domain 4-5 and is about 180 m long. The northern and southern boundary beaches tend to be narrow, approaching 20 m in dry beach width, and are perched so that they sit on the landward sections of marine platforms that approach the cliff base. Some of these platforms extend a couple hundred meters seaward to include intertidal and subtidal zones.
Newport Beach-Cliff-Upland Super Domain
The Newport Beach-Cliff-Upland Super Domain is a littoral coastal belt that contains barrier and mainland beaches that characterize much of the Lincoln County coast. This super domain stretches about 40 km (Table 4) from the Gull Rock Rock Rock-Beach-Cliff-Upland Transition Zone (Domain 4-5) south of Depoe Bay to north of Yachats. The largest part of this super domain is composed of Domain 4-6, which is a Beach-Cliff-Upland (Be-Cl-U) trisequent catena that stretches about 25 km alongshore. Beaches range up to 150 m in width, including a low-tide terrace and dry beach widths around a maximum of 50 m. Overwash is common on some of these beaches, with wave uprushes reaching cliff bases. Cliff crests may reach 20 or 30 m in elevation but are more commonly in the 5 to 10 m range, along much of this coastal stretch. Uplands backing the beach-cliff interface are mostly forested, but some areas are urbanized, especially near Newport and Seal Rock. Domain 4-7 contains a 6-km-long Barrier-Beach-Dune-Wetland-Flat (Ba-Be-Du-W-F) pentasequent catena that occurs in association with estuarine eco-geomorphological units near the Waldport inlet, where the northern barrier spit is about 4 km long and the southern spit ranges up to 1.5 km in length. Domain 4-8 contains a cross-shore Beach-Cliff-Upland (Be-Cl-U) trisequent catena that spans an alongshore distance of about 9 km. Dry beach widths here range up to 80 m and beachback areas with no dunes directly abut cliffs. Cliff tops along this domain are generally low, with crests rarely exceeding 10 m in height above the backbeach.
Yachats Rock-Cliff-Upland Super Domain
The Yachats Rock-Cliff-Upland Super Domain, which occurs on the southwesternmost margin of Lincoln County, bracketing the coastal city of Yachats, is composed of Domain 4-9 (Table 4). This domain features a cross-shore Rock-Cliff-Upland (R-Cl-U) trisequent catena that stretches about 6 km alongshore. The rock archetypes here are characterized by rock platforms up to about 50 m in width and stand about 2 or 3 m above sea level. Most of this domain is bounded by low cliffs that generally stand less than 10 m above the seaward rock platforms and benches. Some isolated and exceptionally high upland peaks rise 150 m above sea level only a few hundred meters inland from the shore. Beach archetypes are absent from Domain 4-9, except where they are marginal to tidal flats on the ebb tidal delta of the Yachats Inlet.
The 46-km-long coastal belt of Lane County is dominantly characterized by littoral cells composed of mainland and barrier beach systems that comprise three super domains named, from north to south, the Searose Beach-Cliff-Upland (Be-Cl-U), Heceta Beach-Dune-Wetland (Be-Du-W), Florence Barrier-Beach-Dune-Wetland (Figure 5, Table 5). The Searose Beach-Cliff-Upland (Be-Cl-U) and Heceta Beach-Dune-Wetland (Be-Du-W) Super Domains contain mainland beaches whereas the Florence Barrier-Beach-Dune-Wetland (Ba-Be-Du-W) Super Domain features barrier beaches backed by dunes and interior wetlands. Rocky headlands occur in the northern part of this coastal belt, but because of their small alongshore extents, they are only indicated graphically by arrowhead symbols pointing seaward. One domain makes up the Searose (Domain 5-1) and Heceta (Domain 5-2) super domains, whereas three domains comprise the Florence Super Domain (Domains 5-3 through 5-5).
Searose Beach-Cliff-Upland Super Domain
The Searose Beach-Cliff-Upland Super Domain contains a cross-shore Beach-Cliff-Upland (Be-Cl-U) trisequent catena that has an alongshore extent of 19 km. The eco-geomorphological units (i.e. beach, cliff, and upland archetypes) in Domain 5-1 that make up this super domain are bounded by rocky headlands that range up to about 170 m in elevation within a few hundred meters of the shore. Cliffs backing the mainland beach archetypes, much lower in contrast, range up to 10 or 20 m above the backbeach area depending on specific locations. Most beaches tend to be sandy, but some are gravelly in the vicinity of inshore rock outcrops in the surf zone. Beaches without inshore rock outcrops are narrow, with dry beach widths falling in the 10- to 20-m range and low tide terraces occurring between 20 and 40 m wide. Back beach cliff tops reach maximum elevations of about 40 m, but most average about 10 to 20 m higher than backbeach areas.
Heceta Beach-Dune-Wetland Super Domain
The cross-shore Beach-Dune-Wetland-Upland (Be-Du-W-U) tetrasequent catena that makes up Domain 5-2 includes wetlands partially overridden by dune sands with vestiges of relict beach ridges. This 9.5-km alongshore stretch of the Be-Du-W-U cross-shore catenary sequence, which extends up to 5 km inland to the seaward margins of upland archetypes, contains stabilized (vegetated) and transverse marching dunes that are up to 10 m higher than the wetlands they area burying. Many small lakes and ponds occur among the wetland archetypes. There are no inshore rock outcrops visible in the satellite imagery.
Florence Barrier-Beach-Dune-Wetland Super Domain
The Florence Barrier-Beach-Dune-Wetland Super Domain contains domains 5-3 through 5-5, which span an alongshore distance of about 17.5 km. Domain 5-3 is characterized by a cross-shore Ba-Be-Du-Br-W-U hexasequent catenary sequence that stretches about 9 km alongshore. This domain near Florence contains an estuary that extends about 15 km inland, but its alongshore presentation is too confined to single out at a county scale. Dry beach widths are about 50 to 70 m and backed by stabilized dunes that are about 150 m wide and about 5 to 6 m higher than the level of the beach berm. Cross-shore sequences of dunes, beach ridges, and wetlands extend up to 3 km inland before the seaward margins of uplands are reached. Some marching dune crests rise about 10 to 20 m above interdunal swales, where the dune field is about 700 m in cross-shore diameter.
Domain 5-4, which contains the cross-shore Ba-Be-Du-Br-Du-W hexasequent catenary sequence, stretches about 6 km alongshore. The dominant alongshore component is a typical Barrier-Beach-Dune-Wetland (Ba-Be-Du-W) archetypical sequence that in this case is backed landward by active (unvegetated) dunes about 1 km inland. The large active dune field shown in the center of this domain (Figure 5), which lies immediately inland of the beach ridge plain, is about 6 km long by about 1.5 km wide, contains dunes that rise 10 m higher than the wetlands, and includes forested landscapes that it is overriding. The dune field contains interdunal lakes and ponds, as well as tree islands surrounded by the marching dunes. Wetland archetypes back the beach ridge–dune sequences.
Domain 5-5 is characterized by a cross-shore Ba-Be-Du-W-Du pentasequent catenary sequence that stretches about 2.5 km alongshore. This barrier beach domain contains a narrow beach ridge plain in its northern section that is about 200 m wide, with its distal margin cut off by the inlet and an associated wetland archetype. The beach ridge plain is interposed between the wetland archetype on the back (landward) side of the coastal foredunes and the inland stabilized dune archetypes. This littoral cell contains no rock outcrops in the surf zone.
The short 28.5-km-long stretch of the Reedsport Barrier-Beach-Dune-Wetland Super Domain in Douglas County (Figure 6 and Table 6) contains four domains that are concised down to one cross-shore Barrier-Beach-Dune-Wetland (Ba-Be-Du-W) tetrasequent super domain. The four domains comprising this super domain are characterized by the presence of beach ridge, dune, wetland, and upland archetypes inland of the initial cross-shore Barrier-Beach-Dune (Ba-Be-Du) trisequent catena. This littoral cell super domain contains no rocky headlands or inshore rock outcrops.
Reedsport Barrier-Beach-Dune-Wetland Super Domain
Domain 6-1, which spans an alongshore distance of about 12.5 km, is characterized by a cross shore Barrier-Beach-Dune-Wetland-Upland (Ba-Be-Du-W-U) pentasequent catena. The barrier beach is backed inland by elongated, shore parallel dunes and wetlands, with lakes and ponds, and some active dunes reach 10 m higher than the surrounding landscape. Vestiges of beach ridge series, about 200 m in width, occur landward of the foredunes and seaward of the inland dune fields. Both active (unvegetated) and stabilized dunes occur in this zone.
The cross-shore Barrier-Beach-Dune-Wetland-Dune-Flat (Ba-Be-Du-W-Du-F) hexasequent catena that makes up Domain 6-2 extends alongshore for a distance of about 3.5 km. The eco-geomorphological units in this domain are notable, because they include tidal flats that are about 1 km wide and extend about 4.5 km upstream, providing a distinctive character to this domain. This domain contains a mixture of stabilized and active dunes.
Domain 6-3 is characterized by a cross-shore Barrier-Beach-Dune-Wetland-Beach Ridge-Dune (Ba-Be-Du-W-Br-Du) hexasequent catena that stretches about 8.5 km alongshore. This domain, which lacks interior tidal flats, features stabilized dune ridges that occur on the beach ridge plain, which extends for about 500 m inland from the beach dunes, and are interspersed by wetlands. Beaches, including a low-tide terrace, are about 100 m wide, with dry beach widths about half that distance. The beach dunes range up to 4 or 5 m above the beach berm and are about 5 or 6 m higher than the landward beach ridges and wetlands. Most active dunes on the landward side of the barrier spit, which are transverse, range up to about 2 m in height and are accompanied by scattered low-coppice dunes.
Domain 6-4 contains a Barrier-Beach-Dune-Upland (Ba-Be-Du-U) tetrasequent catena that extends about 3.5 km inland and downcoast for about 4 km alongshore. Beach dunes that rise about 5 m above the level of the berm are backed by about 150 to 200 m of wetlands and vestiges of beach ridges before the interior dune fields are reached. These spectacular dune fields have massive dune sets that run mostly perpendicular to the shore and rise up 30 to 35 m above the floors of intervening slacks. The dune fields abut older stabilized dunes and bedrock interior uplands. No rock outcrops were observed in the offshore.
The 75.5-km-long Coos County coastal belt contains three super domains: Lakeside Barrier-Beach-Dune (Ba-Be-Du) Super Domain, Shell Island Rock-Cliff-Upland (R-Cl-U) Super Domain, Bandon Beach-Dune-Upland (Be-Du-U) Super Domain and one transition zone, called the Utter Rock-Beach-Dune-Upland (R-Be-Du-U) Transition Zone. Lakeside and Bandon super domains are two large littoral cells bisected by the Utter Rock-Beach-Dune-Upland Transition Zone and Shell Island Rock-Cliff-Upland Super Domain rocky headland. The northern Lakeside Beach-Dune-Upland Super Domain contains Domains 7-1 through 7-4, as shown in Figure 7 and enumerated in Table 7. The southern Bandon Beach-Dune-Upland Super Domain contains Domains 7-7 to 7-11. The Shell Island Rock-Cliff-Upland Super Domain (Domain 7-6) bifurcates the two large barrier beach (Lakeside) and mainland beach (Bandon) super domains and transitions northward through the Utter Rock-Beach-Dune-Upland Transition Zone (Domain 7-5), which is complicated by rocks in the inshore zone fronting beach-dune systems that are backed by uplands.
Lakeside Barrier-Beach-Dune Super Domain
The northern part of the Lakeside Barrier-Beach-Dune (BaBe-Du) Super Domain is marked by spectacular dune fields in Domain 7-1, which is characterized by a cross-shore Barrier-Beach-Beach Ridge-Dune-Upland (Ba-Be-Br-Du-U) pentasequent catena that spans an alongshore distance of about 4 km. Some larger dune crests rise 35 to 40 m above adjacent swales, and the 3-km inland extension of these dune fields makes them one of the largest expanses of temperate coastal sand dunes in the world. A narrow beach ridge plain that is about 500 m wide separates backbeach dunes from the large destabilized dune field that is marching inland and burying coastal coniferous forests. Dune crests on some advancing tongue fronts rise more than 20 m over the forests that are being buried.
Domain 7-2, the longest alongshore stretch in this super domain, is characterized by a cross-shore Barrier-Beach-Dune-Wetland-Upland (Ba-Be-Du-W-U) pentasequent catena that spans an alongshore distance of about 14 km (Table 7). This complex domain contains southern extensions of the active dune field in Domain 7-1 that are interspersed by wetlands, stabilized (vegetated) dunes, and landward uplands. Domain 7-3 marks the southern boundary of the Oregon coastal dune fields and differs from Domain 7-2 in that tidal flats occur inland of the dunes. Domain 7-3, which is about 6 km long, is characterized by a cross-shore Barrier-Beach-Dune-Wetland-Dune-Flat (Ba-Be-Du-W-Du-F) hexasequent catena. The eastern inland margins of the marching dunes are terminated by wetland and tidal flat archetypes that are associated with the estuary that extends about 20 km inland along the river valley. Immediately south lies Domain 7-4, which is characterized by a cross-shore Barrier-Beach-Dune-Flat (Ba-Be-Du-F) tetrasequent catena that spans an alongshore distance of about 6 km. This barrier spit, which terminates at the inlet, is a simplified eco-geomorphological setup compared with Domain 7-3, where wetlands are missing from the cross-shore sequence.
Utter Rock-Beach-Dune-Upland Transition Zone
Domain 7-5, which has an alongshore extent of about 2.5 km, corresponds to the Utter Rock-Beach-Dune-Upland (R-Be-Du-U) Transition Zone, which occurs on the northern flanks of the rocky headland that makes up the Shell Island Rock-Cliff-Upland (R-Cl-U) Super Domain and is composed of Domain 7-6. The transition zone contains a complicated sequence of rocky offshore features, such as small headlands, skerries, rock benches, shoals, low sea stacks, and boilers that are intermixed with beach, cliff, and rock archetypes viz. headland bay beaches, coves, and cliffs. Some cliffs in this domain reach upward of about 20 m, but most are about half that elevation.
Shell Island Rock-Cliff-Upland Super Domain
Domain 7-6 is a rocky headland that is characterized by a Rock-Cliff-Upland (R-Cl-U) trisequent catena that extends alongshore for about 7 km. Cliffs along the headland average about 20 m in height, but some reach upward of 70 m, providing views of impressive bare (unvegetated) cliff faces with rubble footslopes and benches. Shallow rocky areas forming skerries and islets occur up to 900 m offshore in some areas.
Bandon Beach-Dune-Upland Super Domain
The southern margin of the rocky headland embraced by the Shell Island Rock-Cliff-Upland (R-Cl-U) Super Domain terminates where a mainland beach begins in Domain 7-7. This makes up the northernmost section of mainland beach-dune sequences comprising the southern Bandon Beach-Dune-Upland (Be-Du-U) Super Domain that stretches about 30 km alongshore. Domain 7-7 is characterized by a cross-shore Beach-Dune-Upland (Be-Du-U) trisequent catena that stretches about 11 km alongshore. These mainland beaches contain narrow backbeach dune sets that may range up to 50 m in width, whereas some stretches contain no dunes. Older vegetated dunes sometimes occur landward of the modern unvegetated dunes as a bench about 4 to 5 m in height. The vegetated uplands rise about 30 m above the beach. A cross-shore Beach-Dune-Flat (Be-Du-F) trisequent catena makes up Domain 7-8 that spans about 6.5 km alongshore. This spit is about 380 m wide at its narrowest point about 1.5 km north of the stabilized inlet to the estuary at Bandon. Although there are some short tidal flats and associated wetlands on the landward side of the spit, its dominant characteristic is the trisequent catena. The cross-shore Beach-Dune-Upland (Be-Du-U) trisequent catena that makes up Domain 7-9 stretches about 6 km alongshore from the small rocky headland on the south side of the inlet at Bandon. The upland here rises about 10 to 15 m above sea level, and there are low bluffs separating the upland from the backbeach dune archetypes. Domain 7-10 is composed of a cross-shore Beach-Dune-Beach Ridge-Upland (Be-Du-Br-U) tetrasequent catena that is about 4.5 km in alongshore length. This domain differs from the adjacent Domain 7-9 (north) and Domain 7-11 (south), because beach ridges occur landward of the mainland beach-dune system and seaward of the upland that variably rises 10 to 30 m above sea level. The cross-shore Beach-Dune-Wetland-Upland (Be-Du-W-U) tetrasequent catena that makes up Domain 7-11 stretches about 7 km to the southern county line. The wetland archetypes extend up to 4 km inland, following valleys cut into the uplands.
The Curry County coastal belt, which is about 110 km long as the crow flies between county boundaries, contains six super domains and 13 domains, as shown in Figure 8 and enumerated in Table 8. The super domains and transition zone are named, from north to south, the Langlois Beach-Dune-Upland (Be-DuU), the Port Orford Rock-Cliff-Upland (R-Cl-U), the Wedderburn Beach-Dune-Upland (Be-Du-U), the Sabestian Rock-Beach-Cliff-Upland (R-Be-Cl-U) Transition Zone, the Pistol River Beach-Wetland-Flat (Be-W-F), and the Brookings Rock-Cliff-Upland (R-Cl-U). Mainland beach archetypes that are backed by dune, flat, upland, and wetland archetypes provide a minor alongshore characteristic of littoral cells in the Curry coastal belt (i.e. Domains 8-1, 8-2, 8-10, and 8-12) and occur in the Langlois, Wedderburn, and Pistol River super domains. However, the dominant characteristic of the Curry coastal belt is mostly defined by the Port Orford and Brookings rock-cliff-upland super domains that are about 48 and 34 km long in the northern and southern parts of the county, respectively (Figure 8 and Table 8). The northern Port Orford Rock-Cliff-Upland Super Domain is composed of Domains 8-3 to 8-9, whereas the southern Brookings Rock-Cliff-Upland Super Domain is composed of Domain 8-13.
Langlois Beach-Dune-Upland Super Domain
Domains 8-1 and 8-2 make up the Langlois Beach-Dune-Upland (Be-Du-U) Super Domain in northern Curry County that spans a 9.5-km alongshore distance. Domain 8-1 is composed of a cross-shore mainland Beach-Dune-Wetland-Upland (Be-Du-W-U) tetrasequent catena that extends for 7 km alongshore. The beach-dune couplet here is transitional between mainland and barrier and is generally about 200 m wide. A small watercourse lies landward of the beach-dune archetypes, marking the boundary between the landward wetlands and the shore. These wetland archetypes may extend up to 3 km inland before upland archetypes are encountered. The cross-shore Beach-Dune-Upland (Be-Du-U) trisequent catena in Domain 8-2 stretches about 2.5 km alongshore and differs in eco-geomorphological units where the backbeach dunal area abuts cliffs that range up to 15 or 20 m in height. Dune archetypes gradually disappear from the domain in a north-south direction.
Port Orford Rock-Cliff-Upland Super Domain
The Port Orford Rock-Cliff-Upland Super Domain, which is about 48 km long, is the most prominent domain along the north–central Curry coastal belt and contains seven distinct domains (i.e. Domains 8-3 through 8-9). Domains 8-3, 8-7, and 8-9 are Rock-Cliff-Upland (R-Cl-U) trisequent catenas that have respective alongshore distances of 3, 13.5, and 4 km. Domain 8-3 is a rocky promontory that stands about 65 m above sea level and is bounded seaward by inshore rocky zones, small sea stacks, and rock benches at cliff footslopes. Domain 8-7 is more leiomorphic (cf. Finkl, 2004) compared with what is observed along Domain 8-3, but it contains more spectacular sea cliff archetypes, the most prominent of which reaches 535 m in elevation about 800 m inland. Unvegetated sea cliffs reach up to 150 m above sea level in the northern part of this alongshore zone but decrease in elevation southward. The vegetated and more subdued cliff archetypes in Domain 8-9 are about 40 m in height where their footslopes back some small coarse-grained beaches. Rocks occur in the inshore zone, and there are some small sea caves in headlands.
Domains 8-4 and 8-6 that lie north and south of the Port Orford rocky headland (Domain 8-5) are 10 and 7 km long, respectively. Cliffs in Domain 8-4 average about 40 m in height in the northern part but decrease in elevation in the south to 20 m or less. The northern and southern parts of this domain are rockier along the inshore than the central portion. The beach archetype area is generally narrow, ranging from about 60 to 200 m in dry beach width with no backbeach dunes. Inshore rocky zones are more prevalent in Domain 8-6 compared with Domain 8-4, and cliff heights are generally lower, averaging around 20 to 30 m in height but increasing in elevation in the southern part of this domain as it approaches Domain 8-7.
The Port Orford rocky headland makes up Domain 8-5, which is about 3 km in length and composed of a cross-shore Cliff-Upland (Cl-U) disequent catena. The unvegetated sea cliffs are mostly steep-to, plunging directly into the Pacific Ocean. Small sea stacks occur offshore and rise up about 20 m above sea level, and there are some skerries inshore.
The alongshore length of the cross-shore Rock-Cliff-Upland (R-Cl-U) trisequent catena that makes up Domain 8-7 is about 13.5 km. The barren to poorly vegetated cliff archetypes in this domain mostly average about 20 to 40 m in height, with wide variation depending on the particular coastal stretch, whereas some isolated alongshore peaks rise 170 m above sea level. Small sea stacks rising up to 50 m in elevation occur offshore.
Domain 8-8 is composed of a Beach-Cliff-Upland (Be-Cl-U) trisequent catena that stretches about 7.5 km alongshore. The cliff archetypes rise 10 to 20 m above the beaches that range up to 200 m in width in the northern segment of the domain near the entrance to an estuary but are more nominally about 50 to 100 m wide. Some rocky zones occur offshore and inshore on the northern and southern margins of the domain, where it transitions to Domains 8-7 and 8-9, which contain rocky headlands.
The cross-shore Rock-Cliff-Upland (R-Cl-U) trisequent catena that characterizes Domain 8-9 spans an alongshore distance of about 4 km and thus stands in contrast to the beach archetypes occurring in the Rock-Cliff-Upland (R-Cl-U) super domain to the north and the Beach-Dune-Upland (Be-Du-U) super domain to the south. The sea cliff archetypes in Domain 8-9 reach maximum heights of about 40 m and are steep-to on headlands, but they may contain rubble and scree deposits along footslopes, along with narrow coarse-grained beaches and boulder ramparts.
Wedderburn Beach-Dune-Upland Super Domain
The Wedderburn Beach-Dune-Upland Super Domain is composed of a cross-shore Beach-Dune-Upland (Be-Du-U) trisequent catena that makes up Domain 8-10, which has an alongshore extent of about 9 km. This domain extends southward from the inlet at Gold Beach to a rocky headland about 9 km south. Modern dunes in the backbeach area are incipient and scattered along scarped seaward margins of older stabilized dune plains that abut uplands on their shoreward margin in this coastal belt. The dry beach widths average around 50 m but may range up to 130 m where erosional alcoves have penetrated farther into the stabilized dune plain, which is about the same width as the dry beach areas. Upland archetypes gradually range up to 150 m in elevation about 1 km inland.
Sebastian Rock-Beach-Cliff-Upland Transition Zone
The Sebastian Rock-Beach-Cliff-Upland Transition Zone is composed of a cross-shore Rock-Beach-Cliff-Upland (R-Be-Cl-U) tetrasequent catena that makes up Domain 8-11, with an alongshore stretch of about 4.5 km. Cliff tops range up to 200 m above sea level and are mostly steep-to with boulder footslopes, except where there are pocket or headland bay beaches. Low sea stacks, growlers, and boilers occur offshore on the southern margins of this transitional zone. The larger sea stacks rise about 35 m above sea level, but most others are lower, rising less than 10 m out of the water. Some upland archetypes rise 370 m within 2 km of the shore.
Pistol River Beach-Wetland-Flat Super Domain
The Pistol River Beach-Wetland-Flat Super Domain is composed of a cross-shore Beach-Wetland-Flat (Be-W-F) trisequent catena that makes up Domain 8-12, which has an alongshore distance of about 5 km. This coastal belt occurs between two rocky headlands and is dominantly characterized by beaches backed by wetland and flat archetypes in the vicinity of the Pistol River estuary, although there are partially stabilized dune flats south of the inlet that are in some place surmounted by dunes up to 10 m in height. The seaward truncated margins of the dunes stand a few meters above the elevation of the backbeach. The dry beach widths are extremely variable, spanning from 9 to 15 m south of the inlet to dune flat archetypes to 130 m north of the inlet beach before terminating in backbeach overwash flats that are partly submerged. The southern flanks of the Pistol River Super Domain gradually increase in elevation as they approach the northern margin of the Brookings Super Domain, which extends to the border with California.
Brookings Rock-Cliff-Upland Super Domain
The Brookings Rock-Cliff-Upland Super Domain is composed of a cross-shore Rock-Cliff-Upland (R-Cl-U) trisequent catena that makes up Domain 8-13, which has an alongshore distance of about 34 km. This rocky shore contains numerous sub archetypes, such as sea stacks, skerries, growlers, boilers, marine platforms and benches, islets, reentrants, and sea caves. Although most sea cliffs range from about 30 to 100 m in height above the Pacific Ocean and some reach more than 300 m about 1 km inland, the last 2 km of this coastal belt contains increasingly diminutive rock outcrops in the offshore that become less frequent toward the California border, whereas the low-angle slopes of the sea cliffs leading to uplands are only a few meters high and more like bluffs. This Brookings Super Domain contains many headland bay beaches, alcove beaches, and reentrant beaches. Cliff footslopes are marked by ramparts, boulder fields, beaches, and accumulations of driftwood. Some cliff faces are bare rock mass wasting surfaces, whereas others are vegetated. Some rocky headlands extend up to 400 m seaward from the line of the main cliffed shore, forming pronounced promontories whose crests range up to about 60 m above sea level. Cliff-foot beaches tend to be narrow, on the order of 20 to 30 m, whereas some wider ones reach about 70 m in width.
The coast of Oregon contains a complex setup of littoral cells punctuated by rocky headlands that form dramatic lookouts into the Pacific Ocean and alongshore. The Oregon coastal belt was divided into 64 discrete alongshore domains derived from cross-shore catenary sequences that had shore-parallel breadth. Analysis of this coastal classification based on the BCCS features two distinct points of view: one considers geographical aspects by county, and the other breaks down ecomorphological variability according to barrier, beach, beach ridge, cliff, dune, flat, rock, upland, and wetland archetypes as defined by Finkl and Makowski (2020a). Geographical occurrences and frequency distributions of archetypes and their consociations in cross-shore catenas that have alongshore spread provide the basis for interpretation of the data presented in Tables 9–18. The analytics here are derived from the morphometric properties of the archetypes as they relate to alongshore and cross-shore spatial distributions and frequencies of occurrence.
Geographical Distribution of Archetypes and Catenas
County percentages of the Oregon coastal belt are roughly similar for Clatsop (11%), Tillamook (17%), Lincoln (18%), Coos (16%), and Curry (23%) counties, with the exceptions of Lane (9%) and Douglas (6%) counties, which have shorter alongshore extents (Tables 2–8). Clatsop County is mainly a sedimentary coast characterized by a 29-km alongshore stretch of cross-shore Barrier-Beach-Dune (Ba-Be-Du) trisequent catenas followed landward by beach ridge, flat, and wetland archetypes in the Seaside Super Domain (Table 2). The 14-km alongshore stretch of cross-shore Beach-Dune (Be-Du) disequent catenas is followed landward by cliff, upland, and wetland archetypes in the Cannon Super Domain. Rocky shores are prominent features of the Tillamook and Bird Rock Super Domains; they contain rock, beach, cliff, and upland archetypes that comprise cross-shore archetypical sequences that account for about 9 km alongshore distances, making up 11.5 and 5.7%, respectively, of the county coastal belt.
Tillamook and Lincoln counties (Tables 3 and 4) are characterized as sedimentary coastal belts, where most cross-shore archetypical sequences are initiated by the beach archetype. In Tillamook County, beach archetypes are followed landward by dune, wetland, and flat archetypes. In Lincoln County, this cross-shore sequence is truncated by beach-dune couplets followed landward by flat or upland archetypes in the Lincoln Super Domain or Beach-Cliff-Upland (Be-Cl-U) trisequent catenary sequences in the Newport Super Domain, which take up 34 km alongshore length. Both counties include rocky headlands that key out to the Rock-Cliff-Upland (R-Cl-U) catenas that make up the Falcon and Three Rocks Super Domains in Tillamook County, as well as the Depoe Bay, Gull Rock (including a small beach viz. Rock-Beach-Cliff-Upland), and Yachats Super Domains in Lincoln County.
The littoral cells in the coastal belts of Lane, Douglas, and Coos counties are characterized by barrier and mainland beach archetypes (Tables 5–7). The barrier beaches are typified by Barrier-Beach-Dune-Wetland (Ba-Be-Du-W) tetrasequent catenas that are followed landward by beach ridge, dune, or wetland archetypes, as seen in the Florence (Lane County), Reedsport (Douglas County), and Lakeside (Coos County) Super Domains. In these three counties, the combined barrier beach lengths make up about 46 km. When further combined with those in the Seaside and Rockaway Super Domains (29 and 26 km, respectively, in Clatsop and Tillamook counties), the total Barrier-Beach-Dune (Ba-Be-Du) trisequent catenary sequence increases to an approximately 123-km alongshore distance, or about 25% of the Oregon coastal belt.
Curry County is notable for its lack of large littoral cells and the dominating presence of rock archetypes that are followed landward by cliff and upland archetypes to produce the commonly occurring Rock-Cliff-Upland (R-Cl-U) trisequent catena, which is reproduced alongshore in the Port Orford and Brookings Super Domains (Table 8). Beach archetypes are present in the Langlois (9.5 km), Port Orford (24.5 km), Wedderburn (9 km), Sebastian (4.5 km), and Pistol River (5 km) Super Domains. However, Curry County is largely characterized by cliff archetypes that make up 86.5 km of alongshore distance, or 79% of the Curry County coastal belt.
Spatial Distribution of Archetypes and Frequency of Occurrence
Archetypes are unequally distributed along the Oregon coast and disproportionately occur along the shore in various types of cross-shore catenas. Tables 9–17 show the cross-shore dominant catenary sequence (DCS) by individual domain segments in relation to counties and the percentage distributions for the Oregon coastal belt. Comparisons of the percentage distributions of archetypes by county and for the total Oregon coastal belt are instructive and informative, because they highlight spatially dominant archetypes. The dominant catenary sequences (DCS) are analyzed by reference to individual domain segments in which the archetype of interest is present.
The barrier archetype is always followed landward by a beach-dune (Be-Du) couplet in a cross-shore catenary sequence that, in turn, may be followed by wetland, beach ridge, or upland archetypes (Table 9). The longest stretch of the barrier archetype occurs in Tillamook County, which is dominated by the Barrier-Beach-Dune-Wetland-Flat (Ba-Be-Du-W-F) pentasequent catenary sequence in Domains 3-3, 3-5, 3-7, and 3-11 (Figure 3), with the inclusion of 8 km of Barrier-Beach-Dune-Wetland-Upland (Ba-Be-Du-W-U) in Domain 3-12 that makes up 38 km of the alongshore length. This longest alongshore length makes up 46.2% of the Tillamook County coast and 7.4% of the Oregon coastal belt. The next longest stretch of the barrier archetype occurs in Coos County, where the archetype takes in 40% of the county coast and 5.8% of the Oregon coastal belt via Domains 7-1 through 7-4. The barrier archetype in Douglas County accounts for 100% of the county coast, with 28.5 km, and about 6.2% of the total Oregon coastal belt in Domains 6-1 through 6-4. Of all barrier archetypes along the Oregon coast, the shortest segment occurs in Lincoln County (Domain 4-7 in Figure 4), which makes up just 1% of the total Oregon coastal belt length. In these longer penta- or hexasequent concatenations, the barrier (Ba) codification often occurs in a serially preantepenultimate position.
The beach archetype occurs along the entire Oregon coast. In cross-shore catenary sequences, it is preceded by the barrier (Ba) archetype (i.e. Domains 2-1 to 2-4, 3-2 to 3-5, 3-11, 3-12, 4-7, 5-3 to 5-5, 6-1 to 6-4, and 7-1 to 7-4) or rock (R) archetype (i.e. Domains 2-6, 4-5, 7-5, 8-4, 8-6, and 8-11) or by ocean (i.e. Domains 2-7 to 2-9, 3-2 to 3-10, 4-1 to 4-3, 4-6 to 4-8, 5-1, 5-2, 6-4, 7-7 to 7-11, 8-1, 8-2, 8-8 to 8-10, and 8-12; Table 10). The beach archetype is mostly followed landward of the dune archetype, forming the familiar beach-dune (Be-Du) couplet, but sometimes there are no back-beach dunes and the cross-shore catenary sequence simply keys out to beach-cliff (Be-Cl), as in Domains 2-6, 4-5, 4-6, 4-8, and 8-4 to 8-8. The largest percentage of the Oregon coastal belt composed of the beach archetype (barrier beach and mainland beach cross-shore sequences) occurs in Tillamook County, taking up 14.2% of the total Oregon coast and 88% of the county coast. Mainland beaches are evident in Domains 2-7 to 2-9, 3-2, 3-4, 3-6, 3-8 to 3-10, 4-1 to 4-3, 4-8, 5-1, 5-2, 6-4, 7-7 to 7-11, 8-1, 8-2, 8-10, and 8-12. The greatest alongshore lengths of the beach archetype occur in Tillamook (88 km), Lincoln (68 km), and Coos (68 km) counties, which account for 14.2, 13.5, and 13.8%, respectively, of the Oregon coastal belt catenary sequences. The beach archetype dominates all coastal counties, with 80 to 100% frequency of occurrence except in Curry County. Here, beaches take up about 47% of the county coast but 10.3% of the total Oregon coastal belt, which is broadly similar to percentages in other counties.
Beach Ridge Archetype
Beach ridges along the Oregon coast almost always follow landward of Barrier-Beach-Dune (Ba-Be-Du) trisequent cross-shore catenas (e.g., Domains 2-2, 2-3, 5-3, 5-4, and 6-3). They sometimes follow a barrier–beach (Ba-Be) disequent cross-shore catena if there is no seaward dune, as in Domain 7-1, or in mainland beach setups, as in Domain 7-10 (Table 11). The longest stretch of the beach ridge archetype occurs in Clatsop County, where 21 km take up 40.5% of the county length and 4% of the total Oregon coastal belt. Beach ridges occupy 15 km in Lane County and 8.5 km each in Douglas and Coos counties.
The cliff archetype is most prevalent in Curry and Lincoln counties, where it takes up 79 and 65%, respectively, of those coastal belts. Curry County is the county of cliffs, with 86.5 km occurring in seaward association with rock (R) (Domains 8-3, 8-7, 8-9, and 8-13), beach (Be) (Domains 8-4, 8-6, 8-8, and 8-11), or ocean (Domain 8-5) as part of cross-shore catenary sequences. The cliff archetype is always followed landward by the upland archetype, as shown for Clatsop, Tillamook, Lincoln, Lane, Coos, and Curry counties (Table 12). Lincoln and Curry counties take up 11.3 and 17.3% of the total Oregon coastal belt and 65 and 79% of their respective county coastal belts.
The dune archetype is nearly ubiquitous along the Oregon coast, taking up 82.8% of Clatsop, 88% of Tillamook, 35% of Lincoln, 59% of Lane, 100% of Douglas, and 90% of Coos counties (Table 13). This archetype occurs in disequent to hexasequent cross-shore catenary sequences, making them commonplace eco-geomoprhological features along the Oregon coastal belt. Although a common alongshore phenomenon, dune archetypes are most spectacularly developed in Douglas and Coos counties. Dunes take up only 18.5 km of Curry County, which works out to 16% of a county coastal belt that is well known for its rock, cliff, and upland archetypes. Dunes occur in seaward cross-shore catenal associations with barrier (Ba), beach (Be), beach ridge (Br), and rock (R) viz. Domains 2-1 through 2-4, 2-7 through 2-9, 3-2 through 3-12, 4-1 through 4-3 and 4-7, 5-2 through 5-5, 6-1 through 6-4, 7-1 through 7-5 and 7-7 through 7-11, and 8-1, 8-2, and 8-10 (Table 13). In cross-shore catenary sequences, dunes are followed landward by beach ridge (Br) (e.g., Domains 2-2, 2-3, 5-3, 5-4, and 7-10), cliff (Cl) (e.g., 2-8), flat (F) (e.g., Domains 2-1, 4-2, 6-2, 7-3, 7-4, and 7-8), wetland (W) (e.g., Domains 2-4, 2-9, 3-2 to 3-5, 3-7 to 3-9, 3-11, 3-12, 4-7, 5-2, 5-4, 5-5, 6-1, 6-2, 7-2, 7-3, 7-11, and 8-1), and upland (U) (e.g., Domains 2-7, 3-6, 3-10, 4-1, 4-3, 6-4, 7-1, 7-5, 7-7, 7-9, 8-2, and 8-10) archetypes. The longest alongshore stretches of dune archetypes occur in Tillamook and Coos counties, with respective distances of 72 and 68 km and 88 and 90% of those coastal belts. Dune archetypes occupy 100% of Douglas County, but the alongshore distance is only about 28.5 km.
The flat archetype normally occurs as the last digit in a cross-shore concatenation, because that is usually the landwardmost extension of the codification process. These eco-geomorphological features may extend many kilometers inland from inlets via estuarine environments. Flats are normally associated with dune and beach ridge (e.g., Domains 2-2, 6-2, 7-3, 7-4, and 7-8) and with wetland (e.g., Domains 2-2, 3-3, 3-5, 3-7, 3-9, 3-11, 4-7, and 8-12) archetypes in cross-shore catenary sequences (Table 14). With an alongshore length of 33 km, the flat archetype takes up 40.4% of the Tillamook County coastal belt and 6.3% of the total Oregon coastal stretch. Flats occupying about 28.5 km in Douglas County (100% of the county length), taking up about 6.2% of the total Oregon coastal belt.
As the first digit in the cross-shore dominant catenary sequence (DCS), rock (R) although prevalent along much of the Oregon coastal belt, is most dominant in Lincoln and Curry counties, taking up about 26 and 69%, respectively, of those county coastal stretches (Table 15). Concatenations for the rock archetype mostly follow a Rock-Cliff-Upland (R-Cl-U) cross-shore sequence (e.g., Domains 2-5, 3-1, 3-13, 4-4, 4-9, 7-6, 8-3, 8-7, 8-9, and 8-13) but are sometimes followed landward by a beach archetype (e.g., Domains 2-6, 4-5, 7-5, 8-4, 8-6, and 8-11). Along the Oregon coast, the rock archetype is always associated landward by a concatenation that includes the upland archetype, as interpreted from major outcrops observed in satellite images. Smaller occurrences of rock outcrops not mapped here may be followed landward by other archetypes. The longest mostly continuous stretch of rock archetypes occurs in Curry County, which takes up about 15.7% of the total Oregon coastal belt. Data from Lincoln County report 22 km of rock outcrops that take up 26% of the county and 4.3% of the total Oregon coastal belt.
The upland archetype is ubiquitous along the Oregon coast and is commonly the last digit in cross-shore codifications, because this eco-geomorphological feature is usually the landward limit of coastal classification using the BCCS. Counties with the longest stretches of upland archetypes within a few kilometers of the coast and their lengths include Clatsop (80.8 km), Lincoln (93 km), and Curry (95 km) counties (Table 16). Other counties still have respectable alongshore stretches of upland and include Tillamook (48.1 km), Lane (82 km), Douglas (58 km), and Coos (57 km) counties. The largest upland percentages of the total Oregon coastal belt occur in Lincoln and Curry counties, with respective percentages of 15.8 and 21.1. The percentage of county coastal belts can be significant, ranging from 75% in Coos County to 80.8% in Clatsop County, 93% in Lincoln County, and 95% in Curry County. No matter how they are viewed, upland archetypes are common all along the Oregon coastal belt, reaching maximum alongshore extents in Curry County, with 105 km.
The upland archetype in most cross-shore catenary sequences is preceded seaward by cliff archetypes (e.g., Domains 2-5, 2-6, 2-8, 3-1, 3-13, 4-4 through 4-9, 5-1, 7-6, 8-3 through 8-9, 8-11, and 8-13). But other archetypes occur in penultimate digital slots in the BCCS codes, as in the cases of dunes (e.g., Domains 2-7, 3-6, 3-10, 4-1, 4-3, 6-4, 7-1, 7-5, 7-7, and 7-9) and wetlands (e.g., Domains 2-3, 2-4, 3-2, 3-4, 3-12, 5-2, 5-3, 6-1, 7-2, 7-11, and 8-1). Along steep-to coastal belts, the codification may be as simple as a cross-shore disequent catenary sequence of Cliff-Upland (Cl-U) (e.g., Domain 8-5) or more commonly a trisequent catenary sequence if there is rock rubble, scree, or talus at the cliff base (e.g., Domains 2-5, 3-1, 3-13, 4-4, 4-9, 7-6, 8-7, 8-9, and 8-13). The upland archetype may also be preceded by a Be-Du couplet at some locations, for example, in Domains 2-7, 3-6, 3-10, 4-1, 4-3, 7-7, 7-9, 8-2, and 8-10. In less commonly occurring situations, flat (F) or beach ridge (Br) archetypes may transition directly into uplands, as demonstrated in Domains 4-2 and 7-10.
The wetland archetype, which is a common component of cross-shore catenas in BCCS codifications, has the longest alongshore stretch in Tillamook County, where it takes up 62 km of the landwardmost stretches of the coastal belt in consociation with flats (F) (e.g., Domains 2-2, 3-3, 3-5, 3-7, 3-9, 3-11, 4-7, and 8-12) and uplands (U) (e.g., Domains 2-3, 2-4, 2-9, 3-2, 3-4, 3-12, 5-2, 5-3, 5-5, 6-1, 7-2, 7-11, and 8-1; Table 17). The highest percentage of the wetland archetype's total Oregon coastal belt occurs in Tillamook County at 12.2%, and it is 75.7% of the county coastal belt. Alongshore lengths of wetlands are similar in several counties, taking up about 28 km for Clatsop, 27 km for Lane, 24.5 km for Douglas, and 27 km for Coos counties. Lincoln and Curry counties show the shortest alongshore stretches of 6 and 12 km, respectively. The wetland archetype occurs in association with barrier beaches, with or without beach ridges and usually near dune archetypes (e.g., Domains 2-2 through 2-4, 3-3, 3-5, 3-7, 3-11, 3-12, 4-7, 5-3 through 5-5, 6-1 through 6-3, 7-2, and 7-3), as well as landward of mainland beaches (e.g., Domains 2-9, 3-2, 3-4, 3-8, 3-9, 5-2, 7-11, 8-1, and 8-12). Whether associated with barrier or mainland beach systems, the Oregon coast wetlands are almost always associated with the dune archetype, except in the case of Domain 8-12, where the wetland is interspersed between beach (Be) and flat (F) archetypes. Because the wetland archetype occurs inland from the shore, these ecogeomorphological features are found minimally in most cross-shore trisequent catenary sequences (e.g., Domains 3-8, 3-9, and 8-12) and more commonly in tetrasequent to hexasequent consociations (cf. Table 17).
Frequency Distribution of Alongshore Archetype Lengths
The beach archetype had the longest alongshore length of 381 km, which was closely followed by 377 km of the upland archetype, each accounting for about 76.5 and 75.8% of the total Oregon coastal belt (Table 18). The wetland archetype was also well represented in alongshore frequency, with 186.5 km, followed closely by cliff archetypes, with 174 km, each taking up about 37.5 and 34.8%, respectively, of the Oregon coast. With an alongshore distance of 143 km, the barrier archetype accounted for about 28.7% of Oregon coastal features. Dunes were also a prominent coastal archetype, accounting for about 57.4% of the total Oregon coastal belt with an alongshore distance of 287 km. The flat archetype was mostly associated with estuaries and accounted for about 20.8% of the Oregon coast length. The beach ridge archetype was the least common eco-geomorphological feature, accounting for about 10.3% of the Oregon coast with an alongshore spread of about 53 km. Rock outcrops in the classificatory form designated as the rock archetype accounted for 25.7% of the Oregon coastal belt with an alongshore spread of 127 km.
The sea-to-land successions of eco-geomorphological units make up cross-shore domains that have alongshore overlapping spreads. This alongshore overlap is illustrated in the Barrier-Beach-Dune-Wetland-Dune-Flat (Ba-Be-Du-W-Du-F) hexasequent catena of Domain 7-3 in Coos County. This kind of complex cross-shore catena, which is replicated elsewhere along the Oregon coast, is a reminder that the alongshore lengths of the eco-geomorphological units need to be summed in each domain to account for the total distance mapped and classified. Consequently, Table 18 shows that 1835.5 km of coastal Oregon were classified using the BCCS to ascribe unity of notation to catenary domains that have both cross-shore and alongshore measures. That is, because alongshore eco-geomorphological units are successional cross-shore, their frequency of occurrence is repetitious in catenal associations.
The state of Oregon coastal belt (western United States) was selected to test whether the Biophysical Cross-shore Classification System (BCCS) (Finkl and Makowski, 2020a) could be applied in both a cross-shore and an alongshore manner on a regional scale. The concept of a domain was applied as an alongshore classificatory sequence to accommodate cohesive coalescence of cross-shore bio-geomorphological and ecological interpretations. Individual domains were then amalgamated to form super domains, which grouped similar stretches of the coastal belt into consized units to characterize the general biophysical nature of that specific segment (adapted from Finkl and Makowski, 2021). However, some super domains contained a single domain when their cross-shore catena had a uniform alongshore classification, as in the case of some promontories that had a Rock-Cliff-Upland (R-Cl-U) sequenced codification (e.g., Domain 2-5 in Clatsop County, Domains 3-1 and 3-13 in Tillamook County, Domains 4-4 and 4-9 in Lincoln County, and Domain 7-6 in Coos County) or in long stretches of a Beach-Dune-Upland (Be-Du-U) sequenced codification (e.g., Domains 3-6 and 3-10 in Tillamook County and Domain 8-10 in Curry County). For simplification purposes, these singularities in alongshore county stretches were extensively uniform and long enough to call out as distinct super domains.
The resulting coastal classification maps of the Oregon coastal belt were based on the interpretation of satellite imagery and plotted as overlays on imagery for each county. In this way, each coastal county was subdivided into domains that were then consized into super domains to characterize longer coastal stretches. These procedures and resulting products in the form of satellite-based cartographical maps (Figures 2–8) and tabulated morphometrics (Tables 2–18) were not designed to provide an absolute catholic approach to coastal classification. Rather, this novel methodology is suggested as an additional or alternative technique for the classification of coastal environments by using codified sequences to identify a range of bio-geomorphological and ecological features on a regional scale.
The application of the BCCS to the Oregon coast in this study suggests the possibility of a wider scope along other coastal belts throughout the world. One of the advantages of using the BCCS on a regional scale is that it provides a basis for morphometric analyses that are useful for the comprehensive characterization of coastal belts. For example, the measure of individual bio-geomorphological and ecological features (i.e. archetypes) within specific domains provides beneficial data in the form of cross-shore sequencing (i.e. catenary associations) and alongshore distancing. As shown in Tables 2–18, information acquired based on domains can be assembled to show cross-shore catenary sequencing, alongshore lengths, percentages of county coastal belts, and the fraction of the total length of the Oregon coastal belt. This kind of information was heretofore not readily available and provides access to the breakdown of morphometric data either by county (Tables 2–8) or by archetype (Tables 9–18). Using the methods elucidated here (i.e. application of the BCCS with domains and super domains), it is possible to calculate alongshore lengths and frequency of occurrence of barrier (Ba), beach (Be), beach ridge (Br), cliff (Cl), dune (Du), flat (F), rock (R), upland (U), and wetland (W) archetypes for administrative units, such as counties or states. This kind of information has relevance to coastal researchers, specialists, and managers of all sorts, including biologists, ecologists, geographers, geologists, engineers, administrators, and stewards.
Another main advantage of the BCCS is the flexibility and open-endedness of the method, which allows new classification units to be added as required for different coastal belt settings. The plasticity of this classification system is scale dependent in relation to the resolution of the satellite imagery used, as well as the length and width of the coast being studied. In the example of the Oregon coastal belt, a nominal viewing scale of 20 km was found to be adequate for presentation of results, but working scales varied greatly depending on the degree of zooming in for detailed inspection of coastal features and boundary conditions. In the regional Oregon exemplar, only archetypes were applied to the cross-shore codifications, but other larger-scaled (smaller area) studies could allocate more detailed sub archetypes into the BCCS for more thorough descriptions of the coastal belts. Such a procedure might be amenable to the clarification of biophysical features and the presence of transition zones, which were identified in this study as a special type of alongshore domain. This could be resolved by using specific sub archetypes to simplify the intricacies of archetypical sequences by merging from one catenary association to another, as so commonly occurs on the margins of rocky promontories and headlands.
Morphometric analysis of the Oregon coastal belt was based on the recognition of domains representing homogenous cross-shore catenas that have alongshore spread. The resulting morphometrics proved to be beneficial in the description of coastal characteristics and allowed individual coastal segments to be compared and contrasted. The repetition of cross-shore catenary sequences was clearly evident along the Oregon coast, and their designation in domains provided a measure of frequency distributions in terms of alongshore spread in kilometers and percentages of county and state (Tables 2–8). Visualization of the coast in terms of domains permitted the tabulation of archetypes and archetypical sequences (Tables 9–17) so that it was possible to recognize, for example, alongshore extents of Barrier (143 km), Beach (381 km), Cliff (174 km), and Dune (287 km) archetypes and to calculate their percentage frequency of the entire Oregon coastal belt (cf. Table 18). On a regional scale, this kind of morphometric information could be tedious and difficult to obtain; however, this study shows an effective method for obtaining such analytics based on the BCCS cognitive interpretation of satellite imagery.
For smaller-scaled studies that cover larger coastal belt areas and longer stretches of the coast, the CBLC (Coastal Belt Linked Classification) could be appropriately applied as an adjunct to BCCS unit classifications, as previously suggested by Finkl and Makowski (2020d). In this Oregon coastal belt study, the offshore marine environments were all identified with the California Current Large Marine Ecosystem (LME3) (e.g., Sherman, Aquarone, and Adams, 2009), and all inland terrestrial environments were subsumed by the Central Pacific Northwest Coast Forests Ecoregion (ER351) (e.g., Bailey, 1998; Dinerstein et al., 2017). The entire study area occurred within the Marine West Coast climate belt (e.g., Peel, Finlayson, and McMahon, 2007) or a Mediterranean climate (Csa or Csb; e.g., Kottek et al., 2006), which occurs on the western continental coastal margins between 30 and 45° latitude.
Despite attempting to simplify complex coastal environments, this current method is not without difficulties. For example, proper application of this procedure requires an ability to interpret satellite images of coastal belts in a manner suggested by Finkl and Makowski (2020a,b,c,d, 2021), among others (e.g., Finkl and Makowski, 2019a,b; Finkl, Makowski, and Vollmer, 2014; Kelletat, Scheffers, and May, 2013; Klemas, 2014; Makowski, 2014; Makowski and Finkl, 2016; Makowski, Finkl, and Vollmer, 2015, 2016, 2017; Rasid and Pramanik, 1990; Richards and Jia, 1999; Schowengerdt, 1983; Wang et al., 2015). This is facilitated by the Google Earth Pro platform, which provides access to satellite imagery of the world's coasts and allows the application of the BCCS to theoretically take place anywhere. Another difficulty in applying this methodology occurs in the skill set required to identify cross-shore sequences while determining their alongshore extents. For example, determination of catenal sequence boundaries requires the identification of another adjacent domain that has a different geographical distribution. This task becomes vexing when one or more of the bio-geomorphological units in the cross-shore sequence terminate alongshore, thereby causing a boundary that is not easily delineated.
The identification of super domains can sometimes be frustrating or possibly be seen as problematic because they represent a simplification of coterminous domains into more readily comprehendible long stretches of coast. Depending on the nature of coastal environments, some alongshore stretches may be highly complex. This was evident in the classification of Tillamook County (Figure 3) and Lincoln County (Figure 4) during this study, where thirteen (13) individual domains were consized to seven (7) super domains and where nine (9) individual domains are consized to four (4) super domains, respectively. Conversely, there were cases where four (4) individual domains were consized to form one (1) all-encompassing super domain, as occurred in Douglas County (Figure 6). Whatever the number of individual domains required to formulate a super domain, the reduction or simplification process requires acceptance of variations within the super domain that are usually accounted for by the short alongshore distance of outlier domains. Conceptually, this process would be akin to the recognition of inclusions of unlike or dissimilar units within larger categories, as commonly seen in soil, geological, or ecological maps.
Lastly, the alongshore classification of coastal belts in terms of domains and super domains is posited as an alternative means of characterizing coastal environments. As seen in this study's example of the Oregon coast, cognitive recognition of cross-shore catenary sequences that have alongshore extents provides a novel approach to better understanding of the frequency distributions of bio-geomorphological and ecological features as interpreted from satellite imagery. Application of the Biophysical Cross-shore Classification System (BCCS) (Finkl and Makowski, 2020a) is not meant to replace existing coastal classifications but should be used to acquire a more comprehensive understanding of the spatial relationships among coastal archetypes that are so frequently recurring and interrelated. By carrying out a classification in this manner with both cross-shore and alongshore extents, one can obtain a clearer three-dimensional characterization of the coastal belt interface between land and sea.
The Biophysical Cross-shore Classification System (BCCS) (Finkl and Makowski, 2020a), a new alternative method of coastal classification, was applied to the 480-km-long Oregon coastal belt in an effort to show its applicability and flexibility in the regional alongshore characterization of coastal environments that were interpreted from satellite imagery. This study was predicated on the observation that cross-shore biogeomorphological and ecological features occur in repetitive catenal sequences called archetypes. Cross-shore archetypical sequences that have alongshore extents make up individual domains, which can be consized to characterize larger alongshore stretches in the form of super domains. The properties of domains and super domains can then be quantified morphometrically to deduce the alongshore extents of specific archetypes, such as barriers, beaches, beach ridges, cliffs, dunes, flats, rock, uplands, and wetlands. The example of the Oregon coastal belt was organized into sixty-four (64) domains and thirty (30) super domains, where overlapping shore-parallel archetypes amounted to an effective classification of 1835 km of coast. Surprisingly, the alongshore classification of the Oregon coastal belt, along with associated morphometric analyses, showed that approximately 143 km of barrier archetypes took up around 28.7% of the total state coastal belt. Alongshore beach, dune, and upland archetypes took up 76.5, 57.4, and 75.8%, respectively, of the coast as overlapping shore-parallel bio-geomorphological and ecological features. It was concluded that the BCCS is amenable to the morphometrication of coastal belts while providing cogent and succinct descriptions in codified form that provide informative three-dimensional characterizations of cross-shore sequences with alongshore extents.