Coastal erosion hazard zones along the Clatsop Plains, Oregon: Gearhart to Fort Stevens

Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator:
J.C. Allan, Oregon Department of Geology and Mineral Industries
Originator:
G.R. Priest, Oregon Department of Geology and Mineral Industries
Publication_Date: 20011231
Publication_Time: Unknown
Title:
Coastal erosion hazard zones along the Clatsop Plains, Oregon: Gearhart to Fort Stevens
Edition: Preliminary
Geospatial_Data_Presentation_Form: vector digital data
Series_Information:
Series_Name: Open File Report
Issue_Identification: O-01-04
Publication_Information:
Publication_Place: Portland, Oregon
Publisher:
Oregon Department of Geology and Mineral Industries
Other_Citation_Details: A text accompanies the vector digital data
Online_Linkage: www.oregongeology.com
Description:
Abstract:
This report describes and documents a range of coastal hazard zones distinguished for the Clatsop Plains. In particular, the report focuses on identifying maximum potential erosion distances for dune-backed shorelines using the geometric model developed by Komar and others (1999). Four hazard zones have been identified for the Clatsop Plains, an active hazard zone characterized by existing, active erosion processes, and three zones of potential future erosion, high, moderate, and low risk zones that respectively depict decreasing risks of becoming active in the future. Of most interest to planners are the landward boundaries of the high and low risk zones. The landward boundary of the high-risk zone defines a conservative but reasonable limit of expansion of the active hazard zone in the next 60-100 years. The landward boundary of the low-risk zone defines the outermost limit of expansion of the active hazard zone associated with a catastrophic event such as a great earthquake on the Cascadia subduction zone, coupled with severe storms. 0Hazard zones were determined along the Clatsop Planes using a geometric model developed by Komar and others (1999), whereby property erosion occurs when the total water level produced by the combined effect of extreme wave runup (R) plus the tidal elevation (ET), exceeds some critical elevation of the fronting beach, typically the elevation of the beach-dune junction (EJ). Three scenarios were used to model erosion hazard zones on dune-backed beaches: 1Scenario 1 (HIGH-risk). This scenario is based on a large storm wave event (wave heights ~47.6 ft high) occurring over the cycle of an above average high tide, coincident with a 3.3 ft storm surge. Under this scenario, the designated HIGH-risk hazard zone was estimated to be 360 ft, while individual beach sites may vary by a much as 243 ft to 522 ft due to subtle differences in the character of the beach (beach slope and beach/dune junction) The following two scenarios (MODERATE and LOW-risk events) are one of two "worst case" events identified for the Clatsop coastline. Both scenarios have low probabilities of occurrence. Scenario 2 (MODERATE-risk). This scenario is based on an extremely severe storm event (waves ~52.5 ft high) coupled with a large storm surge of 5.6 ft. Under this particular scenario, the maximum potential erosion distances (MPED) vary considerably, with an average MPED that ranged from 390 to 825 ft, while the designated width of the moderate hazard zone was established at 572 ft. Scenario 3 (LOW-risk). This scenario is similar to scenario 2 above but incorporates a 3.3 ft vertical lowering of the coast as a result of a Cascadia subduction zone earthquake. MPED estimated for scenario 3 ranged from 424 to 938 ft, while the designated width of the low hazard zone was established at 635 ft.
Purpose:
To delineate a range of coastal hazard zones along the Clatsop Plains, Oregon: Gearhart to Fort Stevens
Supplemental_Information:
Digital map data files include: digital shorelines - shoreline_187x, _1926, _195x, _1995, _1997, _1998, _1999; hazard zones - active hazard zone, high hazard zone, low hazard zone, moderate hazard zone, clatsop plains beach data.
Time_Period_of_Content:
Currentness_Reference: ground condition
Status:
Progress: In work
Maintenance_and_Update_Frequency: Final report late 2002
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -124.09
East_Bounding_Coordinate: -123.907
North_Bounding_Coordinate: 46.9656
South_Bounding_Coordinate: 46.2418
Keywords:
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: Geology
Theme_Keyword: coastal erosion hazard
Place:
Place_Keyword_Thesaurus: None
Place_Keyword: Oregon
Place_Keyword: Clatsop County
Stratum:
Stratum_Keyword_Thesaurus: None
Temporal:
Temporal_Keyword_Thesaurus: None
Access_Constraints: None
Use_Constraints:
This regional investigation is not intended for use as a site-specific analysis tool. It can be used to identify areas in need of more detailed site-specific geotechnical studies.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Jonathan C. Allan
Contact_Organization:
Oregon Department of Geology and Mineral Industries
Contact_Position: Coastal geomorphologist
Contact_Address:
Address_Type: mailing and physical address
Address: 313 SW 2nd, Suite D
City: Newport
State_or_Province: Oregon
Postal_Code: 97365
Country: USA
Contact_Voice_Telephone: 541 574-6642
Contact_Facsimile_Telephone: 541 265-5241
Browse_Graphic:
Browse_Graphic_File_Name: OFR01-04text
Browse_Graphic_File_Description:
PDF representation of explanatory text accompanying digital map data.
Browse_Graphic_File_Type: PDF
Data_Set_Credit: Jonathan C. Allan
Security_Information:
Security_Classification_System: None
Security_Classification: Unclassified
Security_Handling_Description: None
Native_Data_Set_Environment: MapInfo GIS v 6.0
Data_Quality_Information:
Completeness_Report:
The data set is complete for meeting the requirements of the contract with Clatsop County.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Horizontal_Positional_Accuracy:
Quantitative_Horizontal_Positional_Accuracy_Assessment:
Horizontal_Positional_Accuracy_Value:
±33 feet for the eastern side of the polygons; ±40 feet for the western side
Horizontal_Positional_Accuracy_Explanation:
Eastern side of polygons: standard error for 1:12,000-scale USGS digital orthophoto quadrangles used for plotting. Western side of polygons: standard error for 1:24,000-scale USGS digital raster graphic quadrangles used for shoreline position. 2.4.2.2.1 Vertical Positional Accuracy Value: Varies depending on contour interval for the respective USGS topographic quadrangle. 2.4.2.2.2 Vertical Positional Accuracy Explanation: This maximum vertical positional error is one contour on the respective USGS quadrangle.
Lineage:
Source_Information:
Source_Citation:
Source_Scale_Denominator: 12000
Type_of_Source_Media: digital orthophoto quadrangle
Source_Time_Period_of_Content:
Source_Information:
Source_Citation:
Source_Scale_Denominator: 24000
Type_of_Source_Media: Digital raster graphic
Source_Time_Period_of_Content:
Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Vector
Point_and_Vector_Object_Information:
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: G-Polygon
SDTS_Point_and_Vector_Object_Type: Entity point
SDTS_Point_and_Vector_Object_Type: Point
SDTS_Point_and_Vector_Object_Type: Network chain, planar graph
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Grid_Coordinate_System:
Grid_Coordinate_System_Name:
Universal_Transverse_Mercator:
Universal_Transverse_Mercator:
UTM_Zone_Number: 10
Transverse_Mercator:
Longitude_of_Central_Meridian: -123
Latitude_of_Projection_Origin: 0
False_Easting: 500000
False_Northing: 0
Scale_Factor_at_Central_Meridian: .9996
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:
Abscissa_Resolution: .01
Ordinate_Resolution: .01
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1927
Ellipsoid_Name: Clarke 1866
Semi-major_Axis: 6378206.4
Denominator_of_Flattening_Ratio: 294.98
Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview:
See accompanying text for a discussion and explanation of digital map data attributes.
Entity_and_Attribute_Detail_Citation:
Oregon Department of Geology and Mineral Industries Open File Report O-01-04
Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Nature of the Northwest Info Center (NNWIC)
Contact_Person: Donald Haines
Contact_Position: manager
Contact_Address:
Address_Type: mailing and physical address
Address: 800 NE Oregon Street
City: Portland
State_or_Province: OR
Postal_Code: 97232
Country: USA
Contact_Voice_Telephone: 503/872-2750
Contact_TDD/TTY_Telephone: unavailable
Contact_Facsimile_Telephone: 503/731-4066
Contact_Electronic_Mail_Address: http://www.naturenw.org
Hours_of_Service: 9:00 a.m. to 5:00 p.m. Monday Through Friday
Resource_Description:
Oregon Department of Geology and Mineral Industries Open File Report O-04-01
Distribution_Liability:
Although these data have been processed successfully on a computer system at the Oregon Department of Geology and Mineral Industries (DOGAMI), no warranty expressed or implied is made regarding the accuracy or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. It is strongly recommended that these data are directly acquired from DOGAMI, and not indirectly through other sources which may have changed the data in some way. It is also strongly recommended that careful attention be paid to the contents of the metadata file associated with these data. The Oregon Department of Geology and Mineral Industries shall not be held liable for improper or incorrect use of the data described and/or contained herein.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: MapInfo .tab and .mif/.mid
Format_Version_Number: ver. 6.0
Format_Specification: None
Format_Information_Content: MapInfo native and interchange files
File_Decompression_Technique: No compression applied
Digital_Transfer_Option:
Offline_Option:
Offline_Media: CD-ROM
Compatibility_Information: None
Fees: $10
Custom_Order_Process: None
Technical_Prerequisites: None
Metadata_Reference_Information:
Metadata_Date: 20011231
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Paul Staub
Contact_Organization:
Oregon Department of Geology and Mineral Industries
Contact_Position: Spatial Data Specialist
Contact_Address:
Address_Type: mailing address
Address: Suite 965
Address: 800 NE Oregon Street
City: Portland
State_or_Province: Oregon
Postal_Code: 97232
Country: USA
Contact_Voice_Telephone: 503/731-4100 x224
Contact_Facsimile_Telephone: 503/731-4066
Contact_Electronic_Mail_Address: Paul.Staub@state.or.us
Metadata_Time_Convention:
Metadata_Access_Constraints: None
Metadata_Use_Constraints: None
Metadata_Security_Information:
Metadata_Security_Classification_System: None
Metadata_Security_Classification: Unclassified
Metadata_Security_Handling_Description: None
Generated by mp on Mon Dec 17 10:56:29 2001