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Layer: Beaches and Dunes Overlay Zone (ID: 0)

Name: Beaches and Dunes Overlay Zone

Display Field: Codes

Type: Feature Layer

Geometry Type: esriGeometryPolygon

Description: The objective of this study has been to produce updated information on the spatial extent of beaches and dunes in Tillamook County that may be subject to existing and future storm-induced wave erosion, runup, overtopping and coastal flooding. These data are of importance to the Department of Land Conservation and Development and the seven coastal counties of Oregon in order to implement Statewide Planning Goal 18: Beaches and Dunes. Oregon Statewide Planning Goal 18 requires local jurisdictions adopt a beach and dune overlay zone in their comprehensive plan, which may be used to manage development on or near beaches and dunes. Regional mapping of the coastal geomorphology of the Oregon coast to define the extent of its beaches and dunes were originally undertaken between 1972 and 1975 by the US Department of Agriculture Soil Conservation Service (USDA, 1975). However, in the intervening 45 years, much has changed on the coast resulting in lasting changes to the coastal geomorphology of Oregon. Of particular importance has been the proliferation of European beach grasses that have helped stabilize many coastal dune systems, while many areas of the Tillamook County coastline have experienced significant erosion, especially since the late 1970s. These two factors alone require that the USDA (1975) overlay zone be updated to reflect contemporary conditions. As a result of the updated mapping, our analyses indicate the following broad-scale changes: Overall, areas defined as open sand (OS) have decreased by about ~67% since the 1970s, from 2335 acres to 767 acres. Most of this change can be directly attributed to anthropogenic effects, particularly the introduction of European beach grass (Ammophila arenaria) as well as stabilization from shore Pine (Pinus contorta) and other native plant species; Areas subject to exiting coastal hazards, which includes active foredunes (FDA) and new in 2020, reactivated foredunes (FDR), indicate an overall slight increase in their spatial extent. However, within discrete sections of the littoral cells, some areas have experienced significant loss of active foredunes, including the Rockaway Beach area, followed by Nestuicca Spit and Nehalem Spit; and, Areas classified as recently stabilized foredunes (FD) have seen a significant expansion (~45% increase) in spatial coverage, increasing from ~287 acres in the 1970s to ~522 acres in 2020. Consistent with the changes seen on active foredunes, the increase in stabilized foredunes can be attributed to the proliferation of dune grasses and other native trees and shrubs.

Service Item Id: 92504dbf29aa4b9ca13767dbb80651ff

Copyright Text: This project was funded under award #17054 by the Oregon Coastal Management Program (OCMP) of the Department of Land Conservation and Development agency

Default Visibility: false

MaxRecordCount: 1000

Supported Query Formats: JSON, geoJSON

Min Scale: 0

Max Scale: 0

Supports Advanced Queries: true

Supports Statistics: true

Has Labels: false

Can Modify Layer: true

Can Scale Symbols: false

Use Standardized Queries: true

Supports Datum Transformation: true

Extent:
Drawing Info: Advanced Query Capabilities:
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HasM: false

Has Attachments: false

HTML Popup Type: esriServerHTMLPopupTypeAsHTMLText

Type ID Field: null

Fields:
Supported Operations:   Query   Query Attachments   Generate Renderer   Return Updates

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