T252 Landslide Inventories, Databases, Hazard Maps, Risk Analysis, and Beyond (Posters)

Tuesday, 24 October 2017
9:00 AM - 6:30 PM
Halls 4EF

NECESSARY INTEGRATION OF GEOLOGIC INFORMATION INTO SHORELINE POLICIES

Paper number: T252-13
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

A recent round of grant funding from the U.S. Environmental Protection Agency, administered by the Washington State Dept. of Fish and Wildlife, and awarded to several Puget Sound-adjacent counties and one conservation district, resulted in the launching of five “Shore Friendly” programs around the region. One of those, the Mason Conservation District’s “Shore Friendly Mason” program, fields requests for technical assistance from landowners with shoreline erosion concerns. The erosion is typically assumed by the landowner to be wave-induced and is a common trigger for shoreline armor permit requests.

The Shore Friendly Mason team (consisting of an environmental specialist, an engineer, and a geologist) found that a sizeable percentage of sites with unstable bluffs or banks had symptoms of broader hydrogeologic instability. Review of high-resolution lidar imagery, geologic mapping, and water-well data, in conjunction with site visits conducted to evaluate drainage infrastructure, vegetation management, and other land-use practices, highlight the frequency of upland causes of instability. At several sites, the unstable low bank defined the toe of a deep-seated landslide. Discussions with shoreline planners elsewhere in Puget Sound reveal similar landowner misperceptions and permitting challenges surrounding hydrogeologic processes.

The number of sites showcasing these concerns speak to the need for increased availability of geologic tools to inform the public, development/permit processes, and geotechnical reporting. Identified hurdles include gaps in landslide mapping coverage, funding uncertainties, challenges of transferring GIS-based geologic and landslide data into user-friendly jurisdictional planning tools, and restructuring Critical Areas Ordinances and Shoreline Management Plans to incorporate new data. Urgency to overcome these hurdles increases with growing development pressures and potential liabilities associated with geologic hazard areas.

Collaboration with staff in several Puget Sound counties is underway to improve geologic information accessibility and develop methods for incorporating it into planning and permitting policies and public education. Stakeholder advisory groups and 3rd-party geotechnical peer review pools would further benefit this effort.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-304988

© Copyright 2017 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.