Geologic Hazards Overlay (OZ-2)

Background: 2019 – 2024

The 2019 Wasco County Multi-Jurisdiction Natural Hazard Mitigation Plan (NHMP) included a proposed Action Item for Landslide Hazards, to update the County Landslide Ordinance. Currently, landslide hazards development standards are found in the Geologic Hazards Overlay (OZ-2), formally the Environmental Protection District #2 – Geologic Hazard Overlay Zone, which is Section 3.720 in the Wasco County Land Use and Development Ordinance (WC-LUDO). The purpose of the Geologic Hazards Overlay District is to protect the public health, safety and welfare by establishing standards and requirements for the use and development of land within landslide hazard areas by assuring that development in hazardous or potentially hazardous areas is appropriately planned to mitigate the threat to life and property.

In 2020, Wasco County, partnering with the Oregon Department of Geology and Mineral Industries (DOGAMI), was awarded a Landslide Study Grant by the Federal Emergency Management Agency (FEMA), to update the landslide hazard and risk data and analysis. The study area was limited to the following portion of Wasco County (outlined in red):

In 2023, the study concluded and DOGAMI issued its report LANDSLIDE INVENTORY AND RISK REDUCTION OF THE NORTH AND CENTRAL PORTIONS OF WASCO COUNTY, OREGON. Staff has since worked to update Wasco County’s Landslide Hazards Overlay Zone (OZ-2) code.

Existing Requirements

The current (OZ-2) code does not allow for Ministerial Type-I reviews (less expensive & less time consuming), as all development review requests within the mapped landslide hazard area are all increased to a Type-II Subject to Standard Review, and requires a written Engineering Geologic Report or a Geotechnical Report by a licensed Certified Engineering Geologist (CEG) or a Geotechnical Engineer (GE) registered in the State of Oregon.

Proposed Updates

(LINK TO PROPOSED REVISIONS)

Proposed language will allow for requests to be processed at the same review level as listed in the underlying zone, meaning that Ministerial Type-I requests will no longer be required to be processed as a Type-II Subject to Standards Review.

Agricultural & Accessory Structures

Certain Agricultural Structure and Accessory Structure (Including additions/alterations/restoration/relocation/replacement of existing agricultural/accessory structures) applications will not require a Geologic/Geotechnical Reports, as long as the owner agrees to and can achieve the following:

• The face and footing of proposed structure shall avoid slopes in excess of 33.3%;
• A Geologic Hazard Mitigation Standards Self Certification Form shall be completed, signed, and included with the application; and
• A self-certification form agreeing with Geologic Hazard Area Development Standards shall be recorded with the Wasco County Clerk prior to receiving zoning approval on the building permit application.

Residential, Commercial & Industrial, Public Use & Private or Public Club, and Other Structures

All requested agricultural/accessory structures that don’t meet the requirements above, as well as Residential, Commercial & Industrial, Public Use & Private or Public Club, and Other Structures (Includes conversion of an existing building to these uses), will continue requiring an Engineering Geologic Report or a Geotechnical Report from a licensed CEG or GE detailing building site conditions and recommendations, accompany all applications.

Additionally, a Geologic Hazard Mitigation Standards Self Certification Form shall be completed, signed, and included with the application documents. Within this form, the owner guarantees that the recommendations provided within the submitted Engineering Geologic Report or Geotechnical Report shall be achieved within one year of receiving land use approval on the building permit application and maintained throughout the life of the use or development.

Preliminary Subdivisions

In addition to the Geologic Hazard Mitigation Standards Self Certification Form, proposed subdivisions within designated landslide hazard areas must be accompanied by an Engineering Geologic Report or a Geotechnical Report that illustrates the location of any environmental hazard areas that are unsuitable for building purposes, or lands subject to mass movement, excessive erosion, or similar natural phenomena.

NOTE: If the requested development is Type-II or higher, the applicable Geologic Hazard Area Development standards will be applied through conditions of approval in the Notice of Decision.