Sensitive Groundwater Program
Marion County 's Sensitive Groundwater Overlay (SGO) program was created to implement groundwater resource goals and policies of the Comprehensive Plan. Marion County Code 17.181 (Sensitive Groundwater Overlay Zone) implements this program by reviewing land use applications. The risk that a proposal will adversely affect the sustainability of aquifer production in a specific area is assessed. This program is not intended as a guarantee of an adequate water supply at a particular location. It is also not a guarantee that any existing well will continue to provide adequate water.
The following are links to information and documents related to the Sensitive Groundwater Overlay program:
Map of the Sensitive Groundwater Overlay Zone
Marion County Code Chapter 17.181 - Sensitive Groundwater Overlay Zone
For certain development, Chapter 181 requires evidence of the long-term sustainability of groundwater resources in the vicinity. Partitions, subdivisions and non-residential development proposed within the SGO boundaries using water from non-exempt wells must comply with Chapter 17.181.
Marion County provides the "Hydrogeology Reviews and Studies Manual " to expand upon the Zone Code requirements. It also provides a format for registered geologists and engineering geologists to complete required analyses and reports.
The following are samples of maps and diagrams mentioned in the Hydrogeology Reviews and Studies Manual that may be required.
Sample Complete SGO Study Area Map
Sample Site and Cross Section Location Map
Sample Regional Geologic Map
Sample Well and Cross Section Locations
Sample Water Rights Diagram
Sample Point to Point Cross Section
List of current participating hydrogeologists
Marion County Hydrogeologic Report Peer Review Application
Marion County's "Water Plan"
Our program is based on the "Geologic and Hydrogeologic Study of the Residential Acreage-Zoned Areas of Marion County ..." . It was prepared in 1997 by Northwest Geological Services, Inc. This study compiled existing groundwater and geologic studies for a 144 square mile area of Marion County. The purpose of the study was to evaluate areas zoned Acreage Residential that obtained water from aquifers in the Columbia River Basalt. The Study then identified:
- the amount of groundwater resource presently consumed;
- additional resource available for future development;
- areas where groundwater was being depleted;
- areas where groundwater could be depleted by approved build out; and
- limitations necessary to protect the resource for current residents.
This is a very large document with large-sized maps and diagrams. Contact our office if you would like to obtain a copy of the plan or associated exhibits, maps, etc.
Links to Other Water Resource Related Information
State of Oregon Water Resources Department -well logs, water rights, maps, consumer publications.
Water Quality Division,
- watersheds, searchable water quality database, well owner information, etc.
Oregon Health Authority - groundwater protection, drinking water, and consumer protection.