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U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2008–5059

Estimated Depth to Ground Water and Configuration of the Water Table in the Portland, Oregon Area

Prepared in cooperation with the City of Portland, the City of Gresham, Clackamas County’s Water Environment Services, and Multnomah County

By Daniel T. Snyder

Download PDF (8.5 MB)

Plates

Plate 1. Map showing estimated depth to ground water in the Portland, Oregon area. (PDF, 21.4 MB, Revised 12-31-08)

Plate 2. Map showing estimated water-table elevation in the Portland, Oregon area. (PDF, 25.4 MB, Revised 12-31-08)

Plate 3. Map showing relative uncertainty of the estimated water-table position in the Portland, Oregon area. (PDF, 22.2 MB)

Figures

Figure 1. Location of the study area in the Portland Basin in northwestern Oregon.

Figure 2. Occurrence of ground water, the position of the water table, and the relation between depth-to-water table and water-table elevation.

Figure 3. Location of publicly owned underground injection control systems in the Portland, Oregon area, 2008.

Figure 4. Comparison of hydrogeologic unit terminology for the Portland Basin, Oregon.

Figure 5. Procedures used to develop depth-to-water and water-table elevation maps.

Figure 6. Water-level measurements reported in well-construction records and by the U.S. Geological Survey.

Figure 7. Location of wells, springs, and surface-water features used in the interpolation of the water-table position in the Portland, Oregon area.

Figure 8. Averaged interpolation of the water-table position based on interpolations of depth to water table and water-table elevation.

Figure 9. Semivariogram analysis for depth to water, water-table elevation, and water-table elevation residuals after subtraction of quadratic trend.

Figure 10. Seasonal water-table fluctuations in the Portland, Oregon area.

Figure 11. Estimated seasonal water-table fluctuations by hydrogeologic unit in the Portland, Oregon area.

Tables

Table 1. Semivariogram and kriging parameters used for interpolation of depth to water and water-table elevation.

Table 2. Effective porosity and seasonal water-table fluctuations by hydrogeologic unit in the Portland, Oregon area.

This report is available online in Portable Document Format (PDF). If you do not have the Adobe Reader, it is available for free download from Adobe Systems Incorporated.

- New Interactive Map allows users to find the approximate depth to the water table at any location in the Portland area simply by clicking a point on the map or entering an address.

Document Accessibility: Adobe Systems Incorporated has information about PDFs and the visually impaired. This information provides tools to help make PDF files accessible. These tools convert Adobe PDF documents into HTML or ASCII text, which then can be read by a number of common screen-reading programs that synthesize text as audible speech. In addition, an accessible version of Acrobat Reader 7.0 for Windows (English only), which contains support for screen readers, is available. These tools and the accessible reader may be obtained free from Adobe at Adobe Access.

Send questions or comments about this report to the Groundwater specialist.

For more information about USGS activities in Oregon, visit the USGS Oregon Water Science Center home page.