This data is maintained by and obtained from Metro Data Resource Center. Please go to http://rlisdiscovery.oregonmetro.gov/metadataviewer/display.cfm?meta_layer_id=123 for the complete metadata.

--Additional Information: Category: Boundary Purpose: No purpose information available. Update Frequency: Unknown

© City of Portland, Oregon

This data is maintained by and obtained from Metro GIS. Click the link above to view the Metro GIS metadata for this dataset.

This data is maintained by and obtained from Metro Data Resource Center. Please go to https://gis.oregonmetro.gov/rlis-metadata/#/details/155 for the complete metadata.-- Additional Information: Category: Boundary Purpose: For use as a "base" layer on map products to shade county areas and in analysis to capture areas within each county. Update Frequency: None planned-- Metadata Link: https://www.portlandmaps.com/metadata/index.cfm?&action=DisplayLayer&LayerID=155

Scoggins Dam in northwest Oregon lies within the Gales Creek fault zone (GCF), a northwest-striking system of active faults forming the boundary between the Coast Range and the Tualatin Valley about 25 km east of Portland, Oregon. Geologic mapping published in 2020 shows the dam to lie within a block-faulted releasing stepover between the right-lateral, NW-striking Scoggins Creek and Parsons Creek strands of the GCF. The Scoggins Creek strand is presently mapped beneath the existing dam about 200 m north of the south abutment. Preliminary results from paleoseismic trenching by the U.S. Bureau of Reclamation, Portland State University, and the U.S. Geological Survey indicate that these two major fault strands have had multiple surface rupturing earthquakes in the Holocene. To confirm the accuracy of the 2020 geologic map and the geometry of the GCF in the releasing stepover region, we completed additional geologic mapping of the dam, reservoir, and an alternative dam site downstream between July 2018 and May 2020. Using high-resolution lidar topographic data and satellite imagery on handheld digital tablets, we collected data at ~500 field sites in the heavily forested terrain. We used these detailed field observations to locate and digitally map the main Scoggins Creek and Parsons Creek fault strands, as well as the cross faults linking the two main strands, to produce an improved and more detailed geologic map and cross sections of Scoggins Valley and its existing and proposed dam sites.

Street trees mapped and identified by Portland Parks & Recreation's Urban Forestry division

--Additional Information: Category: Parks Purpose: No purpose information available. Update Frequency: Annually

© City of Portland, Oregon

This layer is sourced from CGIS Open Data.

Area in which urban services are provided by the City of Portland. This includes some parts of Washington, Clackamas, and unincorporated Multnomah County.-- Additional Information: Category: Boundary Purpose: For mapping and analysis of areas where urban services are provided by the City of Portland. Update Frequency: Quarterly-- Metadata Link: https://www.portlandmaps.com/metadata/index.cfm?&action=DisplayLayer&LayerID=52201

The basis for these features is U.S. Geological Survey Scientific Investigation Report 2017-5024 Flood Inundation Mapping Data for Johnson Creek near Sycamore, Oregon. The domain of the HEC-RAS hydraulic model is a 12.9 mile reach of Johnson Creek from just upstream of SE 174th Avenue in Portland, Oregon to its confluence with the Willamette River. Some of the hydraulics used in the model were taken from Federal Emergency Management Agency, 2010, Flood Insurance Study, City of Portland, Oregon, Multnomah, Clackamas and Washington Counties, Volume 1 of 3, November 26, 2010. The Digital Elevation Model (DEM) utilized for the project was developed from LiDAR data flown in 2015 and provided by the Oregon Department of Geology and Mineral Industries. Bridge decks are generally removed from DEMs as standard practice. Therefore, these features may be shown as inundated when they are not. Judgement should be used when estimating the usefulness of a bridge during flood flow. Comparing the bridge to the surrounding ground can be more informative in this respect than simply looking at the bridge itself. Two model plans were used in the creation of the flood layers. The first is a stable model plan using unsteady flow in which the maximum streamflow is held in place for a long period of time (a number of days) in order to replicate a steady model using an unsteady plan. The stable model plan produced the areas of uncertainty contained in the sycor_breach.shp shapefile. The second is an unstable model plan that uses unsteady flow in which the full hydrograph (rising and falling limb) is represented based on the hydrograph shape of the December 2015 peak annual flood. The unstable model plan produced the flood extent polygons contained in the sycor.shp shapefile and the depth rasters and represents the best estimate of flood inundation for the given streamflow at U.S. Geological Survey streamgage 14211500.

This is a 10 meter Hillshade file created by Metro from USGS DEM data provided by the BLM. It covers the 3-county area (Washington, Multnomah, and Clackamas Counties). Date of last data update: 2004 This is official RLIS data. Contact Person: Joe Gordon joe.gordon@oregonmetro.gov 503-797-1587 RLIS Metadata Viewer: https://gis.oregonmetro.gov/rlis-metadata/#/details/2162 RLIS Terms of Use: https://rlisdiscovery.oregonmetro.gov/pages/terms-of-use

This data layer is an element of the Oregon GIS Framework. The TIGER/Line shapefiles and related database files (.dbf) are an extract of selected geographic and cartographic information from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). The MTDB represents a seamless national file with no overlaps or gaps between parts, however, each TIGER/Line shapefile is designed to stand alone as an independent data set, or they can be combined to cover the entire nation.

Census tracts are small, relatively permanent statistical subdivisions of a county or equivalent entity, and were defined by local participants as part of the 2020 Census Participant Statistical Areas Program. The Census Bureau delineated the census tracts in situations where no local participant existed or where all the potential participants declined to participate. The primary purpose of census tracts is to provide a stable set of geographic units for the presentation of census data and comparison back to previous decennial censuses. Census tracts generally have a population size between 1,200 and 8,000 people, with an optimum size of 4,000 people. When first delineated, census tracts were designed to be homogeneous with respect to population characteristics, economic status, and living conditions. The spatial size of census tracts varies widely depending on the density of settlement. Physical changes in street patterns caused by highway construction, new development, and so forth, may require boundary revisions. In addition, census tracts occasionally are split due to population growth, or combined as a result of substantial population decline. Census tract boundaries generally follow visible and identifiable features. They may follow legal boundaries such as minor civil division (MCD) or incorporated place boundaries in some States and situations to allow for census tract-to-governmental unit relationships where the governmental boundaries tend to remain unchanged between censuses. State and county boundaries always are census tract boundaries in the standard census geographic hierarchy. In a few rare instances, a census tract may consist of noncontiguous areas. These noncontiguous areas may occur where the census tracts are coextensive with all or parts of legal entities that are themselves noncontiguous. For the 2010 Census and beyond, the census tract code range of 9400 through 9499 was enforced for census tracts that include a majority American Indian population according to Census 2000 data and/or their area was primarily covered by federally recognized American Indian reservations and/or off-reservation trust lands; the code range 9800 through 9899 was enforced for those census tracts that contained little or no population and represented a relatively large special land use area such as a National Park, military installation, or a business/industrial park; and the code range 9900 through 9998 was enforced for those census tracts that contained only water area, no land area.

County tax assessors tax lots, including rights of way, with associated property data, excluding ownership information. Selected items from each county assessor's file are included and standardized for all three counties. The tax lot spatial features and data associated with the tax lot are compiled by Metro from existing records created and maintained by the local county assessment and taxation offices. This is a downloadable zip file that includes the taxlots shapefile and layer files for visualizing taxlots with or without right of ways. Use the original feature layers if viewing the layers in ArcGIS Online: "Taxlots (Public)" or "Taxlots with Right of Way (Public)." Date of last data update: 2025-10-17 This is official RLIS data. Contact Person: Christine Rutan christine.rutan@oregonmetro.gov 503-797-1669 RLIS Metadata Viewer: https://gis.oregonmetro.gov/rlis-metadata/#/details/3733 RLIS Terms of Use: https://rlisdiscovery.oregonmetro.gov/pages/terms-of-use

This dataset contains polygons representing deposits of hyaloclastic debris that were generated between about 3.5 and 3.0 million years ago when a series of basaltic lava flows entered the canyon of the ancestral Columbia River. The lava flows were erupted from volcanoes in the area of the Hood River graben of McClaughry and others (2012), generally have low-potassium tholeiitic basalt composition, and were part of a widespread pulse of mafic volcanism in the northern Oregon Cascade Range that occurred between about 4.4 and 2.1 million years ago (Conrey and others, 1996). Lava flows that entered the ancestral Columbia River were rapidly chilled and fragmented during interaction with water (Trimble, 1963, Swanson, 1986; McClaughry and others, 2012). The voluminous hyaloclastic debris was swept downstream and accumulated as thick deposits in the eastern Portland Basin (Swanson, 1986). The canyon that the ancestral Columbia River occupied, known as the Bridal Veil channel (Tolan, 1982; Tolan and Beeson, 1984), was eventually filled by the hyaloclastite and related lava flows and the river was diverted to the north, where it has carved its present canyon. Argon–argon (40Ar/39Ar) age determinations for lava flows interbedded with and overlying the hyaloclastite (McClaughry and others, 2012; Fleck and others, 2014) suggest the hyaloclastite was deposited between about 3.5 and 3.0 million years ago. The hyaloclastic deposits (map unit Ttfh) are equivalent to the Troutdale Formation upper member of Tolan and Beeson (1984) and include the Troutdale Formation hyaloclastic sandstone member of Evarts (2006), Evarts and O'Connor (2008), Evarts, O'Connor, and Tolan (2013), and Wells and others (2020). Although the hyaloclastic deposits are generally sandstones in the western Columbia Gorge and Portland Basin, they contain pillow lavas and basaltic breccia in the area between Hood River, Oregon and Bonneville Dam. Most clasts in the hyaloclastic deposits are olivine-phyric basalt that is rich in basaltic glass (sideromelane) that is commonly altered to yellow-brown colored palagonite. At some localities in the western Columbia Gorge, the hyaloclastic deposits include beds of micaceous quartzose sandstone. This dataset also includes polygons representing the partial extents of lava flows (map unit Tlkt) that are either interbedded with or overlie the hyaloclastic deposits. The lava flows generally have tholeiitic basalt composition with low levels of potassium (less than 0.5 weight percent K2O), commonly contain olivine phenocrysts, and often have a diktytaxitic groundmass texture consisting of numerous small angular voids. The lava flows are equivalent to the late Pliocene lavas of the late High Cascades grouping of McClaughry and others (2012). It should be noted that there are numerous lava flows of similar age and composition in the region but this dataset mostly contains those that can be used to constrain the history of the hyaloclastic deposits in the Bridal Veil channel. This data release is a compilation that includes incomplete geologic mapping and it is anticipated that extents of these deposits will be expanded in future geologic maps. The source maps upon which most of this dataset was derived from were intended for use at 1:24,000 scale. References Cited: Conrey, R.M., Sherrod, D.R., Uto, K., and Uchiumi, S., 1996, Potassium-argon ages from Mount Hood area of Cascade Range, northern Oregon: Isochron/West, no. 63, p. 10-20. Evarts, R.C., 2006, Geologic map of the Lacamas Creek quadrangle, Clark County, Washington, U.S. Geological Survey Scientific Investigations Map 2924, scale 1:24,000, https://doi.org/10.3133/sim2924. Evarts, R.C., and O'Connor, J.E., 2008, Geologic map of the Camas Quadrangle, Clark County, Washington, and Multnomah County, Oregon, U.S. Geological Survey Scientific Investigations Map 3017, scale 1:24,000, https://doi.org/10.3133/sim3017. Evarts, R.C., O'Connor, J.E., and Tolan, T.L., 2013, Geologic map of the Washougal quadrangle, Clark County, Washington, and Multnomah County, Oregon, U. S. Geological Survey Scientific Investigations Map 3257, scale 1:24,000, https://doi.org/10.3133/sim3257. Fleck, R.J., Hagstrum, J.T., Calvert, A.T., Evarts, R.C., and Conrey, R.M., 2014, 40Ar/39Ar geochronology, paleomagnetism, and evolution of the Boring volcanic field, Oregon and Washington, USA: Geosphere, v. 10, no. 6, p. 1283-1314, https://doi.org/10.1130/ges00985.1. McClaughry, J.D., Wiley, T.J., Conrey, R.M., Jones, C.B., and Lite, K.E., 2012, Digital geologic map of the Hood River Valley, Hood River and Wasco Counties, Oregon: Open-File Report O-12-03, 130 p., https://www.oregongeology.org/pubs/ofr/p-O-12-03.htm. Swanson, R.D., 1986, A stratigraphic-geochemical study of the Troutdale Formation and Sandy River Mudstone in the Portland basin and lower Columbia River Gorge, Portland State University, M.S. thesis, 115 p, https://doi.org/10.15760/etd.5604. Tolan, T.L., 1982, The stratigraphic relationships of the Columbia River Basalt Group in the lower Columbia River Gorge of Oregon and Washington, Portland State University, M.S. thesis, 169 p, https://doi.org/10.15760/etd.3232. Tolan, T.L., and Beeson, M.H., 1984, Intracanyon flows of the Columbia River Basalt Group in the lower Columbia River Gorge and their relationship to the Troutdale Formation: GSA Bulletin, v. 95, no. 4, p. 463-477, https://doi.org/10.1130/0016-7606(1984)95%3C463:IFOTCR%3E2.0.CO;2. Trimble, D.E., 1963, Geology of Portland, Oregon, and adjacent areas: U. S. Geological Survey Bulletin 1119, https://doi.org/10.3133/b1119. Wells, R.E., Haugerud, R.A., Niem, A.R., Niem, W.A., Ma, L., Evarts, R.C., O'Connor, J.E., Madin, I.P., Sherrod, D.R., Beeson, M.H., Tolan, T.L., Wheeler, K.L., Hanson, W.B., and Sawlan, M.G., 2020, Geologic map of the greater Portland metropolitan area and surrounding region, Oregon and Washington: U.S. Geological Survey Scientific Investigations Map 3443, scale 1:63,360, https://doi.org/10.3133/sim3443.

The Board of County Commissioners meet in the Multnomah Building, 501 SE Hawthorne Blvd., Portland, Oregon, Commissioners Board Room 100 - off the lobby.Other than meeting start time, listed agenda item times are approximate. Agenda items may start earlier or later unless listed as a Time Certain.View upcoming and past Board meetings.