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Description: § 39.5500- PURPOSES. The purposes of the Significant Environmental Concern Overlays, MCC 39.5500 through MCC 39.5860 (collectively, the “SEC”) are to protect, conserve, enhance, restore, and maintain significant natural and human-made features which are of public value, including among other things, river corridors, streams, lakes and islands, domestic water supply watersheds, flood water storage areas, natural shorelines and unique vegetation, wetlands, wildlife and fish habitats, significant geological features, tourist attractions, archaeological features and sites, and scenic views and vistas, and to establish criteria, standards, and procedures for the development, change of use, or alteration of such features or of the lands adjacent thereto. Multnomah County Zoning Code Chapter 39 (https://multco.us/file/76252/download)
Copyright Text: Multnomah County DCS - Land Use Planning
Description: (F) The zoning maps used to designate the SEC-s were created digitally by interpreting various data sources including the hand drawn maps contained in the Goal 5 ESEE reports and Metro’s riparian and wildlife habitat inventories. Care was taken in the creation of the maps, but in some instances mapping inaccuracies have occurred during the process. In the event of a mapping inconsistency, the SEC-s zoning subdistrict shall be interpreted to be the defined Stream Conservation Area as defined in MCC 39.5750.Multnomah County Zoning Code (https://multco.us/file/76252/download)
Copyright Text: Multnomah County DCS - Land Use Planning
Description: The purposes of the Significant Environmental Concern Overlays, MCC 39.5500 through MCC 39.5860 (collectively, the “SEC”) are to protect, conserve, enhance, restore, and maintain significant natural and human-made features which are of public value, including among other things, river corridors, streams, lakes and islands, domestic water supply watersheds, flood water storage areas, natural shorelines and unique vegetation, wetlands, wildlife and fish habitats, significant geological features, tourist attractions, archaeological features and sites, and scenic views and vistas, and to establish criteria, standards, and procedures for the development, change of use, or alteration of such features or of the lands adjacent thereto.Chapter 39 Multnomah County Zoning Code (https://multco.us/file/76252/download)
Copyright Text: Multnomah County DCS - Land Use Planning
Description: The purposes of the Significant Environmental Concern Overlays, MCC 39.5500 through MCC 39.5860 (collectively, the “SEC”) are to protect, conserve, enhance, restore, and maintain significant natural and human-made features which are of public value, including among other things, river corridors, streams, lakes and islands, domestic water supply watersheds, flood water storage areas, natural shorelines and unique vegetation, wetlands, wildlife and fish habitats, significant geological features, tourist attractions, archaeological features and sites, and scenic views and vistas, and to establish criteria, standards, and procedures for the development, change of use, or alteration of such features or of the lands adjacent thereto.MCC 39.5520, an application for development in an area designated SEC-v shall include: (1) Details on the height, shape, colors, outdoor lighting, and exterior building materials of any proposed structure; (2) Elevation drawings showing the appearance of proposed structures when built and surrounding final ground grades; (3) A list of identified viewing areas from which the proposed use would be visible; and, (4) A written description and drawings demonstrating how the proposed development will be visually subordinate as required by subsection (C) below, including information on the type, height and location of any vegetation or other materials which will be used to screen the development from the view of identified viewing areas.Chapter 39 Multnomah County Zoning Code (https://multco.us/file/76252/download)
Copyright Text: Multnomah County DCS - Land Use Planning
Description: Wetland_Areas and Wetland_Lines combined makes up the SEC-w layer.§ 39.5700 Multnomah County Zoning Code (https://multco.us/file/76252/download)
Copyright Text: Multnomah County DCS - Business Services
Description: Data is downloaded from the FEMA Flood Map Service Center (https://msc.fema.gov/portal/home) then clipped to the County's planning jurisdiction. FIRM is the official map of a community on which FEMA has delineated both the special hazard areas and the risk premium zones applicable to the community. Zone AE and A1-A30 are zones that have a 1% annual chance of flooding. According to the 2018 FEMA Flood Insurance Study.
Description: This database is an inventory of existing landslides and includes supplemental photos taken by staff geologists while performing landslide related field work. The landslide inventory is one of the essential data layers used to delineate regional landslide susceptibility. This inventory is not regulatory, and revisions can happen when new information regarding landslides is found or when future (new) landslides occur. Therefore, it is possible that landslides within the mapped area were not identified or occurred after the data was prepared.This data was prepared by following the Protocol for Inventory Mapping of Landslide Deposits from Light Detection and Ranging (Lidar) Imagery developed by Burns and Madin (DOGAMI Special Paper 42, 2009). The three primary tasks include compilation of previously mapped landslides, lidar-based morphologic mapping of landslide features, and review of aerial photographs. Landslides identified by these methods are digitally compiled into this database at varying scales. The recommended map/use scale for these data is 1:8,000. Each landslide is also attributed with classifications for activity, depth of failure, movement type, and confidence of interpretation. The landslide inventory is intended to provide users with basic information regarding landslides. The geologic, terrain, and climatic conditions that led to landslides in the past may provide clues to the locations and conditions of future landslides, and it is intended that this data will provide useful information to develop regional landslide susceptibility maps, to guide site-specific investigations for future developments, and to assist in regional planning and mitigation of existing landslides.
Copyright Text: William J. Burns and Kate Mickelson, OR Dept. of Geology & Mineral Resources (DOGAMI)
Description: The urban and rural reserves reflect a new approach to managing growth in our region. Across the region, civic leaders are engaged in a collaborative planning process to consider the shape of our region over the next several decades. Citizens and officials are working in concert to craft policies and choose investments that will enhance existing communities. As part of this work, Clackamas, Multnomah and Washington counties and Metro led a regional effort to identify land for urban or rural use for the next half century. Under the Oregon land use system, Metro maintains the urban growth boundary (often referred to as the UGB) surrounding the Portland metropolitan area. This line encircling the region separates urban communities from rural lands. Every five years Metro calculates how much acreage is needed to maintain a 20-year supply of land to accommodate projected urban growth and expands the boundary when necessary to respond to that need. Under this longstanding system, every five years the citizens of the region wrestled with identifying areas for urban expansion. This system kept landowners at the edge of the boundary in limbo, never knowing whether or when their lands might be destined for urbanization. It also made it difficult to invest in our communities. After the last urban growth boundary decision, the region's leaders proposed a solution. As a result, in 2007, the Oregon Legislature approved Senate Bill 1011. This legislation enabled us to identify and designate areas outside the current urban growth boundary that are best suited for future housing and employment as urban reserves. SB 1011 also provided a new opportunity to identify areas that should remain working farms and forests or natural areas for the next 40 to 50 years.
Description: This geospatial dataset is a hydrologic unit boundary layer for the Watershed (10-digit) level. The dataset is a subset of the 5th level (field) hydrologic unit boundaries from the Watershed Boundary Dataset (WBD) layer for Oregon. Hydrologic units in the data set represent drainage areas delineated to the 5th level drainage systems. Their boundaries are defined by hydrographic and topographic criteria that delineate an area of land upstream from a specific point on a river, stream, or similar surface waters.Boundaries within the this data set were delineated by Pacific Northwest (PNW) Hydrography Framework Partners and Natural Resources Conservation Service (NRCS) to meet state requirements and to contribute to the national WBD repository. To meet these goals, the WBD must adhere to the "Federal Standards for Delineation of Hydrologic Unit Boundaries", dated October, 2004.These boundaries were made from the Oregon and Washington datasets that have been nationally certified by Natural Resources Conservation Service (NRCS) Prior to submission the dataset was subjected to an iterative review and edit process to ensure that the hydrologic boundaries fully satisfy the federal standards. This work was completed under a Memorandum of Understanding between the Pacific Northwest Hydrography Framework Partnership, NRCS and the US Geological Survey (USGS). The current dataset includes 5th level boundaries that are in all 4th level (8-digit) subbasins that fall within or the four county Metro region.This data was originally downloaded from the PNW Hydrography Framework Clearinghouse (http://hydro.reo.gov/hu.html).The original REO metadata specified the following regarding the original data this layer was extracted from:hydrologic units were incorporated into this dataset from an aggregate of pre-existing HUs. Some new HU boundaries were delineated using flow lines and basins computed from 10- and 30-meter horizontal resolution Digital Elevation based on flow derived from the elevation grid to determine potential pour points. The DEM data is derived from hypsography represented on 1:24000 USGS topographic quadrangles. Additional hydrography data was used as a template to control pourpoint locations for the delineated HUs.20090131
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Description: Multnomah County Design and Construction Manual1.1.1 Roadway Functional Classification The Multnomah County Comprehensive Framework Plan’s Policy 34: Trafficways and the Functional Classification of Trafficways Map, includes nine roadway functional classifications, four within the broad arterial classification (principal, major, minor, and rural), three within the collector classification (major, neighborhood, and rural), and two within the local street classification (urban and rural). A brief description of each classification is presented in this section. In addition, a range of design treatments that can be accommodated within each functional classification will be described in subsection 1.1.2 of this manual. For a more detailed description of each functional classification, see Policy 34: Trafficways and the Functional Classification of Trafficways Map. Arterial streets comprise the regional roadway network, and provide for travel between communities in the County, and between counties. Arterial streets accommodate the full array of travel modes including the regional bikeway system, fixed-route transit network, goods delivery and higher volume automobile traffic than collector streets. Principal Arterial Streets connect to freeways and highways that serve travelers without an origin or destination in the County. This interstate and interregional traffic, including trucks, is in addition to regional traffic traveling between cities and counties, and traffic generated by intensive and higher density land uses along the arterial corridor. The ability to move auto, truck, and regional bicycle traffic is preserved. Major Arterial Streets carry high volumes of traffic between cities in the County as part of the regional trafficway system. Priority may be given to transit- and pedestrian-oriented land uses by way of regional boulevard design treatments. Design and management of major arterial streets emphasizes preservation of the ability to move auto and transit traffic by limiting accesses while also accommodating regional bikeways and pedestrian movements. Minor Arterial Streets are the lowest order arterial facility in the urban regional street network. They typically carry less traffic volume than principal and major arterial streets, but have a high degree of connectivity between communities. Minor arterial streets provide major links in the regional road and bikeway networks; provide for truck mobility and transit corridors; and may serve as significant links in the local pedestrian system, especially where they are designed as community boulevards. Rural Arterial Roads are the primary means of access into the County’s large rural districts, and often connect between counties to accommodate through movements. Rural arterial roads connect to freeways or highways, and link rural collector and local roads to the urban area and other regions. Rural arterial roads carry greater traffic volumes than rural collector roads, including commuters and other homebased trips, natural resources involving trucks, and recreational trips involving autos, bicycles, and equestrians. Multnomah County Design Standards Part I – Design Manual 1 - 2 Collector streets distribute traffic between local streets and the arterial street network. They are not intended to serve trips without an origin or destination inside the County. Collector streets provide for automobile, bicycle and pedestrian circulation, and basic transit service. Major Collector Streets serve several purposes including linking neighborhoods to the regional system of bicycle and automobile streets, and basic transit service. They typically provide direct access between residential and commercial developments, schools, and parks. Neighborhood Collector Streets provide access primarily to residential land uses and link neighborhoods to higher order roads. They generally have higher traffic volumes than local streets but through or nonlocal traffic is discouraged. Rural Collector Roads distribute automobile traffic over large areas and generally connect to urban streets or rural arterial roads. They may also provide for recreational trips by auto, bicycle, and equestrian. Local Streets Local streets provide access to abutting land uses and do not serve through traffic. Local streets may be further classified by adjacent land use, such as residential, commercial, and industrial. Their primary purpose is to serve local pedestrian, bicycle, and automobile trips in urban areas. In rural areas, local roads serve automobile and farm circulation, as well as local pedestrian, bicycle, and equestrian uses. 1.1.2 Roadway Design Treatments Metro’s Regional Transportation Policy’s “Regional Street Design Goals and Objectives,” provides design guidelines for streets in the region. The County’s roadway design treatments have incorporated Metro’s Street Design Guidelines. (For detailed description of each treatment, see Metro’s “Street Design Guidelines for 2040” and the Regional Street Design map in the current Regional Transportation Plan.)Boulevards serve the multi-modal travel needs of the region’s most intensely developed activity centers, including regional centers, station communities, town centers and some main streets. Boulevards are the continuation of the regional street network within more intensively developed activity centers. Boulevards are designed with special amenities that promote pedestrian, bicycle, and public transportation travel in the districts they serve. Boulevards are classified as regional and community scale designs. Regional boulevards are designated on specific major arterial roadways while community boulevards are designated on specific minor arterial roadways. Regional and community boulevards are located within the most intensely developed activity centers with development oriented to the street. These are primarily regional centers, town centers, station Multnomah County Design Standards Part I – Design Manual 1 - 3 communities and some main streets. Regional boulevards consist of four or more vehicle lanes, balanced multi-modal function, and a broad right of way. Features highly desirable on regional boulevards include on-street parking, bicycle lanes, narrower travel lanes than throughways, more intensive land use oriented to the street, wide sidewalks, and landscaped medians. Community boulevards consist of four or fewer vehicle travel lanes, balanced multi-modal function, narrower right of way than a regional boulevard, landscaped medians, no on-street parking, narrower travel lanes than throughways, more intensive land use oriented to the street, and wide sidewalks. Streets serve the multi-modal travel needs of corridors, inner and outer residential neighborhoods and some main streets. Streets typically are more vehicle-oriented and less pedestrian-oriented than boulevards, providing a multi-modal function with an emphasis on vehicle mobility. Streets are classified as regional and community designs. Regional streets are designated on specific major arterial roadways, while the community streets are designated on specific minor arterial roadways. Regional streets consist of four or more vehicle travel lanes, balanced multi-modal function, broad right of way, limited on-street parking, wider travel lanes than boulevards, land use set back from the street, sidewalks with pedestrian buffering from street, and a raised landscaped median or, usually a continuous two way left turn lane. Community streets consist of two to four travel lanes, balanced multi-modal function, narrower right of way than regional streets, on-street parking, narrower or fewer travel lanes than regional streets and residential neighborhood and corridor land use set back from the street. Community streets provide a higher level of local access and street connectivity than regional streets. Community streets have the greatest flexibility in cross sectional elements. Depending on the intensity of adjacent land use and site access needs, community streets can have three different median conditions; center two way left turn lane, narrow landscaped median, or no median.
Copyright Text: Multnomah County DCS - Business Services
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Description: This dataset was derived from the METRO RLIS Streets layer. New additions were added through digitizing using as-builts and assessor maps as references.
Copyright Text: Multnomah County DCS - Business Services
Description: Signs owned and maintained by Multnomah county traffic aids along county ROW. These assets are maintained used Cartegraph OMS and corrected for accuracy by GIS staff. Each sign should be associated with a county support asset where applicable. A small number of signs are not associated with a support asset. Examples include county signs that are fixed to non county supports or temporary signs that are installed without supports.
Copyright Text: Multnomah County DCS - Business Services
ID
(
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Support
(
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Street
(
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, Coded Values:
[10TH ST : 10TH ST ]
, [11TH ST : 11TH ST ]
, [12th ST : 12th ST ]
, ...5034 more...
)
Description: This feature class was created by combining the Willamette River Bridges feature class with the east county bridges feature class. Includes the following attributes:Bridge CodeBridge NameNBIS NameAbutment TypeConstruction YearSpansLanesDeck WidthLength Suffiency Inspection DateMoving SpanVertical Clearing AboveVertical Clearing BelowDeck TypeDeck WearingPier TypeSpan TypeWeight Tables 1-5 Weight Table xWeight Restriction (combination of weight tables 1-x)
Copyright Text: Multnomah County DCS - Business Services
Description: This feature class contains Multnomah County stormwater culvert infrastructure. A variety of methods and data sources were employed to create this data. Existing datasets obtained from neighbor jurisdictions were used as a starting point. Point accuracy (within the county right of way) was then improved using the best available data sources. These sources include resource grade GPS, Ground Based LIDAR, Aerial Photos, Georeferenced As-Built Drawings, Georeferenced Mylar Drawings, Field Visits, and Google Streetview. Depending on the source used to verify the data, the accuracy of this feature class is estimated to be < 3 meters
Copyright Text: Multnomah County DCS - Business Services
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Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: Multnomah County Land Use Zoning Code Chapter 38, § 38.0015 (link)Columbia River Gorge Commission Chapter 350 Division 81 Land Use Ordinance (link)
Copyright Text: Columbia River Gorge Commission (CRGC)
Description: This database is an inventory of existing landslides and includes supplemental photos taken by staff geologists while performing landslide related field work. The landslide inventory is one of the essential data layers used to delineate regional landslide susceptibility. This inventory is not regulatory, and revisions can happen when new information regarding landslides is found or when future (new) landslides occur. Therefore, it is possible that landslides within the mapped area were not identified or occurred after the data was prepared.This data was prepared by following the Protocol for Inventory Mapping of Landslide Deposits from Light Detection and Ranging (Lidar) Imagery developed by Burns and Madin (DOGAMI Special Paper 42, 2009). The three primary tasks include compilation of previously mapped landslides, lidar-based morphologic mapping of landslide features, and review of aerial photographs. Landslides identified by these methods are digitally compiled into this database at varying scales. The recommended map/use scale for these data is 1:8,000. Each landslide is also attributed with classifications for activity, depth of failure, movement type, and confidence of interpretation. The landslide inventory is intended to provide users with basic information regarding landslides. The geologic, terrain, and climatic conditions that led to landslides in the past may provide clues to the locations and conditions of future landslides, and it is intended that this data will provide useful information to develop regional landslide susceptibility maps, to guide site-specific investigations for future developments, and to assist in regional planning and mitigation of existing landslides.
Copyright Text: William J. Burns and Kate Mickelson, OR Dept. of Geology & Mineral Resources (DOGAMI)
Description: Conventional flood hazard maps, like the FEMA Flood Insurance Rate Map (FIRM) series, examine only the hazard posed by standing floodwaters on a given floodplain. Damage from bank erosion as river channels naturally migrate may be far greater locally and may occur even in the absence of major flooding. To address this hazard, channel migration hazard maps were created to identify areas susceptible to future channel movement and erosion. Following the methodology of Rapp and Abbe (2003) and Abbe and others (2008), lidar-derived digital elevations models and serial aerial photography were examined to map the position of the channel over time. Localized erosion rates, potential avulsion sites, areas where erosion may be prevented, and areas where infrastructure is at risk from erosion were identified from these data. The resulting Channel Migration Zone and its subzones represent best estimates of the likely hazard projected 100 years into the future. The analysis area is mostly within the geologic floodplain of the river, with some exceptions where forecasted erosion boundaries intersect active landslides. In these locations, the Channel Migration Zone may include the landslide toe. The channel hazard maps should be used as a guide for local governments, land owners, and infrastructure managers to identify assets potentially at risk and to develop effective mitigation measures. For more information on methodologies, see DOGAMI OFR O-11-09, Channel Migration Hazard Maps, Coos County, Oregon.
Copyright Text: John T. English, Daniel E. Coe, and Robert D. Chappell
Description: This layer was created during the Comprehensive Plan process. The data came from Multnomah County Office of Emergency Management. The source data is from Oregon Department of Forestry (ODF)Part of the 2011 Community WIldfire Protection Plan (link)
Copyright Text: Multnomah County Office of Emergency Management, ODF
Description: Liquefaction is a process where loose, wet sediments lose strength during an earthquake and behave similarly to a liquid. Once a soil liquefies, it will tend to settle vertically and/or spread laterally. With even very slight slopes, liquefied soils tend to move sideways downhill (lteral spreading). Settling or lateral spreading can cause major damage to buildings and to buried infrastructure such as pipes and cables. Prepared by GeoEngineers and APG Date: 10/13/2016Source: DOGAMI 2013 Open-File Report O-13-06, Ground motion, ground deformation, tsunami inundation, coseismic subsidence, and damage potential maps for the 2012 Oregon Resilience Plan for Cascadia Subduction Zone Earthquakes, by Ian P. Madin and William J. Burns(link)
Description: This layer was prepared by GeoEngineers and Angelo Planning Group as part of the 2010 Comprehensive Plan.The source data is from Oregon Department of Geology and Mineral Studies (DOGAMI) Open File Report O-13-06, Ground motion, ground deformation, tsunami inundation, coseismic subsidence, and damage potential maps for the 2012 Oregon Resilience Plan for Cascadia Subduction Zone Earthquakes (link)