Description: There are three Infiltration and Soil Maps to assist with determining the potential for onsite infiltration:
Wetted Drainage Class
Hydrologic Soil Group
Sump Capacity Data by Quarter Section
Description: "Drainage class (natural)" refers to the frequency and duration of wet periods under conditions similar to those
under which the soil formed. Alterations of the water regime by human activities, either through drainage or
irrigation, are not a consideration unless they have significantly changed the morphology of the soil. Seven
classes of natural soil drainage are recognized-excessively drained, somewhat excessively drained, well drained,
moderately well drained, somewhat poorly drained, poorly drained, and very poorly drained. These classes are
defined in the Soil Survey of Multnomah County, Oregon; 1983.
Source: 2007 NRCS. Method for Compilation: All Components (Tie Break Lower).
Description: Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet and receive precipitation from long-duration storms.
Description: Description: A total of 571 data points were used from city-wide sump infiltration tests and were aggregated to the quarter section level. Aggregation was performed using a statistical technique (Block Kriging) that uses a weighted average of the infiltration tests to calculate an estimated infiltration rate for each quarter section.
Description: The Groundwater Maps assist with determining the potential for subsurface infiltration. Where the depth to groundwater is relatively high, subsurface infiltration may not be appropriate. Where groundwater is protected for drinking water, infiltration may be restricted.
USGS - Depth to Seasonal High Groundwater
Taggart D Supplemental Depth to Groundwater
Holgate Lake Supplemental Depth to Groundwater
Plan Districts
Wellfiled Protection Area
Description: The Depth to Seasonal High Groundwater provides the best available city wide groundwater data. The depth to seasonal high water table values are interpolated from observed local groundwater and surface water
elevations where spatial variability due to widely ranging groundwater monitoring locations has not been incorporated. As such, groundwater depth should be verified with field measurements where site specific work is
desired and where depth to groundwater is considered important.
Source: 2008 Final USGS Portland Area Depth to Groundwater. Ranges in Feet.
Copyright Text: BES - System Analysis - UIC Program
Description: Taggard D Conceptual Site Model Depth to Groundwater 1. Source: 2007 GeoDesign, Inc.
Description: A total of 559 data points were collected as part of this study. The data points, consisted of borehole and test pit logs with soil description and groundwater information. Each point was assigned a spatial location, soil unit were classified according to project-specific standard, depth to groundwater (if present) was recorded and a relative assessment of data quality assign. In addition, geographic information systems (GIS) layers were created, regional and study area specific geology and hydrogeology were assessed, lithologic cross sections were produced, and combination of data were used through an iterative process to produce the CSM presented herein.
Development of the CSM involved several assumptions, creating uncertainties. While creating cross sections, borehole data was limited to a maximum distance of approximately 400 feet orthogonal to the section line. Favor was given to those logs closer to the section line and to logs with higher qualifiers. Groundwater data was greatly simplified; groundwater levels vary with time, season, and location. With the objective of identifying potential areas of shallow groundwater, the groundwater measurements representing the highest elevation and, therefore, the shallowest groundwater were used. Due to these variations, the groundwater data must be used with caution.
NOTE: Data were compiled from various sources. This product was developed through digital means and may be updated without notification. No warranty
Name: Holgate Lake Supplemental Depth to Groundwater
Display Field: Lower_
Type: Feature Layer
Geometry Type: esriGeometryPolygon
Description: Holgate Lake Conceptual Site Model Depth to Groundwater 2. Source: 2007 GeoDesign, Inc. Description: A total of 885 data points were collected as part of this study. The data points, consisted of borehole logs, test pit logs, flow-test data, and groundwater depths. Each point was assigned a spatial location, soil units were classified according to the project-specific standards, depth to groundwater (if present) was recorded, and a relative assessment of data quality was assigned. In addition, GIS layers were created, regional and Study Area-specific geology and hydrogeology were assessed, lithologic cross sections were produced, and combination of data were used through an iterative process to produce the CSM presented herein.
Development of the CSM involved several assumptions, creating uncertainties. While creating cross sections, borehole data was limited to a maximum distance of approximately 400 feet orthogonal to the section line. Favor was given to those logs closer to the section line and to logs with higher qualifiers. Groundwater data was greatly simplified; groundwater levels vary with time, season, and location. With the objective of identifying area of shallow groundwater, the groundwater measurements representing the highest elevation and, therefore, the shallowest groundwater were used. Due to these variations, the groundwater data must be used with caution. NOTE: Data were compiled from various sources. This product was developed through digital means and may be updated without notification. No warranty
Description: Some sites within the City of Portland are located within plan districts. Plan districts may have additional regulations that can impact a project.
--Additional Information:
Category: Planning
Copyright Text: Bureau of Planning and Sustainability
Description: Defines the boundary of the Columbia South Shore Protection Zone
--Additional Information:
Category: Boundary
Purpose: To allow Bureau staff to design, construct, utilize, analyze and manage the Bureau's water supply and distribution system.
Update Frequency: As needed
Description: The Percent Slope map identifies local topography at a 5-ft resolution and may assist with identifying sites where infiltration is limited. The Regional Geology and Depth to Fragipan and Lithic Bedrock maps may be useful in stormwater management facility design in that they provide an overall understanding of the subsurface geologic features and identify features that may restrict infiltration.
Description: Source: 2004 DOGAMI
For more information on regional geology, please visit the Oregon Department of Geology website, at:
http://www.oregongeology.com/sub/default.htm
Description: Depth to Lithic Bedrock represents a "restrictive layer" is a nearly continuous layer that has one or more physical, chemical, or thermal properties that significantly impede the movement of water and air through the soil of that restrict roots or otherwise provide an unfavorable root environment. Examples are bedrock, cemented layers, dense layers, and frozen layers. This theme presents the depth to any type of restrictive layer for each map unit. If more than one type of restrictive layer is described for an individual soil type, the depth to the shallowest one is presented. These data only describe map units for which a restrictive layer is present within 200cm (approximately 6.56 feet). A "representative" value indicates the expected value of this attribute for the component. For this soil property, only the representative value is used.
Description: Depth to Fragipan represents a "restrictive layer" is a nearly continuous layer that has one or more physical, chemical, or thermal properties that significantly impede the movement of water and air through the soil of that restrict roots or otherwise provide an unfavorable root environment. Examples are bedrock, cemented layers, dense layers, and frozen layers. This theme presents the depth to any type of restrictive layer for each map unit. If more than one type of restrictive layer is described for an individual soil type, the depth to the shallowest one is presented. These data only describe map units for which a restrictive layer is present within 200cm (approximately 6.56 feet). A "representative" value indicates the expected value of this attribute for the component. For this soil property, only the representative value is used.
Description: Combined and Sanitary Basins were delineated as part of the System Plan as documented in the 2012 Combined and Sanitary Sewer Elements Executive Report.
Provides a way to visualize the collection system contributing area.
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Description: Port of Portland Design Storm Manual boundary which depicts the area where the Port's DSM is applicable. This applies specifically to the Portland International Airport and properties owned by the Port and adjacent to the airfield security fence.