OAR 141-090-0035
Standards and Requirements for Wetland Delineation Reports Submitted to the Department


Report Submittal: All wetland delineation reports (“reports”) submitted to the Department for review, approval and a JD shall meet the technical requirements in OAR 141-090-0030 (Technical Requirements) as well as the minimum standards and requirements in this rule. Reports must conform to the report format provided by the Department.


All wetlands and other waters on the parcel or study area shall be included; the Department will determine whether or not they are “waters of this state” subject to jurisdiction under OAR 141-085, 141-089, 141-093, 141-100 and 141-102.


All report text, maps, aerial photographs, ground photographs, and data forms must be legible.


Reports must be submitted as:


Paper hard copies, reproduced in color as applicable, unbound and, with the exception of photographs, must copy legibly on a black and white copier; or


Digital single PDF files with minimum resolution of 300 dpi and searchable text for the text portion of the report.


Submitting Geographic Information System (GIS) data is optional but recommended for reports covering large study areas and must conform to the GIS format provided by the Department.


All submittals must include a fully completed and signed “Wetland Delineation Report Cover Form” (current form provided by the Department).


Field Methods: The field investigation methods and level of detail required for making and documenting a PJD or JD and mapping wetlands and other waters of this state will vary by site. At a minimum:


The entire parcel (tax lot) or study area must be investigated during a field investigation. If only a portion of a parcel is investigated, the study area with respect to parcel boundaries must be made clear in the report text and shown on the wetland maps.


All waters of this state in addition to wetlands must be identified, described, supported by data as appropriate, and mapped.


Sufficient data and additional information shall be collected for any wetlands and other waters of this state to enable the Department to make a JD and also to determine if removal-fill permit requirements apply or if the feature identified may be specifically exempt from permit requirements.


The wetland delineation must include sample plots that represent the characteristics of each wetland present; represent each adjacent non-wetland(s); are paired and located close enough to either side of the wetland boundary to accurately substantiate the wetland boundary location and are sufficient to characterize long or irregular boundaries.


Wetland determination sample plot data must be provided for any portion of the study area where there is significant deviation from wetlands mapped on the NWI or LWI unless the deviation is due to development that is so significant that it precludes data collection.


At least one sample plot must be placed in all mapped hydric soil units within the study area.


At least one sample plot must be placed in the lowest topographic areas or other locations most likely to contain wetlands.


Study area boundaries, wetland and other water boundaries, and sample plots shall be identified on the ground. For actively managed sites, such as agricultural fields, golf courses, or recreational fields, where it may be impractical to leave the boundary and plot markers on the ground until the JD is issued, their precise location must be readily relocated in the field by the applicant or consultant during a site visit by the Department.


Because sites are highly variable and JD needs also vary, some situations may warrant deviation from the Field Methods requirements outlined in OAR 141-090-0035 (Standards and Requirements for Wetland Delineation Reports Submitted to the Department)(7), for example large geographic areas, linear projects, mosaics, and difficult wetland sites. In such situations, persons conducting wetland delineations are encouraged to consult with the Department regarding appropriate methods.


For farmed sites, field work should be guided by multiple information sources including at least three aerial photos from three different years (early growing season if possible), a detailed topographic survey, and information about site management activities such as subsurface drainage systems and plowing frequency and depth.


Wetland determination and delineation on farmed sites shall follow procedures outlined in the Difficult Wetland Situations Chapter of the appropriate regional supplement.


On sites where the hydrology indicators may be missing or misleading due to natural or hydrologic manipulation, hydrologic monitoring may be needed to verify the absence or presence of wetland hydrology. When a hydrology monitoring method alternative to the manual standard is being pursued, the proposed method shall be submitted to the Department in writing for prior approval.


Wetland boundaries, samples plots, and study area boundaries must be mapped to the standards described in subsection (a) and (b) of this section.


Except as provided in subsection (b) of this section, the map precision standard (precision of transferring boundaries of features located on the ground to a map) for wetland boundaries, data plots and study area boundaries is within one meter (3.28 feet);


The minimum delineation accuracy and map precision standard for voluntary wetland ecosystem restoration projects (see OAR 141-089-0800 (Wetland Ecosystem Restoration - Purpose)) that do not include compensatory mitigation activities or payment-in-lieu is 50 feet.


Mapping procedures may include professional land survey, GPS, measurements made from permanent features identified on the map or on an aerial photo included with the report, or approximated. For most intensive development activities, such as subdivision planning or commercial development, a professional land survey may be necessary. The appropriate map precision for removal-fill permitting is subject to the judgment of the Department.


Report Text: The report text must include:


A detailed description of the site, its landscape setting, and previous and current land uses;


A description, including the approximate year and extent, of any site alterations that likely affected the presence, location or geographic boundaries of any wetlands or other waters on the site (e.g., surface drainage ditches or fill material);


Precipitation for the day(s) of and 2 week period preceding the field investigation(s), observed and percent of normal rainfall for the water year to date, and for the observed rainfall compared to the NRCS WETS table 30% and 70% chance exceedance values for each of the three months preceding the field investigation;


The date(s) of the field investigation and site-specific methods used to conduct the field investigation, select sample plot locations, determine boundaries of wetlands and other waters, interpolate boundaries between paired plots, and make PJDs;


A description of any wetlands and other waters, including whether or not they extend offsite, and the characteristics of the wetland and other water boundaries on the site;


Deviation from NWI mapping, LWI mapping, or previous DSL-approved delineations, supported by wetland determination data or explanation of development in area mapped previously as wetland;


An explanation of how the location of the parcel boundaries, data plots, wetlands, and other features depicted on the delineation map(s) were mapped. A statement of precision must be included with each method used to generate the map.


All preliminary jurisdictional determinations shall be supported with information and rationale sufficient to demonstrate jurisdiction based on OAR 141-085-0515 (Removal-Fill Jurisdiction by Type of Water) criteria. This information can include, but is not limited to:


Documentation of fish presence or absence in a stream or ditch, using published maps or reports or information from an authoritative source (e.g., Oregon Department of Fish and Wildlife field staff);


Information sufficient to determine whether or not an identified water feature is artificially created entirely from upland and the purpose for which it was created.


Information about the water feature’s wetland status, size, average water depth at ordinary high water, topographic and geomorphological location, mapped soil series and hydric status, and evidence of drainage (e.g., drain tiles or ditching).


Hydrology monitoring data;


Historical aerial photographs;


Data or other information on pre-disturbance conditions, such as excavation to an original (formed insitu) soil surface or identification of a former stream course;


A detailed topographic survey;


Data collected at a certain time of year;


Additional plant species identification; or


Documentation from a Removal-fill permit including permit number.
The results and conclusions of the investigation;


The following disclaimer: "This report documents the investigation, best professional judgment and conclusions of the investigator. It is correct and complete to the best of my knowledge. It should be considered a Preliminary Jurisdictional Determination of wetlands and other waters and used at your own risk unless it has been reviewed and approved in writing by the Oregon Department of State Lands in accordance with OAR 141-090-0005 (Purpose) through 141-090-0055 (Effective Date)." and


Appendices, as needed.


Report Figures and Maps: All reports shall include the figures and maps listed in (13)(a) through (13)(g). All maps must include an outline of the study area boundary, a north arrow, a scale bar, and legend of all map elements.


A location map, such as a city map,


Assessors tax lot map(s), which include the entire study area, downloaded as PDFs from the Oregon Department of Revenue’s “ORMAP” website.


The appropriate LWI map(s) or if no LWI has been completed, the NWI map(s),


The county soil survey map including the map unit symbol, name, and hydric status for all soil series mapped within the study area;


At least one recent aerial photograph, preferably taken early in the growing season that includes the month and year of the photo (include at least three aerial photos from three different years for farmed sites).


One or more wetland and other waters maps comprising the wetland and water determination or delineation, as appropriate, that meets the requirements in sections (14) through (16) of this rule.


Ground level color photographs of the site.


The wetland and other waters map(s) must include:


The boundaries of the entire parcel(s) subject to investigation; or


The study area boundary in relation to the parcel boundaries, if only a portion of the parcel(s) was investigated. For large parcels with small study areas, a map in addition to the wetland map may be required to show the relationship between the study area and parcel boundaries.


An index map if a large project study area needs to be divided into more than one detail map for clarity or map scale issues. The index map shall show the precise location and extent of the areas shown on the detail maps in relationship to the larger study area.


Locations of existing structures (unless visible on a current aerial photo included in the report), such as culverts, bridges, tidegates, fencelines, powerlines, and roads, where practicable.


Locations of fill, water diversions, or other major alterations;


The boundaries of all wetlands and other waters and where they extend offsite;


Numbered sample plots corresponding to data forms (see section (17) of this rule);


Photograph locations and direction of view.


A statement of the mapping method and estimated mapping precision for the study area boundary, wetland and non-wetland water boundaries, and data plot points, for example the GPS post-processing error estimate.


The wetlands and other waters identified must be accurately transferred to a linework basemap, legible on a black-and-white photocopy. An aerial photo base layer may be used but the image shall be lightened to maintain map legibility.


The wetland map(s) shall be at a scale suitable for the study area size and for legibility. For most purposes, an appropriate map scale is 1 inch = 100 feet. For large study areas, a scale of 1 inch = 250 feet may be sufficient. Minimum map scale for a JD and for permitting purposes is subject to Department approval.


Data Form Requirements: All reports shall include a wetland determination data form for each sample plot. The data form used must be that provided with the appropriate regional supplement to the manual, or other form provided by the Department. All wetland determination data forms must:


Be fully completed;


Include only data collected from a single sample plot on a single date (additional dates of hydrology data may be reported in the comments section or provided in a table);


Include the full Latin botanical name of all plant species listed per the National Wetland Plant List;


Use standard soils terminology and abbreviations as established by the U.S. Department of Agriculture, Natural Resources Conservation Service; and


Provide remarks for each disturbed or problematic wetland parameter per procedures outlined in the Difficult Wetland Situations Chapter of the appropriate regional supplement.

Source: Rule 141-090-0035 — Standards and Requirements for Wetland Delineation Reports Submitted to the Department, https://secure.­sos.­state.­or.­us/oard/view.­action?ruleNumber=141-090-0035.

Last Updated

Jun. 8, 2021

Rule 141-090-0035’s source at or​.us