US Army Corps of Engineers
Chicago District Website

Delineation Standards

Regulatory Branch, Chicago District
U.S. Army Corps of Engineers
Last updated March, 2021


  • Reference appropriate Supplements to the Corps of Engineers Delineation Manual when conducting delineation fieldwork.  In Chicago District territory, either the Midwest Supplement or the Northcentral and Northeast Supplement will be used.  Determine which Supplement should be used prior to conducting fieldwork.  Both can be found here:

  • Use appropriate Supplement data forms, link to Automated Wetland Determination Data Form and User Guide follows:

  • Reference current National Wetland Plant List (NWPL) for appropriate Supplement:

  • Sample points should be taken in suspect areas in order to demonstrate and document their upland/wetland status.  A suspect area is an area that is mapped as a wetland or an area that exhibits wetland vegetation, hydric soils, and/or wetland hydrology or a combination thereof.   Do not conclude an area is upland without documenting its upland status with a sample point.

  • Use newer Soil Color Chart (Munsell currently recommends replacing Soil Color Chart every two years) to color soils.  Color chips can fade and lead to incorrect interpretation of soil.

  • Use ‘wetland delineation’ print day glo pink (or day glo orange) flagging or ‘wetland delineation’ print pin flags to identify wetland boundary.  Do not use plain flagging or plain pin flags as surveyors and utilities also use these.

  • ‘Wetland delineation’ pin flags or ‘wetland delineation’ flagging tied to wood lathe should be used when possible.

  • When it is necessary to tie/hang ‘wetland delineation’ flagging, tie it on woody vegetation or permanent structure and not on herbaceous vegetation. 

  • Wetland boundary flags should be spaced so that no waters of the US, including wetlands, are omitted between flags.

  • The limits of waterways and drainages must be flagged.  If wetlands exist outside of the Ordinary High Water Mark (OHWM) of a waterway or water body, flag the waterway/water body and abutting wetland as one area, do not flag them as separate areas.

  • Reference Regulatory Guidance Letter (RGL) No. 05-05 when delineating using OHWM:

  • We strongly encourage completion of a wetland delineation course based on the 1987 Corps Wetland Delineation Manual for anyone putting their names as Investigators on data forms.   In addition, we strongly encourage anyone conducting delineation work within our boundaries to have completed training on the use of the Midwest and Northcentral and Northeast Supplements.

  • Conducting delineation work with an experienced delineator (i.e., a Professional Wetland Scientist (PWS) and/or Certified Wetland Specialist (CWS)) prior to conducting solo delineation work is strongly encouraged. 

  • When digging soil pits, we strongly recommend the use of tile spades/Sharpshooters versus the use of soil augers and/or soil probes.  Use of soil augers and/or soil probes can alter the soil profile and therefore alter soil data.

  • We strongly recommend that wetland boundary surveys are prepared by a Professional Land Surveyor (P.L.S.) in Illinois, or by a P.L.S. or P.E. in Indiana, regardless the stage of the project.

  • Delineation boundary surveys prepared by a P.L.S. (or P.E. in Indiana) need to be included with all permit applications so that impact acreages can be calculated accurately.

  • Delineation fieldwork should occur within growing season and under normal circumstances whenever possible.



  • Include description of general site conditions as well as descriptions for each delineated area. This should include acreage and/or square feet for all delineated areas and wetland community types (i.e., emergent, forested, etc.) for each delineated area. If areas were delineated using OHWM you will need to include information on delineated waterways including width, length, flow duration (i.e., perennial, intermittent, ephemeral), flow direction, and condition.

  • Reports should, at minimum, contain the following figures that clearly depict property boundary or limits of project area: general location map, US Geological Survey (USGS) Topographic Map, National Wetlands Inventory (NWI), soils map generated using USDA-NRCS’s Web Soil Survey website (, recent (representative of current land use) aerial photograph showing locations of sample points, and delineation figure (if areas were delineated) consisting of aerial photograph with delineation boundary overlay and/or Plat of Topography/Topographic Map with delineation boundary overlay.

  • Show road names and portions of adjacent lands on all report figures.

  • Provide latitude/longitude in decimal degrees for each delineated area.

  • Provide GIS shapefiles for each delineated area if available.

  • If the project you are working on will require a permit, you should complete a plant inventory for wetland and upland portions of site and generate an Inventory for each using the Inventory Calculator found in the Chicago Region Floristic Quality Calculator (download current version at and also compile a wildlife list for purposes of fulfilling Section 7 of the Endangered Species Act (ESA).


Following these standards will help to expedite our review of delineation work.   Flexibility of these standards may be determined by the District on a case-by-case basis only.  Please remember the Corps has the ability to reject delineation work that is: incomplete, inaccurate and/or conducted outside of the growing season.  


POC:  Mr. Andrew Blackburn, PWS, CWS or Telephone: (312) 846-5543