The Iowa DOT complies with all requirements of Section 404 of the Clean Water Act when constructing transportation projects. The Water Resources Section of the Office of Location and Environment (OLE) determines if the project requires a 404 Permit by reviewing preliminary plans and project concepts for all projects that potentially could trigger the need for a Section 404 Permit. A 404 Permit is required for the discharge of dredged or fill materials into waters of the United States, which includes wetlands, rivers/steams/drainages, ponds and lakes (fill material is the trigger). Typical activities that require Section 404 review include:

·        Grading

·        Widening and Resurfacing

·        Culvert extensions

·        Bridge/culvert replacements or updates

·        Riprap placement and/or flood emergency repairs

·        Any construction on new alignment

·        Any construction in or around streams or wet areas (including clearing and grubbing)

A good rule of thumb is any project that includes new ROW purchase and/or impacts an aquatic resource should be reviewed for Section 404 requirements.


Documents were developed to provide broad information and specifics regarding wetlands, environmental considerations, clearances, and permits associated with highway and bridge construction in the State of Iowa. These documents were created to provide both information and clearer understanding of the requirements on the part of the Iowa DOT, Counties, Cities, the construction industry, and the associated regulatory agencies.


The information, presented as Frequently Asked Questions, covers the topics on the following “tabs”:

·        Wetlands and 404 Permitting

·        Environmental Considerations, clearances and permits

·        EW-401 and construction of temporary stream crossings     


Link to the FAQ’s:




Wetlands are a subset of Waters of the United States that is flooded or saturated by surface or ground water long enough to support vegetation typically adapted for life in saturated soil conditions. From a regulatory standpoint, an area is considered a wetland if it has sufficient wetland hydrology (water), has dominant wetland vegetation, and has hydric soils (wet soils).


Waters of the United States (WUS) do include wetlands, however, they also are identified as rivers, streams, creeks, drainage ditches, and ravines.  Basically, any drainage that has some sort of sustained surface flow has potential to be a WUS.  


Waters of the United States, including wetlands, are protected in Iowa by federal and state laws and Iowa DOT policy (PPM 500.03).


Waters of the United States, including wetlands are regulated in Iowa by the U.S. Army Corps of Engineers (Corps), who authorize projects in compliance with Section 404 of the Clean Water Act; U.S. Environmental Protection Agency (EPA), who enforce Section 404; and the Iowa Department of Natural Resources (DNR), who issue Section 401 Water Quality Certifications for all Section 404 Permits. In addition, the U.S. Fish & Wildlife Service, Natural Resource Conservation Service, Federal Highway Administration, and State Historical Preservation Officer all play important roles in the 404 Permitting process.



During design and construction phases of projects, state and federal laws require the Iowa DOT to avoid any protected resources where possible,. The Iowa DOT is required to minimize the unavoidable impacts, and then provide compensatory mitigation for any remaining impacts that exceed a certain threshold. OLE secures all 404 permits/401 certifications for all Iowa DOT projects prior to project letting. Typically, contractors are responsible for obtaining a 404 permit and other environmental clearances for borrows, value engineering techniques, dredging, or any activities outside of approved right of way.


When a project has unavoidable impacts to a WUS, OLE applies for a 404 Permit.  The Iowa DOT will receive either a Nationwide permit(s), Regional permit, or an Individual permit.


Nationwide permits and regional permits are issued for projects that have minimal environmental impacts. They provide a simplified, expedited process that allows project development to proceed with little or no delay. Most projects are normally covered by nationwide permits; however, regional permits may be issued if impacts from a project exceed the limits for nationwide permits but are not large enough to require an Individual permit. An Iowa DNR 401 certification is automatically issued when the U.S. Army Corps of Engineers issues a nationwide or regional permit.


Section 404 Authorization is requested by preparing either a Pre-Construction Notice, in the case of a General Permit, or an Individual Permit Application. Both documents contain project concept, locations, history, schedule, plans, cross-sections, wetland avoidance and minimization efforts, wetland delineations and other detailed site data, a proposed mitigation plan, and many other types of information.


A 404 Permit that authorizes a project contains requirements and conditions specific to the proposed construction project. It is imperative that the Iowa DOT field construction staff AND the contractor are aware of all permit requirements and work together to ensure compliance. Failure to comply with a Section 404 permit may result in an enforcement action against the Department including a cease and desist order to stop all project work and fines of up to $25,000 per day until compliance is met. Corps, EPA and DNR inspectors may and do visit construction projects without prior notice.


Upon issuance of a Section 404 authorization, the Water Resources project manager will prepare a clearance memo highlighting any issues of particular concern and forward the memo and 404 permit to the District Construction Engineer The Office of Contracts may include the 404 permit in the contract documents at the request of the Office of Location and Environment for environmentally sensitive projects. For any project that requires a permit, the 404 Permit should be available at the site until completion of the project. The clearance memo and permit can also be found in the Electronic Records Management System and can be accessed by the public at http://www.envpermits.iowadot.gov/Collections.aspx?AppId=ENVIRONMENTAL.


10.43     MITIGATION

Mitigation for impacts to wetlands and streams must occur in a specific sequence. The first step of mitigation is to avoid impacts to wetlands or streams. When impacts exceed 0.1 acre of wetland, the Iowa DOT needs to provide compensatory mitigation to replace those impacts.  The Iowa DOT also provides stream mitigation for stream impacts, however this is on a case by case basis. Compensation, or compensatory mitigation, is when DOT  restores, creates, enhances, or in exceptional circumstances, preserves a wetland and/or other aquatic resource for the purpose of compensating for unavoidable adverse impacts resulting from construction of highway projects. Currently, DOT compensates at a minimum 1.5:1 ratio, meaning 1.5 acres of wetland are replaced for every 1 acre of wetland impacted.  Special circumstances may require DOT to compensate at a higher mitigation ratio.


When required, mitigation projects are designed by OLE or OLE’s wetland consultants and let as a separate project. In some cases, mitigation may be accomplished in conjunction with the primary project by modifying a project feature such as a stream crossing, ditch, or borrow. Iowa DOT buys wetland credits from a private wetland bank when available, thus reducing the need for an Iowa DOT designed wetland mitigation site/project.  The Corps requires that mitigation (which includes credit purchase when available) must be completed prior to or concurrent with wetland fill activities along the primary project.


Mitigation projects may include site grading, construction of water control structures, removal of existing drainage features, planting of both uplands and wetlands with native seed, live plugs, and/or trees. It is important for the contractor to understand that mitigation projects often require work in wet soil conditions.


One of the most critical elements for mitigation success is construction to the proper elevations.  This ensures that the water necessary to sustain the mitigation wetlands will be available as designed. Sometimes, it is generally desirable to leave finish grades rough and uneven with shallow and variable slopes and to create undulating bottom surfaces with diverse water depths. Removal of tile from wetland areas works best if the tile line is removed in its entirety.  Wetland seeding is most successful when performed in the spring time on moist soil.  These types of important activities will be identified in project plans; therefore, plan reference notes should be carefully followed.


The Water Resources Section in the Office of Location and Environment have biological, construction and engineering staff available to discuss wetland mitigation projects.  When in doubt, please check with the Water Resources Section.



The Corps of Engineers’ Section 404 Permit requires that a Post Construction Report (PCR) be submitted to the Corps of Engineers’ within 30 days of the completion of the mitigation site. These drawings are separate from the usual DOT “As-Built” plans. The PCR typically includes before/after cross-sections, location and elevation of water control structures, monitoring sites, final boundary of constructed wetlands, list of plant species, photos, depth of transplanted topsoil, geometry and treatment of buffer areas, ditch plugs, drain tiles and boundary markers. 


The PCR’s are reviewed by the regulatory agencies to ensure that the regulated resources were adequately mitigated. Preparation of the PCR’s is coordinated by OLE’s engineers in cooperation with the Water Resources project manager. Post Construction Reports do not need a signature by a licensed engineer.



Mitigation projects will be monitored annually by the OLE project manager for a minimum of five years. Monitoring involves regular site visits and investigation to document development of project features, primarily hydrology, vegetation, and soil characteristics. Monitoring also includes inspection of constructed features to identify any needed remedial actions. Open construction contracts may be utilized for remedial actions when appropriate. District staff may be requested by OLE to visit the site.



All mitigation projects should include a discussion of the permit conditions and responsibilities at the preconstruction conference. It is important to invite OLE staff to attend the conference to explain the permit requirements and the responsibilities and obligations of the Department and contractor, as well as to answer any questions.



A Section 404 Permit may contain a Completed Work Certification Form to be completed by the Resident Construction Engineer upon completion of any project that required a permit. The Project Scheduling System (PSS) will automatically notify OLE upon completion of the highway project. 



Occasionally, a contractor may propose work beyond that shown on the project plans. If that work affects areas outside the ROW and/or includes additional impacts to aquatic resources, the OLE Water Resources project manager should be contacted by district staff to ensure permit compliance.