US Army Corps of Engineers
Baltimore District

Frequently Asked Questions (FAQs)

Various questions are often asked about the regulatory program. It is hoped that these answers will help you to understand the program better.

The term "waters of the United States" means:

  • All interstate waters including interstate wetlands;
  • All other waters such as intrastate lakes, rivers, streams (including intermittent streams), mudflats, sandflats, wetlands, sloughs, prairiepotholes, wet meadows, playa lakes, or natural ponds, the use, degradation or destruction of which could affect interstate or foreign commerce including any such waters:
    • (i) Which are or could be used by interstate or foreign travelers for recreational or other purposes; or 

    • (ii) From which fish or shellfish are or could be taken and sold in interstate or foreign commerce; or
    • (iii) Which are used or could be used for industrial purposes by industries in interstate commerce;

  • All impoundments of waters otherwise defined as waters of the United States under this definition;

  • Tributaries of waters identified in paragraphs (s)(1) through (4) of this section;

  • The territorial sea;

  • Wetlands adjacent to waters (other than waters that are themselves wetlands) identified in paragraphs (s)(1) through (6) of this section; waste treatment systems, including treatment ponds or lagoons designed to meet the requirements of CWA (other than cooling ponds as defined in 40 CFR 423.11(m) which also meet the criteria of this definition) are not waters of the United States.

Waters of the United States do not include prior converted cropland. Notwithstanding the determination of an area's status as prior converted cropland by any other federal agency, for the purposes of the Clean Water Act, the final authority regarding Clean Water Act jurisdiction remains with EPA

Navigable Waters of the United States are those waters of the United States that are subject to the ebb and flow of the tide shoreward to the mean high water mark. They are also presently used and have been used in the past or may be susceptible to use to transport interstate or foreign commerce.
Wetlands are areas that are periodically or permanently inundated by surface o r ground water and support vegetation adapted for life in saturated soil. Wetlands include swamps, marshes, bogs and similar areas. As a significant natural resource, wetlands serve important functions relating to fish and wildlife. Such functions include food chain production, habitat, nesting spawning, rearing and resting sites for aquatic and land species. They also provide protection of other areas from wave action and erosion; storage areas for storm and flood waters; natural recharge areas where ground and surface water are interconnected; and natural water filtration and purification functions.

Although individual alterations of wetlands may constitute a minor change, the cumulative effect of numerous changes often results in major damage to wetland resources. The review of applications for alteration of wetlands will include consideration of whether the proposed activity is dependent upon being located in an aquatic environment.

The U. S. Army Corps of Engineers uses three characteristics to determine if an area is a wetland: vegetation, soil and hydrology. Unless an area has been altered or is a rare natural situation, indicators of all three characteristics must be present for an area to be a wetland. Additional Guidance is provided in the Corps' 1987 Wetlands Delineation Manual.

Vegetation: Wetland vegetation consists of plants that require saturated soils to survive as well as plants that gain a competitive advantage over others because they can tolerate prolonged wet soil conditions. Over 5,000 plant types in the United States may occur in wetlands. For example: cattails, bulrushes, cordgrass, sphagnum moss, bald cypress, willows, mangroves, sedges, rushes, arrowheads and water plantains usually occur in wetlands. Also, wetland vegetation may sometimes exhibit physical adaptations, which indicate the presence of water. The adaptations include shallow root systems, swollen trunks or roots growing from the plant stem or trunk above the soil surface.

Soils: Soils that occur in wetlands are called hydric soils. Hydric soils have characteristics that indicate they were developed in conditions where soil oxygen is/or was limited by the presence of water for long periods of the growing season. By examining the soil, one can determine if hydric indicators are present. Following are some indicators of hydric soils:

  • contain predominantly decomposed plant material (peat or muck)
  • have a bluish gray or gray color at 10 to 12 inches below the surface layer
  • have dark and dull (brownish black or black) soil as the major color have the odor of rotten eggs
  • may be sandy and have dark stains or streaks of organic material in the upper layer (3 to 12 inches below the surface)


Hydrology: Wetland hydrology refers to the presence of water, either above the soil surface or within the soil, but near the surface (12 to 18 inches below the soil surface, depending on the soil type). For a sufficient period of the year, to deprive the soils of oxygen and significantly influence the plant types which occur in the area. Gauging station or ground water well data provides the most reliable evidence. However, there are field indicators that provide evidence of the periodic presence of inundation or soil saturation. Some include:

  • Standing or flowing water
  • Waterlogged soil
  • Water marks on trees
  • Drift lines, which are piles of debris oriented in the direction of water movement
  • Debris lodged in trees
  • Thin layers of sediment deposited on leaves or other objects.

These layers of sediment often become consolidated with small plant parts to form crusts on the soil surface. You should ask the Corps office to determine whether an area is a wetland if it has any of the following conditions:

  • The area is flooded or ponded, and occurs in a floodplain or has low spots or is poorly drained such that water is present just below or collects above the soil surface for part of the growing season?

  • The area has plant communities that commonly occur in areas having standing water for part of the growing season
  • The area has peat or mucky soils or is soft enough that it compresses under foot
  • The area is periodically flooded by tides
  • CAUTION: Wetlands may not be obvious for particular wetland types or at all times of the year.

The term ordinary high water mark means that line on the shore established by the fluctuations of water and indicated by physical characteristics such as a clear, natural line impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, the presence of litter and debris, or other appropriate means that consider the characteristics of the surrounding areas.

The line on the shore in tidal areas established by the fluctuations of water and indicated by physical characteristics such as a clear, natural line impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, the presence of litter and debris, or other appropriate means that consider the characteristics of the surrounding area.

Rooted aquatic plants, also called submerged aquatic vegetation (SAV), represent an important component of many coastal ecosystems. SAV supports the health of these ecosystems by generating food and habitat for waterfowl, fish, shellfish, and invertebrates; adding oxygen to the water column during photosynthesis; filtering and trapping sediment that otherwise would bury benthic organisms and cloud the water column; inhibiting wave action that erodes shorelines; and absorbing nutrients, such as nitrogen and phosphorus, that otherwise could fuel the growth of unwanted planktonic algae.

To learn more about SAV, select the following links:

U.S. Environmental Protection Agency Submerged Aquatic Vegetation in the Chesapeake Bay:

Virginia Institute of Marine Science Submerged Aquatic Vegetation (SAV) in Chesapeake Bay and Delmarva:

The U.S. Army Corps of Engineers has been regulating activities in the nation’s waters since 1890. Until the 1960s the primary purpose of the regulatory program was to protect navigation. Since then, as a result of laws and court decisions, the program has been broadened so that it now considers the full public interest for both the protection and utilization of water resources. The regulatory authorities and responsibilities of the Corps of Engineers are based on the following laws:

  • Section 9 of the Rivers and Harbors Act approved March 3, 1899, (33 U.S.C. 401) prohibits the construction of any dam or dike across any navigable water of the United States in the absence of Congressional consent and approval of the plans by the Chief of Engineers and the Secretary of the Army.

  • Section 10 of the Rivers and Harbors Act (33 U.S.C. 403) prohibits the obstruction or alteration of navigable waters of the United States without a permit from the Corps of Engineers.

  • Section 404 of the Clean Water Act (33 U.S.C. 1344) prohibits the discharge of dredged or fill material into waters of the United States without a permit from the Corps of Engineers.

  • Section 103 of the Marine Protection, Research, and Sanctuaries Act of 1972, as amended (33 U.S.C. 1413) authorizes the Corps of Engineers to issue permits for the transportation of dredged material for the purpose of dumping it into ocean waters.

The initial step in the permit application process is to identify and delineate those waterbodies and wetlands that are subject to CWA and RHA jurisdiction. The JD process provides important information to a landowner or investor for planning purposes or carrying out certain activities on a given parcel of land. Accurately identifying jurisdictional waters is essential in making an application for a permit from the Corps to determine if work would occur in regulated waters of the United States.

The identification and location of jurisdictional Waters of the United States including wetlands regulated by the Corps under Section 404 of the CWA and Sections 9 and 10 of the RHA is determined through a process known as a Jurisdictional Determination (JD). The Corps uses a multi-parameter approach defined in Technical Report Y-87-1, Corps of Engineers Wetlands Delineation Manual, dated January 1987, and supplemental guidance when making wetland determinations. It generally requires positive evidence of hydrophytic vegetation, hydric soils, and wetlands hydrology for some portion of the growing season for a determination that an area is a federally-regulated wetland.

There are two types of JD procedures used by the Baltimore District.  Preliminary JDs are advisory in nature and may not be appealed. A landowner, permit applicant, or other "affected party" may elect to use a preliminary JD to voluntarily waive or set aside questions regarding CWA/RHA jurisdiction over a particular site, usually in the interest of allowing the landowner or other "affected party" to move ahead expeditiously to obtain a Corps permit authorization where the party determines that is in his or her best interest to do so. We encourage permit applicants to submit a completed, signed copy of the Preliminary JD Form and copies of the referenced supporting data with your permit application or JD request.


An approved JD is an official Corps determination that jurisdictional waters of the United States are either present or absent on a particular site. An approved JD is valid for five years and can be appealed through the Corps administrative appeal process set out at 33 CFR Part 331. The information on the Baltimore District Approved JD Information Checklist is recommended for all approved JD requests and will assist Corps staff in delineating waters of the U.S and completing accurate JDs. This documentation must allow for a reasonably accurate replication of the delineation or determination at a future date.

Any person, firm, or agency (including Federal, state, and local government agencies) planning to work in navigable waters of the United States, or discharge (dump, place, deposit) dredged or fill material in waters of the United States, including wetlands, must first obtain a permit from the Corps of Engineers. Permits, licenses, variances, or similar authorization may also be required by other Federal, state and local statutes.

Since three to four months is normally required to process a routine application involving a public notice, you should apply as early as possible to be sure you have all required approvals before your planned beginning date. For a large or complex activity that may take longer, it is often helpful to have a "pre-application consultation" or informal meeting with the Corps during the early planning phase of your project. You may receive helpful information at this point, which could prevent delays later. When in doubt as to whether a permit may be required or what you need to do, don’t hesitate to call a district regulatory office.

The Baltimore District Corps organization consists of a Branch Office, Maryland Section, which includes D.C., and the military bases in northern Virginia and a Pennsylvania Section for that area of the Commonwealth of Pennsylvania in the Baltimore District Regulatory boundaries. The Maryland Section has two regions; Maryland Section Northern and Maryland Section Southern, the division of counties for these two regions is shown on the enclosed maps. The Regulatory Branch organization maintains a geographic approach to maximize each of the counties in the Baltimore District.

It is possible you may not have to obtain an individual permit, depending on the type or location of work. The Corps has many general permits, which authorize minor activities without the need for individual processing. Check with your Corps district regulatory office for information on general permits. When a general permit does not apply, you may still be required to obtain an individual permit.

Nationwide, less than three percent of all requests for permits are denied. Those few applicants who have been denied permits usually have refused to change the design, timing, or location of the proposed activity. When a permit is denied, an applicant may redesign the project and submit a new application. To avoid unnecessary delays pre-application conferences, particularly for applications for major activities, are recommended. The Corps will endeavor to give you helpful information, including factors, which will be considered during the public interest review, and alternatives to consider that may prove to be useful in designing a project.

If  your activity is located in an area of tidal waters, the best way to avoid the need for a permit is to select a site that is above the high tide line and avoids wetlands or other water-bodies. In the vicinity of fresh water, stay above ordinary high water and avoid wetlands adjacent to the stream or lake. Also, it is possible that your activity is exempt and does not need a Corps Permit. Another possibility for minor activities is that a Nationwide or a Regional General Permit may have authorized them. So, before you build, dredge or fill, contact the Corps district regulatory office in your area for specific information about location, exemptions, and regional and nationwide general permits.

Performing unauthorized work in waters of the United States or failure to comply with the terms of a valid permit can have serious consequences. You would be in violation of federal law and could face stiff penalties, including fines and/or requirements to restore the area.

Enforcement is an important part of the Corps regulatory program. Corps surveillance and monitoring activities are often aided by various agencies, groups, and individuals, who report suspected violations. When in doubt as to whether a planned activity needs a permit, contact the nearest district regulatory office. It could save a lot of unnecessary trouble later.

Information about the regulatory program is available from any Corps district regulatory office.

The objective of the Clean Water Act (CWA) is to restore and maintain the chemical, physical, and biological integrity of the Nations waters. Toward achievement of this goal, the CWA prohibits the discharge of dredged or fill material into wetlands, streams, and other waters of the United States unless a permit issued by the U.S. Army Corps of Engineers (Corps) or approved State under CWA Section 404 authorizes such a discharge. When there is a proposed discharge, all appropriate and practicable steps must first be taken to avoid and minimize impacts to aquatic resources. For unavoidable impacts, compensatory mitigation is required to replace the loss of wetland, stream, and/or other aquatic resource functions. The Corps (or approved state authority) is responsible for determining the appropriate form and amount of compensatory mitigation required. Methods of providing compensatory mitigation include aquatic resource restoration, establishment, enhancement, and in certain circumstances, preservation.

Compensatory mitigation is typically accomplished through the following three ways:


  • Mitigation Banks: A permit applicant may obtain credits from a mitigation bank. A mitigation bank is a wetland, stream or other aquatic resource area that has been restored, established, enhanced, or preserved. This resource area is then set aside to compensate for future impacts to aquatic resources resulting from permitted activities. The value of a bank is determined by quantifying the aquatic resource functions restored, established, enhanced, and/or preserved in terms of "credits." Permittees, upon approval of regulatory agencies, can acquire these credits to meet their requirements for compensatory mitigation.

  • In-Lieu Fee Mitigation: A permit applicant may make a payment to an in-lieu fee program that will conduct wetland, stream or other aquatic resource restoration, creation, enhancement, or preservation activities. In-lieu fee programs are generally administered by government agencies or non-profit organizations that have established an agreement with the regulatory agencies to use in-lieu fee payments collected from permit applicants.

  • Permittee-Responsible Mitigation: A permittee may be required to provide compensatory mitigation through an aquatic resource restoration, establishment, enhancement and/or preservation activity. This compensatory mitigation may be provided at or adjacent the impact site (i.e., on-site mitigation) or at another location, usually within the same watershed as the permitted impact (i.e., off-site mitigation). The permittee retains responsibility for the implementation and success of the mitigation project.

Mitigation banks and in-lieu fee mitigation are forms of "third-party" compensation because a third party, the bank or in-lieu fee sponsor, assumes responsibility from the permittee for the implementation and success of the compensatory mitigation.

The 2008 USACE/EPA Mitigation Rule improves and consolidates existing regulations and guidance, to establish equivalent standards for all types of mitigation under the Clean Water Act Section 404 regulatory program. The new rule will also provide one set of regulations for compensatory mitigation, instead of the numerous separate guidance documents that have been in use up to now. This rule uses improved science and results-oriented standards to increase the quality and effectiveness of wetland and stream restoration and conservation practices. The rule does not change when compensatory mitigation is required, but it does change where and how it is required.

The rule establishes equivalent sets of standards that are based on better science, increased public participation, and innovative market-based tools. These equivalent standards take into account the inherent differences among mitigation banks, in-lieu fee programs, and permittee-responsible mitigation, in an effort to maximize the number of ecologically-successful compensatory mitigation projects that project proponents can use to offset their permitted losses of aquatic resources. We believe that this rule will substantially improve compensatory mitigation project performance and accountability.

The most significant change required by the new rule is that compensation projects provided by all three compensation mechanisms (i.e., permittee-responsible compensatory mitigation, mitigation banks, and in-lieu fee mitigation) must have mitigation plans which include the same 12 fundamental components: objectives; site selection criteria; site protection instruments (e.g., conservation easements); baseline information (for impact and compensation sites); credit determination methodology; a mitigation work plan; a maintenance plan; ecological performance standards; monitoring requirements; a long-term management plan; an adaptive management plan; and financial assurances. This important change will dramatically improve the planning, implementation and management of all compensation projects and ensure more effective wetland and stream replacement projects.

In order to reduce risk and uncertainty and help ensure that the required compensation is provided, the rule establishes a preference hierarchy for mitigation options. The most preferred option is mitigation bank credits, which are usually in place before the activity is permitted. In-lieu fee program credits are second in the preference hierarchy, because they may involve larger, more ecologically valuable compensatory mitigation projects as compared to permittee-responsible mitigation. Permittee-responsible mitigation is the third option, with three possible circumstances: (1) conducted under a watershed approach, (2) on-site and in kind, and (3) off-site/out-of-kind. While on-site/in-kind mitigation approaches will continue to be evaluated, the rule acknowledges that there are circumstances where off-site or out-of-kind compensatory mitigation may be more beneficial for a watershed.

The primary goals of this rule are to:

  • Implement environmentally effective standards for compensatory mitigation that are based on best available science and incorporate key National Research Council (NRC) recommendations for improving the success of compensatory mitigation;
  • Create a "level playing field" among the three compensatory mitigation mechanisms through equivalent standards and greater accountability, so that providers of timely, high-quality mitigation are preferred, because there is greater assurance that the compensatory mitigation will be successful;
  • Increase the efficiency and predictability of the process of proposing compensatory mitigation and approving new mitigation banks and in-lieu fee programs; and
  • Enhance public participation in compensatory mitigation decision-making.

Mitigation banks are a "performance-based" form of wetland and stream replacement because, unlike in-lieu fee mitigation and permittee-responsible mitigation, the tradable aquatic resource restoration credits generated by banks are tied to demonstrated achievement of project goals. Thus, the rule establishes a preference for the use of credits from mitigation banks when appropriate credits are available. The new rule encourages the use of mitigation banks and in-lieu fee programs over use of permittee-responsible mitigation because mitigation banks and in-lieu fee programs usually provide consolidated compensatory mitigation projects that have less risk and uncertainty.

In its 2001 critique of wetland replacement practices, the NRC highlighted advantages of third-party compensation such as mitigation banks and in-lieu fee programs noting that:


  • Mitigation banks and in-lieu fee programs use a multi-resource agency process that brings more expertise and collaboration into the planning, approval, and oversight of wetland restoration and protection projects; and

  • Mitigation banks and in-lieu fee programs have less risk than permittee-responsible mitigation projects to achieve desired long-term outcomes and to provide wetlands, streams, and other aquatic habitats that are protected in perpetuity by organizations dedicated to resource conservation.

The rule revises and improves the requirements for in-lieu fee programs in order to address concerns regarding their past performance and equivalency with the standards imposed on mitigation banks and permittee-responsible mitigation. These reforms are based to a large extent on existing practices of the most successful in-lieu fee programs currently operating. The reforms to improve accountability and performance include:

  • An advance planning requirement;

  • A cap on the number of advance credits that can be released for sale before an in-lieu fee project site is secured and a mitigation plan is approved;

  • Improved financial accounting requirements;

  • The same interagency/public review and ecological/administrative requirements as mitigation banks; and

  • Limiting in-lieu fee sponsors to government agencies and non-profit organizations.

The rule is specifically designed to improve our ability to ensure no net loss of wetlands by addressing key recommendations associated with compensatory planning, monitoring, and long-term maintenance raised by the NR C in its 2001 report evaluating compensatory mitigation. The NRC report summarized many studies which suggested that compensatory mitigation practices were falling short of providing for "no net loss" of wetland quality and quantity.

Yes. The mitigation sequence established by the Clean Water Act Section 404(b)(1) Guidelines has been retained in this rule. Proposed impacts must be avoided to the maximum extent practicable; remaining unavoidable impacts must then be minimized, and finally compensated for to the extent appropriate and practicable. The final rule affirms the mitigation sequence and clarifies the criteria for appropriate measures to compensate for unavoidable losses.

Yes. The rule clarifies the consideration of watershed-scale factors in the selection of appropriate mitigation sites. This clarification may increase the practical viability of mitigation proposals involving off-site or out-of-kind replacement that still provide appropriate aquatic resource replacement in ways that are beneficial to the watershed. Compensatory mitigation options available to permittees include on-site mitigation, off-site mitigation, or a combination of on-site and off-site mitigation within the watershed. Off-site mitigation may be provided by mitigation banks or in-lieu fee programs, or through permittee-responsible mitigation. The Corps is the final decision-maker regarding whether a proposed compensatory mitigation option provides appropriate compensation for a Department of the Army permit.

Since 1990, there has been a general and flexible preference that mitigation should occur on-site and in-kind. This rule retains a flexible preference for in-kind mitigation however it replaces the on-site preference with a hierarchy that considers compensation options in the following order 1) use of credits from a mitigation bank, 2) use of credits from an in-lieu fee program, 3) permittee-responsible compensatory mitigation developed using a watershed approach, 4) on-site/in-kind permittee-responsible mitigation, and 5) off-site/out-of-kind permittee-responsible mitigation.

Yes, this rule states that, where appropriate and practicable, compensatory mitigation decisions should be made from a watershed perspective in which the type and location of compensatory mitigation follows from an analytically-based watershed assessment to assure that the proposed compensation furthers watershed goals. This assessment may take the form of a watershed plan, which typically involves an intensive regional planning effort involving many stakeholders. It may also be a less formal "watershed approach," involving the analysis of data concerning regional environmental issues, efforts to inventory historic trends in aquatic resource condition, and the prioritization of aquatic resource restoration opportunities. Such an approach involves consultation with stakeholders, resource agencies and environmental experts as appropriate.