Section 10 of the Rivers and Harbors Act of 1899 governs work impacting navigable waters.

Examples of activities requiring Section 10 permits:

• Construction or installation of piers, wharves, bulkheads, dolphins, marinas, ramps, floats, overhanging decks, buoys, boat lifts, jet ski lifts, intake structures, outfall pipes, and cable or pipeline crossings
• Dredging and excavation.
• Overhead transmission lines, tunnels, or directional bore holes.

Section 404 of the Clean Water Act regulates the placement of dredged or fill material into waters of the United States.

Examples of activities requiring Section 404 permits: 

• Depositing fill, dredged, or excavated material. 
• Grading or mechanized land clearing of wetlands. 
• Ditch excavation activities in wetlands and associated discharge of dredged materials into wetlands. 
• Fill for residential, commercial, or recreational developments. 
• Construction of revetments, groins, breakwaters, beach enhancement, jetties, levees, dams, dikes, and weirs. 
• Placement of riprap and road fills. 
• Bank and stream channel stabilization projects.

Section 404 exemptions (33 CFR 323.4):
You do not generally need a permit under Section 404 for activities associated with normal farming, ranching, and forestry activities that are established and ongoing. Some of these activities include plowing, cultivating, minor drainage, and harvesting for the production of food, fiber and forest products. To find out whether specific activities are exempt, contact your local Corps office.

Navigable waters of the United States are regulated under Section 10 of the Rivers and Harbors Act. These are waters that are subject to the ebb and flow of the tide and/or are presently used, have been used in the past or could be used to transport interstate or foreign commerce. 

See a list of Oregon’s navigable riverways, harbors and bays here.

These waters are regulated under Section 404 of the Clean Water Act. These include navigable waters, lakes, ponds, small streams, ditches, and adjacent wetlands. Waters without a direct hydrological connection such as old river scars, cutoff sloughs, prairie potholes and abandoned construction and mining pits may also be waters of the United States. An important point is that waters of the United States include natural areas as well as areas that are man-made. If you are unclear about whether you have waters of the United States in your project area, please check with your local Corps Project Manager.

The US Army Corps of Engineers (Corps) and the US Environmental Protection Agency define wetlands as follows:

Wetlands are areas that are covered by water or have waterlogged soils for long periods during the growing season. Plants growing in wetlands are capable of living in saturated soil conditions for at least part of the growing season. Wetlands such as swamps and marshes are often obvious, but some wetlands are not easily recognized, often because they are dry during part of the year or "they just don't look very wet" from the roadside.

Some of these wetland types include, but are not limited to, many bottomland forests, pocosins, pine savannahs, bogs, wet meadows, potholes, and wet tundra. The information presented here usually will enable you to determine whether you might have a wetland. If you intend to place dredged or fill material in a wetland or in an area that might be a wetland, contact the local Corps District Office for assistance in determining if a permit is required.

Section 404 of the Clean Water Act requires that anyone interested in depositing dredged or fill material into "waters of the United States, including wetlands," must receive authorization for such activities. The Corps has been assigned responsibility for administering the Section 404 permitting process. Activities in wetlands for which permits may be required include, but are not limited to:

• Placement of fill material.
• Ditching activities when the excavated material is sidecast.
• Levee and dike construction.
• Mechanized land clearing.
• Land leveling.
• Most road construction.
• Dam construction.

The final determination of whether an area is a wetland and whether the activity requires a permit must be made by the appropriate Corps District Office.

The Corps uses three characteristics of wetlands when making wetland determinations: vegetation, soil, and hydrology. Unless an area has been altered or is a rare natural situation, wetland indicators of all three characteristics must be present during some portion of the growing season for an area to be a wetland. Each characteristic is discussed below.

However, there are some general situations in which an area has a strong probability of being a wetland. If any of the following situations occur, you should ask the local Corps office to determine whether the area is a wetland:

• Area occurs in a floodplain or otherwise has low spots in which water stands at or above the soil surface during the growing season. Caution: Most wetlands lack both standing water and waterlogged soils during at least part of the growing season.
• Area has plant communities that commonly occur in areas having standing water for part of the growing season (e.g., cypress-gum swamps, cordgrass marshes, cattail marshes, bulrush and tule marshes, and sphagnum bogs).
• Area has soils that are called peats or mucks.
• Area is periodically flooded by tides, even if only by strong, wind-driven, or spring tides.

Many wetlands can be readily identified by the general situation stated above. For the boundary of these areas and numerous other wetlands, however, it is unclear whether these situations occur.

In such cases, it is necessary to carefully examine the area for wetland indicators of the three major characteristics of wetlands: vegetation, soil, and hydrology. Wetland indicators of these characteristics, which may indicate that the area is a wetland, are described on the following pages.

Nearly 5,000 plant types in the United States may occur in wetlands. These plants, known as hydrophytic vegetation, are listed in regional publications of the US Fish and Wildlife Service.

The National Wetland Plant List plays a critical role in identifying wetlands and the likelihood of particular plant species in specific geographic locations. The NWPL is a list of wetland plants and their assigned indicator statuses.  An indicator status reflects the likelihood that a particular plant occurs in a wetland or upland.

However, you can usually determine if wetland vegetation is present by knowing a relatively few plant types that commonly occur in your area. For example, cattails, bulrushes, cordgrass, sphagnum moss, bald cypress, willows, mangroves, sedges, rushes, arrowheads, and water plantains usually occur in wetlands.

Other indicators of plants growing in wetlands include trees having shallow root systems, swollen trunks (e.g., bald cypress, tupelo gum), or roots found growing from the plant stem or trunk above the soil surface. Several Corps offices have published pictorial guides of representative wetland plant types.

If you cannot determine whether the plant types in your area are those that commonly occur in wetlands, ask the local Corps District Office or a local botanist for assistance.

There are approximately 2,000 named soils in the United States that may occur in wetlands. Such soils, called hydric soils, have characteristics that indicate they were developed in conditions where soil oxygen is limited by the presence of saturated soil for long periods during the growing season. If the soil in your area is listed as hydric by the US Soil Conservation Service (CSC), the area might be a wetland.

If the name of the soil in your area is not known, an examination of the soil can determine the presence of any hydric soil indicators, including:

• Soil consists predominantly of decomposed plant material (peats or mucks).
• Soil has a thick layer of decomposing plant material on the surface.
• Soil has a bluish gray or gray color below the surface, or the major color of the soil at this depth is dark (brownish black or black) and dull.
• Soil has the odor of rotten eggs.
• Soil is sandy and has a layer of decomposing plant material at the soil surface.
• Soil is sandy and has dark stains or dark streaks of organic material in the upper layer below the soil surface. These streaks are decomposed plant material attached to the soil particles. When soil from these streaks is rubbed between the fingers, a dark stain is left on the fingers.

Wetland hydrology refers to the presence of water at or above the soil surface for a sufficient period of the year to significantly influence the plant types and soils that occur in the area. Although the most reliable evidence of wetland hydrology may be provided by gaging station or groundwater well data, such information is limited for most areas and, when available, requires analysis by trained individuals. Thus, most hydrologic indicators are those that can be observed during field inspection. Most do not reveal either the frequency, timing, or duration of flooding or the soil saturation.

However, the following indicators provide some evidence of the periodic presence of flooding or soil saturation:

• Standing or flowing water is observed on the area during the growing season.
• Soil is waterlogged during the growing season.
• Water marks are present on trees or other erect object. Such marks indicate that water periodically covers the area to the depth shown on the objects.
• Drift lines, which are small piles of debris oriented in the direction of water movement through an area, are present. These often occur along contours and represent the approximate extent of flooding in an area.
• Debris is lodged in trees or piled against other object by water.
• Thin layers of sediments are deposited on leaves or other objects. Sometimes these become consolidated with small plant parts to form discernible crust on the soil surface.

One or more indicators of wetland vegetation, hydric soil, and wetland hydrology must be present for an area to be a wetland. If you observe definite indicators of any of the three characteristics, you should seek assistance from either the local Corps District Office or someone who is an expert at making wetland determinations.