United States Department of Agriculture 658-CPS-1

NRCS, NHCP

July 2022

NRCS reviews and periodically updates conservation practice standards. To obtain the current 

version of this standard, contact your Natural Resources Conservation Service State office or 

visit the Field Office Technical Guide online by going to the NRCS website at 

https://www.nrcs.usda.gov/ and type FOTG in the search field. 

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Natural Resources Conservation Service 

CONSERVATION PRACTICE STANDARD 

WETLAND CREATION 

CODE 658 

(ac)

DEFINITION 

A wetland created on a site location that was historically not a wetland. 

PURPOSE 

This practice is used to accomplish one or more of the following primary purposes: 

• Create wetland functional capacity for floodwater storage 

• Create wetland functional capacity to provide fish and wildlife habitat 

• Create a native plant community adapted to growth and regeneration in anaerobic conditions 

In addition to one or more of the primary purposes, this practice can be applied to create wetland funtional

capacity to improve water quality. 

CONDITIONS WHERE PRACTICE APPLIES 

This practice applies to all Natural Resources Conservation Service (NRCS) land uses, where wetland

hydrology can be established on a site that was historically not a wetland. 

This practice does not apply to— 

• Wetlands for the single purpose of treating wastewater or providing other water quality functions.

Use NRCS Conservation Practice Standard (CPS) Constructed Wetland (Code 656). 

• Water impoundment for the exclusive purpose of storing permeant water. Use NRCS CPS Pond

(Code 378). 

• The management of fish and wildlife habitat created under this standard. Use NRCS CPS Wetland

Wildlife Habitat Management (Code 644). 

• The management of water for the exclusive purpose of providing seasonal habitat for fish and/or

wildlife. Use NRCS CPS Shallow Water Development and Management (Code 646). 

• The treatment of point and nonpoint sources of water pollution. Use NRCS CPS Constructed

Wetland (Code 656). 

• The rehabilitation of a degraded wetland or the reestablishment of a former wetland so that soils,

hydrology, vegetative community, and habitat are a close approximation of the original natural

condition and boundary that existed prior to the modification. Use NRCS CPS Wetland Restoration

(Code 657). 

• The rehabilitation of a degraded wetland, the reestablishment of a former wetland, or the

modification of an existing wetland, where specific wetland functions are augmented beyond the

original natural conditions; possibly at the expense of other functions. Use NRCS CPS Wetland

Enhancement (Code 659). 

• Construction of a dam with significant or high hazard potential as defined in the NRCS National
Engineering Manual (Title 210), Part 520, Subpart C, “Dams,” Section 520.21. 

CRITERIA 

General Criteria Applicable to All Purposes 

The created wetland must support wetland hydrology. For this practice, wetland hydrology is defined

broadly as shallow inundation or saturation at or near the surface of the substrate (National Research

Council, 1995), for a duration sufficient to create anerobic conditions within the plant rooting zone. 

The hydroperiod (depth, duration, frequency, and timing of wetting events) and dominant water source

must meet the wetland creation objectives. 

The minimum wetland hydrology design criteria for this standard is (i) shallow inundation for 14

consecutive days during the growing season or (ii) soil saturation within 6 inches of the soil surface for 14

consecutive days during the growing season. The growing season is determined with the use of NRCS

Wetlands (WETS) Climate Tables, using 28 degrees Fahrenheit and 50 percent probability and can be

found at http://agacis.rcc-acis.org. Utilize DrainMod, SPAW or another NRCS approved water budget

based analysis tool identified in the NRCS National Engineering Handbook (Title 210), Part 650, Chapter

19, “Hydrology Tools for Wetland Identification and Analysis”, to predict hydroperiod details for wetland

creations with surface runoff hydrologic source. Design elevations need to consider water source

elevations for created wetlands influenced primarily by ground water. 

Soil and geologic material investigations, such as a pit trench, boring or other suitable investigations shall

be conducted to characterize suitability of soil materials to support wetland hydrology. 

Remove, render inoperable, or relocate any surface or subsurface drains that exist in the planned wetland

area. This includes the perimeter of the wetland area for a distance equal to or greater than the lateral

effect distance of the subsurface drain, as computed using methods in the NRCS National Engineering

Handbook (Title 210), Part 650, Chapter 19, “Hydrology Tools for Wetland Identification and Analysis.”

Treatment for subsurface drains may also include replacing perforated pipe with nonperforated pipe.

Treatment for surface drains may include ditch plugs, with or without water control structures, to ensure

that the site can hold water and water flow is controlled in a nonerosive manner. If ditch plugs are used,

design according to the criteria in NRCS CPS Dike (Code 356). 

If an embankment is needed to accomplish the wetland objectives, design the embankment according to

NRCS CPS Dike (Code 356). Include a principal spillway according to NRCS CPS Structure for Water

Control (Code 587) as needed for water level control and to maintain the target pool level for adequate

freeboard. 

For noncropped areas, ensure the created wetland supports wetland vegetation adapted for growth under

prolonged periods of soil saturation or inundation. Where natural colonization of species meeting the

practice purpose is expected, the created wetland may be left to revegetate naturally. Otherwise, target

plant species will be established by seeding or planting using a vegetative establishment NRCS

conservation practice standard meeting the project purpose. For cropped areas, modify the cropping

system in consideration of the planned wetland hydrologic regime. 

If tree planting is conducted, use NRCS CPS Tree/Shrub Establishment (Code 612) or Riparian Forest

Buffer (Code 391). 

If planting herbaceous vegetation, use NRCS CPS Conservation Cover (Code 327) or Wildlife Habitat

Planting (Code 420). 

If needed to meet the practice purpose, ensure adequate water rights are available (timing and amount of

water). 

Avoidor implement mitigation measures if the site is suspected or confirmed ofcontaining hazardous

material. 

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Additional Criteria for Creating Wetland Functional Capacity for Floodwater Storage or Storage of

Water to Reduce Downstream Flooding 

If needed, install a water control structure according to NRCS CPS Structure for Water Control (Code

587). 

• Manage the structure to ensure floodwater storage capacity is available prior to the normal wet

season. 

• Utilize WebWIMP (Matsuura et al., 2003) https://davinci.geog.udel.edu/~wimp/ or another climatebased prediction tool, to determine the normal wet portion of the year. 

• Design the water control structure to allow for a maximum 7-day drawdown period, while

maintaining the designed minimum wetland hydrology. 

• Manage the structure to maintain wetland hydrology criteria following drawdown. 

Additional Criteria for Creating Wetland Functional Capacity for Fish and Wildlife Habitat 

Conduct a suitable wildlife habitat evaluation based on as-built conditions to ensure needs of target

species will be met. 

Utilize NRCS CPS Wildlife Habitat Planting (Code 420) for all herbaceous or shrub vegetative plantings

within the wetland. If Wildlife Habitat Planting (Code 420) is not available, the use of NRCS CPS

Conservation Cover (Code 327) can be utilized but be implemented with wildlife as the purpose. 

If NRCS CPS Structure for Water Control (Code 587) is implemented, NRCS CPS Shallow Water

Development and Management (Code 646) or NRCS CPS Wildlife Habitat Management (Code 644) will

be applied to optimize the management of water for the target fish or wildlife species. 

Additional Criteria for Creating a Native Plant Community Adapted to Growth and Regeneration of

Anaerobic Conditions 

Identify the target native plant community with the use of a local reference site, NRCS ecological site

description, or another source (e.g., Nature Serve). 

Additional Criteria for Creating Wetland Functional Capacity for Water Quality 

For noncropped areas, establish vegetation based on the plants’ ability to address the identified water

quality concern (e.g., filter sediments and sequester nutrients and pesticides). For cropped areas, select

a cropping system to ensure water quality function addresses the water quality concern. 

When nitrate sequestration is an objective— 

• Design the wetland to maximize the number of periods of anaerobic and aerobic conditions in the

substrate during the growing season. 

• If a cropped wetland, utilize crops with high nitrogen demand. Forego application of nitrogen

fertilizer. 

CONSIDERATIONS 

On all wetlands being created— 

• Treat excessive soil erosion within the wetland’s immediate watershed to ensure the wetland

functions as designed over the practice life. If this is not feasible, utilize NRCS CPS Sediment Basin

(Code 350). 

• Excavation, grading, mechanical compaction, or soil amendments may be needed to support

wetland hydrology. 

• Avoid sites with steep toporaphic gradients, consider and use sites with natural topography when

possible. 

• Avoid the construction on sites where large amounts of sulfur (S), iron (Fe) and aluminum (Al) or

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any acid sulfate bearing minerals (examples: jarosite, pyrate) could be present. 

• Adjust target conditions based on the nutrient and pesticide tolerance of the plant and animal

species likely to occur where known nutrient and pesticide contamination exists. 

• If soil carbon is inadequate, add coarse woody debris or sawdust, as appropriate to improve soil

carbon content. 

• Establish fish and wildlife corridors by linking the site to adjacent landscapes, streams, and

waterbodies. This may increase the potential for colonization of the site by native flora and fauna. 

• Add substrate materials from a donor wetland to provide organic matter and a seed bank of

hydrophytes if the target conditions are local genotypes, and such materials are not commercially

available. Inventory donor site to determine risk of introducing invasive and noxious plants. 

• Control invasive and noxious plants. 

• Modify design to minimize offsite impacts related to water temperature, flows, and water availability. 

On created wetlands with water control capabilities— 

• Assess the potential increased predation of aquatic organisms under planned water management

regimes. Modify water management as needed. 

• Implement NRCS CPS Aquatic Organism Passage (Code 396). 

PLANS AND SPECIFICATIONS 

Prepare plans and specifications in accordance with the criteria of this standard and describe the

requirements for applying the practice to achieve its intended purpose. As a minimum,include— 

• A site-specific plan view of the practice showing the main features of the project. 

• Typical profiles and cross sections of berms, excavated side slopes, spillways, and other earthen

features. 

• Detail drawings of structures and appurtenances, as applicable. 

• Specifications that include materials, quantities, methods, sequence, and timing of project

implementation needed to create the target hydroperiod (depth, duration, timing, and frequency) of

saturation or inundation. 

• Conservation practice standard specifications for the vegetative establishment practice used

including a schedule of the measurable or observable success criteria for target vegetative

conditions. 

OPERATION AND MAINTENANCE 

The operation and maintenance plan will include the actions necessary to ensure installed conservation

practice standards are maintained for the life of the practice. It will include— 

• Inspection schedules. 

• A list of items requiring inspection. 

• Procedures and documentation requirements for inspections. 

REFERENCES 

National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, D.C.: The

National Academies Press. https://doi.org/10.17226/4766 

Matsuura K., C. Willmott, and D. Legates. 2003. “WebWIMP, The Web-Based Water-Budget, Interactive,

Modeling Program.” University of Delaware. Accessed July 14, 2020. https://davinci.geog.udel.edu/~wimp/

USDA NRCS. 2008. National Engineering Handbook (Title 210), Part 650, Chapter 13, Wetland

Restoration, Enhancement, or Creation. Washington, D.C.https://directives.sc.egov.usda.gov/

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USDA NRCS. 2015. National Engineering Handbook (Title 210), Part 650, Chapter 19, Hydrology Tools for

Wetland Identification and Analysis. Washington, D.C.https://directives.sc.egov.usda.gov/

USDA NRCS. 2003. Technical Note (Title 190), Biology 15, Wetland Restoration, Enhancement, and

Management. Washington, D.C.

https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs143_010838.pdf

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