Freshwater Wetlands Program

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Freshwater Wetlands Program

The New York State Legislature passed The Freshwater Wetlands Act (Environmental Conservation Law Article 24) in 1975 with the intent to preserve, protect, and conserve freshwater wetlands and their benefits, consistent with the general welfare and beneficial economic, social and agricultural development of the state. 

Wetlands are essential for maintaining biodiversity, mitigating flooding, and protecting water quality. Through this program, the DEC ensures that wetlands are appropriately classified and regulated to support ecological and community resilience.

For a wetland to meet jurisdictional criteria for protection it must:

  • Have an area of 12.4 acres (5 hectares) in size or greater. As of January 1, 2028, the threshold will decrease to 7.4 acres (3 hectares).
  • Meet any of 11 Unusual Importance criteria.
  • To ensure the functions and benefits of jurisdictional wetlands are preserved, the department regulates a 100 foot adjacent area to maintain protective buffers.

The DEC does not regulate wetlands within the Adirondack Park; this responsibility falls to the Adirondack Park Agency (APA). Any public inquiries regarding wetland jurisdiction should be directed to the APA's Jurisdictional Inquiry Form office. You can submit your inquiry by filling out the form and emailing it to [email protected]. For guidance on the necessary forms for your project, the APA recommends contacting them at 518-891-4050 before you begin.

Wetland Classification

Different types of wetlands provide different functions and benefits. The Act requires wetlands be ranked based on the benefits and values provided. This system establishes four classes that rank wetlands according to their ability to perform wetland functions and provide wetland benefits. Wetlands are ranked Class I as the highest level of protections through Class IV as the lowest level of protections. It often is more difficult to get a permit to alter a Class I wetland than a Class II or III wetland because Class I wetlands provide more important wetland benefits.  Lower ranked wetlands still provide important functions and benefits but typically require less protection to continue to provide these functions.

The federal Clean Water Act regulates activities in a similar manner but has slightly different requirements. Landowners are encouraged to contact the U.S. Army Corps of Engineers if they anticipate undertaking activities in or near wet areas.

Wetland Maps

These mapping tools identify potential jurisdictional wetlands. It is important to note that the only way to confirm or deny the presence of regulated freshwater wetlands is by submitting a Parcel JD. 

Environmental Resource Mapper (ERM)

  • The Previously Mapped Freshwater Wetlands is represented by the green layer, on the DEC Environmental Resource Mapper (ERM). This the only layer that confirms presence of regulated wetlands, as it includes those wetlands that were under jurisdictional before the regulatory changes that took effect on Jan. 1, 2025.
  • Freshwater Wetland Informational Maps – Created to assist identifying wetland areas that may be jurisdictional, DEC use the ERM Freshwater Wetlands Layer to view These maps display as pink, are for informational purposes only and cannot be relied upon to determine the presence or absence of freshwater wetlands regulated by DEC. The NYS Article 24 Freshwater Wetland Informational Maps were created by The Institute for Resource Information Sciences (IRIS) at Cornell University and combines a decision tree, statistical analysis, and a process that used Digital Elevation Model (DEM) to identify wetlands depicted.
  • National Wetland Inventory (NWI) Maps: The U.S. Fish and Wildlife Service (USFWS) National Wetlands Inventory (NWI) maps contain information on the location and characteristics of wetlands and deep-water habitats. Wetlands are federally classified using the method described in the Classification of Wetlands and Deepwater Habitats of the United States. 

New York State GIS Clearinghouse: DEC Informational Freshwater Wetland Mapping and Previously Mapped Freshwater Wetlands, in addition to wetlands of unusual importance criteria for Urban Areas and Significant Flooding  are available for download through the New York State GIS Clearinghouse.

National Land Cover Database (NLCD): A dataset produced by the U.S. Geological Survey (USGS) in collaboration with the Multi-Resolution Land Characteristics Consortium (MRLC). It provides detailed land cover information for the United States, including data on land cover change, at a 30-meter spatial resolution.  

Wetlands of Unusual Importance

Wetlands of any size that possess any of the following 11 Usual Importance characteristics meet jurisdictional criteria for protection:

DEC established criteria for identifying watersheds prone to significant flooding by analyzing the smallest Hydrological Unit Codes (HUC) 12 from the United States Geological Survey. To qualify as a watershed with significant flooding, an area must meet all three of the following conditions: 

  1. An impervious surface greater than 2%
  2. A water storage area of less than 5%.
  3. Proximity to an urban area within 4 kilometers (2.48 miles). 

This approach allows the department to consider runoff, water retention capacity, and human risk in developing these criteria. The below image displays all the watersheds with significant flooding in the state. 

The below image displays all the watersheds with significant flooding in the state. Shape files located NYS GIS Clearinghouse Data.

Floodable areas in New York State

A wetland that meets the Unusual Importance criterion by being located within or next to an urban area is defined by the US Census Bureau. Below is a map illustrating these urban areas, with shape files located at NYS GIS Clearinghouse Data.

Designated urban areas in New York State

Contains a plant species occurring in fewer than 35 sites statewide or having fewer than 5000 individuals statewide, as documented by DEC and New York Natural Heritage Program Modeled Data. 

Resources: https://www.nynhp.org/modeled-data/

Meets one or more of the following criteria:

  1. It contains habitat that is utilized for an essential behavior of a species listed as endangered in Part 182 of this Title or listed as endangered by the United States Department of the Interior in the Code of Federal Regulations (50 CFR Part 17); or
  2. It contains habitat that is utilized for an essential behavior of a species listed as threatened in Part 182 of this Title or listed as threatened by the United States Department of the Interior in the Code of Federal Regulations (50 CFR Part 17); or
  3. It contains habitat that is utilized for an essential behavior of species of special concern. Species of special concern are native species of fish and wildlife found by the department to be at risk of becoming threatened in New York based on the criteria for listing in Part 182 of this Title; or 
  4. It contains habitat that is utilized for an essential behavior of a species of greatest conservation need listed in the New York State Wildlife Action Plan (Sept. 2015) with habitat loss having been identified by the department as a moderate to very high threat to New York populations.

Previously mapped and classified as a wetland of unusual local importance and contain wetland characteristics described in section 24-0107(1) of the Act.

State regulation of vernal pools under the Freshwater Wetlands Act is limited to those vernal pools known to DEC to be productive for amphibian breeding. DEC maintains a list of productive vernal pools and updates that list in the Environmental Notice Bulletin. DEC’s list of vernal pools regulated under the Freshwater Wetlands Act will only include pools that have been determined by DEC to be productive for amphibian breeding based on egg mass counts of specific target species within the Hudson-Mohawk, Great Lakes, Lower Hudson – New York City – Long Island, Adirondack, and Southern Tier regions of the state. 

Specific locations of vernal pools containing endangered and threatened species will not be included in the publicly available vernal pool listings or in the updates but will be considered when making jurisdictional determinations. When conducting jurisdictional determinations, DEC will consult the productive vernal pool list. Only those productive vernal pools known to DEC at the time of a jurisdictional determination may be regulated.

The regulations provide the opportunity for landowners to report information to DEC that a vernal pool occurs on their property that meets one or more of the productivity criteria contained on the regulations. The process that DEC will use to receive, process, and respond to vernal pool addition requests is currently under development. To date, the department has not posted a vernal pools list. When we do it will be in the Environmental Notice Bulletin and listed here. If interested in submitting information, please email [email protected].

Summary of Vernal Pool Criteria
RegionSpotted SalamanderWood FrogJefferson Salamander, Blue-Spotted Salamander, or hybridsEastern Tiger Salamander or Marbled Salamander
Hudson-Mohawk  25 or more egg masses10 or more egg masses;20 or more egg masses or larvaeone or more egg masses or larvae
Lower Hudson, NYC, Long Island, and Adirondacks10 or more egg masses 15 or more egg massesone or more egg masses or larvaeone or more egg masses or larvae
Southern Tier10 or more egg masses15 or more egg masses20 or more egg masses or larvaeone or more egg masses or larvae
Great LakesTwo or more egg massesTwo or more egg masses20 or more egg masses or larvaeone or more egg masses or larvae

Class I wetlands are special areas that play an important role in our environment. These wetlands have specific characteristics that make them vital for wildlife and plant species. Here are the key points about Class I wetlands:

  1. Endangered or Threatened Species Habitat: Class I wetlands provide homes for animals that are endangered or threatened. These are species that are at risk of disappearing, and these wetlands help them survive by offering a safe place to live and reproduce.
  2. Endangered or Threatened Plants: These wetlands may also contain plants that are considered endangered or threatened. Protecting these plants is crucial for maintaining biodiversity.
  3. Significant Coastal Habitats: Some Class I wetlands are part of important coastal fish and wildlife habitats. The Department of State recognizes these areas because they support a variety of living organisms.
  4. Tidally Influenced Wetlands: Some Class I wetlands are affected by tides (the rise and fall of sea levels). These wetlands help manage water levels and provide habitats for many species.
  5. Connection to Regulated Wetlands: If a Class I wetland is next to another wetland that is regulated, it is also considered important for conservation efforts.
  6. Critically Imperiled Plant Community: Class I wetlands may have specific plant communities that are in danger of disappearing. Protecting these areas helps preserve these unique plants.
  7. Nutrient Poor Wetlands: Some wetlands are classified as nutrient poor, which means they have fewer nutrients than other wetlands. These areas can be crucial for certain plants and animals that thrive in such environments.
  8. Floodway Designation: If a wetland is located in a floodway, as shown on maps created by FEMA, it is classified as Class I. Floodways are areas that can experience flooding, and these wetlands help absorb excess water.
  9. Connection to Clean Water: Class I wetlands are often found next to clean surface waters. These connections are important for maintaining the health of both the wetland and the nearby water bodies.

In summary, Class I wetlands are essential ecosystems that support endangered species, unique plants, and help maintain clean water and healthy habitats. Protecting these areas is important for the environment and biodiversity.

GREEN LAYER on the Environmental Resource Mapper (ERM) -- It was previously included on the New York State Freshwater Wetland Maps by the department as a regulated wetland on or before December 31, 2024, and contain wetland characteristics described in section 240107(1) of the Act.

Launch DEC Environmental Resource Mapper and turn on the ‘Wetland Layer’ (Green Layer) and zoom in to view previously mapped wetlands. 

It has wetland functions and values that are of local or regional significance because it meets one or more of the following criteria: 

  1. the wetland is located within an area specifically designated, pursuant to Part 617 of this Title, as a Critical Environmental Area (CEA) with specific reference to wetland protection by a local agency in its written justification supporting the designation; or 
  2. the wetland is partially located within the Adirondack Park and under the jurisdiction of the Adirondack Park Agency. 

Resources: Critical Environmental Area (CEA) Appendix F

It is located in an area designated as a floodway on the Digital Flood Insurance Rate Map (DFIRM) ‘National Flood Hazard Layer’, produced by the Federal Emergency Management Agency.

The wetland has significant importance to protecting the State's water quality based on substantial evidence, as determined by the commissioner in writing. The commissioner’s written determination shall describe the reasons why the wetland is of significant importance to protecting the State’s water quality. This may include a description of why the wetland is of significant importance in preventing exceedances of any water quality standards or guidance values derived pursuant to Part 702 of this Title. The commissioner’s determinations pursuant to this subdivision shall be posted on the department’s website. Currently the DEC commissioner has not deemed any wetland as having significant importance to protecting the State’s water quality. When this happens, it will be listed in the Environmental Notice Bulletin and listed here on our website.

Wetland Maps

These mapping tools identify potential jurisdictional wetlands. It is important to note that the only way to confirm or deny the presence of regulated freshwater wetlands is by submitting a Parcel JD. 

Environmental Resource Mapper (ERM)

  • The Previously Mapped Freshwater Wetlands is represented by the green layer, on the DEC Environmental Resource Mapper (ERM). This the only layer that confirms presence of regulated wetlands, as it includes those wetlands that were under jurisdictional before the regulatory changes that took effect on Jan. 1, 2025.
  • Freshwater Wetland Informational Maps – Created to assist identifying wetland areas that may be jurisdictional, DEC use the ERM Freshwater Wetlands Layer to view These maps display as pink, are for informational purposes only and cannot be relied upon to determine the presence or absence of freshwater wetlands regulated by DEC. The NYS Article 24 Freshwater Wetland Informational Maps were created by The Institute for Resource Information Sciences (IRIS) at Cornell University and combines a decision tree, statistical analysis, and a process that used Digital Elevation Model (DEM) to identify wetlands depicted.
  • National Wetland Inventory (NWI) Maps: The U.S. Fish and Wildlife Service (USFWS) National Wetlands Inventory (NWI) maps contain information on the location and characteristics of wetlands and deep-water habitats. Wetlands are federally classified using the method described in the Classification of Wetlands and Deepwater Habitats of the United States. 

New York State GIS Clearinghouse: DEC Informational Freshwater Wetland Mapping and Previously Mapped Freshwater Wetlands, in addition to wetlands of unusual importance criteria for Urban Areas and Significant Flooding  are available for download through the New York State GIS Clearinghouse.

National Land Cover Database (NLCD): A dataset produced by the U.S. Geological Survey (USGS) in collaboration with the Multi-Resolution Land Characteristics Consortium (MRLC). It provides detailed land cover information for the United States, including data on land cover change, at a 30-meter spatial resolution.  

Regulated Activities

Under the Freshwater Wetlands Act, DEC regulates activities in freshwater wetlands and in their adjacent areas. DEC regulates such activities to prevent, or at least to minimize, impairment of wetland functions.

The wetland categories used in the regulations are identified by the types of vegetation present. The regulations identify:

  • classifications of uses;
  • procedures for conducting activities in wetlands; and
  • requirements for conducting activities in wetlands.

Almost any activity which may adversely impact the natural values of the wetlands or their adjacent areas is regulated. Some activities requiring a permit include:

  • construction of buildings, roadways, septic systems, bulkheads, dikes, or dams;
  • placement of fill, excavation, or grading;
  • modification, expansion, or extensive restoration of existing structures;
  • drainage, except for agriculture; and
  • application of pesticides in wetlands.

A permit is required to conduct any regulated activity in a protected wetland or its adjacent area. The permit standards in the regulations require that impacts to wetlands be avoided and minimized. 

  • If the proposed activity will not seriously affect the wetland, a permit with various conditions is usually issued.
  • If the proposed activity will affect the wetland, the benefits gained by allowing the action to occur must outweigh the wetland benefits lost, in order for a permit to be issued.
  • Compensatory mitigation often is required for significant impacts to wetlands. This may include creating or restoring wetlands to replace the benefits lost by the proposed project.

General Permits for Freshwater Wetlands

  • DEC is proposing statewide general permits to ease permitting and streamline the approval of specific activities. General permits are only for activities that have been determined to have limited impact on the environment. They allow similar types of work not unique to a particular location, require less time to process and no application fees.
  • Currently, there are two available general permits, Fresh Water Wetland Permit (GP-25-003) and Lakes and Shorelines General Permit (GP-0-25-007). Additionally, DEC has proposed four general permits to address regulated activities within jurisdictional wetlands and adjacent areas. 

Real Property Assessment

Real property valuation is assessed at the local level, not through DEC at the state level. The Freshwater Wetlands Act recognizes that land use may influence property valuation. For more information, visit the Real Property Assessment webpage.

Revised Regulations

In 2022, New York's Freshwater Wetlands Act (Environmental Conservation Law Article 24) was amended to make several important changes. On January 1, 2025, those changes to 6 NYCRR Part 664, went into effect. The newly adopted regulations define key terms, describe the revised freshwater wetland classification system, present criteria for the identification of Wetlands of Unusual Importance, and describe procedures DEC uses in making jurisdictional determinations to enhance consistency and conservation.

Regulation Resources

Informational Webinar

DEC hosted a webinar to provide information and answer questions about the updated Freshwater Wetlands Program regulations. 

Contacts for Freshwater Wetlands

DEC's Freshwater Wetlands Program resides in the Division of Fish and Wildlife. Most aspects of the wetlands program are implemented by staff in regional offices and can be reached at the below emails.

Contacts for Freshwater Wetlands

RegionMailing AddressEmail
1 (Nassau and Suffolk Counties)NYSDEC Region 1
SUNY @ Stony Brook
50 Circle Road
Stony Brook, NY 11790-3409		[email protected]
2 (Bronx, Kings, New York, Queens, and Richmond Counties)NYSDEC Region 2
1 Hunters Point Plaza
47-40 21st Street
Long Island City, NY 11101-5401		[email protected]
3 (Dutchess, Orange, Putnam, Rockland, Sullivan, Ulster, and Westchester Counties)NYSDEC Region 3 
21 South Putt Corners Road 
New Paltz, NY 12561-1696		[email protected]
4 (Albany, Columbia, Delaware, Greene, Montgomery, Otsego, Rensselaer, Schenectady, and Schoharie Counties)NYSDEC Region 4
Stamford Sub-Office
65561 State Highway 10, Suite 1 
Stamford, NY 12167		[email protected]
5 (Clinton, Essex, Franklin, Fulton, Hamilton, Saratoga, Warren, and Washington Counties)

(North) NYSDEC Region 5
1115 NYS Route 86
P.O. Box 296
Ray Brook, NY 12977-0296

(South) NYSDEC Region 5 
Warrensburg Sub-Office
232 Golf Course Road
Warrensburg, NY 12885

[email protected]
6 (Herkimer, Jefferson, Lewis, Oneida, and St. Lawrence Counties)

(North) NYSDEC Region 6 
317 Washington Street
Watertown, NY 13601-3787

(South) NYSDEC Region 6
Utica Sub-Office 
207 Genesee Street
Utica, NY 13501

[email protected]
7 (Broome, Cayuga, Chenango, Cortland, Madison, Onondaga, Oswego, Tioga, and Tompkins Counties)NYSDEC Region 7
5786 Widewaters Parkway
Syracuse, NY 13214-1867		[email protected]
8 (Chemung, Genesee, Livingston, Monroe, Ontario, Orleans, Schuyler, Seneca, Steuben, Wayne, and Yates Counties)NYSDEC Region 8
6274 East Avon-Lima Road
Avon, NY 14414-9519		[email protected]
9 (Allegany, Cattaraugus, Chautauqua, Erie, Niagara, and Wyoming Counties)NYSDEC Region 9
700 Delaware Avenue
Buffalo, NY 14209		[email protected]

Important Links

Programs To Conserve Wetlands
Contact for this Page

DFW, Bureau of Ecosystem Health
625 Broadway
Albany, NY 12233

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