The Canadian National Wetlands Inventory (CNWI) is a comprehensive, publicly available national geodatabase developed by the Canadian Wildlife Service (CWS) of Environment and Climate Change Canada (ECCC), in collaboration with federal, provincial, and territorial governments, academia, Indigenous groups, and Non-Governmental Organizations (NGOs). It consists of the best available wetland mapping data, along with its metadata, published in a standardized manner.The CNWI is continuously updated through the compilation of existing data and the acquisition of new high-resolution datasets to address coverage gaps, with an emphasis on peatlands and coastal wetlands, which are key habitats for greenhouse gas (GHG) sequestration. ECCC plans to use the CNWI to train and validate machine-learning algorithms to delineate and classify wetlands at a national scale and to measure trends over time. This will directly support Canada’s Nature-Based Climate Solutions by informing biodiversity conservation, guiding climate change mitigation and adaptation strategies, and supporting GHG emissions reporting.The CNWI was initially released in February 2024 with 13 source datasets. In June 2025, the Inventory was updated to include 14 additional datasets. Collectively, these 27 source datasets comprise approximately 12.1 million wetland polygon features, covering a total area of roughly 640,000 square kilometers across ten provinces and territories (BC, MB, NB, NL, NS, PE, ON, QC, SK, YT). These source datasets were cross-walked into a standardized CNWI classification schema, which is based on two foundational documents: the Canadian Wetland Classification System (National Wetlands Working Group, 1997) and the Canadian Wetland Inventory Data Model (2016).The CNWI Schema contains five major wetland classes (Bog, Fen, Swamp, Marsh, and Shallow/Open Water) and eight subclasses (Rich Fen, Poor Fen, Organic Swamp, Mineral Swamp, Organic Marsh, Mineral Marsh, Shallow Water, and Open Water). Non-conforming wetlands can be categorized into three groups: Peatland, Mixed, and Unclassified. For more information on the CNWI and the related database, please refer to the CNWI User Manual and other supporting documents that accompany this publication. The User Manual provides detailed information on how data are collected, managed, and distributed to meet CNWI data standards.

The data represents the density of wetland habitat in the agricultural region of Alberta in 2002. Wetlands are depressional areas that are wet for a long enough period that the plant and animals living in them are adapted to, and often dependent on, living in wet conditions for at least part of their life cycle. In drier areas of the province, wetlands tend to be more intermittent, while in wetter areas, wetlands tend to be more persistent. Topography also affects the occurrence of wetlands. Hummocky landscapes allow for pooling of water in depressions, while landscapes with longer slopes (e.g. the foothills) generally have better defined surface drainage patterns. A wetland in influenced by the interaction between the wet area, the wetland margin and upland area.Wetlands provide important habitat for waterfowl and many other types of wildlife. Wetlands reduce the impact of flooding, provide erosion control, purify water by removing sediment and nutrients, and contribute to groundwater recharge. This resource was created using ArcGIS.

Wetlands are lands that are seasonally or permanently flooded by shallow water. They also include lands where the water table is close to the surface. The wetland polygons are managed independently from other hydro data classes and may overlap water bodies or other hydro data. Not all wetlands have been identified and mapped. Active maintenance is ongoing province wide. The currency and accuracy of the spatial representation is variable and requires on-the-ground verification.

Set of wetlands in the City of Rouyn-Noranda**This third party metadata element was translated using an automated translation tool (Amazon Translate).**

To support the WAWA program at the Department of Environment and Local Government and alert primary users to the location of wetlands and possible regulatory requirements for land development. The wetlands map is intended for planning purposes only. The wetland boundaries are only approximate.

The national wetland layer contains wetland data compiled from the best available data from each region, classified by wetland type. Wetlands are mapped as polygons in geographic layers, which are integrated into a master geodatabase at the national scale.Information from each contributing dataset was classified based on the Canadian Wetland Classification System, which contains five main wetland classes (Bog, Fen, Marsh, Swamp, and Shallow Water) that represent the types of wetlands encountered in Canada. An additional category, “partially classified” was used to preserve boundary information for wetlands that could not be classified into the main categories with existing information.

The version 3A of the Canadian Wetland Inventory contains five main wetland classes (Bog, Fen, Marsh, Swamp, and Shallow Water) that represent the types of wetlands encountered in Canada. **This third party metadata element follows the Spatio Temporal Asset Catalog (STAC) specification.**

The version 3A of the Canadian Wetland Inventory contains five main wetland classes (Bog, Fen, Marsh, Swamp, and Shallow Water) that represent the types of wetlands encountered in Canada. **This third party metadata element follows the Spatio Temporal Asset Catalog (STAC) specification.**

The goal of this carbon cycle study is to: * better understand wetland carbon uptake and losses to the atmosphere across watersheds * evaluate wetland carbon’s usefulness as a natural climate solution __Study sites__ Study sites for this project are: * Big Creek Watershed in Southern Ontario * White River in the experimental forest area in Northern Ontario We chose these sites to represent relatively data-scarce regions of Ontario, and locations that represent: * recently restored wetland * an undisturbed wetland These locations can show how wetlands can act as natural climate solutions. __Wetlands and climate change__ Wetlands absorb and release atmospheric carbon as plants grow and decompose. If wetlands absorb more carbon than they release, they can act as natural climate solutions. Wetland restoration and wetland preservation: * promotes carbon uptake by wetlands in Ontario * slows future climate warming Wetland carbon exchange with the atmosphere varies immensely across space and time. These continuous measurements are used to: * calculate the amount of carbon moving between the air, plants and soils of wetlands * improve numerical models that will help us predict how wetland carbon exchanges might respond to climate warming at these locations and other locations __Download the study data__ We submit this data to Ameriflux, which is a network of sites measuring ecosystem CO2, water and energy fluxes in North, Central and South America. You can download the data from [Ameriflux](https://ameriflux.lbl.gov/).

Annual and five-year (5YA) average wet deposition maps for the ammonium ion are available. The file formats include geodatabase files (*.gdb) compatible with geospatial software (e.g. ESRI ArcGIS) and KMZ files compatible with virtual globe software (e.g. Google Earth™). Maps can also be viewed online via Open Maps and the ArcGIS online viewer. Annual deposition from each site was screened for completeness using the following criteria: (1) precipitation amounts were recorded for >90% of the year and >60% of each quarter, and (2) ammonium concentrations were reported for >70% of the precipitation measured over the year and for >60% of each quarter. Five-year average wet deposition values are averaged annual deposition values with a completeness criterion >60% for the five-year period. Units for wet deposition fluxes are in kg of NH4 per hectare per year (kg ha-1 y-1). Sources of measurement data and spatial interpolation method are described here: https://doi.org/10.18164/e8896575-1fb8-4e53-8acd-8579c3c055c2. Recommended citation: Environment and Climate Change Canada, [year published]. NH4 Wet Deposition Maps. Air Quality Research Division, Environment and Climate Change Canada, Toronto, Ontario, Canada. [URL/DOI], accessed [date].Recommended acknowledgement: The author(s) acknowledge Environment and Climate Change Canada for the provision of Canada-U.S. wet deposition kriging maps accessed from the Government of Canada Open Government Portal at open.canada.ca, and the data providers referenced therein.