DOI: 10.5061/dryad.4qrfj6qj1
title: How wet must a wetland be to have federal protections in post-Sackett US?

description: In 2023, the US Supreme Court’s majority ruled
 in Sackett v. Environmental Protection
 Agency that only wetlands that are “indistinguishable” from
 federally protected waters “due to a continuous surface connection” are
 federally protected. This study estimates the potential impact of
 interpretations of the ruling on federal wetlands protections, using a
 qualitative measure of wetland “wetness” as a proxy for the new
 requirement. An estimated area ranging from ~17 million acres (19%) to
 nearly all 90 million acres of nontidal wetlands in the conterminous
 United States could be without federal protections, and variability in
 state protections creates hotspots of risk. The high-level estimates
 provided here represent a first step toward understanding the long-term
 impacts of Sackett v. Environmental Protection
 Agency on federal wetlands protections and highlight the uncertainty
 introduced by the ruling.
description: This dataset represents estimated federal jurisdictional status
 of wetlands for the conterminuous US using different potential
 interpretations of the Supreme Court's majority opinion in Sackett v.
 EPA. For the full methodology, refer to the linked preprint's
 "methods" section. These data were produced
 using the National Wetlands Inventory (NWI), National Hydrography Dataset
 Plus High Resolution (NHDPlus HR), NWI Difference Product line, and the
 PAD-US dataset. Wetland polygons from the NWI were filtered to better
 align with the US Army Corps of Engineer's 3-factor definition of
 wetlands and intersected with select buffered NHDPlus HR features. Wetland
 "wetness", derived from the NWI's Coward Code Water Regime
 modifier, was used as a proxy for different interpretations of a
 "continuous surface connection", such that spatially contiguous
 wetland polygons that met or exceeded a specific "wetness" were
 estimated as jurisdictional if any polygon in a group was estimated
 jurisdictional. NWI polygons with an NWI difference product impervious
 surface percentage of 5% or greater were excluded.
description: # How wet must a wetland be to have federal protections in post-Sackett
 US?
 [https://doi.org/10.5061/dryad.4qrfj6qj1](https://doi.org/10.5061/dryad.4qrfj6qj1) This dataset contains a CSV (*wetlands_for_dryad.csv*) and a zipped ESRI geodatabase (*wetlands_for_dryad.gdb.zip*) representing wetland polygons with attributes that can be used to estimate federal jurisdictional status. **NOTE:** Reading the un-zipped ESRI geodatabase (*wetlands_for_dryad.gdb*) requires [GDAL 3.9 or higher](https://gdal.org/en/stable/drivers/vector/openfilegdb.html#bit-integer-field-support) due to the use of INT64 columns in the dataset. ESRI File Geodatabases produced with ArcGIS Pro 3.2 or later use [INT64 columns](https://pro.arcgis.com/en/pro-app/latest/help/data/geodatabases/overview/arcgis-field-data-types.htm#ESRI_SECTION2_8BF2454C879941258DC44AF6BB31F386), and older versions of GDAL do not support them. ## Description of the data and file structure The CSV and ESRI geodatabase contain the same information, except the CSV does not contain geospatial information. Missing values are denoted as "NA" in both datasets. Both datasets contain the following columns: * **ATTRIBUTE**: NWI Cowardin code (See [NWI Code Definitions Download Package](https://www.fws.gov/program/national-wetlands-inventory/classification-codes) for code definitions) * **WETLAND_TYPE**: NWI wetland type * **ACRES**: Area of wetland polygon in US acres * **STATE**: US state (abbreviation) where wetland polygon is located * **SYSTEM_NAM**: NWI system type * **SUBSYSTEM_**: NWI sub-system type * **CLASS_NAME**: NWI class * **SPLIT_CLAS**: NWI secondary (split) class * **WATER_REGI**: NWI water regime modifier * **WATER_RE_1**: NWI tidal/non-tidal modifier * **FIRST_MODI**: NWI modifier descriptor * **SECOND_MOD**: NWI modifier descriptor * **MIN_IMAGE_YR**: NWI metadata denoting year of imagery used for delineation of polygon * **MIN_IMAGE_SCALE**: NWI metadata denoting scale of imagery used for delineation of polygon * **MAX_ImpPer**: NWI difference product impervious percentage of wetland polygon * **MAX_ImpAre**: NWI difference product impervious area of wetland polygon * **MIN_yearNWI**: NWI wetland polygon creation year * **wetland_index**: unique index for each wetland polygon * **GROUP_ID**: Identifier for contiguous wetland polygons with no distinction between wetland type or attributes * **flow_class**: Hydrographic classification of wetland polygons that directly intersect the stream and water network (NHDPlus HR) as described in Gold 2024 methods. * **group_flow_class**: Minimum hydrographic classification of contiguous wetland polygon groups, based on GROUP_ID, from intersecting the stream and water network (NHDPlus HR) as described in Gold 2024 methods * **water_regime_number**: Numeric form of NWI water regime. Temporarily flooded = 1, Seasonally saturated = 2, Continuously saturated = 3, Seasonally flooded = 4, Seasonally flooded/saturated = 5, Semi-permanently flooded = 6, Intermittently exposed = 7, Permanently flooded = 8. * **water_regime_1_cutoff**: Boolean column (0=F, 1 = T) indicating if wetland polygon has a water regime number value greater than 1 * **water_regime_2_cutoff**: Boolean column (0=F, 1 = T) indicating if wetland polygon has a water regime number value greater than 2 * **water_regime_3_cutoff**: Boolean column (0=F, 1 = T) indicating if wetland polygon has a water regime number value greater than 3 * **water_regime_4_cutoff**: Boolean column (0=F, 1 = T) indicating if wetland polygon has a water regime number value greater than 4 * **water_regime_5_cutoff**: Boolean column (0=F, 1 = T) indicating if wetland polygon has a water regime number value greater than 5 * **water_regime_6_cutoff**: Boolean column (0=F, 1 = T) indicating if wetland polygon has a water regime number value greater than 6 * **water_regime_7_cutoff**: Boolean column (0=F, 1 = T) indicating if wetland polygon has a water regime number value greater than 7 * **Mang_Type**: Manager type of wetland polygon from PAD-US dataset * **Mang_Name**: Manager name of wetland polygon from PAD-US dataset * **GAP_Sts**: Conservation GAP status from PAD-US dataset * **wr_1_cut_flow_class**: Hydrographic classification of wetlands using a **water_regime_number** threshold of 1 (water_regime_1_cutoff == 1), where wetland polygons that do not meet the threshold (water_regime_1_cutoff == 0) have a value of 6 (set as "isolated") and polygons that meet or exceed the threshold have hydrographic classification values indicating intersection with perennial, intermittent, canals/ditches, ephemeral, or unknown water features (as described in Gold 2024) * **wr_2_cut_flow_class**: Hydrographic classification of wetlands using a **water_regime_number** threshold of 2 (water_regime_2_cutoff == 1), where wetland polygons that do not meet the threshold (water_regime_2_cutoff == 0) have a value of 6 (set as "isolated") and polygons that meet or exceed the threshold have hydrographic classification values indicating intersection with perennial, intermittent, canals/ditches, ephemeral, or unknown water features (as described in Gold 2024) * **wr_3_cut_flow_class**: Hydrographic classification of wetlands using a **water_regime_number** threshold of 3 (water_regime_3_cutoff == 1), where wetland polygons that do not meet the threshold (water_regime_3_cutoff == 0) have a value of 6 (set as "isolated") and polygons that meet or exceed the threshold have hydrographic classification values indicating intersection with perennial, intermittent, canals/ditches, ephemeral, or unknown water features (as described in Gold 2024) * **wr_4_cut_flow_class**: Hydrographic classification of wetlands using a **water_regime_number** threshold of 4 (water_regime_4_cutoff == 1), where wetland polygons that do not meet the threshold (water_regime_4_cutoff == 0) have a value of 6 (set as "isolated") and polygons that meet or exceed the threshold have hydrographic classification values indicating intersection with perennial, intermittent, canals/ditches, ephemeral, or unknown water features (as described in Gold 2024) * **wr_5_cut_flow_class**: Hydrographic classification of wetlands using a **water_regime_number** threshold of 5 (water_regime_5_cutoff == 1), where wetland polygons that do not meet the threshold (water_regime_5_cutoff == 0) have a value of 6 (set as "isolated") and polygons that meet or exceed the threshold have hydrographic classification values indicating intersection with perennial, intermittent, canals/ditches, ephemeral, or unknown water features (as described in Gold 2024) * **wr_6_cut_flow_class**: Hydrographic classification of wetlands using a **water_regime_number** threshold of 6 (water_regime_6_cutoff == 1), where wetland polygons that do not meet the threshold (water_regime_6_cutoff == 0) have a value of 6 (set as "isolated") and polygons that meet or exceed the threshold have hydrographic classification values indicating intersection with perennial, intermittent, canals/ditches, ephemeral, or unknown water features (as described in Gold 2024) * **wr_7_cut_flow_class**: Hydrographic classification of wetlands using a **water_regime_number** threshold of 7 (water_regime_7_cutoff == 1), where wetland polygons that do not meet the threshold (water_regime_7_cutoff == 0) have a value of 6 (set as "isolated") and polygons that meet or exceed the threshold have hydrographic classification values indicating intersection with perennial, intermittent, canals/ditches, ephemeral, or unknown water features (as described in Gold 2024) * **wr_1_cut_GROUP_ID**: Identifier for contiguous wetland polygons that are grouped based on if they do or do not exceed a wetland water regime value of 1. * **wr_2_cut_GROUP_ID**: Identifier for contiguous wetland polygons that are grouped based on if they do or do not exceed a wetland water regime value of 2. * **wr_3_cut_GROUP_ID**: Identifier for contiguous wetland polygons that are grouped based on if they do or do not exceed a wetland water regime value of 3. * **wr_4_cut_GROUP_ID**: Identifier for contiguous wetland polygons that are grouped based on if they do or do not exceed a wetland water regime value of 4. * **wr_5_cut_GROUP_ID**: Identifier for contiguous wetland polygons that are grouped based on if they do or do not exceed a wetland water regime value of 5. * **wr_6_cut_GROUP_ID**: Identifier for contiguous wetland polygons that are grouped based on if they do or do not exceed a wetland water regime value of 6. * **wr_7_cut_GROUP_ID**: Identifier for contiguous wetland polygons that are grouped based on if they do or do not exceed a wetland water regime value of 7. * **type**: Non-tidal or Tidal designation based on WATER_RE_1 ## Sharing/Access information Data was derived from the following sources: * [National Wetlands Inventory](https://www.fws.gov/program/national-wetlands-inventory) (NWI) * [National Hydrography Dataset Plus High Resolution](https://www.sciencebase.gov/catalog/item/57645ff2e4b07657d19ba8e8) (NHDPlus HR) * [NWI Difference Product line](https://www.fws.gov/project/national-wetlands-inventory-difference-product-line#:~:text=The%20Difference%20Product%20shows%20that,been%20lost%20to%20impervious%20surface) * [NWI Code Definitions Download Package](https://www.fws.gov/program/national-wetlands-inventory/classification-codes) * [PAD-US](https://www.sciencebase.gov/catalog/item/61955a0bd34eb622f6908f88) ## Code/Software Code used to create this dataset is available on [GitHub](https://github.com/acgold/wotus-wetlands-wetness) and archived on [Zenodo](https://doi.org/10.5281/zenodo.12522624). ## Changelog * **2/18/2025** - A note was added at the top of the README to inform users that reading the un-zipped ESRI geodatabase (*wetlands_for_dryad.gdb*) requires [GDAL 3.9 or higher](https://gdal.org/en/stable/drivers/vector/openfilegdb.html#bit-integer-field-support) due to the use of INT64 columns in the dataset. ESRI File Geodatabases produced with ArcGIS Pro 3.2 or later use [INT64 columns](https://pro.arcgis.com/en/pro-app/latest/help/data/geodatabases/overview/arcgis-field-data-types.htm#ESRI_SECTION2_8BF2454C879941258DC44AF6BB31F386), and older versions of GDAL do not support them. * **1/6/2025** - Descriptions of the columns **wr_1_cut_flow_class** - **wr_7_cut_flow_class** in the README were corrected. The previous descriptions of these columns incorrectly referred to the same threshold value.