In 2023, the U.S. Geological Survey (USGS), in collaboration with the Cook County Bureau of Technology (BoT), conducted comprehensive hydrographic and water quality surveys, along with activity and disturbance assessments of 58 total water bodies encompassing lakes, rivers, and canals within Cook County, Illinois. These surveys and assessments describe the bathymetry, water-quality conditions, and on-site field crew observations and impressions for each water body and its surrounding catchment area. Data collected may assist BoT with resource management decisions and practices, as well as contribute to an inventory that can be shared with other local governmental agencies. Included in this data release are bathymetric, water quality, and observational findings gathered in 2023 for the following 58 water bodies listed in alphabetical order: 59th Street Harbor, Beck Lake, Belleau Lake, Bergman Slough, Beverly Lake, Big Bend, Big Marsh, Big Marsh NE (3 Fingers Pond), Burnham Prairie Marsh West, Columbus Park Lagoon, Crawdad Slough, Diversey Harbor, Douglass Park Lagoon, Garfield Park Lagoon, Goose Lake (East and West), Humboldt Park Lagoon, Jackson Park East Lagoon, Jackson Park Inner Harbor, Jackson Park Outer Harbor, Jackson Park West Lagoon, Joes Pond, Lake Calumet, Lake Glenview, Lake Ida, Lake Shermerville, Longjohn Slough, Marquette Park Lagoon, McGinnis Slough, McGinty Slough, McKinley Park Lagoon, North Pond (Lincoln Park), Palatine Marsh South, Pogie Lake, Sag Quarry East, Sherman Park Lagoon, Skokie Lagoons 1 through 7, South Pond (Lincoln Park), Tampier Lake, Tampier Slough North, Tampier Slough South, Tampier Slough West, Tampier Slough Will Cook Rd., Tomahawk Slough, Tryners Pond, Tuma Lake, Turtlehead Lake, Unknown A27280010, Unknown A27330013, Unknown A33290005, and Washington Park Lagoon. This data release provides water body survey data in three parts: (1) Single-beam data for lakes surveyed in 2023 except Lake Calumet. (2) Lake Calumet multibeam survey from June 30, 2023. (3) Lake Calumet single-beam survey from July 18-19, 2023. First posted June 26, 2024, ver. 1.0 Revised November 12, 2024, ver. 2.0

In 2023, the U.S. Geological Survey (USGS), in collaboration with the Cook County Bureau of Technology (BoT), conducted comprehensive hydrographic and water quality surveys, along with activity and disturbance assessments of 58 total water bodies encompassing lakes, rivers, and canals within Cook County, Illinois. These surveys and assessments describe the bathymetry, water-quality conditions, and on-site field crew observations and impressions for each water body and its surrounding catchment area. Data collected may assist BoT with resource management decisions and practices, as well as contribute to an inventory that can be shared with other local governmental agencies. Included in this data release are bathymetric, water quality, and observational findings gathered in 2023 for the following 58 water bodies listed in alphabetical order: 59th Street Harbor, Beck Lake, Belleau Lake, Bergman Slough, Beverly Lake, Big Bend, Big Marsh, Big Marsh NE (3 Fingers Pond), Burnham Prairie Marsh West, Columbus Park Lagoon, Crawdad Slough, Diversey Harbor, Douglass Park Lagoon, Garfield Park Lagoon, Goose Lake (East and West), Humboldt Park Lagoon, Jackson Park East Lagoon, Jackson Park Inner Harbor, Jackson Park Outer Harbor, Jackson Park West Lagoon, Joes Pond, Lake Calumet, Lake Glenview, Lake Ida, Lake Shermerville, Longjohn Slough, Marquette Park Lagoon, McGinnis Slough, McGinty Slough, McKinley Park Lagoon, North Pond (Lincoln Park), Palatine Marsh South, Pogie Lake, Sag Quarry East, Sherman Park Lagoon, Skokie Lagoons 1 through 7, South Pond (Lincoln Park), Tampier Lake, Tampier Slough North, Tampier Slough South, Tampier Slough West, Tampier Slough Will Cook Rd., Tomahawk Slough, Tryners Pond, Tuma Lake, Turtlehead Lake, Unknown A27280010, Unknown A27330013, Unknown A33290005, and Washington Park Lagoon. This data release provides water body survey data in three parts: (1) Single-beam data for lakes surveyed in 2023 except Lake Calumet. (2) Lake Calumet multibeam survey from June 30, 2023. (3) Lake Calumet single-beam survey from July 18-19, 2023. First posted June 26, 2024, ver. 1.0 Revised November 12, 2024, ver. 2.0

In 2023, the U.S. Geological Survey (USGS), in collaboration with the Cook County Bureau of Technology (BoT), conducted comprehensive hydrographic and water quality surveys, along with activity and disturbance assessments of 58 total waterbodies encompassing lakes, rivers, and canals within Cook County, Illinois. These surveys and assessments describe the bathymetry, water-quality conditions, and on-site field crew observations and impressions for each water body and its surrounding catchment area. Data collected may assist BoT with resource management decisions and practices, as well as contribute to an inventory that can be shared with other local governmental agencies. Included in this data release are bathymetric, water quality, and observational findings gathered in 2023 for the following waterbodies listed in alphabetical order: 59th Street Harbor, Beck Lake, Belleau Lake, Bergman Slough, Beverly Lake, Big Marsh, Big Marsh NE (3 Fingers Pond), Burnham Prairie Marsh West, Columbus Park Lagoon, Crawdad Slough, Diversey Harbor, Douglass Park Lagoon, Garfield Park Lagoon, Goose Lake, Humboldt Park Lagoon, Jackson Park Columbia Basin, Jackson Park Inner Harbor, Jackson Park Outer Harbor, Jackson Park East Lagoon, Jackson Park West Lagoon, Joes Pond, Lake Calumet, Lake Glenview, Lake Ida, Lake Shermerville, Longjohn Slough, Marquette Park Lagoon, McGinnis Slough, McGinty Slough, McKinley Park Lagoon, North Pond (Lincoln Park), Palatine Marsh South, Pogie Lake, Sag Quarry East, Sherman Park Lagoon, Skokie Lagoons 1 through 7, South Pond (Lincoln Park), Tampier Lake, Tampier Slough North, Tampier Slough South, Tampier Slough West, Tampier Slough Will Cook Rd., Tomahawk Slough, Tryners Pond, Tuma Lake, Turtlehead Lake, Unknown A27280010, Unknown A27330013, Unknown A33290005, and Washington Park Lagoon. This data release provides water body survey data in three parts: (1) Single-beam data for lakes surveyed in 2023 except Lake Calumet. (2) Lake Calumet multibeam survey from June 30, 2023. (3) Lake Calumet single-beam survey from July 18-19, 2023.

In 2025, the U.S. Geological Survey (USGS), in collaboration with the Cook County Bureau of Technology (BOT), carried out comprehensive hydrographic and water-quality surveys, and activity and disturbance assessments of 34 total water bodies within Cook County, Illinois. These surveys and assessments describe the bathymetry, water-quality conditions, and on-site field crew observations and impressions for each water body and its surrounding catchment area. Data collected may assist the BOT with resource management decisions and practices and contribute to an inventory that can be shared with other local governmental agencies. Included in this data release are bathymetric, water quality, and observational findings gathered in 2025 for the following water bodies listed in alphabetical order: Beck Pond, Bluff Spring Fen Central Pond, Bluff Spring Fen North Pond, Bluff Spring Fen South Pond, Bulrush Pond, Busse Lake Main Pool, Busse Lake North Pool, Busse Lake South Pool, Busse Woods Reservoir, Deer Creek Quarry, Deer Grove Lake, Hambone Lake, Highland Woods Golf Course Hole 6 Pond, Highland Woods Golf Course Hole 13 Pond, Lake Carriage Way, Lake Katherine, Lake Leaky, Lake Regina, Leon Lake, McGinnis Pond, Midlothian Creek Detention Reservoir, Mud Lake, Potawatomi Pond, Salt Creek, Sand Ridge Pond, Skokie Lagoon 4, Skokie River, Spring Creek Lake, Spring Lake, Sulky Pond, Turtlehead Pond, Unknown A22360006, West Pond, and Wetfoot Lake.

In 2022, the U.S. Geological Survey (USGS), in collaboration with the Cook County Bureau of Technology (BOT), carried out comprehensive hydrographic and water quality surveys, along with activity and disturbance assessments of 41 total water bodies encompassing lakes, rivers, and canals within Cook County, Illinois. These surveys and assessments describe the bathymetry, water-quality conditions, and on-site field crew observations and impressions for each water body and its surrounding catchment area. Data collected may assist BOT with resource management decisions and practices, as well as contribute to an inventory that can be shared with other local governmental agencies. Included in this data release are bathymetric, water quality, and observational findings gathered in 2022 for the following water bodies listed in alphabetical order: Axehead Lake, Baker's Lake, Belly Deep Slough, Bode Lake North, Bode Lake South, Bull Frog Lake, Busse Lake Main Pool, Busse Lake North Pool, Busse Lake South Pool, Busse Woods Reservoir, Consumers Quarry, Crabtree Lake, Doughnut Lake, Flatfoot Lake, Forge Quarry, Great Lakes Quarries East, Great Lakes Quarries West, Green Lake, Horsetail Lake, Icebox Quarry, Lake Arlington, Lake Arrowhead, Lake Charlemagne, Lake Opeka, Maple Lake, Midlothian Reservoir East, Midlothian Reservoir West, Papoose Lake, Powderhorn Lake South, Sag Quarry West, Saganashkee Slough, Sauk Lake, Vollmer Road Wildlife Pond East, Vollmer Road Wildlife Pond Middle, Vollmer Road Wildlife Pond West, Wampum Lake, Westbury Park Lake, Wolf Lake Pond 1, Wolf Lake Pond 2, Wolf Lake Pond 3, Wolf Lake Pond 4, and Wolf Lake Pond 8. First posted July 17, 2023, ver. 1.0 Revised January 17, 2025, ver. 2.0

In 2022, the U.S. Geological Survey (USGS), in collaboration with the Cook County Bureau of Technology (BOT), carried out comprehensive hydrographic and water quality surveys, along with activity and disturbance assessments of 41 total water bodies encompassing lakes, rivers, and canals within Cook County, Illinois. These surveys and assessments describe the bathymetry, water-quality conditions, and on-site field crew observations and impressions for each water body and its surrounding catchment area. Data collected may assist BOT with resource management decisions and practices, as well as contribute to an inventory that can be shared with other local governmental agencies. Included in this data release are bathymetric, water quality, and observational findings gathered in 2022 for the following water bodies listed in alphabetical order: Axehead Lake, Baker's Lake, Belly Deep Slough, Bode Lake North, Bode Lake South, Bull Frog Lake, Busse Lake Main Pool, Busse Lake North Pool, Busse Lake South Pool, Busse Woods Reservoir, Consumers Quarry, Crabtree Lake, Doughnut Lake, Flatfoot Lake, Forge Quarry, Great Lakes Quarries East, Great Lakes Quarries West, Green Lake, Horsetail Lake, Icebox Quarry, Lake Arlington, Lake Arrowhead, Lake Charlemagne, Lake Opeka, Maple Lake, Midlothian Reservoir East, Midlothian Reservoir West, Papoose Lake, Powderhorn Lake South, Sag Quarry West, Saganashkee Slough, Sauk Lake, Vollmer Road Wildlife Pond East, Vollmer Road Wildlife Pond Middle, Vollmer Road Wildlife Pond West, Wampum Lake, Westbury Park Lake, Wolf Lake Pond 1, Wolf Lake Pond 2, Wolf Lake Pond 3, Wolf Lake Pond 4, and Wolf Lake Pond 8. First posted July 17, 2023, ver. 1.0 Revised January 17, 2025, ver. 2.0

In 2022, the U.S. Geological Survey (USGS), in collaboration with the Cook County Bureau of Technology (BOT), carried out comprehensive hydrographic and water quality surveys, along with activity and disturbance assessments of 41 total water bodies encompassing lakes, rivers, and canals within Cook County, Illinois. These surveys and assessments describe the bathymetry, water-quality conditions, and on-site field crew observations and impressions for each water body and its surrounding catchment area. Data collected may assist BOT with resource management decisions and practices, as well as contribute to an inventory that can be shared with other local governmental agencies. Included in this data release are bathymetric, water quality, and observational findings gathered in 2022 for the following water bodies listed in alphabetical order: Axehead Lake, Baker's Lake, Belly Deep Slough, Bode Lake North, Bode Lake South, Bull Frog Lake, Busse Lake Main Pool, Busse Lake North Pool, Busse Lake South Pool, Busse Woods Reservoir, Consumers Quarry, Crabtree Lake, Doughnut Lake, Flatfoot Lake, Forge Quarry, Great Lakes Quarries East, Great Lakes Quarries West, Green Lake, Horsetail Lake, Icebox Quarry, Lake Arlington, Lake Arrowhead, Lake Charlemagne, Lake Opeka, Maple Lake, Midlothian Reservoir East, Midlothian Reservoir West, Papoose Lake, Powderhorn Lake South, Sag Quarry West, Saganashkee Slough, Sauk Lake, Vollmer Road Wildlife Pond East, Vollmer Road Wildlife Pond Middle, Vollmer Road Wildlife Pond West, Wampum Lake, Westbury Park Lake, Wolf Lake Pond 1, Wolf Lake Pond 2, Wolf Lake Pond 3, Wolf Lake Pond 4, and Wolf Lake Pond 8. First posted July 17, 2023, ver. 1.0 Revised January 17, 2025, ver. 2.0

These data are single-beam bathymetry points compiled in comma separated values (CSV) file format, generated from a hydrographic survey of the northern portion of Lake Calumet in Cook County, Illinois. Hydrographic data were collected July 18-19, 2023, using a single-beam echosounder (SBES) integrated with a Global Navigation Satellite System (GNSS) mounted on a marine survey vessel. Surface water elevation data were collected July 18 utilizing a single-base real-time kinematic (RTK)/GNSS unit. Bathymetric data points were collected as the vessel traversed the northern portions of the lake along overlapping survey lines. The SBES internally collected and stored the depth data from the echosounder and the horizontal and vertical position data of the vessel from the GNSS in real time. Data processing required specialized computer software to export bathymetry data from the raw data files. A Python script was written to calculate the lakebed elevations and identify outliers in the dataset. These data are provided in comma separated values (CSV) format as LakeCalumet_SBES_20230718.csv. Data points are stored as a series of x (longitude), y (latitude), and z (elevation or depth) points along with variable length records specific to the data transects.

These data are single-beam bathymetry points compiled in comma separated values (CSV) file format, generated from a hydrographic survey of the northern portion of Lake Calumet in Cook County, Illinois. Hydrographic data were collected July 18-19, 2023, using a single-beam echosounder (SBES) integrated with a Global Navigation Satellite System (GNSS) mounted on a marine survey vessel. Surface water elevation data were collected July 18 utilizing a single-base real-time kinematic (RTK)/GNSS unit. Bathymetric data points were collected as the vessel traversed the northern portions of the lake along overlapping survey lines. The SBES internally collected and stored the depth data from the echosounder and the horizontal and vertical position data of the vessel from the GNSS in real time. Data processing required specialized computer software to export bathymetry data from the raw data files. A Python script was written to calculate the lakebed elevations and identify outliers in the dataset. These data are provided in comma separated values (CSV) format as LakeCalumet_SBES_20230718.csv. Data points are stored as a series of x (longitude), y (latitude), and z (elevation or depth) points along with variable length records specific to the data transects.

These data are high-resolution bathymetry (lakebed elevation) of the southern portion of Lake Calumet in Cook County, Illinois, acquired from a hydrographic survey on June 30, 2023. This dataset is provided as American Society for Photogrammetry and Remove Sensing (ASPRS) compressed LAS (*laz) files, a standardized binary format for storing three-dimensional point cloud data as a series of x (longitude), y (latitude), and z (elevation) points and attributes (ASPRS, 2011). This survey utilized a multibeam echosounder mapping system (MBMS), which consists of a multibeam echosounder (MBES) and an internal navigation system (INS) mounted on a marine survey vessel. Data were collected as the vessel traversed the lake along overlapping longitudinal survey lines. Data collection software integrated and stored the depth data from the MBES, along with the horizontal position and vertical attitude data of the vessel from the INS in real time. Proprietary computer software was used to post-process bathymetry data from the real-time data files for final export. The northern portion of the lake, characterized by shallower depths, was surveyed using a single-beam echosounder in July 2023; those data are available within this data release but are not included in the compressed LAS files. The bathymetric dataset, provided in ASPRS compressed LAS format as "LakeCalumet_MBES_20230630_fullres.laz," represents the data at its full resolution obtained during data collection with minimal cleanup to preserve as much detail as possible. Any edits made to the dataset were focused on removing obvious outliers clearly distinguishable from genuine bathymetric details. Please note that the full-resolution dataset is large and may not be readily viewable without specialized software. A reduced-resolution version of the full dataset was created featuring a nominal 0.5-meter (m) point spacing to enhance accessibility and usability. This downscaled dataset is provided in ASPRS compressed LAS format as "LakeCalumet_MBES_20230630_reducedres.laz."