The National Water Quality Network (NWQN) for Rivers and Streams includes 113 surface-water river and stream sites monitored by the U.S. Geological Survey (USGS) National Water Quality Program (NWQP). The NWQN represents the consolidation of four historical national networks: the USGS National Water-Quality Assessment (NAWQA) Project, the USGS National Stream Quality Accounting Network (NASQAN), the National Monitoring Network (NMN), and the Hydrologic Benchmark Network (HBN). The NWQN includes 22 large river coastal sites, 41 large river inland sites, 30 wadeable stream reference sites, 10 wadeable stream urban sites, and 10 wadeable stream agricultural sites. In addition to the 113 NWQN sites, 3 large inland river monitoring sites from the USGS Cooperative Matching Funds (Co-op) program are also included in this annual water-quality reporting Web site to be consistent with previous USGS studies of nutrient transport in the Mississippi-Atchafalaya River Basin. This data release contains geo-referenced digital data and associated attributes of watershed boundaries for 113 NWQN and 3 Co-op sites. Two sites, "Wax Lake Outlet at Calumet, LA"; 07381590, and "Lower Atchafalaya River at Morgan City, LA"; 07381600, are outflow distributaries into the Gulf of Mexico. Watershed boundaries were delineated for the portion of the watersheds between "Red River near Alexandria, LA"; 07355500 and "Atchafalaya River at Melville, LA"; 07381495 to the two distributary sites respectively. Drainage area was undetermined for these two distributary sites because the main stream channel outflows into many smaller channels so that streamflow is no longer relative to the watershed area. NWQN watershed boundaries were derived from the Watershed Boundary Dataset-12-digit hydrologic units (WBD-12). The development of the WBD-12 was a coordinated effort between the United States Department of Agriculture-Natural Resources Conservation Service (USDA-NRCS), the USGS, and the Environmental Protection Agency (EPA) (U.S. Department of Agriculture-Natural Resources Conservation Service, 2012). A hydrologic unit is a drainage area delineated to nest in a multi-level, hierarchical drainage system. Its boundaries are defined by hydrographic and topographic criteria that delineate an area of land upstream from a specific point on a river, stream or similar surface waters. The United States is divided and sub-divided into successively smaller hydrologic units identified by a unique hydrologic unit code (HUC) consisting of two to 12 digits based on the six levels of classification in the hydrologic unit system: regions, sub-regions, accounting units, cataloging units, watersheds, and sub-watersheds. NWQN watershed boundaries were delineated by selecting all sub-watershed polygons that flow into the most downstream WBD-12 polygon in which the NWQN site is located. The WBD-12 attribute table contains 8-digit, 10-digit, and 12-digit HUCs which were used to identify which sub-watersheds flow into the watershed pour point at the NWQN site location. When the NWQN site was located above the pour point of the most downstream sub-watershed, the sub-watershed was edited to make the NWQN site the pour point of that sub-watershed. To aid editing, USGS 1:24,000 digital topographic maps were used to determine the hydrologic divide from the sub-watershed boundary to the NWQN pour point. The number of sub-watersheds which are contained within the NWQN watersheds ranged from less than one to nearly 32,000 internal sub-watersheds. Internal sub-watershed boundaries were dissolved so that a single watershed boundary was generated for each NWQN watershed. Data from this release are presented at the USGS Tracking Water Quality page: http://cida.usgs.gov/quality/rivers/home (Deacon and others, 2015). Watershed boundaries delineated for this release do not take into account non-contributing area, diversions out of the watershed, or return flows into the watershed. Delineations are based solely on contributing WBD-12 polygons with modifications done only to the watershed boundary at the NWQN site location pour point. For this reason calculated drainage areas for these delineated watersheds may not match National Water Information System (MWIS) published drainage areas (http://dx.doi.org/10.5066/F7P55KJN). Deacon, J.R., Lee, C.J., Toccalino, P.L., Warren, M.P., Baker, N.T., Crawford, C.G., Gilliom, R.G., and Woodside, M.D., 2015, Tracking water-quality of the Nation’s rivers and streams, U.S. Geological Survey Web page: http://cida.usgs.gov/quality/rivers, https://dx.doi.org/doi:10.5066/F70G3H51. U.S. Department of Agriculture-Natural Resources Conservation Service, 2012, Watershed Boundary Dataset-12-digit hydrologic units: NRCS National Cartography and Geospatial Center, Fort Worth, Tex., WBDHU12_10May2012_9.3 version, accessed June 2012 at http://datagateway.nrcs.usda.gov.
This is a layer of water service boundaries for 44,786 community water systems that deliver tap water to 307.1 million people in the US. This amounts to 97% of the population reportedly served by active community water systems and 91% of active community water systems. The layer is based on multiple data sources and a methodology developed by SimpleLab and collaborators called a Tiered, Explicit, Match, and Model approach–or TEMM, for short. The name of the approach reflects exactly how the nationwide data layer was developed. The TEMM is composed of three hierarchical tiers, arranged by data and model fidelity. First, we use explicit water service boundaries provided by states. These are spatial polygon data, typically provided at the state-level. We call systems with explicit boundaries Tier 1. In the absence of explicit water service boundary data, we use a matching algorithm to match water systems to the boundary of a town or city (Census Place TIGER polygons). When a water system and TIGER place match one-to-one, we label this Tier 2a. When multiple water systems match to the same TIGER place, we label this Tier 2b. In v1.0.0, Tier 2b reflects overlapping boundaries for multiple systems. In v2.0.0 Tier 2b is removed through a "best match" algorithm that assigns one water system to one TIGER place. Finally, in the absence of an explicit water service boundary (Tier 1) or a TIGER place polygon match (Tier 2a), a statistical model trained on explicit water service boundary data (Tier 1) is used to estimate a reasonable radius at provided water system centroids, and model a spherical water system boundary (Tier 3).
Several limitations to this data exist–and the layer should be used with these in mind. The case of assigning a Census Place TIGER polygon to the "best match" water system in v2.0.0 requires further validation. Many systems were then assigned to Tier 3. Tier 3 boundaries have modeled radii stemming from a lat/long centroid of a water system facility; but the underlying lat/long centroids for water system facilities are of variable quality. It is critical to evaluate the "geometry quality" column (included from the EPA ECHO data source) when looking at Tier 3 boundaries; fidelity is very low when geometry quality is a county or state centroid– but we did not exclude the data from the layer. Future iterations plan to improve upon geometry quality for modeled systems. Missing water systems are typically those without a centroid, in a U.S. territory, or missing population and connection data. Finally, Tier 1 systems are assumed to be high fidelity, but rely on the accuracy of state data collection and maintenance.
All data, methods, documentation, and contributions are open-source and available here: https://github.com/SimpleLab-Inc/wsb.
This product contains 1,297 watershed boundaries for water quality study sites of the U.S. Geological Survey (USGS) National Water Quality Program (NWQP) Surface Water Trends project. These include sites where water quality information was collected by both USGS and non-USGS agencies. The data consist of 1,285 boundaries in the conterminous United States, and 12 in Puerto Rico. Twenty-seven percent of boundaries were assembled from other efforts within the USGS which are using the same sites, and 73 percent of boundaries were created new for this project. The data are posted as a single shapefile with separate polygons for each boundary.
In order to provide an accurate data set of service area boundaries for California drinking water systems, the Division of Drinking Water of the California Water Resources Control Board (SWRCB DDW) has undertaken a project to vet and verify the data collected by the Tracking California's Water Boundary Tool (WBT).Note: This feature layer is updated on a regular basis. However, in some locations where it is shared, it shows the “Data Updated” date as the last time the item has changed, not the data. To accurately determine when the data was last updated, open the data table and sort by Last Edited Date field.SWRCB DDW downloaded a copy of the current water system service areas loaded in the WBT as of June 27, 2019. Additional attribute fields indicating verification status, verification staff and system type were appended to the data set. SWRCB DDW staff are reviewing and validating the displayed boundaries of each service area as well as contacting the service providers regarding necessary corrections. The verification status of any particular service area may be found in the Verification Status field.For any questions regarding this dataset, please contact the Data Support Unit at DDW-DSU@waterboards.ca.gov.
The New Mexico Public Water System (PWS) boundaries is a dataset of non-transient PWS service areas.
Associated documentation on these datasets can be accessed here. In 2023, the New Mexico Legislature passed the Regional Water System Resiliency Act, which allowed the formation of regional water authorities to strengthen the state's aging water infrastructure. The law allows public water systems to organize as recognized political subdivisions, which enables the pooling of resources to hire staff, implement new projects and programs, and access funding for system improvements. The law requires new authorities to file information showing their service area boundary with the Office of the State Engineer (OSE). New service area boundaries provided to the OSE will be incorporated into this dataset as appropriate.
The New Mexico Public Water System (PWS) Boundaries is a dataset of non-transient PWS service areas. The data was compiled by the OSE Water Use and Conservation Bureau with contractor assistance. For systems not providing a service area boundary, best approximation polygons were created using municipal boundaries, census data, and aerial imagery.
This custom dataset was developed by NOAA's MPA Center to support analysis of marine protected areas coverage throughout the U.S. Dataset was compiled through integration of NOAA's medium resolution shoreline merged with the US EEZ maritime limits and edited to include coastal bays and estuaries and the Great Lakes. This is not a formal representation of US marine holdings and is not intended to represent US maritime limits. Related references:NOAA Maritime boundarieshttps://maritimeboundaries.noaa.gov/arcgis/rest/services/MaritimeBoundaries/US_Maritime_Limits_Boundaries/MapServer
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Data OriginThe dataset provided by Ofwat is rooted in legal records. The dataset is digitised from the official appointments of companies as water and sewage undertakers, which include legally binding documents and maps. These documents establish the specific geographic areas each water company is responsible for. The dataset was sourced from Constituency information: Water companiesData TriageAnonymisation is not required for this dataset, since the data is publicly available and focuses on geographical boundaries of water companies rather than individual or sensitive information. The shapefile serves a specific purpose related to geospatial analysis and regulatory compliance, offering transparent information about the service areas of different water companies as designated by Ofwat.Further ReadingBelow is a curated selection of links for additional reading, which provide a deeper understanding of the water company boundaries datasetOfwat (The Water Services Regulation Authority): As the regulatory body for water and wastewater services in England and Wales, Ofwat's website is a primary source for detailed information about the water industry, including company boundaries.Data.gov.uk: This site provides access to national datasets, including the Water Resource Zone GIS Data (WRMP19), which covers all water resource zones in England. This dataset is crucial for understanding geographical boundaries related to water management.Water UK: As a trade body representing UK water and wastewater service providers, Water UK's website offers insights into the industry's workings, including aspects related to geographical boundaries.Specifications and CaveatsWhen compiling the dataset, the following specifications and caveats were made:This shapefile is intended solely for geospatial analysis. The authoritative legal delineation of areas is maintained in the maps and additional details specified in the official appointments of companies as water and/or sewerage undertakers, along with any alterations to their areas.The shapefile does not encompass data on any structures or properties that, despite being outside the designated boundary, are included in the area, or those within the boundary yet excluded from the area.In terms of geospatial analysis and visual representation, the Mean High Water Line has been utilized to define any boundary extending into the sea, though it's more probable that the actual boundary aligns with the low water mark. Furthermore, islands that are incorporated into the area might not be included in this representation.Ofwat’s data was last updated on 25th May 2022Contact Details If you have a query about this dataset, please email foi@ofwat.gov.uk
These data show the geographic representation of Federal and State Waters for the purpose of display in the MarineCadastre.gov OceanReports application. The boundary between state and federal waters was determined by consulting The Submerged Lands Act (43 U.S.C. §§ 1301 et seq.), 48 U.S.C. §§ 1705 and The Abandoned Shipwreck Act (43 U.S.C. §§ 2101). Some boundary delineations based on the SLA were approximated in this data set, including areas in Hawaii, Alaska, and Washington State. Although state boarders do not extend over water, it was necessary to approximate these borders to produce this data set. The boundaries depicted in this data set are for visual purposes only. The placement of these boundaries was extrapolated from the Federal Outer Continental Shelf (OCS) Administrative Boundaries as described here http://edocket.access.gpo.gov/2006/pdf/05-24659.pdf. The delineation between waters under US sovereign territory jurisdiction and that of federal governance is also approximate. Although based upon legislation, these data do not represent legal boundaries, especially in the case of Navassa Island, The Northern Mariana Islands, Baker Island, Howland Island, Johnston Atoll, Kingman Reef, Palmyra Atoll, Wake Islands and Jarvis Island.The seaward limit of this data set is the boundary of the 200nm US Exclusive Economic Zone. The EEZ is measured from the US baseline, recognized as the low-water line along the coast as marked on NOAA's nautical charts in accordance with articles of the Laws of the Sea. These limits are ambulatory and subject to revision based on changes in coastline geometry. This dataset was produced based on an update to the Maritime Limits published in September, 2013. To view the most up-to-date Maritime Limits, please see http://www.nauticalcharts.noaa.gov/csdl/mbound.htm. Navassa Island does not have an EEZ around it, so the seaward extent of the federal waters surrounding it were based on the 12 mile offshore boundary of the USFWS National Wildlife Refuge established on the island. All data is displayed in WGS_1984_World_Mercator. Area calculations for all states except Alaska were completed in the same projection. Area calculations for Alaska were completed in Alaska Albers Equal Area Conic.
This data represents the general service area of the place of use for organizations with water rights who qualify as municipalities or municipal providers under I.C. Title 42 or the 1996 Municipal Water Rights Act and who have a municipal water right on file at IDWR. The service area is for illustrative purposes. This data does not necessarily represent the boundary of city limits. Drainage Districts and Tribal boundaries are not represented in this data.This dataset is derived from the following queries of IDWR water right and recommendation databases: Status = Active, LPOU = Yes, And (WaterUse = Municipal or WaterUse = Municipal From Storage). A Large POU (LPOU) is a water right place of use for which the delivery of water is described with a digital boundary as defined by I.C. Section 42-202B(2) and authorized pursuant to I.C. Section 42-1411(2)(h). If a specific owner has multiple rights represented by different PlaceOfUseIDs, the PlaceofUseID representing the largest area is used. If there is significant divergence in location between different PlaceofUseIDs, the shapes are merged and PlaceofUseID of -999 is assigned.
This hosted feature layer has been published in RI State Plane Feet NAD 83Water Type Boundary lines describe those points along a coastline where one water use type changes to another. Each mapped boundary is coded by number with verbal descriptions found in the Maps of Water Use Categories in the Coastal Resources Management Plan https://www.crmc.ri.gov/regulations/RICRMP.pdf. Except where otherwise noted, the water use classifications along any shoreline reach and between two boundary line designations run parallel to the general coastal trend and extend 500 feet seaward from the mean high water mark.
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(Version 4.0, 7/26/2013) Maritime limits for the United States are measured from the U.S. baseline, which is recognized as the low-water line along the coast as marked on the official U.S. nautical charts in accordance with the articles of the Law of the Sea. The baseline and related maritime limits are reviewed and approved by the interagency U.S. Baseline Committee. The primary purpose of this dataset is to update the official depiction of these maritime limits and boundaries on NOAA's nautical charts. The Office of Coast Survey depicts on its nautical charts the territorial sea (12 nautical miles), contiguous zone (24nm), and exclusive economic zone (200nm, plus maritime boundaries with adjacent/opposite countries). U.S. maritime limits are ambulatory and are subject to revision based on accretion or erosion of the charted low water line. For more information about U.S. Maritime Limits/Boundaries, and to download data, see: https://nauticalcharts.noaa.gov/data/us-maritime-limits-and-boundaries.html For the full FGDC metadata record, see: https://www.fisheries.noaa.gov/inport/item/39963
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The Watershed Boundary Dataset (WBD) is a comprehensive aggregated collection of hydrologic unit data consistent with the national criteria for delineation and resolution. It defines the areal extent of surface water drainage to a point except in coastal or lake front areas where there could be multiple outlets as stated by the "Federal Standards and Procedures for the National Watershed Boundary Dataset (WBD)" "Standard" (https://pubs.usgs.gov/tm/11/a3/). Watershed boundaries are determined solely upon science-based hydrologic principles, not favoring any administrative boundaries or special projects, nor particular program or agency. This dataset represents the hydrologic unit boundaries to the 12-digit for the entire United States. Some areas may also include additional subdivisions representing the 14- and 16-digit hydrologic unit (HU). At a minimum, the HUs are delineated at 1:24,000-scale in the conterminous United States, 1:25,000-scale in Hawaii, Pacific basin and the Cari ...
Boundaries of boroughs (water areas included). All previously released versions of this data are available on the DCP Website: BYTES of the BIG APPLE. Current version: 25c
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This submission includes publicly available data extracted in its original form. If you have questions about the underlying data stored here, please contact the EPA through email klawitter.chandler@epa.gov or contact form. https://www.epa.gov/ground-water-and-drinking-water/forms/online-form-epas-office-ground-water-and-drinking-water This upload contains Geospatial Data File, Data Standard File and Metadata File. A cloned GitHub repository of the code and data is available at this link: https://github.com/USEPA-clone/ORD_SAB_Model "The Service Area Boundary Dataset provides a comprehensive representation of the geographic areas served by community water systems (CWS) across the United States. With nearly 50,000 CWS supplying drinking water to the majority of the U.S. population, defining these service areas is essential for understanding water sources, assessing water quality, and addressing community needs. The dataset integrates both EPA-modeled boundaries and those sourced directly from water systems and state agencies." [Quote from: https://www.epa.gov/ground-water-and-drinking-water/community-water-system-service-area-boundaries]
This data release consists of the data used to develop SPAtially Referenced Regression On Watershed(SPARROW) attributes models for estimating loads of total phosphorus and total nitrogen in Tennessee streams. These data support the publication containing the Tennessee SPARROW models results (Hoos and others, 2019) and include model input used in the South Atlantic-Gulf Drainages and Tennessee River Basin (SAGT) nutrient SPARROW models (Hoos and McMahon, 2009; Garcia and others, 2011) as well as model input for river basins in Tennessee not included in the domain of the published SAGT SPARROW models. Also included in this data release are model coefficients, the software required to execute the Tennessee SPARROW models, and the model output for all streams in Tennessee. Each data set is listed in this data release with an accompanying file containing metadata for the dataset. For additional details, please refer to the README.txt file.
NOAA is responsible for depicting on its nautical charts the limits of the 12 nautical mile Territorial Sea, 24 nautical mile Contiguous Zone, and 200 nautical mile Exclusive Economic Zone (EEZ). The outer limit of each of these zones is measured from the U.S. normal baseline, which coincides with the low water line depicted on NOAA charts and includes closing lines across the entrances of legal bays and rivers, consistent with international law. The U.S. baseline and associated maritime limits are reviewed and approved through the interagency U.S. Baseline Committee, which is chaired by the U.S. Department of State. The Committee serves the function of gaining interagency consensus on the proper location of the baseline using the provisions of the 1958 Convention on the Territorial Sea and the Contiguous Zone, to ensure that the seaward extent of U.S. maritime zones do not exceed the breadth that is permitted by international law. In 2002 and in response to mounting requests for digital maritime zones, NOAA launched a project to re-evaluate the U.S. baseline in partnership with other federal agencies via the U.S. Baseline Committee. The focus of the baseline evaluation was NOAA's largest scale, most recent edition nautical charts as well as supplemental source materials for verification of certain charted features. This dataset is a result of the 2002-present initiative and reflects a multi-year iterative project whereby the baseline and associated maritime limits were re-evaluated on a state or regional basis. In addition to the U.S. maritime limits, the U.S. maritime boundaries with opposite or adjacent countries as well as the US/Canada International Boundary (on land and through the Great Lakes) are also included in this dataset.
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This Water Basin Dataset of HUC codes 2-12 that intersect with the Metropolitan North Georgia Water Planning District is published by the Natural Resources Department at the Atlanta Region from the Water Boundary Dataset of the National Hydrography Dataset.Description of the Water Boundary Dataset from the USGS:The Watershed Boundary Dataset (WBD) is a comprehensive aggregated collection of hydrologic unit data consistent with the national criteria for delineation and resolution. It defines the areal extent of surface water drainage to a point except in coastal or lake front areas where there could be multiple outlets as stated by the "Federal Standards and Procedures for the National Watershed Boundary Dataset (WBD)" “Standard” (https://pubs.usgs.gov/tm/11/a3/). Watershed boundaries are determined solely upon science-based hydrologic principles, not favoring any administrative boundaries or special projects, nor particular program or agency. This dataset represents the hydrologic unit boundaries to the 12-digit (6th level) for the entire United States. Some areas may also include additional subdivisions representing the 14- and 16-digit hydrologic unit (HU). At a minimum, the HUs are delineated at 1:24,000-scale in the conterminous United States, 1:25,000-scale in Hawaii, Pacific basin and the Caribbean, and 1:63,360-scale in Alaska, meeting the National Map Accuracy Standards (NMAS). Higher resolution boundaries are being developed where partners and data exist and will be incorporated back into the WBD. WBD data are delivered as a dataset of polygons and corresponding lines that define the boundary of the polygon. WBD polygon attributes include hydrologic unit codes (HUC), size (in the form of acres and square kilometers), name, downstream hydrologic unit code, type of watershed, non-contributing areas, and flow modifications. The HUC describes where the unit is in the country and the level of the unit. WBD line attributes contain the highest level of hydrologic unit for each boundary, line source information and flow modifications.For more information, see https://www.usgs.gov/national-hydrography/national-hydrography-dataset
A digital map of all North Carolina water system service-area boundaries based on information available in 2019. See the readme file for information on data sources, digitization process, coverage, and important provisos. When using this geopackage, please cite: Gonsenhauser, R., Hansen, K., Grimshaw, W., Morris, J., Albertin, K. and Mullin, M. (2020), Digitizing a Statewide Map of Community Water System Service Areas. J Am Water Works Assoc, 112: 56-61. https://doi.org/10.1002/awwa.1595
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This resource represents new contributions to the national water service boundaries dataset, which also functions as the geoconnex.us reference feature set. This resource is managed by a workflow that incorporates community contributions to supplement, and intended to replace polygons available from https://www.hydroshare.org/resource/20b908d73a784fc1a097a3b3f2b58bfb . This workflow is available here: https://github.com/cgs-earth/ref_pws
This is the archived 2022 version of the Aquifer Risk Map. The most recent version is available here.This aquifer risk map is developed to fulfill requirements of SB-200 and is intended to help prioritize areas where domestic wells and state small water systems may be accessing raw source groundwater that does not meet primary drinking water standards (maximum contaminant level or MCL). In accordance with SB-200, the risk map is to be made available to the public and is to be updated annually starting January 1, 2021. The Fund Expenditure Plan states the risk map will be used by Water Boards staff to help prioritize areas for available SAFER funding. This is the final 2022 map based upon feedback received from the 2021 map. A summary of methodology updates to the 2022 map can be found here.This map displays raw source groundwater quality risk per square mile section. The water quality data is based on depth-filtered, declustered water quality results from public and domestic supply wells. The process used to create this map is described in the 2022 Aquifer Risk Map Methodology document. Data processing scripts are available on GitHub. Download/export links are provided in this app under the Data Download widget.This version was last updated December 1, 2021.Water quality risk: This layer contains summarized water quality risk per square mile section and well point. The section water quality risk is determined by analyzing the long-tern (20-year) section average and the maximum recent (within 5 years) result for all sampled contaminants. These values are compared to the MCL and sections with values above the MCL are “high risk”, sections with values within 80%-100% of the MCL are “medium risk” and sections with values below 80% of the MCL are “low risk”. The specific contaminants above or close to the MCL are listed as well. The water quality data is based on depth-filtered, de-clustered water quality results from public and domestic supply wells.Individual contaminants: This layer shows de-clustered water quality data for arsenic, nitrate, 1,2,3-trichloropropane, uranium, and hexavalent chromium per square mile section.Domestic Well Density: This layer shows the count of domestic well records per square mile. The domestic well density per square mile is based on well completion report data from the Department of Water Resources Online System for Well Completion Reports, with records drilled prior to 1970 removed and records of “destruction” removed.State Small Water Systems: This layer displays point locations for state small water systems based on location data from the Division of Drinking Water.Public Water System Boundaries: This layer displays the approximate service boundaries for public water systems based on location data from the Division of Drinking Water.Reference layers: This layer contains several reference boundaries, including boundaries of CV-SALTS basins with their priority status, Groundwater Sustainability Agency boundaries, census block group boundaries, county boundaries, and groundwater unit boundaries.
The National Water Quality Network (NWQN) for Rivers and Streams includes 113 surface-water river and stream sites monitored by the U.S. Geological Survey (USGS) National Water Quality Program (NWQP). The NWQN represents the consolidation of four historical national networks: the USGS National Water-Quality Assessment (NAWQA) Project, the USGS National Stream Quality Accounting Network (NASQAN), the National Monitoring Network (NMN), and the Hydrologic Benchmark Network (HBN). The NWQN includes 22 large river coastal sites, 41 large river inland sites, 30 wadeable stream reference sites, 10 wadeable stream urban sites, and 10 wadeable stream agricultural sites. In addition to the 113 NWQN sites, 3 large inland river monitoring sites from the USGS Cooperative Matching Funds (Co-op) program are also included in this annual water-quality reporting Web site to be consistent with previous USGS studies of nutrient transport in the Mississippi-Atchafalaya River Basin. This data release contains geo-referenced digital data and associated attributes of watershed boundaries for 113 NWQN and 3 Co-op sites. Two sites, "Wax Lake Outlet at Calumet, LA"; 07381590, and "Lower Atchafalaya River at Morgan City, LA"; 07381600, are outflow distributaries into the Gulf of Mexico. Watershed boundaries were delineated for the portion of the watersheds between "Red River near Alexandria, LA"; 07355500 and "Atchafalaya River at Melville, LA"; 07381495 to the two distributary sites respectively. Drainage area was undetermined for these two distributary sites because the main stream channel outflows into many smaller channels so that streamflow is no longer relative to the watershed area. NWQN watershed boundaries were derived from the Watershed Boundary Dataset-12-digit hydrologic units (WBD-12). The development of the WBD-12 was a coordinated effort between the United States Department of Agriculture-Natural Resources Conservation Service (USDA-NRCS), the USGS, and the Environmental Protection Agency (EPA) (U.S. Department of Agriculture-Natural Resources Conservation Service, 2012). A hydrologic unit is a drainage area delineated to nest in a multi-level, hierarchical drainage system. Its boundaries are defined by hydrographic and topographic criteria that delineate an area of land upstream from a specific point on a river, stream or similar surface waters. The United States is divided and sub-divided into successively smaller hydrologic units identified by a unique hydrologic unit code (HUC) consisting of two to 12 digits based on the six levels of classification in the hydrologic unit system: regions, sub-regions, accounting units, cataloging units, watersheds, and sub-watersheds. NWQN watershed boundaries were delineated by selecting all sub-watershed polygons that flow into the most downstream WBD-12 polygon in which the NWQN site is located. The WBD-12 attribute table contains 8-digit, 10-digit, and 12-digit HUCs which were used to identify which sub-watersheds flow into the watershed pour point at the NWQN site location. When the NWQN site was located above the pour point of the most downstream sub-watershed, the sub-watershed was edited to make the NWQN site the pour point of that sub-watershed. To aid editing, USGS 1:24,000 digital topographic maps were used to determine the hydrologic divide from the sub-watershed boundary to the NWQN pour point. The number of sub-watersheds which are contained within the NWQN watersheds ranged from less than one to nearly 32,000 internal sub-watersheds. Internal sub-watershed boundaries were dissolved so that a single watershed boundary was generated for each NWQN watershed. Data from this release are presented at the USGS Tracking Water Quality page: http://cida.usgs.gov/quality/rivers/home (Deacon and others, 2015). Watershed boundaries delineated for this release do not take into account non-contributing area, diversions out of the watershed, or return flows into the watershed. Delineations are based solely on contributing WBD-12 polygons with modifications done only to the watershed boundary at the NWQN site location pour point. For this reason calculated drainage areas for these delineated watersheds may not match National Water Information System (MWIS) published drainage areas (http://dx.doi.org/10.5066/F7P55KJN). Deacon, J.R., Lee, C.J., Toccalino, P.L., Warren, M.P., Baker, N.T., Crawford, C.G., Gilliom, R.G., and Woodside, M.D., 2015, Tracking water-quality of the Nation’s rivers and streams, U.S. Geological Survey Web page: http://cida.usgs.gov/quality/rivers, https://dx.doi.org/doi:10.5066/F70G3H51. U.S. Department of Agriculture-Natural Resources Conservation Service, 2012, Watershed Boundary Dataset-12-digit hydrologic units: NRCS National Cartography and Geospatial Center, Fort Worth, Tex., WBDHU12_10May2012_9.3 version, accessed June 2012 at http://datagateway.nrcs.usda.gov.