USGS HUC Watersheds

United States Geological Survey (USGS) Hydrologic Unit Code (HUC) zones represent watershed basins. This layer contains HUC 8, HUC 10, and HUC 12 watersheds that are within and surround Forsyth County. Data exported from NHD (National Hydrography Dataset) in 2022 Source: https://www.usgs.gov/national-hydrography/national-hydrography-dataset In 2024, the USGS shifted from maintaining the National Hydrography Dataset (NHD), the Watershed Boundary Dataset (WBD), and the NHDPlus High-Resolution to production of 3D Hydrography Program products. While these legacy products are no longer updated and maintained, they are provided here as both downloadable products and as services for reference purposes. More information about the legacy datasets is available on the About National Hydrography Products webpage. For any accessibility comments, questions, or concerns please contact [e-mail] The Watershed Boundary Dataset (WBD) is a seamless, national hydrologic unit dataset. Simply put, hydrologic units represent the area of the landscape that drains to a portion of the stream network. More specifically, a hydrologic unit defines the areal extent of surface water drainage to an outlet point on a dendritic stream network or to multiple outlet points where the stream network is not dendritic. A hydrologic unit may represent all or only part of the total drainage area to an outlet point so that multiple hydrologic units may be required to define the entire drainage area at a given outlet. Hydrologic unit boundaries in the WBD are determined based on topographic, hydrologic, and other relevant landscape characteristics without regard for administrative, political, or jurisdictional boundaries. The WBD seamlessly represents hydrologic units at six required and two optional hierarchical levels. The hydrologic units (HU) in the WBD form a standardized system for organizing, collecting, managing, and reporting hydrologic information for the nation. The HU in the WBD are arranged in a nested, hierarchical system with each HU in the system identified using a unique code. Hydrologic unit codes (HUC) are developed using a progressive two-digit system where each successively smaller areal unit is identified by adding two digits to the identifying code the smaller unit is nested within. WBD contains eight levels of progressive hydrologic units identified by unique 2- to 16-digit codes. The dataset is complete for the United States to the 12-digit hydrologic unit. The 14- and 16-digit hydrologic units are optional and are not complete for the nation. Efforts are ongoing to complete 10- and 12-digit unit delineations within 8-digit hydrologic units extending across the U.S. – Canada border. Additional information about this effort and access to data is linked on the “resources” section on this page. A similar effort is complete for the 10- and 12-digit units extending across the U.S. – Mexico border. More information can be found here: https://www.usgs.gov/core-science-systems/ngp/national-hydrography/watershed-boundary-dataset?qt-science_support_page_related_con=4#qt-science_support_page_related_con

美国地质调查局（United States Geological Survey，USGS）水文单元代码（Hydrologic Unit Code，HUC）区域代表流域盆地。本图层包含福赛斯县境内及周边的HUC 8、HUC 10与HUC 12级流域。数据源自2022年导出的国家水文数据集（National Hydrography Dataset，NHD），来源地址：https://www.usgs.gov/national-hydrography/national-hydrography-dataset。2024年，美国地质调查局已停止维护国家水文数据集（NHD）、流域边界数据集（Watershed Boundary Dataset，WBD）以及NHDPlus高分辨率产品，转而开展三维水文项目（3D Hydrography Program）产品的生产。尽管上述传统产品不再更新与维护，本数据集仍以可下载产品及服务形式提供，仅供参考。如需了解更多传统数据集的相关信息，可访问国家水文产品简介网页。如有无障碍相关的意见、疑问或诉求，请联系[e-mail]。流域边界数据集（Watershed Boundary Dataset，WBD）是一套无缝衔接的全国性水文单元数据集。简言之，水文单元指地表径流汇入河网特定区段的陆地区域。更具体地说，水文单元定义了地表径流汇入树状河网出水口点的面范围，或在河网非树状情况下汇入多个出水口点的面范围。单个水文单元可能仅代表某出水口点总汇水区的一部分，因此需多个水文单元方可定义给定出水口点的完整汇水区。WBD中的水文单元边界基于地形、水文及其他相关景观特征划定，不考虑行政、政治或管辖边界。WBD包含6个强制层级与2个可选层级的水文单元，形成无缝覆盖的层级体系。WBD中的水文单元（Hydrologic Unit，HU）构成一套标准化体系，用于全美水文信息的组织、采集、管理与汇报。WBD中的水文单元采用嵌套层级结构，每个单元均配有唯一标识码。水文单元代码（HUC）采用递进式两位编码规则：每一级更小的面状单元通过在其所嵌套的上级单元标识码后追加两位数字进行标识。WBD共包含8级递进式水文单元，以2至16位不等的唯一代码进行标识。美国全境的12位水文单元数据已完整覆盖，14位与16位水文单元为可选层级，尚未实现全国范围的完整覆盖。目前相关团队正推进美加边境沿线8位水文单元内的10位与12位单元的划界工作。该项目的更多信息及数据获取方式，可通过本页面“资源”板块获取。美墨边境沿线的10位与12位水文单元的划界工作已完成，相关更多信息可访问：https://www.usgs.gov/core-science-systems/ngp/national-hydrography/watershed-boundary-dataset?qt-science_support_page_related_con=4#qt-science_support_page_related_con