Kentucky 14-digit Hydrologic Units

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 14-digit (7th level) for the entire state of Kentucky, as well as some intersecting watershed boundaries from bordering states including: Tennessee, Virginia, West Virginia, Ohio, Indiana, Illinois, and Missouri. The naming and numbering conventions follow USGS standards, and were assigned by the Kentucky Division of Water, GIS and Data Analysis Section. 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. Download Link: https://ky.box.com/s/jejj1vquou2ou6zc7yb1dbu7jaa9nef1流域边界数据集（Watershed Boundary Dataset，简称WBD）是一套符合国家级划定与分辨率标准的综合聚合水文单元数据集。其定义了地表水汇至某一点的区域范围，但沿海或湖滨区域除外——此类区域可存在多个出水口，符合《国家级流域边界数据集（WBD）联邦标准与规程》中的相关规定，具体可参考：https://pubs.usgs.gov/tm/11/a3/。流域边界仅基于科学水文原则划定，不偏向任何行政边界、特殊项目、特定规划或机构。本数据集覆盖肯塔基州全域的14位（第7级）水文单元边界，同时包含来自邻州田纳西州、弗吉尼亚州、西弗吉尼亚州、俄亥俄州、印第安纳州、伊利诺伊州及密苏里州的部分交汇流域边界。其命名与编号规则遵循美国地质调查局（United States Geological Survey，USGS）标准，由肯塔基州水资源部GIS与数据分析科制定。水文单元（Hydrologic Unit，简称HUs）的最低制图比例尺为：美国本土48州采用1:24000，夏威夷州、太平洋流域及加勒比地区采用1:25000，阿拉斯加州采用1:63360，所有比例尺均符合《国家地图精度标准（National Map Accuracy Standards，简称NMAS）》。在具备合作方与数据源的区域，正开发更高分辨率的流域边界，并将其整合回WBD数据集。WBD数据以多边形及用于定义多边形边界的对应线要素数据集形式交付。WBD多边形要素的属性字段包含：水文单元代码（Hydrologic Unit Code，HUC）、面积（以英亩与平方千米为单位）、名称、下游水文单元代码、流域类型、非汇水区以及径流改造情况。HUC用于标识该水文单元在全国范围内的位置与等级。WBD线要素的属性字段包含各边界对应的最高等级水文单元、线要素来源信息以及径流改造情况。下载链接：https://ky.box.com/s/jejj1vquou2ou6zc7yb1dbu7jaa9nef1