Hydrography - NHD Waterbodies

The NHD is a national framework for assigning reach addresses to water-related entities, such as industrial discharges, drinking water supplies, fish habitat areas, wild and scenic rivers. Reach addresses establish the locations of these entities relative to one another within the NHD surface water drainage network, much like addresses on streets. Once linked to the NHD by their reach addresses, the upstream/downstream relationships of these water-related entities--and any associated information about them--can be analyzed using software tools ranging from spreadsheets to geographic information systems (GIS). GIS can also be used to combine NHD-based network analysis with other data layers, such as soils, land use and population, to help understand and display their respective effects upon one another. Furthermore, because the NHD provides a nationally consistent framework for addressing and analysis, water-related information linked to reach addresses by one organization (national, state, local) can be shared with other organizations and easily integrated into many different types of applications to the benefit of all.The WA State National Hydrography Dataset (NHD) is the standard hydrography for Washington. NHD Waterbody along with WA NHD Area represent the polygon water features. NHD Flowline contains the linear watercourses. NHDWaterbody types and their corresponding FType Codes are Estuary(493), LakePond(390), SwampMarsh(466), Constructed Reservoir(436), Ice Mass(378), and Playa(361). The WA State National Hydrography Dataset (NHD) is the standard hydrography for Washington. NHD Lines represent linear NHD hydrographic landmark features used for cartographic representation. Some of these are: Bridge, Dam, Flume, Gate, Levee, Sounding Datum Line. NHD Lines should not be confused with NHD Flowlines which are the major blue line data. NHD Line data for Washington are developed at a resolution of 1:4,800 to 1:24,000. This dataset was extracted from and projected into WA State Plane Coordinates South. The National Hydrography Dataset (NHD) is a feature-based database that as a whole interconnects and uniquely identifies the stream segments or reaches that make up the nation's surface water drainage system. This high-resolution NHD, generally is developed at 1:24,000/1:12,000 scale, but many areas of Washington State have been improved to 1:4800 scale. NHD data was originally developed at 1:100,000-scale and exists at that scale for the whole country. Local resolution NHD is being developed where partners and data exist. The NHD contains reach codes for networked features, flow direction, names, and centerline representations for areal water bodies. Reaches are also defined on waterbodies and the approximate shorelines of the Great Lakes, the Atlantic and Pacific Oceans and the Gulf of Mexico. The NHD also incorporates the National Spatial Data Infrastructure framework criteria established by the Federal Geographic Data Committee. A detailed data dictionary is available at https://nhd.usgs.gov/userguide.html?url=NHD_User_Guide/Feature_Catalog/NHD_Feature_Catalog.htm国家水文数据集（National Hydrography Dataset，NHD）是一套为涉水实体分配河段地址的国家级框架，此类涉水实体涵盖工业排放点、饮用水水源地、鱼类栖息地、野生与风景河流等。河段地址可明确各涉水实体在NHD地表水排水网络中的相对位置，恰似街道门牌号一般。一旦通过河段地址与NHD建立关联，便可借助从电子表格到地理信息系统（Geographic Information System，GIS）等各类软件工具，分析这些涉水实体的上下游关系及其关联信息。GIS还可将基于NHD的网络分析与土壤、土地利用、人口等其他数据图层相结合，助力理解并可视化展示各类要素间的相互影响。此外，由于NHD提供了统一的国家级地址分配与分析框架，由国家、州或地方机构通过河段地址关联的涉水信息可在不同机构间共享，并能轻松集成至各类应用场景中，惠及全体相关方。 华盛顿州国家水文数据集（Washington State National Hydrography Dataset，WA NHD）是华盛顿州的标准水文数据产品。NHD水体（NHD Waterbody）与华盛顿州NHD面要素（WA NHD Area）共同构成面状水体要素。NHD水流线（NHD Flowline）包含线状水道要素。NHD水体类型及其对应的FType代码分别为：河口（Estuary，493）、湖塘（LakePond，390）、沼泽湿地（SwampMarsh，466）、人工水库（Constructed Reservoir，436）、冰体（Ice Mass，378）以及干盐湖（Playa，361）。华盛顿州国家水文数据集（WA NHD）是华盛顿州的标准水文数据产品。NHD线要素（NHD Lines）代表用于制图表达的线状NHD水文地标要素，此类要素包括桥梁、大坝、渡槽、闸门、堤防以及测深基准线等。需注意勿将NHD线要素与作为核心蓝线数据的NHD水流线（NHD Flowline）混淆。华盛顿州的NHD线要素数据分辨率为1:4800至1:24000。该数据集基于华盛顿州南平面坐标系进行提取与投影。 国家水文数据集（NHD）是一套基于要素的数据库，整体上可互连构成全美地表水排水系统的河流河段，并为其赋予唯一标识。该高分辨率NHD通常以1:24000/1:12000的比例尺构建，但华盛顿州的多数区域已将分辨率提升至1:4800。NHD数据最初以1:100000的比例尺开发，全美范围内均有该比例尺的数据集。目前，在具备合作方与数据资源的区域，正推进本地化分辨率的NHD建设。NHD包含网络化要素的河段代码、水流方向、名称信息，以及面状水体的中心线表达数据。河段的定义范围还覆盖了水体、五大湖、大西洋、太平洋以及墨西哥湾的近似岸线区域。NHD同时遵循由联邦地理数据委员会（Federal Geographic Data Committee）制定的国家空间数据基础设施框架标准。详细的数据字典可访问以下链接获取：https://nhd.usgs.gov/userguide.html?url=NHD_User_Guide/Feature_Catalog/NHD_Feature_Catalog.htm