NHD Plus 100K Stream Order in Kentucky (Legacy)

This high-level metadata data document will be supplemented with detailed regional metadata at a later date. The NHDPlusV2 is an integrated suite of application-ready geospatial data sets that incorporate many of the best features of the National Hydrography Dataset (NHD) and the National Elevation Dataset (NED). Interest in estimating stream flow volume and velocity to support pollutant fate-and-transport modeling was the driver behind the joint USEPA and USGS effort to develop the initial NHDPlus, referenced in this document as NHDPlusV1. NHDPlusV1 has been used in a wide variety of applications since its initial release in the fall of 2006. This widespread positive response prompted the multi-agency NHDPlus team to develop NHDPlus Version 2 (NHDPlusV2). The NHDPlusV2 includes a stream network (based on the 1:100,000-scale NHD), improved networking, naming, and "value-added attributes" (VAA's). NHDPlusV2 also includes elevation-derived catchments (drainage areas) produced using a drainage enforcement technique first broadly applied in New England, and thus dubbed "The New-England Method". This technique involves "burning-in" the 1:100,000-scale NHD and building "walls" using the national Watershed Boundary Dataset (WBD). The hydro-enforced digital elevation model (DEM) is used to produce hydrologic derivatives that agree with the NHD and WBD. An interdisciplinary team from the USGS, USEPA and contractors, has found this method to produce the best quality NHD catchments using an automated process. The VAAs include greatly enhanced capabilities for upstream and downstream navigation, analysis and modeling. Examples include: retrieve all flowlines (predominantly confluence-to-confluence stream segments) and catchments upstream of a given flowline using queries rather than by slower flowline-by-flowline navigation; retrieve flowlines by stream order; select a stream level path sorted in hydrologic order for stream profile mapping, analysis and plotting; and, calculate cumulative catchment attributes using streamlined VAA hydrologic sequencing routing attributes. The VAAs include results from the use of these cumulative routing techniques, including cumulative drainage areas, precipitation, temperature, and runoff distributions. Several of these cumulative attributes are used to estimate mean annual flow and velocity as part of the VAAs. NHDPlusV2 contains a snapshot (2012) of the 1:100,000-scale NHD that has been extensively improved over the snapshot used in NHDPlusV1. While these updates will eventually be stored in the central NHD repository at USGS, this will not be accomplished prior to distribution of NHDPlusV2. NHDPlusV2 users may not make updates to the NHD portions of NHDPlusV2 with the intent of sending these updates back to the USGS. Updates to the 1:100,000-scale NHD snapshot in NHDPlusV2 should be sent to the USEPA as the primary steward. Purpose: The geospatial data sets included in NHDPlusV2 are intended to support a variety of water-related applications. They already have been used in an application to develop estimates of mean annual streamflow and velocity for each NHDFlowline feature in the conterminous United States. The results of these analyses are included with the NHDPlusV2 data. NHDPlusV2 serves as the sample frame for the stream and lake surveys conducted by the USEPA under the National Aquatic Resources Surveys program. A water-quality model developed by the U.S. Geological Survey (USGS) called SPARROW (Spatially Referenced Regressions on Watershed Attributes), can utilizes the NHDPlusV2 network functionality to track the downstream transport of nutrients, sediments, or other substances. NHDPlusV2 water bodies and estimates of streamflow and velocity are used in SPARROW to identify reservoir retention and in-stream loss factors. NHDPlusV2 climatic and land surface attributes can be used in SPARROW to identify potential factors in the delivery of nutrients from the land surface to streams. NHDPlusV2 data is also being used in select areas for a USGS Web-based application, called StreamStats. StreamStats provides tools to interactively select any point in the implemented areas, delineate watersheds, and to obtain streamflow and watershed characteristics for the selected point. NHDPlusV2 has been designed to accommodate many users' needs for future applications. NHDPlusV2 provides the framework and tools necessary to customize the behavior of the network relationships as well as building upon the attribute database, for which the user can assign their own data to the network.本高阶元数据文档将于后续补充详细的区域元数据。NHDPlusV2是一套集成化的可直接投入应用的地理空间数据集套件，整合了美国国家水文数据集（National Hydrography Dataset, NHD）与美国国家高程数据集（National Elevation Dataset, NED）的诸多优质特性。最初促使美国环境保护署（United States Environmental Protection Agency, USEPA）与美国地质调查局（United States Geological Survey, USGS）联合开发初代NHDPlus（即本文所述的NHDPlusV1）的核心动因，是为了估算河川径流量与流速，以支撑污染物归趋与迁移模拟工作。NHDPlusV1自2006年秋季首次发布以来，已被广泛应用于各类场景，其广受好评的应用反馈促使多机构组成的NHDPlus团队开发出NHDPlus第二版（NHDPlusV2）。 NHDPlusV2包含基于1:10万比例尺NHD构建的河网，优化了网络拓扑、命名规则与增值属性（value-added attributes, VAA）。此外，NHDPlusV2还包含采用排水强化技术生成的高程驱动汇水区，该技术最早在新英格兰地区大规模应用，因此被称为“新英格兰方法”。该技术通过“烧入”1:10万比例尺NHD数据，并利用全国流域边界数据集（Watershed Boundary Dataset, WBD）构建边界屏障。经水文强化的数字高程模型（Digital Elevation Model, DEM）可用于生成与NHD和WBD一致的水文衍生数据。由USGS、USEPA及合同方组成的跨学科团队证实，该方法可通过自动化流程生成最高质量的NHD汇水区。 增值属性（VAA）大幅提升了上下游导航、分析与建模的能力，具体示例包括：无需逐河段导航即可通过查询获取指定河段上游的所有流线（主要为汇点间河段）与汇水区；按河流水系等级检索河段；选取按水文顺序排列的河流水系路径用于河道剖面制图、分析与绘图；以及通过优化的VAA水文序列路由属性计算累积汇水区属性。VAA还包含上述累积路由技术的计算结果，如累积汇水面积、降水、气温与径流分布。其中多项累积属性被用于估算年均径流量与流速，作为VAA的组成部分。 NHDPlusV2采用的1:10万比例尺NHD快照（2012年版）相较于NHDPlusV1所使用的快照版本，已得到全面优化。尽管这些更新最终将被存储至USGS的中央NHD知识库，但无法在NHDPlusV2发布前完成。NHDPlusV2的用户不得修改NHDPlusV2中的NHD部分，并试图将修改内容返还至USGS。若需对NHDPlusV2中的1:10万比例尺NHD快照进行更新，应将修改内容提交至作为主要管理方的USEPA。 用途：NHDPlusV2所包含的地理空间数据集旨在支撑各类水相关应用。目前其已被用于为美国本土内的每个NHDFlowline要素估算年均径流量与流速，相关分析结果已随NHDPlusV2数据一同发布。NHDPlusV2可作为美国环境保护署（USEPA）在国家水生资源调查（National Aquatic Resources Surveys）项目中开展河川与湖泊调查的抽样框架。由美国地质调查局（USGS）开发的水质模型SPARROW（Spatially Referenced Regressions on Watershed Attributes）可利用NHDPlusV2的网络功能追踪营养物、沉积物或其他物质的下游输运过程。NHDPlusV2的水体数据与径流量、流速估算结果被用于SPARROW模型中，以识别水库滞留与河道损失因子。NHDPlusV2的气候与地表属性可辅助SPARROW模型识别营养物从地表向河川输运的潜在影响因子。此外，NHDPlusV2数据还在部分区域被用于USGS基于网页的应用StreamStats。StreamStats提供工具以交互式选取目标区域内的任意点、划定汇水区，并获取该点的径流量与汇水区特征参数。 NHDPlusV2的设计初衷是满足众多用户未来应用的需求。其提供了必要的框架与工具，既支持自定义网络关系的行为逻辑，也可在属性数据库的基础上进行拓展，用户可将自有数据挂载至该数据集的河网中。