Richardson Wetlands

Data set has been modified to only show information within the City of Richardson's municipal boundary. This data set represents the extent, approximate location and type of wetlands and deepwater habitats in the United States and its Territories. These data delineate the areal extent of wetlands and surface waters as defined by Cowardin et al. (1979). The National Wetlands Inventory - Version 2, Surface Waters and Wetlands Inventory was derived by retaining the wetland and deepwater polygons that compose the NWI digital wetlands spatial data layer and reintroducing any linear wetland or surface water features that were orphaned from the original NWI hard copy maps by converting them to narrow polygonal features. Additionally, the data are supplemented with hydrography data, buffered to become polygonal features, as a secondary source for any single-line stream features not mapped by the NWI and to complete segmented connections. Wetland mapping conducted in WA, OR, CA, NV and ID after 2012 and most other projects mapped after 2015 were mapped to include all surface water features and are not derived data. The linear hydrography dataset used to derive Version 2 was the U.S. Geological Survey's National Hydrography Dataset (NHD). Specific information on the NHD version used to derive Version 2 and where Version 2 was mapped can be found in the 'comments' field of the Wetlands_Project_Metadata feature class. Certain wetland habitats are excluded from the National mapping program because of the limitations of aerial imagery as the primary data source used to detect wetlands. These habitats include seagrasses or submerged aquatic vegetation that are found in the intertidal and subtidal zones of estuaries and near shore coastal waters. Some deepwater reef communities (coral or tuberficid worm reefs) have also been excluded from the inventory. These habitats, because of their depth, go undetected by aerial imagery. By policy, the Service also excludes certain types of "farmed wetlands" as may be defined by the Food Security Act or that do not coincide with the Cowardin et al. definition. Contact the Service's Regional Wetland Coordinator for additional information on what types of farmed wetlands are included on wetland maps. This dataset should be used in conjunction with the Wetlands_Project_Metadata layer, which contains project specific wetlands mapping procedures and information on dates, scales and emulsion of imagery used to map the wetlands within specific project boundaries.本数据集已完成裁剪，仅保留理查森市（City of Richardson）行政边界范围内的相关信息。本数据集呈现了美国及其领地内湿地与深水生境的分布范围、大致位置与类型。这些数据按照考尔丁等人（Cowardin et al., 1979）提出的定义，勾勒出湿地与地表水体的面积范围。 美国国家湿地清单第二版（National Wetlands Inventory - Version 2）地表水体与湿地清单，通过保留构成美国国家湿地清单（National Wetlands Inventory，简称NWI）数字湿地空间数据层的湿地与深水多边形要素，并将原始NWI纸质地图中丢失的线性湿地或地表水体要素转换为窄幅多边形要素，重新纳入这些特征而生成。此外，本数据集辅以水文数据，将其缓冲区转换为多边形要素，以此作为NWI未绘制的单线路流要素的补充数据源，并完善分段水系的连接。 2012年后在华盛顿州、俄勒冈州、加利福尼亚州、内华达州与爱达荷州开展的湿地测绘工作，以及2015年后开展的绝大多数其他测绘项目，均已覆盖全部地表水体要素，不属于衍生数据。用于生成第二版数据集的线性水文数据集为美国地质调查局（U.S. Geological Survey）的国家水文数据集（National Hydrography Dataset，简称NHD）。关于第二版数据集所采用的NHD版本，以及第二版数据集的测绘范围，可在Wetlands_Project_Metadata要素类的"comments"（注释）字段中查询详情。 由于航空影像作为湿地探测的主要数据源存在局限性，部分湿地生境未纳入国家测绘项目。这些生境包括分布在河口潮间带、潮下带以及近岸海域的海草或沉水水生植被。部分深水礁群落（珊瑚或管栖蠕虫礁）也未纳入本清单——这类生境因所处水深较大，无法通过航空影像探测到。根据政策，该局还会排除《食品安全法》（Food Security Act）定义的部分“农用湿地”，或不符合考尔丁等人定义的湿地。如需了解湿地地图中包含的农用湿地类型详情，请联系该局区域湿地协调专员。 本数据集需与Wetlands_Project_Metadata图层配合使用，该图层包含项目专属的湿地测绘流程，以及特定项目边界内用于湿地测绘的影像日期、比例尺与感光乳剂类型等相关信息。