Resource Protection Areas RPA

King George County falls in the Chesapeake Bay Preservation Area and is regulated by the Virginia Department of Environmental Quality (DEQ) to comply with the Chesapeake Bay Preservation Act of 1988. Part of this compliance requires King George County to create and maintain a Resource Protection Area (RPA) map. RPA, "Resource Protection Area", means that component of the Chesapeake Bay Preservation Area comprised of lands adjacent to water bodies with perennial flow that have an intrinsic water quality value due to the ecological and biological processes they perform or are sensitive to impacts which may result in significant degradation to the quality of state waters (DEQ definition). The RPA layer is made up of a 100 foot buffer around perennial streams (USGS), tidal wetlands (USFWS), and non-tidal wetlands (USFWS) that are contiguous to perennial streams and tidal wetlands. The USGS (United States Geological Survey) flowline datalayer, which is part of the national hydrography dataset, shows perennial and intermittent streams. The U.S. Fish & Wildlife Service, USFWS, developed the National Wetland Inventory, NWI, to help identify and protect wetlands. The NWI uses a wetland classification code comprising a series of letter and number codes that have been developed to adapt the national wetland classification system to map form. These alpha-numeric codes correspond to the classification nomenclature that best describes a particular wetland habitat. For example, PFO1A = Palustrine (P), Forested (FO), Broad-leaved Deciduous (1), Temporarily Flooded (A). Tidal wetlands are made of Marine, Estuarine, and Riverine (subsystem-1) wetlands as designated in the NWI wetland classification codes. Non-tidal wetlands are made of Riverine (subsytems 2-4), Lacustrine, and Palustrine wetlands as designated in the NWI wetland classification codes. King George County is approximately 188 square miles. There are approximately 43 square miles of RPA, or about 23% of King George County is in the RPA. Both the USGS streams and USFW NWI's were developed at a scale of 1:24,000 and are used for general planning purposes. Site specific RPA delineation work requires an engineer.乔治国王县（King George County）地处切萨皮克湾保护区（Chesapeake Bay Preservation Area）范围内，需遵守弗吉尼亚州环境质量部（Virginia Department of Environmental Quality, DEQ）依据1988年《切萨皮克湾保护法案》制定的监管要求。 该项合规义务的核心内容之一，是乔治国王县需编制并维护资源保护区（Resource Protection Area, RPA）地图。根据弗吉尼亚州环境质量部的定义，资源保护区（RPA）指切萨皮克湾保护区中，毗邻常年径流水体的土地组分——此类水体凭借自身运行的生态与生物过程具备固有水质价值，或对可能导致州域水体质量显著退化的外界影响具有敏感性。 RPA图层由环绕常年溪流（美国地质调查局，USGS）、潮汐湿地（美国鱼类及野生动物管理局，USFWS），以及与常年溪流和潮汐湿地连片的非潮汐湿地（USFWS）的100英尺缓冲带构成。 美国地质调查局（United States Geological Survey, USGS）的流线数据图层隶属于国家水文数据集，可展示常年溪流与间歇溪流的分布情况。 美国鱼类及野生动物管理局（U.S. Fish & Wildlife Service, USFWS）牵头编制了国家湿地目录（National Wetland Inventory, NWI），旨在辅助湿地的识别与保护工作。该目录采用由字母与数字组成的分类编码体系，该体系适配全国湿地分类标准并可落地于地图制图，此类字母数字编码与能够精准描述特定湿地生境的分类命名规则一一对应。 例如，编码PFO1A代表：内陆淡水湿地型（Palustrine, P）、森林湿地（Forested, FO）、阔叶落叶型（Broad-leaved Deciduous, 1）、临时淹水型（Temporarily Flooded, A）。 潮汐湿地对应国家湿地目录分类编码中划定的海洋、河口与河滨（子系统1）湿地；非潮汐湿地则对应该目录中划定的河滨（子系统2-4）、湖泊与内陆淡水湿地。 乔治国王县总面积约188平方英里，其中资源保护区面积约43平方英里，占全县总面积的23%左右。 美国地质调查局的溪流数据与美国鱼类及野生动物管理局的国家湿地目录均采用1:24000的比例尺制作，仅适用于通用规划场景。 若需开展针对特定地块的资源保护区划界工作，需由专业工程师完成。