MS4 Regulated Areas

Municipalities and other entities, such as universities and prisons, that meet certain standards must obtain NPDES permit coverage for discharges of stormwater from their municipal separate storm sewer system (MS4s). The part of the municipality regulated by the permittee's MS4 permit is the portion of the municipality designated by the 2010 Census as urbanized area, plus any additional areas designated by the 2020 Census as urban areas with a population of 50,000 or more. This dataset was created using two shapefiles from the Census Bureau. The census data is a snapshot in time. When data from the 2030 Census becomes available a new dataset will be created. This dataset shows the current area regulated by MS4 permits throughout the state.符合特定标准的市政当局及其他实体（如高校、监狱等），需针对其市政独立雨水管网系统（Municipal Separate Storm Sewer System, MS4s）的雨水排放，取得国家污染物排放消除系统（National Pollutant Discharge Elimination System, NPDES）的许可资质。该许可持证方的市政独立雨水管网许可所监管的市政区域，为2010年人口普查划定的城市化区域，以及2020年人口普查划定的人口达5万及以上的城镇区域。本数据集由美国人口普查局提供的两份shapefiles构建而成。普查数据为特定时间节点的静态快照，待2030年人口普查数据公开后，将生成全新的数据集。本数据集展示了当前全州范围内受市政独立雨水管网许可监管的区域范围。