Index of Estuarine Condition Estuarine Flow Barriers

IEC2021_BARRIERS indicates locations of estuarine barriers (partial and complete) that were used in the 2021 Index of Estuarine Condition. A combination of existing data sources and field data collection was used to identify the existence of artificial barriers and whether these structures represented partial or complete barriers (Pope et al. 2015). Partial barriers were those that were considered to allow limited or intermittent movement of biota. Complete barriers were those that represented an absolute and permanent barrier to biota. Where artificial barriers were identified, the most likely location of the natural (pre-1750) inland extent (length) of the estuary was derived from historical documents, field observations, elevation data and geomorphology to provide a `natural estuary length¿.

IEC2021_BARRIERS数据集标注了用于2021年河口状况指数（Index of Estuarine Condition）的河口人工拦阻设施（部分型与完全型）的空间位置。本数据集结合现有数据源与野外实地数据采集工作，识别人工拦阻设施的存在情况，并判定此类设施属于部分型还是完全型拦阻设施（Pope等，2015）。其中，部分型拦阻设施指允许生物群落开展有限或间歇性移动的设施；完全型拦阻设施则指对生物群落移动构成绝对且永久性阻碍的设施。在识别出人工拦阻设施的区域，研究人员通过历史文献、野外实地观测、高程数据与地貌学特征，推导得到该河口在1750年以前的自然内陆延伸范围（长度）的最可能位置，以此得到自然河口长度（natural estuary length）。