Geomorphic Surface and Channel Boundaries for the Lower 7.5 Kilometers of the Taiya River Valley, Southeast Alaska, 2018

The USGS mapped geomorphic features in the lower 7.5 kilometers of the Taiya River valley bottom in and near Klondike Gold Rush National Historical Park near Skagway, Alaska. This dataset presents delineations of off-main-stem channels and geomorphic surfaces. Boundaries were prepared from 2003 lidar elevation data and updated using 2017 and 2018 aerial orthophotographs at eroding riverbanks, such that the dataset generally represents 2018 conditions. Channel attributes include physical and hydrologic conditions related to water sources and were determined from 2003, 2017, and 2018 aerial imagery and field observations. Interpretations of surface age primarily used 2003 lidar data and aerial imagery from 1948 and 2003. Mapped surfaces consist of the 2003 active main stem (Taiya River and West Creek wetted channel, bars, islands, and major sloughs), additional areas recruited to the main stem by 2018, main stem surfaces abandoned between the 1940s and 2003, main stem surfaces abandoned prior to the 1940s, alluvial fans, and emergent tidal flats.

美国地质调查局（USGS）对阿拉斯加州斯卡圭市周边的克朗代克淘金热国家历史公园及其毗邻区域内，泰亚河河谷底部下游7.5千米河段的地貌特征开展了测绘。本数据集涵盖主河道旁侧河道与地貌地表的划定范围。数据集边界基于2003年激光雷达（lidar）高程数据绘制，并针对受侵蚀河岸利用2017、2018年的航空正射影像完成更新，因此整体反映2018年的地表状况。河道属性包含与水源相关的物理及水文条件，其推导依据为2003、2017、2018年的航空影像与野外实地观测数据。地表年代解译主要依托2003年激光雷达数据，以及1948年、2003年的航空影像完成。本次测绘的地表类型包括：2003年的活跃主河道（泰亚河与西溪的过水河道、沙洲、岛屿及主要沼泽水道）、截至2018年并入主河道的新增区域、1940年代至2003年间废弃的主河道地表、1940年代之前废弃的主河道地表、冲积扇以及潮间带滩涂。