Channel centerline for the Coquille River, Oregon in 1967

The Coquille River system is an unregulated system that encompasses 2,745 square kilometers of southwestern Oregon and flows into the Pacific Ocean near the town of Bandon, Oregon. Beginning in the Rogue River-Siskiyou National Forest, the South Fork Coquille River gains the Middle Fork Coquille River (drainage area 798 square kilometers) and shortly thereafter the North Fork Coquille River (749 square kilometers). In cooperation with the U.S. Army Corps of Engineers, the U.S. Geological Survey completed a reconnaissance-level assessment of channel condition and bed-material transport relevant to the permitting of in-stream gravel extraction along the the South Fork Coquille River from river kilometer (RKM) 115.4 near its confluence with Upper Land Creek to RKM 58.5 at its confluence with the North Fork Coquille River, the mainstem Coquille River from RKM 58.5 at the confluence of the South and North Forks of the Coquille River to its mouth, the Middle Fork Coquille River from RKM 15.4 to its confluence with the South Fork Coquille River, and the North Fork Coquille River from RKM 14.6 to its confluence with the South Fork Coquille River. To support these analyses, digital channel maps were produced to depict channel and floodplain conditions in the Coquille River basin from different time periods. GIS layers defining the wetted channel and bar features and channel centerline of Hunter Creek were developed for four time periods: 1939, 1967, 2005, and 2009. For this project, the active channel was defined as area typically inundated during annual high flows, and includes the low-flow channel as well as side channels, islands, and channel-flanking gravel bars. The wetted channel and bar feature datasets were developed by digitizing from aerial photographs. Aerial photographs from 1939 and 1967 were scanned, rectified, and mosaicked for this project (See metadata for each photograph set for more information on the rectification process and resolution of each dataset). Digital orthophotographs from 2005 and 2009 are publicly available.

科奎尔河系（Coquille River system）是一处未受调控的河系，流域面积达2745平方千米，涵盖美国俄勒冈州西南部区域，最终在俄勒冈州班登镇附近注入太平洋。该河系源起于罗格河-西斯基尤国家森林（Rogue River-Siskiyou National Forest）内的南支科奎尔河（South Fork Coquille River），先后汇入中支科奎尔河（Middle Fork Coquille River，流域面积798平方千米），随后不久又汇入北支科奎尔河（North Fork Coquille River，流域面积749平方千米）。美国地质调查局（U.S. Geological Survey）与美国陆军工程兵团（U.S. Army Corps of Engineers）合作，针对以下河段开展了与河道内砾石开采许可相关的河道状况与河床物质输运侦察级评估：南支科奎尔河从其与上兰德溪汇流处附近的河道里程（river kilometer, RKM）115.4处，至其与北支科奎尔河汇流处的RKM 58.5处河段；科奎尔河干流从南北支汇流处的RKM 58.5处至河口河段；中支科奎尔河从RKM 15.4处至其与南支科奎尔河汇流处河段；北支科奎尔河从RKM 14.6处至其与南支科奎尔河汇流处河段。为支撑上述评估分析，研究团队制作了数字化河道地图，以呈现科奎尔河流域不同历史时期的河道与漫滩状况。针对亨特溪（Hunter Creek）的过水河道与沙洲要素、河道中心线的GIS图层（GIS layer），开发了四个时期的版本：1939年、1967年、2005年及2009年。本项目中，有效河道被定义为年度高水位期间通常会被淹没的区域，包含低流量河道、支汊河道、沙洲以及河道两侧的砾石滩。过水河道与沙洲要素数据集通过对航空影像进行数字化处理生成：1939年与1967年的航空影像经扫描、校正与拼接后用于本项目，有关校正流程与各数据集分辨率的详细信息，请参见各影像集的元数据；2005年与2009年的数字正射影像（digital orthophotograph）为公开可用资源。