Aerial photo mosaic of the Bandon Reach, Coquille River, Oregon in 1939

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，流域总面积达2745平方公里，覆盖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。其源头源自罗格河-西斯基尤国家森林公园（Rogue River-Siskiyou National Forest），南福克科奎尔河（South Fork Coquille River）先后汇入中福克科奎尔河（Middle Fork Coquille River，流域面积798平方公里）与北福克科奎尔河（North Fork Coquille River，流域面积749平方公里）。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适配河道内砾石开采许可审批需求的勘察级河道状况与河床物质输运评估：南福克科奎尔河从其与上兰德溪汇流处附近的河道里程（RKM）115.4段，至其与北福克科奎尔河汇流处的RKM 58.5段；科奎尔河干流从南北福克汇流处的RKM 58.5段至河口；中福克科奎尔河从RKM 15.4段至其与南福克科奎尔河的汇流处；以及北福克科奎尔河从RKM 14.6段至其与南福克科奎尔河的汇流处。为支撑上述分析工作，研究团队生成了数字化河道地图，用以呈现科奎尔河流域不同历史时期的河道与漫滩状况。此外，还针对亨特溪（Hunter Creek）的过水河道、沙洲特征与河道中心线，开发了覆盖1939年、1967年、2005年及2009年四个时期的地理信息系统（GIS）图层。本项目中将活动河道定义为年度高水位期间通常会被淹没的区域，涵盖低流量河道、支汊河道、江心洲以及河道两侧的砾石滩。过水河道与沙洲特征数据集通过对航空影像进行数字化矢量化处理得到。1939年与1967年的航空影像经扫描、几何校正与镶嵌后用于本项目（有关影像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文档）。2005年与2009年的数字正射影像为公开可用数据。