Alsea Watershed Study Revisited

Forest harvesting practices can expose mineral soils, decrease infiltration capacities of soils, disturb the stream bank and channel, and increase erosion and fine sediment supply to stream channels. To reduce nonpoint source sediment pollution associated with forest management activities and to maintain the high water quality typically provided from forests, best management practices (BMPs) were developed and implemented. The Alsea Watershed Study was an important early research site that lead to the development of contemporary forest management practices to protect water quality and fish habitat in Oregon and elsewhere. By returning to the same watersheds that were harvested in 1966, this is one of the few times that a watershed-scale study is able to directly compare and contrast the effects of historical practices with contemporary practices. The Alsea Watershed Study Revisited includes the same three watersheds as the original study. Flynn Creek (FCG, 219 ha) is an old-growth dominated reference watershed. Deer Creek (DCG, 315 ha) is an extensively managed watershed that was patch-cut during the original study. Needle Branch (NBLG, 94 ha) was clearcut harvested in the original study and again in the recent study, but with contemporary BMPs, including riparian buffers. The upper portion of Needle Branch was harvested in 2009 (Phase I), while the lower portion of the watershed was harvested in 2015 (Phase II). This data set suspended sediments and discharge from WY 2006–2016.

森林采伐作业会裸露矿质土壤，降低土壤入渗能力，扰动河岸与河道，加剧侵蚀作用并向河道输入更多细颗粒泥沙。为减少森林经营活动引发的非点源泥沙污染，维持森林一贯提供的优良水质，研究人员研发并推行了最佳管理措施（Best Management Practices，BMPs）。阿尔西流域研究（Alsea Watershed Study）是一项具有重要意义的早期研究项目，其成果推动了俄勒冈州及其他地区用于保护水质与鱼类栖息地的现代森林经营措施的发展。本次研究重回1966年曾开展采伐作业的同一流域，是少数能够直接对比历史与现代森林经营措施影响的流域尺度研究之一。“重访阿尔西流域研究”（Alsea Watershed Study Revisited）沿用了原始研究中的三个流域：弗林溪（Flynn Creek，FCG，219公顷）是以原始林为主的参照流域；鹿溪（Deer Creek，DCG，315公顷）为高强度经营流域，在原始研究中采用了块状采伐方式；针溪支流（Needle Branch，NBLG，94公顷）在原始研究与本次近期研究中均实施了皆伐作业，但本次研究采用了包含河岸缓冲带在内的现代最佳管理措施。针溪支流的上游区域于2009年完成采伐（一期），下游区域则于2015年完成采伐（二期）。本数据集涵盖2006至2016水文年的悬移质泥沙与径流数据。