Little Tonsina Bridge Project

The Copper River Watershed Project worked with partners, ADF&G, ADOT/PF, USFWS, BLM, Chugach Alaska Corporation, the Copper River Native Association and the Native Village of Tazlina to remove a critical barrier to fish passage on the Little Tonsina River through replacement of a blocked, dual culvert structure, to a bridge, which was started in 2022 and completed by Alaska DOT during the fall of 2023. The new bridge was constructed slightly north of the culverts, and is a concrete deck bulb tee single span bridge, 103 feet long by 27 feet wide. The new bridge allowed for better fish passage The completed 100% design employed USFWS guidelines for maximizing ecological function, including better flood mitigation, and formation of a more natural stream. Land access and right of way was granted by Alyeska Pipeline and Chugach Regional Corporation for the fish passage improvement. After the construction of the new bridge, extensive streambank restoration ensued with establishing root-wad habitat for juvenile fish congregating areas, the planting of over 1500 native plants during the summer 2024 season, and temperature and stream mechanics monitoring.铜河流域项目（Copper River Watershed Project）联合阿拉斯加鱼类与狩猎局（ADF&G）、阿拉斯加州交通与公共设施部（ADOT/PF）、美国鱼类及野生动物管理局（USFWS）、美国土地管理局（BLM）、楚加奇阿拉斯加公司、铜河原住民协会以及塔兹利纳原住民村落等合作伙伴，通过将一处堵塞的双涵洞结构替换为桥梁，消除了小托尼纳河上阻碍鱼类洄游的关键障碍。该工程于2022年启动，由阿拉斯加州交通与公共设施部于2023年秋季完工。新桥建于原涵洞稍北位置，为混凝土桥面灯泡形T梁单跨桥，长103英尺、宽27英尺，大幅改善了鱼类洄游条件。整套100%完成的设计遵循了美国鱼类及野生动物管理局的生态功能最大化准则，涵盖优化洪水缓解措施、构建更自然的河道形态等内容。阿拉斯加输油管道公司（Alyeska Pipeline）与楚加奇区域公司为本次鱼类洄游改善工程提供了土地通行权与用地权限。新桥建成后，项目团队开展了大规模河岸修复工作，包括搭建供幼鱼聚集栖息的根团生境，于2024年夏季种植超1500株本土植物，并同步开展水温与河道力学监测。