美国正在大规模移除河流大坝以恢复鱼类洄游通道，这一趋势在东北部尤为明显。自1912年以来，美国已从水道中移除超过2300座大坝，其中大部分在过去25年内完成1。2024年的大坝移除工作连通了超过2500英里的曾经碎片化河道1，为鱼类种群的回升创造了条件。
大坝移除的生态效果显著。缅因州彭布斯科特河在2025年迎来600万尾河鲱回归，较两年前翻倍1。在马萨诸塞州普利茅斯镇，移除大坝后年均回归河鲱从约25000尾激增至超过200000尾1。更大规模的项目如克拉马斯河四座水电大坝的移除开放了400英里的产卵栖息地，已有数千条奇努克鲑重新殖民该流域1。这一耗资5亿美元、耗时数年的工程至2024年8月实现河流完全自由流动1。
然而，东北部仍有大量工作待做。该地区至少35000座大坝仍然阻断鱼类洄游，其中马萨诸塞州3000多座、康涅狄格州5000座、纽约州9000座1。美国河流组织的目标是到本世纪中叶移除30000座大坝1。特朗普政府通过削减国家海洋和大气管理局经费、阻滞《涵洞水生生物通道计划》（拨款10亿美元）等方式阻碍了这一工作的推进1。
The northeastern United States is experiencing a wave of dam removals aimed at reopening waterways that have been blocked to migrating fish for decades. Since 1912, the United States has removed more than 2,300 dams from its waterways, with the majority completed over the past 25 years 1. In 2024 alone, dam removals reconnected over 2,500 miles of previously fragmented river systems 1. While the Northeast accounts for a smaller proportion of total removals nationally, the region leads in the number of individual projects undertaken 1.
The ecological benefits are becoming evident. In Plymouth, Massachusetts, herring populations on Brook Creek surged from an average annual return of approximately 25,000 fish to over 200,000 following dam removal 1. In 2025, Maine's Penobscot River saw 6 million river herring return, double the number from two years prior 1. The Klamath River provides a more dramatic example: removal of four hydroelectric dams opened 400 miles of spawning habitat, with thousands of Chinook salmon now recolonizing the watershed 1. The Klamath project, which cost $500 million and took years to complete, achieved full river free flow by August 2024 1.
Despite these successes, significant challenges remain. The Northeast still has at least 35,000 dams blocking fish passage, including more than 3,000 in Massachusetts, approximately 5,000 in Connecticut, and roughly 9,000 in New York 1. The Trump administration has impeded dam removal efforts by cutting funding to the National Oceanic and Atmospheric Administration and halting the Culvert Aquatic Organism Passage Program, which provided $1 billion in grants 1. The American Rivers organization aims to remove 30,000 dams by mid-century 1.
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