有时候，解决问题的最佳办法或许就是移除某些东西。马里兰州比肖普维尔（Bishopville）就发生了这样的事。马里兰州自然资源部（Maryland Department of Natural Resources）2015年发布的一份新闻稿解释说，一座高四英尺的薄钢板大坝已被635线性英尺（约193.5米）的稳定河道和湿地栖息地所取代。该项目历时十年，新闻稿发布时已接近完工。
Sometimes the best way to solve a problem might just be to take something away. That's what happened in Bishopville, Maryland. A 2015 news release from the Maryland Department of Natural Resources explained that a four-foot sheet metal dam was replaced by 635 linear feet of stable stream channel and wetland habitat. The project spanned a decade, and it was nearly complete when the release was issued.
据该新闻稿称，七英里（约11.3公里）溪流已成为关键鱼类可进入的产卵和育苗栖息地，且已在当地发现了叉鳞鲱（alewives）。比肖普维尔发生了什么变化这座旧大坝位于邦廷支流（Bunting’s Branch）上，这是一条流入圣马丁河（St. Martin's River）的小溪，沿马里兰州367号公路（Maryland Route 367）而行。
As of that release, seven miles of creek were accessible spawning and nursery habitat for key fish species, and alewives had already been spotted there. What changed at BishopvilleThe old dam was located on Bunting’s Branch, a small stream flowing into the St. Martin's River, along Maryland Route 367.
这座薄钢板大坝被一组深潭、急流段和堰坝所取代。这些设施使河道更加自然，为鱼类提供了更便捷的通道，并减少了营养污染。项目总成本为150万美元，其中超过50%的资金由马里兰州自然资源部通过切萨皮克和大西洋沿海海湾信托基金（Chesapeake and Atlantic Coastal Bays Trust Fund）提供。该部门栖息地恢复与保护处（Habitat Restoration and Conservation Division）负责人凯瑟琳·尚克斯（Catherine Shanks）表示，新设计同时满足了社区和环境的需求。
The sheet-metal dam was replaced by a set of pools, runs, and weirs. They make the channel more natural, provide easier passage for fish, and reduce nutrient pollution. The total cost of the project was $1.5 million, and over 50 percent of the funds were provided by the Maryland DNR through the Chesapeake and Atlantic Coastal Bays Trust Fund. Catherine Shanks, who heads the department's Habitat Restoration and Conservation Division, says the new design meets the needs of both the community and environment.
一座小坝为何重要四英尺对你来说可能不算高，但对鱼而言，墙就是墙。叉鳞鲱是一种河鲱鱼。它们主要生活在海洋中，并洄游至淡水溪流产卵。比肖普维尔的工程打通了七英里溪流，为叉鳞鲱、蓝背鲱（blueback herring）和美洲鳗（American eel）提供了产卵和育苗栖息地。更宏观的图景呈现在一项2026年发表于《生态学与进化前沿》（Frontiers in Ecology and Evolution）的研究中。
Why one small dam mattersFour feet may not seem like much to you, but for a fish, a wall is a wall. Alewives are a type of river herring. They live mostly in the ocean and migrate into the freshwater streams to spawn. The work done in Bishopville opened up seven miles of creek that provides spawning and nursery habitat for alewives, blueback herring, and American eel. The bigger picture is presented in a 2026 study published in Frontiers in Ecology and Evolution.
研究人员肖恩·斯奈德（Shawn Snyder）、丹尼尔·施蒂奇（Daniel Stich）和约瑟夫·兹德莱夫斯基（Joseph Zydlewski）估计，北美东海岸约52%的叉鳞鲱栖息地位于大坝上游。他们的模型估算，叉鳞鲱因大坝在全海岸范围内损失了约8.8亿潜在产卵个体。不过，这些仍属于理论估算。
Researchers Shawn Snyder, Daniel Stich, and Joseph Zydlewski estimate that about 52 percent of alewife habitat along the East Coast of North America is upstream of dams. Their model estimates alewives have lost about 880 million potential spawners to dams, coast-wide. These, however, are theoretical estimates.
研究还发现，与拆除大坝相比，目前的鱼道结构仅能带来微小的收益。水质与野生动物的早期成果鱼类并非唯一的早期好消息。在施工期间，马里兰州沿海海湾项目和自然资源部一直在监测水质。他们已经观测到项目地点下游水域的溶氧水平增加了20%。这是溶解在水中供鱼类和其他水生动物呼吸所需的氧气含量。现场还种植了约1000棵树，主要是大西洋白柏，由志愿者、索尔兹伯里大学的学生和马里兰州环保团种植。
The study also found that the current fish passage structures add only small gains as compared to dam removal. Early wins for water and wildlifeFish were not the only early good news. Maryland Coastal Bays Program and DNR kept an eye on the water quality while the construction went on. They had already observed a 20 percent increase in the level of dissolved oxygen in the waters downstream of the project site. This is the amount of oxygen dissolved in the water that fish and other aquatic animals need for respiration. The site also saw about 1,000 trees, mostly Atlantic white cedars, planted by volunteers, students from Salisbury University, and the Maryland Conservation Corps.
这些树木将既能稳固地基，又能过滤雨洪径流。随着工程接近完工，许多人前来参加剪彩仪式。出席者包括该部门代表、马里兰州沿海海湾项目代表，以及比肖普维尔圣马丁内克社区协会代表。州参议员詹姆斯·马蒂亚斯和伍斯特县专员吉姆·邦廷也到场出席。这证明了什么、未证明什么负责自然资源部水生栖息地恢复项目的凯文·史密斯表示，如果没有当地居民和马里兰州沿海海湾项目，这个项目绝不可能实现。
The trees will both stabilize the ground and filter stormwater. As the work was nearing completion, a lot of people came out for a ribbon-cutting ceremony. Among those present were representatives from the department, the Maryland Coastal Bays Program, and the Bishopville Saint Martin's Neck Community Association. State Senator James Mathias and Worcester County Commissioner Jim Bunting were also there. What this does and doesn't proveKevin Smith, who leads aquatic restoration projects for the DNR, said this project would never have happened without local residents and the Maryland Coastal Bays Program.
他希望居民能享受成果，甚至能钓上一两条鱼。该项目的科学协调员罗曼·耶西恩表示，这项工作不仅仅是堆石填沙。他希望该地点能成为一个课堂，展示恢复工作应有的做法。
He hopes residents get to enjoy it and maybe even catch a fish or two. Roman Jesien, science coordinator for the program, said the work wasn't just dumping rocks and sand. He hopes the site can be a classroom showing the way restoration should be done.
尽管看到大鳞大麻哈鱼令人鼓舞，但这并不意味着鱼群已经回归。这份新闻稿发布于2015年10月，当时项目接近尾声，并声明后续将继续监测。这个故事表明，通过移除障碍、再精心重建溪流，真正的栖息地可以被打通。有时，进步始于四英尺长的金属管和一群希望小溪重新流淌的社区居民。
While it's encouraging to see alewives, that doesn't mean the fish are back. The news release was issued in October 2015 when the project was almost finished and stated that more monitoring was to follow. The story shows that real habitat can be opened up by removing a barrier, then carefully rebuilding a stream. Sometimes progress starts with four feet of metal and the community that wants a creek to flow again.