我们大多数人可能每天都会跨越小溪却浑然不觉。道路、车道或桥梁架在溪流上方,溪水通过下方的管道流过。然而对鱼类而言,那根管道却像是一扇紧锁的大门。这样的一扇“门”曾矗立在华盛顿州奥卡斯岛西海滩溪的入海口处。
Most of us probably cross small streams every day without even noticing. A road, a driveway, or a bridge sits on top of it, and the water flows through a pipe below. For a fish, however, that pipe is like a locked door. One such door once stood at the mouth of West Beach Creek on Orcas Island, Washington.
据普吉特海湾合作组织——这家领导保护普吉特海湾工作的华盛顿州政府机构——称,西北海峡基金会拆除了一座小型水坝。这座水坝建在面向总统海峡的私人海滨地产上,原本用于蓄水成池。拆除工程于2014年完工。将其替换为一座更大的涵洞,最终让1584英尺(约合0.3英里)的溪流重新向大马哈鱼开放。
According to Puget Sound Partnership, the Washington state agency that leads efforts to protect Puget Sound, the Northwest Straits Foundation removed a small dam built to make a pond on private shoreline property facing President's Channel. The work was completed in 2014. Replacing it with a larger culvert ended up opening 1,584 feet of stream to salmon.A pond, a driveway, and two little pipesWest Beach Creek is one of the few streams in the San Juan Islands that are not obstructed by a natural barrier.
一个池塘、一条车道和两根小管道西海滩溪是圣胡安群岛为数不多的没有天然障碍阻隔的溪流之一。因此,历史上大马哈鱼一直可以进入这条溪流。一座小型水坝改变了这一切。两根直径24英寸的涵洞穿过同时充当水坝作用的车道底下。该机构的项目摘要指出,这些管道阻止了鱼类到达上游栖息地。它们还限制了溪流流量,导致泥沙一直堆积在通往西海滩路涵洞的河道中。
So, it’s been historically accessible to salmon. A small dam changed all that. Two 24-inch culverts ran under the driveway that also served as a dam. The agency’s project summary notes that these pipes kept fish from reaching upstream habitat. They also limited creek flow and allowed sediment to build in the channel all the way to the culvert at West Beach Road.
该项目打通了这条溪流1584英尺(约合0.3英里)的河段。原有的涵洞和水坝被一根直径16英尺的涵洞取代。新通道的建设充分考虑了高潮位和未来海平面上升的因素。项目的目标是恢复幼年及成年克拉克氏鳟、幼年王鲑、大鳞大马哈鱼、粉红鲑和银鲑的通行通道。
The project opened 1,584 feet, about 0.3 miles, of that stream. The culverts and dam were replaced by a 16-foot-diameter culvert. The new passage was built with high tides and future sea level in mind. The project’s goal was to reestablish access for young and adult cutthroat trout and young Chinook, chum, pink, and coho salmon.
大马哈鱼一年内现身成效来得很快。大马哈鱼在大坝拆除仅一年后就出现在项目地点的上游。泥沙开始从溪流中排出,自然泥沙输送过程在一年内得到恢复。溪流回归其自然河道,并从上游聚集了大量枯木。该项目恢复了一英亩河口栖息地,供幼年大马哈鱼在进入大海前生长和休憩。
Salmon showed up within a yearThe results came fast. Salmon were seen upstream of the project site just one year after the dam was removed. Sediment started moving out of the stream, and the natural sediment flow was restored within a year. The stream followed its natural course and gathered a good deal of wood from upstream. The project has restored one acre of estuary habitat for young salmon to grow and rest before entering the ocean.
报告未说明有多少条鲑鱼,也未指出是何种品种,但这是一个早期迹象。西海滩溪只是一个地点,因此更广泛的研究可能会有所帮助。克拉克、罗尼、基顿和佩斯在《渔业管理与生态学》2020年发表的一项研究,调查了内陆哥伦比亚河流域32个已拆除或更换障碍物的地点。作者得出结论,在小溪流上拆除障碍物能提供足够的鱼类通道。
The report doesn't say how many salmon or what species, but this is an early sign. West Beach Creek is just one site, so wider research might help. A 2020 study in Fisheries Management and Ecology by Clark, Roni, Keeton, and Pess surveyed 32 sites in the interior Columbia River Basin where barriers had been removed or replaced. The authors concluded that removing barriers on small streams provided adequate fish passage.
这似乎还增加了栖息地,并使旧障碍物上游仅短距离处的幼鱼数量增加。该研究在内陆溪流开展,而非像西海滩溪那样的潮汐溪流,因此无法证明奥卡斯岛会有相同结果。但它确实表明,在太平洋西北部其他地方,拆除小型障碍物可以恢复鱼类通道。该项目背后的团队圣胡安之友协调了溪边种植工作,招募了志愿者,并确保新栽植物得到浇水。
It also appeared to add habitat and increase the number of young fish just upstream of old barriers. The study took place in inland streams, not tidal streams like West Beach Creek, so it cannot prove the same result for Orcas Island. It does show that removing small barriers can restore fish passage elsewhere in the Pacific Northwest. The team behind the projectFriends of San Juans coordinated the planting along the creek, enlisted volunteers, and ensured that the new plants were watered.
华盛顿州自然资源部普吉特海湾团提供了劳动力。该机构表示,本地植物将降低水温,并为鲑鱼提供食用昆虫。资金来源包括鲑鱼恢复资金委员会、普吉特海湾收购与恢复计划、美国鱼类和野生动物管理局以及阿尔科亚基金会。该机构还指出,拥有该地产的家族将该项目视为一种传承之作,与志愿者和团体合作创造了一种主人翁感。
Labor was added by the Washington Department of Natural Resources Puget Sound Corps. The native plants will cool the water and provide insects for salmon to eat, says the agency. Funding sources include the Salmon Recovery Funding Board, Puget Sound Acquisition and Restoration, U.S. Fish and Wildlife Service, and Alcoa Foundation. The agency also notes that the family that owned the property saw the project as a work of legacy, and working with volunteers and groups created a sense of ownership.
西海滩溪展示了如何通过与民众和机构合作,重新打通一条溪流,为前路漫漫的鱼儿提供一个良好的休憩之所。
West Beach Creek shows how, by working with people and agencies, a stream was reopened, providing a good resting spot for the fish with a long journey ahead of them.