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Layman's question: don't the reservoirs create a new habitat for fish? They'd be "artificial" in a way but eh, so is everything else. Or is the problem that the
by HPsquared 3y ago
Layman's question: don't the reservoirs create a new habitat for fish? They'd be "artificial" in a way but eh, so is everything else. Or is the problem that they all get turned into fish pie in the turbine...
- voakbasda 3y agoRiver fish need different habitat than lake fish. And in many areas, migratory fish are impeded from reaching their spawning grounds. Fish ladders and other contrivances are a poor workaround for an unimpeded flow.
- nereye 3y agoOne of the main issues is that dams tend to block access to the upstream spawning grounds for species such as Coho salmon. E.g. see https://www.reuters.com/world/us/save-salmon-us-approves-largest-dam-removal-history-2022-11-17/ https://www.reuters.com/world/us/save-salmon-us-approves-lar....
- bilekas 3y agoNot sure how prevalent they are bit aren't fish ladders built with dams for this exact reason? https://www.sciencedirect.com/science/article/pii/S0925857416305936 https://www.sciencedirect.com/science/article/pii/S092585741...
- burkaman 3y agoYes, but it's very hard to get fish to use them. Some species are almost completely blocked even if there is a ladder.
- bobthepanda 3y agoThey don't work for many species. For example, one study found that 3% of American shad were able to use a fish ladder. https://e360.yale.edu/features/blocked_migration_fish_ladders_on_us_dams_are_not_effective https://e360.yale.edu/features/blocked_migration_fish_ladder... Fish ladders are akin to greenwashing.
- belorn 3y agoFish ladders are expensive and have a fairly large negative impact on yearly electric output. Forcing upgrades makes most dams too expensive, which would mean they get replaced by fossil fueled power plants which can more cheaply operate as backup for wind and solar. As a result, most hydro power in Europe is in direct violation of environmental laws, but are also given exceptions given the yearly and regular energy crisis.
- latchkey 3y agoImagine in countries like Vietnam/Cambodia/Laos where they dam up rivers for hydro so badly that it prevents downstream flows, wiping out the downstream natural ecology. They also have wet/dry seasons, so for part of the year everything gets flooded, overruns the dams and wipes out whole villages. Pretty much a complete eco disaster that few talk about.
- sdflhasjd 3y agoIs that for hydro or water storage though? Surely you want the flow for hydro.
- latchkey 3y agoThis isn't about storage. They build hydro dams on running rivers.
- mdorazio 3y agoThat’s not how it works. After it fills up you have to let water out of the dammed reservoir at the same rate it flows in (on average) or else it overflows. The issues created are related to sediments and flow consistency. More info in the top response here: https://earthscience.stackexchange.com/questions/18287/do-dams-reduce-the-flow-of-river-downstream https://earthscience.stackexchange.com/questions/18287/do-da...
- latchkey 3y agoI don't appreciate the downvote because you aren't listening to what I'm saying. When it rains, it floods. They (stupidly) build dams for rate of flow during low season (cause it isn't raining)... then the wet season comes and the dams all overflow. Poor construction practices doesn't help either. They also build dam after dam along the same river... I've see 10+ of these things... ends up being a chain of mess when the first one fails. Just a bit of googling to give you examples: "Dam design and greed may factor into flood devastation in Vietnam" https://www.refworld.org/docid/58f9ca0c13.html https://www.refworld.org/docid/58f9ca0c13.html https://tuoitrenews.vn/news/society/20231012/investigation-underway-for-broken-hydroelectric-dams-wall-in-vietnams-central-highlands/76126.html https://tuoitrenews.vn/news/society/20231012/investigation-u... https://www.voanews.com/a/vietnam-must-improve-flood-resilience-as-extreme-weather-hits-central-coast-say-experts/7331626.html https://www.voanews.com/a/vietnam-must-improve-flood-resilie...
- audunw 3y agoLook at pictures of a hydro power plant reservoir. Look at the water edge when the water level is lower. It’s like a desert. When the water level goes up and down it kills all life along the edge. That life is an important food source for fish.
- m4rtink 3y agoThat's pretty much how seasonal rivers work & other natural intermittent water reservoirs.
- gosub100 3y agopeople already mentioned fish, but still water harbors bacteria and generally has lower oxygen levels than turbulent water. also nutrient-rich sediment piles up at the base of the dam instead of getting distributed evenly down the river.