It's an interesting question, here's some napkin math.
There's almost 19 gigaliters of water in Crater Lake. To pump that amount of water in a year would require pumping 52 megaliters of water per day. A small city produces about 200 megaliters of sewage in a day. (LA produces about 2 gigaliters per day.)
So it should be possible but would be very expensive. Maybe on the order of running the drinking water infrastructure for a town. I suspect I'm overestimating though, I think you might only have to pump half of the water to achieve good mixing. (ETA: After a tiny bit of research I think you might be able to do it with much less than half due to entrainment.)
You would also kill a lot of animals and microorganisms in the process. Pumps driven by impellers create cavitation that cracks open microorganisms, and things like peristaltic pumps which avoid this can't handle these volumes. As this material is decomposed by bacteria, they will reproduce and increase the biological oxygen demand in the water, which might end up making the lake anoxic anyway.
I wonder if there are any elegant passive solutions... like a floating sun-exposed surface that conducts heat down to a lower anchored point. Or lake-bottom structures that re-channel water movements from subtle tides or seiches.
I think that's the wrong way round: climate change causes longer summers and shorter winters, so the problem is one of cooling, not heating.
Shade balls[0] could work, but then they'd have to cover part of the lake with that.
EDIT: And of course, that also comes with a reduction in total light reaching the lake, which may have different side effects beyond temperature alone.
Modern society is falling apart over the cost of getting to net zero. I don't think we have the funds to put lakes on artificial life support in the foreseeable future.
Is it the cost of net zero? Or is it the cost of everything else pretending to be relevant to net zero?
Of the interests pushing for net zero, the bulk of them are only doing it insofar as it can be done in a way that basically guarantees them incomes and all of these earmarks are what's driving the non-starter cost while simultaneously souring people on the whole premise. You'd think that people who allege to think on environmental time scales wouldn't need to be told that a movement that looks like branded rent seeking and legalized corruption when viewed through the perspective of anyone who isn't rolling in money isn't gonna last long enough to do its job.
Why not use pumps to increase mixing?
It's an interesting question, here's some napkin math.
There's almost 19 gigaliters of water in Crater Lake. To pump that amount of water in a year would require pumping 52 megaliters of water per day. A small city produces about 200 megaliters of sewage in a day. (LA produces about 2 gigaliters per day.)
So it should be possible but would be very expensive. Maybe on the order of running the drinking water infrastructure for a town. I suspect I'm overestimating though, I think you might only have to pump half of the water to achieve good mixing. (ETA: After a tiny bit of research I think you might be able to do it with much less than half due to entrainment.)
You would also kill a lot of animals and microorganisms in the process. Pumps driven by impellers create cavitation that cracks open microorganisms, and things like peristaltic pumps which avoid this can't handle these volumes. As this material is decomposed by bacteria, they will reproduce and increase the biological oxygen demand in the water, which might end up making the lake anoxic anyway.
I wonder if there are any elegant passive solutions... like a floating sun-exposed surface that conducts heat down to a lower anchored point. Or lake-bottom structures that re-channel water movements from subtle tides or seiches.
I think that's the wrong way round: climate change causes longer summers and shorter winters, so the problem is one of cooling, not heating.
Shade balls[0] could work, but then they'd have to cover part of the lake with that.
EDIT: And of course, that also comes with a reduction in total light reaching the lake, which may have different side effects beyond temperature alone.
[0] https://www.youtube.com/watch?v=uxPdPpi5W4o
In addition to that, how many lakes would need to be pumped or would it be a feel-good project for famous lakes?
Perhaps a large horizontal whisk.
Do fluids appreciate sheer force when it is parallel to gravity?
Modern society is falling apart over the cost of getting to net zero. I don't think we have the funds to put lakes on artificial life support in the foreseeable future.
Actually it’s already done in some places. https://www.easthamptonct.gov/sites/g/files/vyhlif7556/f/upl...
Is it the cost of net zero? Or is it the cost of everything else pretending to be relevant to net zero?
Of the interests pushing for net zero, the bulk of them are only doing it insofar as it can be done in a way that basically guarantees them incomes and all of these earmarks are what's driving the non-starter cost while simultaneously souring people on the whole premise. You'd think that people who allege to think on environmental time scales wouldn't need to be told that a movement that looks like branded rent seeking and legalized corruption when viewed through the perspective of anyone who isn't rolling in money isn't gonna last long enough to do its job.
Based on nothing, I suspect a giant spoon would be better