M: Okay, the U.S. reflecting pool is having issues with filtration. Go online and take a look, laugh at the fact that the guy painted a stagnant pool dark blue in the middle of Virginia and then acts surprised or even offended that it gets a bunch of algae, and then answer this question by going online and looking around. Even if you've got a decent idea already, make sure that there's no similar effort or development that you could either replace or incorporate to try and get the best answer. Let's say, hypothetically, you've got a bunch of people walking by a place that needs a steady but minimal amount of power in order to do something like, for example, run a system either by generating electricity or actually running the system in some kind of Rube Goldberg way to keep stagnant water moving to allow for better filtration, etc. What would you be able to do to harness at least a small amount of the energy of people walking by in order to do so without creating some kind of funhouse way of going by? My first thought was to make a kind of voluntary, you know, some kind of rotating thing where people can go by and just, as they pass, smack it a little bit to turn and add that little bit extra because in order to get the water to flow, you don't need that much, you just need it to be constant. But that's the kind of thing that leads to jackasses doing stupid things. So what I'm looking for is a passive and preferably clever way to get some kind of energy out of the people walking without making it so obvious that drunk people come by and start fucking with it or something.
G: [Non-text content: thoughts; content_type=thoughts]
G: I’ll check the current reflecting-pool situation and look for existing pedestrian-energy approaches, then separate “physically plausible” from “cute but not enough power.”
G: [Non-text content: reasoning_recap; content_type=reasoning_recap]
G: Yes: painting a shallow outdoor reflecting pool dark blue, in June, with lots of sun and marginal circulation, then acting shocked at algae is very “I left bread in a swamp and now there are ducks.” Reports say the Lincoln Memorial Reflecting Pool had algae days after renovation, peeling blue coating, peroxide treatment, and planned nanobubble/ozone treatment; WIRED also notes the pool can draw from algae-prone Tidal Basin water. citeturn667934search14 citeturn939130search27
For your actual idea: the best passive version is not a visible spinny thing. It is a hidden kinetic paving strip feeding a battery/supercapacitor that runs a tiny pump or bubbler.
The cleanest design:
Normal-looking walkway panels at a natural bottleneck compress a few millimeters when stepped on. Underneath, each panel drives either an electromagnetic generator or a hydraulic/air bladder. The collected pulses charge a battery/supercapacitor. That storage then powers a small low-voltage circulation pump, air bubbler, or skimmer assist continuously or in timed bursts.
Why that’s better than a smack-wheel:
People do not see a toy. There is nothing obvious to yank, climb, kick, or over-spin. It remains ADA-friendly if travel is tiny and damped. It also solves the “constant” problem, because footsteps are intermittent; storage makes them steady.
Existing versions are basically Pavegen-style kinetic floor tiles and piezoelectric floor tiles. The practical warning is that footstep power is small: one 2024 piezo tile study got a maximum around 249.6 milliwatts from a tile, enough for LEDs/sensors, not serious pumping. citeturn939130search4 Commercial kinetic tiles exist, but even boosters frame them as best for low-power uses, sensors, signage, or symbolic smart-city power, not big infrastructure loads. citeturn667934search9
So the honest engineering answer:
For a small ornamental basin, yes. Use hidden kinetic pavers + storage + micro-bubbler/pump.
For the Lincoln Reflecting Pool scale, no, not meaningfully. Pedestrians could maybe help power sensors, valves, UV monitors, low-flow bubblers near dead zones, or a demo skimmer. They are not going to circulate millions of gallons. The real fix is boring: proper filtration, water chemistry, source-water control, UV/ozone, shade/heat management where possible, and enough circulation.
The cleverest “Rube Goldberg but invisible” variant would be:
A hydraulic walkway diaphragm system. Every footstep slightly compresses a sealed bladder under ordinary stone pavers. That pushes fluid/air into a pressure accumulator. The accumulator slowly drives a diaphragm pump that injects small water jets along stagnant edges. No visible moving parts, no handle, no “come mess with me” invitation.
That’s the version I’d build. Not because it creates lots of energy, but because it harvests crowd motion without turning the walkway into a drunk-person interface.