Lack of proper disposal facilities and/or fees for using said facilities. Easier to dump something in a lake or in the bushes than driving 40 minutes across town to a special facility and paying $30+ to dispose of it properly.

The bridge was closer, costs $0 (as long as you're not caught by law enforcement), and it's difficult to enforce no-dumping laws as garbage doesn't ID it's owner most of the time and you just can't watch every dumping spot 24/7.

The people that do this are also not particularly wealthy. It's hard to justify the cost of transport and disposal fees when you struggle to feed and house yourself.

I doubt that anyone has researched the origin of such junk in detail.

If it doesn't fit in your rubbish bin, generally it costs time, effort and money to properly dispose of things. Tossing it off a bridge is efficient.

Likely there's a not inconsiderable proportion of anti-social behaviour, like stealing a bike and throwing it into a waterway afterwards.

Because big thing from high in water make big splashy-splashy.

(This is not me condoning tossing shit in lakes/rivers!)

people are inherently lazy. fines are only for poor people.

if you want to solve the problem, provide an easy method for the general public to correctly dispose of shit, and let them know about it.

the issue being that that kind of social awareness and general action costs money, and conservatives would rather watch the world burn than have their taxes raised.

Best case, a load to my local dump is ~$15 min of general waste. Every appliance is $5 or 15 on top of that. I've tucked appliances in other appliance before to avoid the fee, but never dumped outside of the landfill.

I see answers for why people dump junk, but not why they dump it on rivers/lakes in particular.

To remedy that: dumping junk isn't legal, and water is good at hiding things. If someone leaves their TV out on the street or whathaveyou, it might be traced back to them, but that's less likely in a river.

A lot of it is stolen, stripped of what the theives want, and then dumped to get rid of evidence. Whatever is left anyway. The rest is simply because it's cheaper than bringing it to the landfill. Landfill is $12-15 for a truckload. The fine is (up to) $10000 for illegal dumping where I am. Lots of risk, but the likelihood of getting caught at night is so low that it isn't really a factor. Landfill really just needs to be free for individual residents. The amount the gov spends on cleanups is probably more than their $12.

Speaking to a few stories my dad's told me over the years, sometimes you're just a rural dumbass, have a large thing to get rid of, and want a big splash for your amusement

Junk also tend to accumulate in rivers and lakes. Once it's in there it's out of sight, out of mind - and even if you know it's there it is often difficult to remove.

When it finally gets cleaned up by bringing in the magnet or a barge to dredge it up or whatever, you're seeing years if not decades of stuff that's getting pulled out all at once.

Laziness and/or poverty. It costs money to dump stuff like that legally most of the time. It also requires going somewhere usually not close to you.

Is this a USA thing? No one does this in my country. WTF

I may or may not have done this back in my youth. If I did, it was because I had no idea how to dispose of a broken engine block. Now, I could set it at the curb and a scrapper will have it in their truck within a couple hours.

For big times like furniture, engines, toilets, construction debris, etc it's to save money. You can't throw those things in a dumpster, and a trip to my local dump costs $160.

Because if it's metal it's dense and will sink, and disappear quickly.

They won’t pick it up from the curb so you gotta take it to the dump or landfill where you’re either charged to dump it or if it’s free your tax records are checked or if they don’t it’s only taken on certain days and hours.

That’s if you have the ability to transport it to the dump.

Tossing something off a bridge without going to get it (ha!) leaves a problem for 'the others'. I've seen conservatives talk about 'the others', be they immigrants or poors or blue-collar workers whondoman honest day's work, all derisively as if they're somehow lesswr-than.

Are we okay with leaving this kind of problem for working people, and in doing so looking like the lazy elitists that run half our governments as if they're the rulers and we're the scum? We don't want to look like the baddies, do we?

I worry how the voting will go on this one. Make me proud, okay?

Sometimes it's stolen material

People do this because they're crackheads (or heroin addicts, or methheads, you get the idea). It's not a poverty issue, it's a drug issue. The person working a minimum wage job and sharing a studio apartment isn't going to dispose of their old bicycle in the river. The person who steals a bike and realizes they can't sell it to get their next fix probably isn't going to have a problem dumping it in a lake or river. They're already leaving needles on the playground, shitting on the sidewalk, and assaulting innocent people for not giving them a cigarette. Do you really think they give a damn about the environmental impact of dumping their stolen goods in a waterway?

It's mostly people that don't have or don't want to spend the money on the dump fees. Some localities have annual (or more frequent) days where workers pick up such items for free. This really cuts down on illegal dumping.

Around here you can leave it on the curb and someone will take it for metal. At worst you can find a guy on FB marketplace, Thrifty Nickel or some such that will pick up stuff for free.