Waterfalls make mist, and mist makes your dwarves happy... No one wants unhappy dwarves

waterfalls can be used to generate energy, water can clear the air and i assume that waterfalls are good for the mental health

@adaliabooks Sure you do. Unhappy dwarves is FUN.

In Willy Wonka & the Chocolate Factory (1971), a waterfall mixed the chocolate.

Watermill-punk sounds a bit silly, but look up the London Hydraulic Power Company (city-sized example but many smaller systems have existed elsewhere). Water is a great way of transmitting mechanical power, making it efficient if you have pipes strong enough to withstand the pressure.

Clean pop from your street. Just a flush

Waterfall make a lot of noise, ideal for sleep and masking distracting sounds. Good sleep + no one hear his wife conplains = Utopia.

Not an answer as it seems you're looking for something more industrial rather than built for human well-being, but waterfalls to keep people happy isn't just an aesthetic or relaxation thing: there have been studies suggesting that depression is reduced by air with a high density of negative ions, and waterfalls are one natural source of negative ions in the air. Here's a summary study: ncbi.nlm.nih.gov/pmc/articles/PMC3598548

@adaliabooks Just be sure to build them in the Dining Hall to maximize happiness and FUN

@adaliabooks 40d, really?

In Logan's run, I'm pretty sure its supposed to be a tidal energy generator. Trap water at high tide, let it out through turbines at low tide.

@immibis I just grabbed the first link, I didn't spot it was an older version one. I wasn't sure how many people here would get the reference without the link (though I think I needn't have worried judging the amount of upvotes it got)

Or for evaporative cooling the water itself. The characteristic shape of a nuclear power plant's largest structures are cooling towers used to sink the waste heat from the energy generation process into the atmosphere. water.usgs.gov/edu/gallery/watercyclekids/evaporation-beg.ht‌​ml Turning the cooling towers inside out and integrating them into the landscape/architecture might be a good utilitarianism.

@Aethenosity I was thinking about a river lead to the city - but if it would be used for power generation, it would flow through generators and not as an open waterfall. So I would go back to the "health and mental health" point. Oh - what if there is a big river and the city has to be placed in the river for some reasons? Then you would need to let the river water some way..

Pumping up and generating on the way down may only lead to a small loss. Nothing about thermodynamics requires is to cost way more, it just can't cost less. In energy of course. Actual real world power plants operate this way because they use cheap energy at one time and then they supply energy at a time when there is a high demand and therefore a high price. The perspective in that picture does not make is obvious that the waterfalls are not at the same level as the body of water behind the city so there may be no pumping required.

Isn't that Theed?

The term "utilitarian excuse" is a contradiction in itself - either waterfalls have their utility or they don't. Second point - aesthetics and pleasure are of utility as well, actually of very high utility.

@Pavel, that's so "interesting".... Maybe you could write that information into an answer so we can vote on it?

@wetcircuit What I ment is just rewording "what's the utilitarian excuse for" to "what's the utility of". There is a long way from thought to a coherent and meaningful statement, it took your comment for me to get my own comment right.