... And if it absolutely has to, then such river should overflow in predictable matter.

I have city idea in mind, where such city has a river contained in artificial tunnel beneath such city. I instantly know one huge design flaw of such city, which is the floods.

So, I have to take one step back and come up with design of a river which does not overflow.

Setup

• Earth-based planet, but not necessarily Earth
• Such river may be on island or on a continent, I do not really care
• However the land mass around a city sitting on such river should be big enough to support city of at least 100 000 citizens
• Weather should support civilization, best would be northern Europe -like weather (seasons, temperatures between -30 to +35 degrees Celsius, long term average 18 C)
• River itself should be at least 50 km long and at least 4m wide on widest point

So, is it possible to come up with setup which supports predictable river?

... And if it absolutely has to, then such river should overflow in predictable matter.

I have a city idea in mind, where such the city has a river contained in an artificial tunnel beneath such city. I instantly know one huge design flaw of such a city, which is the floods.

So, I have to take one step back and come up with a design of a river which does not overflow.

Setup

• Earth-based planet, but not necessarily Earth
• This river may be on an island or on a continent, I do not really care
• The land mass around a city sitting on such river should be big enough to support city of at least 100 000 citizens
• The weather should support civilization, best would be northern Europe -like weather (seasons, temperatures between -30 to +35 degrees Celsius, long term average 18 C)
• The river itself should be at least 50 km long and at least 4m wide on widest point

So, is it possible to come up with setup which supports a predictable river?