Nepal pictures, history, people, facts

  Considering the communicating vessels law, why on earth did Romans build aqueducts ? Couln't they rather let their conducts follow the ground, or dig them ? What interest is there to build water bridges ?

The technology of mechanically powered pumps and pigs was not available to the Romans. In consequence the aqueducts needed arches to bridge undulations, nearly but not quite the same as railway or road bridges. More economical than the mix of tunnelling and above-ground channels required for a smooth gradient, and avoiding the problems of line clearance within closed pipes. B:    The Romans did indeed use tunnels, and open channels to a greater extent than commonly realized. The arched aqueducts over valleys are rare, but the most obvious parts of the water delivery system. It was in fact cheaper to set the army and the work crews to build a stone structure, than it was to build a lead pipe of equivalent diameter across the floor of the valley!    Once the water flow was started, it was not turned off. At the city terminus of the water system, the end point was often a fountain. Overflow would the go into the sewers, and then to the rivers.

  Considering the communicating vessels law, why on earth did Romans build aqueducts ? Couln't they rather let their conducts follow the ground, or dig them ? What interest is there to build water bridges ?         Because water doesn't flow uphill?

The romans did not know how to make the joints of thier water pipes pressure tite.         Of course they could. They had solder. They issue is the strength of the joints and to the quality of the joints.         They were made by rolling over and soldering the ends together along the length. So the quality of the joint had to be good an uniform the entire length. Then the joining points had to be soldered, something done in the field rather than in the factory.         The joints were the weakest points. Their strength determined the maximum pressure the pipes could take. (A larger pipe could take more pressure on the same joint as well as a thicker pipe taking more pressure.)         So the maximum downhill and back uphill a pipe could take was limited by that strength.         Down at the bottom is where all the sediment collects. It shouldn't take more than the first spring runoff to block the pipe completely. And then how do you clean it?         California builds aquaducts. It just runs pipes on them instead of open water.

  So, when in the western world did people generally build pipes instead of acqeducts and superseded these roman preference for acqueducts (out of three reasons, I understand (each sufficient for oneself) : 1. clearance  2. Cost of lead transport  3. high-pressure problems on the solder) ?