Run away water in the slope in WDN

Don't worry. Outflow from the system is controlled by the opening of faucets, showers and other orifices. It is not as if pipes are just discharging to atmosphere.

Hi

I think it is needed that I explain more and ask some more questions:

I have designed one water distribution network in a village where there is a main road and the houses are spread two sides of it. The main road is in slope, the slope is about 9% and the height difference between reservoir and the lowest point is about 60 meters. I simulated the main pipe in the main road and then split it and branched in each lane.

 Now I want to know if enough water reaches the connections in upstream or all the water moves through the main pipe towards the houses of downstream?

On the other hand, if I wouldn't be sure about the reservoir outlet to be full (along the pipe, to the end of it), how can I simulate this and see the results?

Thanks

Hello Zeinab,

Regarding "I want to know if enough water reaches the connections" - are you wanting the model to tell you, based on the pressure at certain points, what the demand would be? (how much flow could leave?) Are you concerned that high pressure at the bottom of the hill will cause high outflow and reduce the pressure / outflow on the upstream side? If so, then as Tom said, your demands are likely not just from holes open to the atmosphere, so they will be controlled by faucets/showers/etc. Typically you would determine what the house demands would be, enter those as the demands on your nodes in the model, then the model will solve the pressure based on those assumed demands and the upstream boundary condition.

If you find that the pressure it too high on the downstream end, then perhaps smaller diameter pipes or a PRV would help.

If your outflow/demand points are very sensitive to pressure, you can use pressure dependent demands, and the demand will be higher as the pressure becomes higher. See: Using Pressure Dependent Demands

Regarding the concern about the part full flow, if you mean that the upstream-most pipe may not necessarily be submerged, you can adjust the reservoir element's elevation accordingly. If you are comfortable with the negative pressure that will be reported on the upstream-most end, then this should be OK. If a significant portion of the piping is partially full, you may consider this article: Modeling Fixed Inflow from a Marginal Source

Hi Jesse

I exactly mean this:   Are you concerned that high pressure at the bottom of the hill will cause high outflow and reduce the pressure / outflow on the upstream side? 

Then you mean it wouldn't happen whenever every user opens a faucet? It won't happen even if the water level in the reservoir reduces? 

Sorry if I repeat the questions again. 

if you have a 6 inch (150 mm) pipe in the street and you open up a half inch (10 mm) faucet, how can that drain the system?

There are systems al over the world with 60 m pressure and none of them drain.

Unless the pies upstream are grossly undersized or the source runs dry, there should be no problem.

If the problem is with the source draining out, see the article linked to in my previous response: Modeling Fixed Inflow from a Marginal Source

If the problem is with the source draining out, see the article linked to in my previous response: Modeling Fixed Inflow from a Marginal Source