In MiTS 3, we introduced the additional node head column in the water reticulation module.

When Additional Node Head is Applied? #

Users may assign additional node head when they want to differentiate between the absolute node head and the additional node head. For example, you have an elevated water tank which you want to assign the height plus water level to be the additional node head and the tapping point as the fixed head. So the total head will be absolute node head plus with the additional node head. 

From the simplified diagram below, say the ground level of the tapping point is 50 m and the elevated water tank plus with the water level is 10 m. The total head will be equal to 60 m.

Example of another condition when additional node head is applied is when the platform of the water tank is raised from the ground level. In short, you may apply additional node head when there is any structure that raises the water level above the ground.

Where to Apply the Additional Node Head? #

Once you input your water reticulation network, you may find that there is one column available for assigning the Additional Node Head. If you go to the Main > Water Reticulation > Input > Node > Spread Input, you will find the Additional Node Head column in the Tapping settings section. This Additional Node Head can only be added once you assign your node to be the Fixed Head = Yes.

How does the Software Compute when Additional Head is Included? #

Case 1: No Additional Node Head Included #

When there is no additional node head assigned to the water network, software will directly take the fixed node head minus the head loss to compute the available head.

From the analysis result, we can see that the available head (HGL) is computed to be:

Node 1: Available Head = 50.000

Node 2: Available Head = 50.000 – 0.117 (Head Loss) = 49.883

Node 3: Available Head = 49.883 – 0.254 (Head Loss) = 49.629

Node 4: Available Head = 49.629 – 0.012 (Head Loss) = 49.617

 

Case 2: Additional Node Head Included #

When there is an additional node head assigned to the water network, software will take the fixed node head plus with the additional node head and minus the head loss to compute the available head.

From the analysis result, we can see that the available head (HGL) is computed to be:

Node 1: Available Head = 50.000 + 10.000 (Additional Node Head) = 60.000

Node 2: Available Head = 60.000 – 0.117 (Head Loss) = 59.883

Node 3: Available Head = 59.883 – 0.254 (Head Loss) = 59.629

Node 4: Available Head = 59.629 – 0.012 (Head Loss) = 59.617

 

What can be concluded? #

From the exact same water reticulation network design, applying additional node head changed the available head. When the additional node head is applied to the water network, the residual pressure will increase simultaneously.