Pressure Threshold for Resilience indices like Todini and MRI

[namratathakkar06]

Summary
Hello, I am trying to calculate Todini and Modified Resilience indices for water networks like Net2, Net3, and Anytown Network. The required pressure in Epanet is 0.1 psi. However, when this pressure is used I do not correct values.

For example, I get a value of -132 for the Net2 water network.

Is there any way to figure out what threshold pressure should be used to get reasonable values of these indices?

I would greatly appreciate any help.

Thank you
Namrata Thakkar

[kaklise]

The default value for required pressure in WNTR is 0.07 m (0.1 psi). This matches EPANET specifications. If you do not increase the required pressure value, then a PDD simulation will be very similar to a DD simulation.

When computing the Todini and Modified Resilience Index, you specify a pressure threshold. This value may or may not equal the required pressure used in a PDD simulation. We typically use 21.09 m (30 psi), but this depends on network hydraulics and can change through out a network as a function of elevation. The following reference provides an good explanation.

Jeong, G., Wicaksono, A., & Kang, D. (2017). Revisiting the resilience index for water distribution networks. Journal of Water Resources Planning and Management, 143(8), 04017035.

[namratathakkar06]

Thank you very much for the response. This publication is very helpful for my query.
Is there a reason why 21.09 m is usually used for the simulation?