The benefit of the hydraulic performance is measured by using junction pressure (P) improvements. Two types of pressure benefit are provided in Darwin Designer, namely dimensionless benefit and unitized benefit.

Dimensionless Pressure Benefit

The pressure improvement for dimensionless benefit is proposed as a ratio of pressure difference between the actual pressure and a user-defined reference pressure. The benefit is normalized by the junction demand (JQ). The factors are also introduced to enable a modeler to convert and customize the hydraulic benefit function.

Unitized Pressure Benefit

Pressure benefit resulting from a design and rehabilitation can also be quantified by using the unitized average pressure improvement across the entire system. The benefit functions can be given as follows:

The advantage of using the unitized pressure benefit function is that a modeler is able to evaluate the average pressure enhancement for the investment. It is worth being aware of the value of the dollars spent.