EAM.4:5.2 - Build the scenario from its components

In a separate constructed district, Westbank, compatible observations of an unrestricted critical hour give 1,000 m³/h at the inlet: 600 for households, 300 for other users and 100 losses. The case supplies compatible measurement coverage and the loss estimate. Proposed usable capability at the same inlet is 1,200 m³/h; required quality is unchanged.

Component at the common critical hour	Observed base, m³/h	Scenario assumption	Scenario demand, m³/h
Household use	600	10% more use on the same service basis	660
Other use	300	No material change	300
Losses	100	Qualified future estimate of 140	140
Total at the inlet	1,000	Sum of compatible components	1,100

The calculation is 600 × 1.10 + 300 + 140 = 1,100. It leaves 100 m³/h of contribution available within the proposed capability. A separately supported new industrial requirement of 150 during that same hour gives 1,250 and exceeds capability by 50. The industrial addition is counted once: it was absent from the 300 base.

If the industrial maximum occurs at another hour, the practitioner obtains the other components for that hour before forming its total. Adding unrelated maxima would not establish the actual peak. If the original 1,000 observation was rationed, the unrestricted baseline first needs an applicable estimate of suppressed use.

A proposed leakage measure may reduce the scenario’s losses from 140 to 80. With the industrial addition, the total would then be 660 + 300 + 150 + 80 = 1,190. EAM.7 can compare that measure with added supply, using its cost and evidence of achievable reduction. The ten-unit margin exists only while the assumed reduction, coincidence and other contributions remain supported. Treating the proposed 80 as the unchanged-policy loss estimate would hide the intervention that makes the option work.

These values illustrate the construction. They neither reconstruct CityWater’s supplied demand figures nor establish an empirical forecast for another district.