This is the level where distribution math stops being a set of separate topics and becomes one continuous chain: a demand number at the start of the problem determines a storage volume, which determines where a tank sits and how hard a pump has to work to fill it, which determines an energy bill at the end of the month. A Class 4 operator is expected to walk that entire chain without losing the thread — and to recognize, at each link, which upstream number is actually driving the downstream one. This guide works one fully integrated scenario end to end, in four connected parts. Part II of this pair covers water audit mathematics, the Infrastructure Leakage Index, and a mock exam problem set of additional integrated scenarios.
The Scenario
A distribution system has three pressure zones feeding from a single elevated storage tank and pump station:
| Zone | ADD (MGD) | Peaking Factor