EAM.6:5.1 - A sufficient outage and buffer bound

CityWater’s North area has 1,000 m³/h usable capability before C is modified and needs 700 during the dry work window. Removing A’s 200 leaves 800; removing C’s 300 leaves 700. Each isolated outage passes the quantity bound. Removing both leaves 500, a 200 m³/h shortfall. Their individual feasibility therefore does not justify simultaneous work.

In an additional constructed variant, an independently qualified usable buffer contains 400 m³ and can cover that deficit at the required delivery conditions. The arithmetic gives 400 ÷ 200 = two hours. It cannot support a three-hour combined outage without another qualified contribution. This calculation assumes the stated usable volume and delivery rate; it does not derive them from tank size or establish water quality.

After the selected 200 m³/h addition, normal North capability is 1,200 against the wet minimum of 1,100. That comparison does not establish performance under every loss of station, power or control. Any such stronger claim needs its own applicable scenario or model.