After a break or repair, where should BEE collect samples?

• A. Upstream
• B. Downstream
• C. Upstream and downstream
• D. Downstream or in both directions if flow is unknown

Answer: (D)

The key idea is to track the movement of any contaminants released during a break or repair by following the water’s direction of flow. Contaminants will travel downstream with the flow, so sampling downstream from the break is the best way to detect whether the plume has entered the system and how far it has spread. If the flow direction is uncertain or may reverse during hydraulic transients, collecting samples in both directions ensures you don’t miss contamination that could move opposite to an assumed flow direction. Upstream samples can provide a baseline, but for assessing contamination caused by the break, downstream sampling is essential, and both directions if flow is unknown.