Cross-connections are actual or potential connections between safe drinking water (potable) supply and a source of contamination or pollution. The submerged hoses in the photos illustrate a direct cross connection between non-potable water and your drinking water.
A loss of pressure like a water main break or system repair in the public water system or running too many in-house water sources at once (think shower, washer, dishwasher, and sprinkler system all at the same time) can cause backsiphongage. This loss of pressure creates a siphon effect in the plumbing system which can draw water out of a sink, bucket, or pool and back into your water or public water system.
Cross-connections must be properly protected or eliminated to protect the city’s drinking water supply from backsiphonage or backflow. In this case, either remove the hoses from the pool or barrel or install a hose connection vacuum breaker on the faucet.