You must consider the line relative to the water flowing over the left side of the road (the grass section).
If the water is pooled on the road like it is in this image, that is not at the line. The water is considered at the line when it is flowing over the grass on the left at the line.
When the water is at the green line it is generally safe for most cars. Anything after the green line has risk. Vehicle type, driver confidence and possible debris on the causeway or floating down the river are contributing factors. This is NOT a fixed format and driver discretion is required for each crossing.
Use the fence poles on the right of the road as general indicators to establish your personal Go/No go before leaving your house to attempt to cross.
