For a vessel what matters is how deep the water is under the keel, not how high the surface is. The navigation page shows depths, and the station level is only one of their ingredients.
The level says how high the water surface is above the gauge zero. Depth says how far it is from the surface down to the fairway bed. They are two different quantities, measured in different places.
A high level does not guarantee deep water: on a stretch with a sandbank, the water can be shallow even at a normal level. A low level does not mean the passage is closed either: the minimum depth along the route is what counts.
ScreenshotThe screenshot puts the station level next to the minimum depth of a sector, so that the two different figures can be seen: the level in centimetres above the gauge zero, the depth in centimetres below the surface.
What ENR is
ENR is the reference level for low water on the lower Danube — the navigable regulation low water. It is used when talking about fairway depth.
When you hear “depth at ENR”, the figure describes the fairway at that reference level, not at today’s gauge. It is a point of comparison between years and sectors, not a promise for today.
LDC and HDC remain the station’s low-water and high-water references; ENR is the Romanian reference for fairway depth on the lower sector. They are not three alarm thresholds, but three reading references.
ScreenshotThe screenshot shows the navigation page legend: the three references LDC, HDC and ENR, each with its full name, next to a sector depth, so that it is clear which reference belongs to the level and which to the depth.
Critical points
A critical point is a place in the fairway where the water can become too shallow for a loaded vessel: a sandbank, a dredged stretch, a bridge or a lock.
The minimum depth there comes from a survey and is adjusted by the change in level since the survey. It is not a measurement taken today: it may be from last week or last year.
The survey date says how old the figure is. An old survey may no longer describe today’s fairway, and a negative depth means the surveyed shoal is above the water: at the current level, the sector is not navigable.
ScreenshotThe screenshot shows the critical points table: the Point, RKM, Type, Minimum depth and Survey columns, with one row marked “shallow” and one without a value. The survey date is visible next to each depth.
Before you sail
The page is informative. It does not replace the official notices of the waterway authority: depths change with the water level, and an old survey can be misleading.
Before you sail, check the notices. A row without a depth does not mean “clear”: it means there is no reliable figure. And at bridges and locks, clear height may matter rather than depth.
For navigation, LDC is the low-water reference: as the level approaches it, the fairway narrows and a loaded vessel has to carry less. HDC is the high-water reference, above which speed and draught restrictions apply.
ScreenshotThe screenshot shows the sector cards on the navigation page: the lowest depth today, the point that gives it, the survey date and the “shallow” or “good” marker.
Keep in mind
Depth is not read like a level: it is an estimate for the fairway, valid at the level on the survey day and adjusted to today. Check the official notices before you sail.