* "Deep channel" refers to that area of the marked fairway which has the width required for a 4-unit convoy travelling downstream. The respective width of the fairway is dependent on the river bend radii involved. Accordingly, passing and overtaking within the confines of the deep channel is generally not possible. When necessary, and in accordance with Articles 6.04, 6.05 and 6.10 of the Waterway Traffic Act, vessels should wait at a suitable location until it is possible to proceed through a shallow area using the deep channel of the main fairway.

Information on the course of the deep channel is available in the area map for the respective shallow section. The course of the fairway is indicated by buoyage and marking.

The published minimum fairway depths are calculated on the current water levels available every quarter of an hour at the respective reference gauging station and are thus updated every 15 minutes. Information concerning the respective reference gauge is available in the area map for the shallow section (PDF).

At shallow sections in the free-flowing Danube of the Wachau valley and east of Vienna water depths are monitored on a monthly basis. As the riverbed in free-flowing sections of the river is constantly changing, the data provided relating to water depths should be regarded purely as a snapshot of current conditions. No liability can therefore be assumed for their accuracy at the time of the request for information. Shallow sections in which dredging measures are currently performed are indicated in the list above by a dredger symbol and identified by corresponding waterway signs and marking on site. Additional information can be obtained from the Notices to Skippers (NtS) currently in force.

Furthermore, please note that the provided forecast for fairway depth in the deep channel at shallow sections is to be considered as a service for navigation during low water periods only. In periods of medium or high water levels no forecast for fairway depths will be published. Information concerning water levels in periods of high water can be accessed on the websites of the hydrological services in Lower Austria and Upper Austria.

Accuracy of forecasts: The 24h forecasts have an accuracy of +/- 10cm and a probability of about 80%. Neither viadonau nor any other data supplier shall be liable for the accuracy of the data provided.