Statistics

Statistics by country and year

Yearly summaries computed from the daily readings of every station: how many station-days were spent below the low-water level (LDC) or above the high-water level (HDC) — as a count and as a share of the station-days with thresholds. Useful for agriculture (irrigation seasons with low water) and navigation (days with restricted draught).

Agriculture: station-days below LDC mark the low-water periods when irrigation intakes and water availability are under pressure.
Navigation: days below LDC mean draught restrictions on that sector; days above HDC mean suspended traffic.

Daily data from 1879 to 6 November 2026

Download this tab’s data (CSV)

LDC: Low-water mark. The river stays above it on 94 of 100 ice-free days; below it, ships cannot sail fully loaded.
HDC: High-water mark. The river exceeds it on 1 day in 100; above it, navigation can be suspended.
Station-days: One station-day is one station measured for one day: 13 stations over 10 days make 130 station-days. It shows how widely and how long something lasted.

Irrigation season 1951: Bulgaria spent the longest below LDC, 1 % of days

Irrigation season (April–September)

Station-days below LDC in the irrigation season, by country and year, against the average of the other years; the longest uninterrupted spells below LDC.

1%5%

1951Meanbelow LDC in season

Irrigation season (April–September) 1951
countries	station-days in season	below LDC in season	%	vs. average
Austria	183	0	0%	-1 pp
Hungary	2,745	0	0%	-2 pp
Croatia	549	0	0%	-1 pp
Bulgaria	1,098	10	1%	-4 pp

Longest spells below LDC

Uninterrupted periods of at least 5 days below LDC, by station.

Longest spells below LDC
Station	countries	From	To	days
Ybbs	Austria	1951-10-15	1951-11-02	19
Silistra	Bulgaria	1951-10-29	1951-11-07	10
Oryahovo	Bulgaria	1951-10-28	1951-11-04	8
Silistra	Bulgaria	1951-09-26	1951-10-01	6
Oryahovo	Bulgaria	1951-09-23	1951-09-27	5

The daily series uses the first reading of each day.