# All Waters Run to the Danube
### The Hydrological Atlas of Romania: 4,891 Rivers and Their Descent to the Sea

A single raindrop falling on the Carpathian crests obeys a single physical law: gravity. In Romania, 97.8% of the entire land area drains into a single common collector: the Danube. From glacial torrents in the Făgăraș Massif dropping over two thousand metres down to the sluggish meanders of the southern plains, every river finds its step and reaches the sea.

## Key Metrics
- **97.8%** of Romania (233,150 km² out of 238,397 km²) drains into the Danube
- **2,290 m**: highest spring elevation in Romania (Buda stream, beneath Moldoveanu Peak)
- **761 km**: longest river running within Romania (Mureș, 789 km total)
- **615 km**: longest river exclusively within Romania (Olt)
- **42,890 km²**: largest internal catchment basin (Siret, 18.0% of Romania area)
- **2.2%**: only rivers that never touch the Danube (coastal Dobrogea streams: Casimcea, Taița, Telița)

## The Mountain Divide: Hășmaș (Mureș vs Olt)
In the Hășmaș Mountains, less than 5 km apart, spring the Mureș (elevation 850 m) and the Olt (elevation 1,440 m). The Mureș travels west through Transylvania (761 km in Romania) and joins the Tisza in Hungary. The Olt turns south, carves through the Southern Carpathians via the Turnu Roșu gorge, and empties directly into the Danube at Islaz (615 km).

## The 12 Catchment Basins
1. **Siret**: 42,890 km² (18.0%) → Danube (Galați)
2. **Mureș**: 27,890 km² (11.7%) → Tisza (Hungary)
3. **Olt**: 24,050 km² (10.1%) → Danube (Islaz)
4. **Banat**: 18,320 km² (7.7%) → Danube & Tisza
5. **Someș - Tisa**: 15,740 km² (6.6%) → Tisza (Hungary)
6. **Crișuri**: 14,860 km² (6.2%) → Tisza (Hungary)
7. **Argeș**: 12,550 km² (5.3%) → Danube (Oltenița)
8. **Prut - Bârlad**: 10,990 km² (4.6%) → Danube (Giurgiulești)
9. **Ialomița - Călmățui**: 10,350 km² (4.3%) → Danube (Giurgeni)
10. **Jiu**: 10,080 km² (4.2%) → Danube (Zăval)
11. **Vedea**: 5,430 km² (2.3%) → Danube (Bujoru)
12. **Dobrogea (Coast)**: 5,247 km² (2.2%) → Black Sea / Razim

Sources: Atlas of the Water Cadastre of Romania, ANAR, INHGA.
Author: Marius Comper (https://mariuscomper.uk/en/)