West, then back east
The Mureș collects water from Transylvania and carries it into the Tisza in Hungary. The Tisza joins the Danube in Serbia. For water near Arad, the sea lies east and the journey starts west.
THE PATH OF RAIN · A WATER ATLAS
Where does
the rain here go?
At Arad, the Mureș flows west: through the Tisza, then into the Danube and the Black Sea. Pick a place to follow the water, then discover the land that feeds it.
Terrain-based flow model · HydroSHEDS · roughly 1 km grid
What the map can tell you ↗
Loading rivers and terrain…
Click anywhere in Romania. You can also enter coordinates.
Flow networkSelected routeUpstream area
Terrain-based route
Mureș → Tisza → Danube → Black Sea
Terrain-based flow model · HydroSHEDS · roughly 1 km grid
Choose coordinates
Before the first river, the line shows estimated overland flow. Gutters, sewers and infiltration need other data.
THE GEOGRAPHY OF A JOURNEY
The way to the sea
can start in the other direction.
Terrain divides water into catchments. National borders cut across them.
A mountain divides the rain
A watershed divide is the boundary between two catchments. Drops falling on opposite sides of a ridge can set off towards different rivers. Move your selected point on the map and compare the routes.
Close to the sea, another outlet
Most of Romania lies within the Danube basin. Along the coast, some catchments drain directly towards the Black Sea. The model may also end some routes at an inland depression.
The Mureș–Tisza–Danube connection: ICPDR · Tisza basin
© Krzysztof Ziarnek, Kenraiz · Wikimedia Commons · CC BY-SA 4.0 · resized.
REVERSE THE QUESTION
Everything upstream,
gathered into one shape.
In “Where it gathers” mode, the map finds every terrain cell whose flow directions lead to the selected point. On a hillside, that area may be small. On a large river, it can include mountains, fields and towns in several countries.
To explore a nearby river’s catchment, choose “At the first river downstream”. The map follows the flow to that river and separately marks the new calculation point. The shaded area describes a potential surface connection; it does not measure how much rainfall actually arrives.
THE MEETING WITH THE SEA
At the end, the water branches.
In its delta, the Danube divides its water between distributaries. The satellite image shows the branches and sediment carried towards the sea. Our map’s model assigns one direction to each cell, so its final line is a simplification.
NASA Earth Observatory / Jesse Allen & Robert Simmon · EO-1 ALI: NASA & USGS · Source · Reuse.
WHAT THE MAP KNOWS
How the route is calculated
The map follows HydroSHEDS v1 flow directions for Europe on a 30 arc-second grid. In Romania, a cell measures roughly 0.6 × 0.9 km. Terrain is represented at this scale; individual roofs and ditches cannot be identified.
From a point, downstream
Each cell points to one of its eight neighbours. We follow these links to a model endpoint. The animated drop illustrates the order of places; its speed does not represent actual water travel time.
Back towards the upstream area
Starting at the selected cell, we recursively find neighbours that send water to it. We add the areas of the cells, accounting for latitude. Endpoints and results near the data boundary are labelled accordingly.
What changes the real journey
Infiltration, evaporation, sewers, dams, diversions and branching channels can alter water movement. The map does not calculate flood risk, flow volume, travel time or drainage from a street address.
Rivers and borders
Blue lines come from accumulated flow in the same model. Names and borders provide orientation and are cartographically generalised. The study area includes the Danube basin outside Romania; point selection starts inside Romania.
Sources and reuse
Data and imagery accessed 7–8 September 2026.
- HydroSHEDS v1 — flow direction and accumulation. Lehner, Verdin & Jarvis (2008). Technical documentation and licence.
- ICPDR — Tisza basin; Danube basin countries.
- Natural Earth — borders and river labels, public domain.
- NASA Earth Observatory — Where the Danube Meets the Black Sea. Jesse Allen & Robert Simmon; EO-1 ALI / NASA EO-1 team & USGS. NASA reuse guidelines.
- Bâlea — Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0; resized.
HydroSHEDS · licence and end-user terms
This product Drumul ploii incorporates data from the HydroSHEDS version 1 database which is © World Wildlife Fund, Inc. (2006-2022) and has been used herein under license. WWF has not evaluated the data as altered and incorporated within Drumul ploii, and therefore gives no warranty regarding its accuracy, completeness, currency or suitability for any particular purpose. Portions of the HydroSHEDS v1 database incorporate data which are the intellectual property rights of © USGS (2006-2008), NASA (2000-2005), ESRI (1992-1998), CIAT (2004-2006), UNEP-WCMC (1993), WWF (2004), Commonwealth of Australia (2007), and Her Royal Majesty and the British Crown and are used under license. The HydroSHEDS v1 database and more information are available at https://www.hydrosheds.org.
Incorporated data are subject to the HydroSHEDS licence, including its restrictions, disclaimers and attribution requirements. Standalone redistribution is prohibited. HydroSHEDS licence.