The Erythropotamos (, meaning "red river") or Luda reka (, meaning "mad river") is a river in southern

Bulgaria Bulgaria, officially the Republic of Bulgaria, is a country in Southeast Europe. It is situated on the eastern portion of the Balkans directly south of the Danube river and west of the Black Sea. Bulgaria is bordered by Greece and Turkey t ...

(

Haskovo Province Haskovo Province (; former name ''Haskovo okrug'') is a province in southern Bulgaria, neighbouring Greece and Turkey to the southeast, comprising parts of the Thracian valley along the river Maritsa. It is named after its administrative and i ...

) and northeastern

Greece Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to th ...

( Evros regional unit). Its Turkish name was ''Kızıldelisu''. Its source is near Mega Dereio. It flows into the

Maritsa Maritsa or Maritza ( ), also known as Evros ( ) and Meriç ( ), is a river that runs through the Balkans in Southeast Europe. With a length of ,

(Evros) near

Didymoteicho Didymoteicho ( ) is a town located on the eastern edge of the Evros (regional unit), Evros regional unit of Eastern Macedonia and Thrace, in northeastern Greece. It is the seat of the municipality of the same name. The town (pop. 8,681 in 2021 ...

Geography

The source of the river is in the eastern

Rhodope Mountains The Rhodopes (; , ; , ''Rodopi''; ) are a mountain range in Southeastern Europe, and the largest by area in Bulgaria, with over 83% of its area in the southern part of the country and the remainder in Greece. Golyam Perelik is its highest peak ...

in the western Evros regional unit,

, near the village Mikro Dereio. It crosses the border with

near Gorno Lukovo in the

Ivaylovgrad Ivaylovgrad (, "city of Ivaylo", , Turkish :Ortaköy, "Middle Village") is a town in Haskovo Province in the south of Bulgaria set near the river Arda in the easternmost part of the Rhodope Mountains, and is the administrative centre of the h ...

municipality, and forms the Greek-Bulgarian border for several kilometers. It crosses back into Greece between the villages Siv Kladenets and Alepochori. It passes the villages

Metaxades Metaxades (Greek language, Greek: Μεταξάδες, ) is a large village, municipal unit and a former municipality in the Evros (regional unit), Evros regional unit, East Macedonia and Thrace, Greece. This lowland settlement, situated at an alt ...

, Ladi,

Mani Mani may refer to: People * Mani (name), (), a given name and surname (including a list of people with the name) ** Mani (prophet) (c. 216–274), a 3rd century Iranian prophet who founded Manichaeism ** Mani (musician) (born 1962), an English ...

and Koufovouno before flowing into the Evros just beyond

. Its largest tributary is the Byala reka ("white river") in

, which flows into the Luda reka near the village Odrintsi.

Hydrology

The Erythropotamos River basin covers an area of approximately 1,618.5 km², with most of it in Greece's

Thrace Thrace (, ; ; ; ) is a geographical and historical region in Southeast Europe roughly corresponding to the province of Thrace in the Roman Empire. Bounded by the Balkan Mountains to the north, the Aegean Sea to the south, and the Black Se ...

region and a smaller part in

. The region's geological formations include orthogneisses, augen gneisses, pegmatites, marbles, amphibolites, and sediments. Elevations range from 16 meters to 1,258 meters above mean sea level, with a predominantly hilly terrain.

Flood Events and Susceptibility

The Erythropotamos River is prone to frequent flooding, particularly in its lower reaches. Significant flood events have occurred in 2010, 2017, and 2018, causing considerable damage. Flood susceptibility mapping has been carried out using

GIS A geographic information system (GIS) consists of integrated computer hardware and software that store, manage, analyze, edit, output, and visualize geographic data. Much of this often happens within a spatial database; however, this is not ...

and remote sensing technologies, identifying high-risk zones and validating them with SAR imagery. Approximately 60% of recent flood areas intersect with high susceptibility zones on these maps.

Invasive Species

The Erythropotamos River has been affected by the introduction of invasive species, such as the Asian clam ('' Corbicula fluminea''). This species was first recorded in

within the Erythropotamos River, likely spreading downstream from

. The presence of this species poses ecological risks and challenges for river basin management.

References

{{Reflist Rivers of Bulgaria Rivers of Greece International rivers of Europe Geography of Thrace Rivers of Eastern Macedonia and Thrace Landforms of Evros (regional unit) Landforms of Haskovo Province Bulgaria–Greece border Border rivers