The Evros (Greek: Εβρος, Romanized as Hebrus, Bulgarian: Марица, Turkish: Meriç) river is ca. 480 km long. It has its origin in the Rila Mountains in Western Bulgaria, flowing south east between the Balkans and Rhodope Mountains, past Plovdiv, to Edirne, Turkey the northern branch of the river runs entirely in Turkey while the southern branch flows with the border near Kastanies, where it turns south to enter the Aegean Sea near Enez and is a delta. The Tundzha is its chief tributary and the other is the Ardas (Bulgarian: Арда). The Maritsa's lower course forms part of the Bulgarian-Greek border and the Greek-Turkish line. The upper Maritsa valley is a principal east-west route in Bulgaria. The unnavigable river is used for power production and irrigation.
The reservoir on the Evros includes the Kiprinos Dam.
On February 18, 2005, floods devastated much of the low-lying areas of the northeastern part of the Evros prefecture and the Edirne area. The flood happened when the area received above average of rainfall and snowfall which caused a dike to burst and flooded beyond its banks and far inland as at 5 to 10 km. The weather was raining. The water levels went as high as 6.5 m above ground, thats 10 cm above the embankment level which is danger to its residents. Pythio was flooded. It devastated hydro lines, train tracks, roads and damaged a lot of farms including wheat farms and flooded many villages and houses. Many roads were closed. Teams throughtou the prefecture blew up dikes in Pythio, Lavara and Amorio as flood control conducted 15,000 acres (61 km²) of land. The flood lasted from February 17 to 22. Three days later, the weater level dropped to 5.48 m, below the danger level of 5.70 m. The water level in Ardas dropped to 4.8 m.
Another flood which began from March 1, 2005 flooded several places again and a town which flooded a local school that has a playground leaving the basketball unflooded in Pythio. Several other buildings, roads and streets were also flooded. A day later on March 2, the flood reached Didymoteicho and Lavara to the southwest. The rainfall amounts to about 5 m, 4.6 m in some areas including the Ardas and as high as 6.5 m. Firemen with boats and workers were rescuing and helping people. The rail linking to the northern part of Evros were closed. The flooding of the valley also flooded the Turkish side.
A third round of floods began near Edirne in the Turkish side and Kastanies in the Greek side on March 7. The river was flowing at nearly 1,000 m³ every second. Kastanies became a lagoon which flooded the entire community including streets and homes and stranded people in their homes. The flood waters merged with the waters of Ardas causing it to flood Kastanies. Farmlands were underwater. The northern branch of the river also flooded houses and properties in Edirne in the Turkish side and several communities around Edirne. Workers put sandbaks to prevent the flooding of properties. The flood later reached the low lying areas of Pythio, Amorio and Lavara along with Didymoteicho. The water level on March 8 was 5.8 m, 5 m at the Kiprinos Dam.
Five months later, another flooding occurred on Thursday, August 11, 2005 in the northeastern part of the Greek prefecture of Evros between Orestiada and Didymoteicho, farmlands of the low-lying areas were flooded and damaged, crops including corn were completely destroyed, the valley became a lake. The railway connecting Orestiada and Didymoteicho shut down as a result of the flooding of the tracks. The flood was smaller than the major 2005 flooding. One of the dikes near the river broke and caused the flooding.