Boyalashka reka

The Boyalashka reka (Bulgarian: Боялъшка река) is a 33 km long river in southern Bulgaria, a right tributary of the river Arapliyska reka, itself a left tributary of the Popovska reka of the Tundzha basin. It is the largest tributary of the Arapliyska reka.^[1]

Boyalashka reka
Location
Country	Bulgaria
Physical characteristics
Source
• location	Dervent Heights
• coordinates	41°59′0.96″N 26°51′0″E
• elevation	502 m (1,647 ft)
Mouth
• location	Arapliyska reka
• coordinates	42°6′43.92″N 26°36′45″E
• elevation	117 m (384 ft)
Length	33 km (21 mi)
Basin size	159 km2 (61 sq mi)
Basin features
Progression	Arapliyska reka→ Popovska reka→ Tundzha→ Maritsa

The river takes its source under the name Chakarlia an altitude of 502 m in the Dervent Heights, some 7005 m south of their highest point Gyurgenbair (555 m), which is situated in Bulgarian territory just north of the Bulgaria–Turkey border. It flows in a narrow forested valley through the northern slopes of the Dervent Heights in direction northwest. It flows into the Arapliyska at an altitude of 117 m some 200 m east of the village of Chernozem.^[1]

Its drainage basin covers a territory of 159 km² or 45.3% of the Popovska reka's total.^[1] The Boyalashka reka has predominantly rain feed with high water in autumn and winter.^[1]

The river flows entirely in Yambol Province. There is only one settlement along its course, the village of Lalkovo in Elhovo Municipality. Its waters are utilised for irrigation.^[1]