Nidelva (Agder)

Nidelva
Nidelva near Blakstad in Froland
Nidelva (Agder) is located in Agder
Nidelva (Agder)
Location of the river
Nidelva (Agder) is located in Norway
Nidelva (Agder)
Nidelva (Agder) (Norway)
Location
CountryNorway
CountiesAgder, Telemark
MunicipalitiesGrimstad, Arendal, Froland, Åmli, Nissedal
Physical characteristics
SourceConfluence of Nisserelva and Fyresdalsåna rivers
 • locationHaugsjåsund, Nissedal, Telemark
 • coordinates58°56′26″N 8°30′04″E / 58.9406°N 08.5011°E / 58.9406; 08.5011
 • elevation160 metres (520 ft)
MouthSkaggerak
 • location
Arendal, Agder
 • coordinates
58°26′06″N 8°42′49″E / 58.4349°N 08.7137°E / 58.4349; 08.7137
 • elevation
0 metres (0 ft)
Length221.7 km (137.8 mi)
Basin size4,011 km2 (1,549 sq mi)
Discharge 
 • locationRykene, Arendal
 • average114.4 m3/s (4,040 cu ft/s)
Basin features
River systemArendalvassdraget
Tributaries 
 • leftKarlsåna, Katteråsåna
 • rightBlekevja, Gjøv, Sigridneskilen, Songeelva, Trevann, Rore
WaterbodiesNelaug
WaterfallsKastefossen

Nidelva is the main river in the Arendal drainage basin in Agder county, Norway. The 221.7-kilometre (137.8 mi) long river begins at the confluence of two rivers: Nisserelva and Fyreselv. The confluence is located by the village of Haugsjåsund in Nissedal municipality in southern Telemark county. The river flows south into the Skagerrak at the city of Arendal. The watershed covers 4,011 square kilometres (1,549 sq mi) and has an average waterflow of 114.4 cubic metres per second (4,040 cu ft/s) at Rykene near the mouth. The highest waterflow ever recorded on the river was 1,200 cubic metres per second (42,000 cu ft/s) in the autumn of 1987.