07. August 2018

Flooding in Skaftá River.

A glacial outburst (Jökulhlaup) is currently taking place in Skeiðará river in South-Iceland. The river runs between Vík and Kirkjubæjarklaustur. The ringroad is currently closed on the flood site. Bypass on road 204 - Meðallandsvegur. 

From the Icelandic Met Office
A Glacial Outburst flood is ongoing in Skaftá River in S-Iceland. 
Water discharge in Sveinstindur has decreased since midnight yesterday. Water level was at its maximum in Eldvatn on 5. August and water floods over Eldhraun lava field. Water is now flowing over the main road in two places. The flood is expected to slowly decrease but it might take several days for the river to return to normal levels. 
Geothermal water is flowing into Múlakvísl river. A strong smell of Sulphur has been reported close to the river, SSE of Mýrdalsjökull. Gas sensor measured H2S there last evening, 6th of August. Travellers are urged to minimize their exposure to the gas and to stay clear from low points in the landscape by the riverbed.
Written by a specialist at 07 Aug 13:32 GMT


More information on the River:

Skaftá River

Skaftá River is one of the large glacial rivers present in the region. It is particularly voluminous and long. Its length from source to estuary is about 115 kilometres. Skaftá is a mixed glacial and spring-fed river. The main sources of the glacial meltwater are in Skaftárjökull at Vatnajökull Glacier and spring water from Lake Langasjór is rapidly added into the meltwater. In summer, Skaftá River is coloured by mud from glacial meltwater, whereas in winter it is most often crystal clear. The uppermost farmstead by Skaftá River is called Skaftárdalur; where the nearby river basin is about 1400 km² with an average flow of 115 m³/s. Above Skaftárdalur, a number of rivers and streams run into the Skaftá River, the most prominent being Grjótá, Hellisá including the South- and North-Ófæra, all of which are spring creeks. Below Skaftárdalur, the Skaftá River expands and diverges into two main branches. To the west, there is the Eldvatn River (also called Ása-Eldvatn) which runs west along the Skaftártunga area and over into the Kúðafljót River. To the east flows the Skaftá River itself, which bends east along the Síða hillside, by the town of Kirkjubæjarklaustur and finally into the ocean around the estuary Veiðiós. A portion of the Eldvatn and Skaftá rivers branches around grooved lava are called Ásakvíslar on the one hand and Árkvíslar on the other; They have, however, changed a bit the last years due to road construction. A portion of the water that runs into the lava disppears into it and emerges as spring water at the southern edge of Skaftáreldahraun Lava Field, at Eldvatn in Meðalland among other places.

Glacial outburst floods (Icelandic: jökulhlaup) are common in the Skaftá River and as a general rule it floods every two years. The floods result in much water running all over around lowland areas, with tremendous deposition. The size of Skaftá River floods is variable, but the flow can get up to 1500 m³/s by Skaftárdalur during the largest floods. For comparison, the largest floods in Iceland’s history have been during Katla’s eruptions with their maximum flow rate estimated to reach up to 300,000 m³/s. Floods in the Skaftá River originate at Skaftárkatlar (Skaftá Depressions) which are beneath Vatnajökull Glacier, northwest of Grímsvötn Volcano. The floodwater is meltwater from geothermal energy which builds up in the depressions and emerges when the depressions fill up; the glacier then rises up and the water forges a path for itself under the ice.

Transportation then and now

The Skaftá River and Skaftá-Fires Lava Field were thought to pose significant problems for transportations here in previous years. Transportation in the region changed little from the settlement of Iceland up to the third decade of the last century when the horse was the only land vehicle. While there were no bridges over the rivers, one had to trust the horse and vatnamenn’s (waders’) competence. A vatnamaður was given that title if he or she was skilful at finding favourable locations to wade in moving water. This tested both the shrewdness and boldness of individuals as well as the horse’s foot-sureness and reliability.

Before the bridges, there were ferries at four locations: over the Skaftá River at Skaftárdalur and at Kirkjubæjarklaustur,at Ása-Eldvatn by Svínadalur and at Eldvatn by Fljót in Meðalland. In 1903, the first bridge over the Skaftá River was put in place at Kirkjubæjarklaustur and few years later over Ása-Eldvatn. Around the same time, or in 1910, a path had begun to be cleared for a road over the Skaftá-Fires Lava Field. The age of the automobile arrived right about 1930 here in West Skaftafellssýsla County and accordingly it was then necessary to think about road improvements and bridge-building in a different way than before. After various difficulties in bridge construction, it was decided to feed the Ásakvíslar River back into Eldvatn with a lot of leveeing. It went so badly the bridge’s foundation, along with the bridge itself, washed away in river swelling. In the aftermath, the rich runoff from the glacial meltwater of the Ásakvíslar River dwindled. The land dried up and soil erosion set in.

Interplay of humans and nature

It is safe to say that it is difficult to harness the elements and this is perhaps proved best here in this region where glacial meltwater, sandstorms, lava flows and drifting ash are constantly shaping the land. Ever since people began to settle in Iceland, it is likely that no inhabited areas in the country have experienced anything like the desertification as counties of Skaftafellsýsla. The diversity of terrain and vegetation is so great, from glacier to the ocean, fertile oases and eroded emptiness are often together side by side. Generously fertile lands have vanished in glacial outburst flooding or under lava and ash, so much so, that inhabited areas have disappeared. But everything eventually clears up sooner or later. There have been periods of good and bad in the region’s history. The power of destruction has even sometimes increased the prosperity of those who managed to stick through the tougher times.

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