| Large dams
including the construction of toe berms on the downstream side, rock fill rip-rap on the upstream side, additional instrumentation, refurbishing of spillway gates, stabilization of concrete structures, and measures in the spillway channel. Storfinnforsen hydropower dam in the river
Faxälven is an example of a dam constructed late in the early era with a thin buttress dam and a wooden diaphragm embankment dam. Storfinnforsen has three main dams constructed between 1948-1954: a 25m high and 350m long earth-fill, a 40m high and 700m long concrete buttress dam and an 8m high and 150m long concrete gravity dam. Extensive dam safety measures were undertaken between 2008 and 2017, including enhancing the stability of the concrete dam, improving the safety of the earth fill dam, renovating and recommissioning the bottom outlet, and implementing rock stabilization measures in the outlet channel.
Project details Porjus Owner Purpose Location River
Drainage basin area (km²) Mean annual flow (m³/s) 100-year flow (m³/s) Year of construction
Dam Type
Height (m)
Crest length (m) Foundation type
Spillway Type
Maximum discharge capacity (m³/s)
Storfinnforsen
Vattenfall Vattenkraft AB Sydkraft Hydropower AB Hydropower
Hydropower
Jokkmokks municipality, Norrbottens county
Luleälven -
268 1043
1910 - 1915 and 1971 - 1980
Rock fill dam 25 2100 Bedrock Surface Spillway -
Sollefteå municipality, Sollefteå municipality, Västernorrlands county
Faxälven/Ångermanälven 6791 124 543
1948-1954
Earth fill dam and concrete buttress dam
40 1198 Bedrock
Surface spillway and bottom outlet
1170 at RL
Trängslet Fortum
Hydropower
Älvdalen municipality, Dalarnas county
Dalälven 4518 64
930 (inflow) 1955-1960
Rock fill dam
125 900
Bedrock
Surface spillway with segment gates
876 m³/s
Trängslet dam in the river Dalälven is the tallest dam in Sweden and an example of an embankment dam of a modern design. It was constructed between 1955 and 1960 as a rock fill dam with an impervious till core. The dam has a height of 125m, a crest length of 900m, and a crest width of 10m. Since its construction, the dam has undergone two dam safety projects. In the first project, the dam’s crest and core were raised by 1.5-2m to improve safety. In an ongoing safety project, a bottom outlet is being constructed to increase the dam’s discharge capacity, and a dam toe berm is being constructed on the downstream side to enhance the dam’s ability to withstand hypothetical scenarios involving internal erosion and severe leakage.
Dams in Sweden today. Today, hydropower accounts for nearly half of
Sweden’s electricity, and mining is strategically important in facilitating other industrial activities.
Above: Section through the Porjus dam showing the original diaphragm embankment dam with central concrete wall on the left side, is now part of the upstream support fill; the current, taller, rock fill dam consisting of a centrally located symmetrical core made of till, surrounded by filters and supported by blasted rock fill; and the new rock fill toe berm added to the downstream slope. The dam facility is mainly founded on bedrock
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