Lake Laitaure
The distal part of the hydrographic map of Lake Laitaure.
The bottom configuration in Lake Laitaure is very irregular. The greatest depths in are found in the central part of the rectangular, western lake basin. In 1959 the maximum depth was 17.8 m, the mean depth 4.1 m, the lake area (exclusive of islands) amounted to 10.0 km2, and the water volume to 41.4 million m3. Because of the advance of the delta front the lake area has now (in 2005) decreased to about 9.5 km2.
Calculated amounts of sediment remaining in suspension at the outlet section
of Lake Laitaure (marked on the map above), or deposited within the lake upstream
of this section, in percentage of the amounts discharged into the lake from
the deltaic distributaries. The calculations are based on a water temperature
of 8 degrees C, a density of the sediment particles of 2.65 g/cm3,
and that on an average 1/3 of the lake volume is taking part in the through
flow. From Axelsson 1967 (Geogr. Ann. 49 A).
Sediment discharges at the outlet section, estimated by means of this diagram
are of the same order as those estimated by the suspended-sediment rating curve,
but gives somewhat lower discharges of coarser particles than espected on the
basis of the grain-size analyses. The background for the calculations is the
sediment deposition model worked out by Sundborg.
A soil sampler with metal foils was used for coring
in Lake Laitaure and in the Laitaure Delta in 1954.
A special type of bottom placed sediment traps (without
permanent walls) have been used for measuring sedimentation in Lake Laitaure.
During August 1954 the rate of sedimentation amounted to 3 cm about 300 m in
front of the Laitaure delta, to 3 mm in the central part of the lake, and to
about 1 mm in the distal part of Lake Laitaure. The sedimentation in Lake Laitaure
has later been studied by Hans
Andrén, who used the methods described in the manual:
"X-ray radiographic techniques in studying sedimentary properties, sedimentary
sequences, and rates of sedimentation".
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