Its maximum depth of 58.4 m makes Svitiaz the deepest natural lake in Ukraine. Yet that record figure gives a misleading picture of the basin if taken alone: most of the lake is nothing like a narrow deep bowl.
Two contrasting parts of one lake
The bed of Svitiaz is strongly asymmetric. The east is largely shallow, with broad areas at around 4–6 m and sandy shoals extending from the shore. This gently sloping relief forms the familiar recreational shallows.
Relief in the west and north-west is much more complex. Karst depressions and steep slopes descend towards Hlyb, the deepest feature, north of the island. Other local depressions and underwater rises surround it.
What covers the bed
Sand dominates the shallows. Finer organic and mineral deposits — sapropel, marl and calcareous material — accumulate in deeper areas. Sapropel reaches a thickness of about 2.5 m in parts of the deep basin.
The distribution reflects relief and water movement. Wave action hinders the settling of fine particles on exposed shallows, while depressions act as natural sediment traps.
Where the depth map comes from
One historical foundation is the bathymetric scheme based on Stanisław Lencewicz’s 1931 soundings. Later researchers reviewed the old material, refined the morphometry and stressed the value of a modern high-resolution survey.
The interactive cross-section below is an editorial visualisation assembled from isobaths and published depths at named underwater features. It is not a continuous echo-sounder transect along a route actually travelled by a survey boat. It explains the broad asymmetry and characteristic forms of the bed, but it is not a navigation chart.
Why the mean is far below the maximum
The mean depth is about 6.9 m, despite the 58.4 m maximum. The contrast exists because shallow water occupies a large share of the lake, while the record depression covers only a small part of the basin.