A New Bathymetric Survey of the Suwałki Landscape Park Lakes

The results of the latest bathymetric survey of 21 lakes in the Suwałki Landscape Park (SLP) are presented here. Measurements of the underwater lake topography were carried out in the years 2012–2013 using the hydroacoustic method (sonar Lawrence 480M). In the case of four lakes (Błędne, Pogorzałek, Purwin, Wodziłki) this was the first time a bathymetric survey had been performed. Field material was used to prepare bathymetric maps, which were then used for calculating the basic size and shape parameters of the lake basins. The results of the studies are shown against the nearly 90 year history of bathymetric surveying of the SLP lakes. In the light of the current measurements, the total area of the SLP lakes is over 634 hm² and its limnic ratio is 10%. Lake water resources in the park were estimated at 143 037.1 dam³. This value corresponds to a retention index of 2257 mm. In addition, studies have shown that the previous morphometric data are not very accurate. The relative differences in the lake surface areas ranged from –14.1 to 9.1%, and in the case of volume—from –32.2 to 35.3%. The greatest differences in the volume, expressed in absolute values, were found in the largest SLP lakes: Hańcza (1716.1 dam³), Szurpiły (1282.0 dam³), Jaczno (816.4 dam³), Perty (427.1 dam³), Jegłówek (391.2 dam³) and Kojle (286.2 dam³). The smallest disparities were observed with respect to the data obtained by the IRS (Inland Fisheries Institute in Olsztyn). The IMGW (Institute of Meteorology and Water Management) bathymetric measurements were affected by some significant errors, and morphometric parameters determined on their basis are only approximate.