Spatial variation of basin supply as a factor of water quality in a shallow, flow-through lake
Lake Syczyńskie is a water body that represents a group of the smallest Łęczna-Włodawa Lakes. The lake is supplied with waters from the four streams, while the outlet from the lake is directed into the Świnka River. The residence time of water is very short in Lake Syczyńskie. A role and variation of water supply from the catchment area were calculated using the mean seasonal loads transported from lakes sub-basins. A range of ionic migration into the basin of the lake was presented by means of daily and five-day radiuses. Among all inflows, C2 and C4 streams that drained Chełm Hills structure, were the most stable ones. The C3 stream that drained lake vicinity, was less important in shaping the quality of the lake water, while stream C1 was the one with a wide range of seasonal loads inconstancy. The highest fluviodynamic and matter transport occurred during the cold season. However, during the warm season in-lake processes were significant in terms of shaping the quality of lake water.
The research was carried out in three Łęczna-Włodawa lake-catchment systems, during the hydrological years 2007-2009. The observed lakes varied in terms of basin morphometry and catchment features. The hydrological functioning of the lakes resulted from three main factors: 1) storage capacity of the lake basin, 2) catchment area and relief, 3) human impact on water distribution. The vertical water exchange ratio in Lake Sumin was almost four-times higher than flushing time. In Lakes Rotcze and Syczyńskie horizontal water exchange, presented as flushing time was significantly higher than the vertical one.