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Before the lesson, ponder about your knowledge concerning lakes. Write down your thoughts below.

Still surface waters in Poland

In the territory of Poland, there is about 9.3 thousands of lakes which in total cover the area of 3169.3 kmIndeks górny 2² (a bit more than 1% of Poland’s total area). These lakes, in their majority, originate from the erosive and accumulative activity of the latest glaciation.
Lake distribution in Poland is very uneven – the largest concentrations are in the north. These include 3 major lakelands: Pomeranian, Masurian and Greater Poland Lakeland.
Most lakes are located in the Pomeranian Lakeland (about 4130), however, a mere fraction achieved significant size. In the Masurian Lakeland, there are far fewer lakes (about 2560), however, they cover up much larger area (almost 45% of total lake area in Poland). This region boasts with the largest one – Śniardwy (113,8 kmIndeks górny 2²) – and the deepest one – Hańcza (108.5 m).
In the southern part of Poland, in the Tatra Mountains and the Giant Mountains (Karkonosze), post‑glacial depressions contributed to the formation of cirque lakes. Most frequently, they are called “staw”, as in Czarny Staw, Przedni Staw in the Tatra Mountains, Wielki Staw and Mały Staw in Karkonosze.
The most popular mountain lake in Poland is Morskie Oko.

The list below contains types of lakes present in Poland.

The applicationin e‑book depicts the process of formation of a coastal lake. What lakes of this type do you know of?

Apart from natural lakes, there are also many artificial lakes in the territory of Poland. Such reservoirs have various functions, e.g. they enable river engineering or hold water surplus during increased water discharge or may be used for sports and recreation; banked up water is used to drive turbines of hydropower plants.

Another work of a human, related to hydraulic engineering, are canals. These are used, inter alia, for inland transport. The most important artificial waterways in Poland are the following canals: Augustów Canal, Gliwice Canal, Ślesiński Canal, Notecki Canal, Bydgoszcz Canal, Żerański Canal, and ElblągCanal, with an inclined plane system, unique on a global level, which assists vessels in overcoming more than 100 m level difference. The longest waterway in Poland is the Wieprz‑Krzna Canal, a drainage channel reaching 140 km.

Lands permanently saturated with water, namely swamps and marshes, are formed on an impermeable bed. They are overgrown with typical hygrophilous vegetation, dominated by moss (e.g. peat moss), grass (e.g. reed) and sedge. The largest concentrations of swamps and marshes in Poland are located in the catchment area of Narew and Biebrza and in the Lublin Polesie. Besides, boggy lands may be encountered, inter alia, in other river valleys and in the lakelands.

Currently, water in the permanently frozen state - meaning ice‑sheet, mountain glaciers, floating ice or permafrost - does not appear in Poland. Neither do salt plains which are typical for dry and hot climate.

Underground waters

Underground waters exist under the surface of rocky aquifers which were formed on an impermeable bed.

Underground waters are categorised in the following way, according to their depth:

Underground waters in Poland are present in loose Caenozoic rocks and solid rocks as crevice waters and, locally, karst waters. Some of the confined groundwater, accumulated mainly in sands and clays, formed a system of artesian aquifersartesian aquiferartesian aquifers and subartesian aquifers where water is subject to hydrostatic pressure. An example may be found in the Masovian Lowland.

Some waters circulating underground becomes highly mineralised, as a result of the dissolution of some elements. This is a way of formation of mineral waters such as:

• saline waters – containing dissolved rock salt;

• oxalates – containing acid calcium carbonates and sodium carbonates;

• sulphur waters - containing sodium sulphates and calcium sulphates.

The towns located in places where mineral water is present may obtain spa status. Their distinctive trait is a suffix “Zdrój” in their names. In Poland, spa towns are concentrated in three major regions:

• Sudetes - e.g. Kudowa‑Zdrój, Polanica‑Zdrój, Duszniki‑Zdrój, Szczawno‑Zdrój, Świeradów‑Zdrój;

• Carpathians and Subcarpathia - e.g. Krynica‑Zdrój, Piwniczna‑Zdrój, Rabka‑Zdrój, Iwonicz‑Zdrój, Busko‑Zdrój;

• Kuyavia and West Pomerania - e.g. Ciechocinek, Połczyn_Zdrój, Kamień Pomorski.

Such locations as Cieplice Śląskie‑Zdrój (a district of Jelenia Góra), Lądek‑Zdrój, and Zakopane are rich in thermal source waters, also called hot springs. These waters are warmer than average annual air temperature on location, for example, in Cieplice, the water temperature of 61.5°C has been recorded, setting the record for Polish underground waters.
Thermal waters are universally applied in medicine and recreation, and are also more and more frequently used for home heating.

Keywords

lake, mineral waters, saline waters, coastal lake, delta like, moraine‑dammend like, cirque like, thermal

source waters

Glossary