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The Water Cycle

Water follows an invariable cycle as the following figure well illustrates:

Impacts of water resistant soils on the natural hydrography of an area with weak to average density

Source: Québec, La gestion durable des eaux de pluie, 2010.
 

As we all know, water falls as rain. In the Brome Lake region, the average yearly water fall is 1267 mm.
The water is absorbed by the ground to ensure that the water table is recharged; part of the water is also absorbed by plants and trees to help them grow and it eventually rises as steam into the atmosphere (evapo-transpiration). In a natural setting,  with little artificialisation, the use of water for percolation and evaporation represents at least 40% of the fallen water. In the major cities, it is frequently less than 10% which percolates or evaporates, the remainder flows at great speed through the culverts and lakes.
At Brome Lake, we estimate that run-off water counts for about 60% of the water in the lake. Water evaporates because of the effects of the sun and returns to the atmosphere. 
We should also note that every drop of rain which falls on the territory will one day or another find itself in the lake, whether it falls 100 metres or 10 kilometres from the lake.   The notion of a drainage basin well explains this phenomenon