What weather condition could increase the concentration of salts in lakes?

Question

This is for a school project

thaks if you could help :)

Answer 1

mmm...i would think that if it is hot...then more water would be evaporated...leaving more salt in the lakes.

Answer 2

Both of the above answers come close to the right answer.

Salt lakes are formed where there is a negative annual water balance, ie, there is more evaporation than rainfall.  Think of the salt lakes in the East African Rift (eg, Lake Manyara) and in the Great Basin (eg, Great Salt Lake).  Those are lakes in hot dry climates where water flows in from rivers and streams carrying trace amounts of dissolved salt.  There is no drainage from the lakes, so evaporation of the water causes the salt to concentrate.  And the amount of salt that can be dissolved in water is dependent on temperature, as solubility is proportional to temperature.

Increased rainfall will have the effect of decreasing salt concentration by dilution because the inflowing water will have less salt than the lake itself.  The lake level will rise, eventually causing the lake to overflow, resulting in replacement of the lake water with fresh water and causing the salt concentrations to decrease even further.  Colder temperatures will do the same thing by reducing evaporation.  That is why there are no salt lakes in areas with cold temperatures and/or high rainfall.

So the answer to your question would be hotter and/or drier weather.

By the way, most of the lakes in the two inland drainage basins that I mentioned are getting saltier due to prolonged drought conditions in those areas.

Answer 3

Well this is an interesting question.

In a round about way, a winter with more than average precipitation could be a culprit.  Frequent snowfalls could result in increased number of days where the county road commission applies salt to the county roads and municipalities salt their surface streets, the increased salt usage would  ultimately cause more than normal quantities to wash into the streams and eventually lakes, causing salt concentrations to raise. Also looking at this from a different perspective, a protracted drought would drive off water leaving behind dissolved salts in lakes, just think of the Great Salt Lake, of course this is really the remnant of an inland sea, the idea is the same.