There are many reasons why a person drown and die from lakes and rivers. Most of the time is due to the lack of swimming skills. But what I talked about above is about grown men and women that are very good at swimming. When there are several good swimmers die from a lake or river, we have to look deep inside the lake or river and see what we find. In the cast I mentioned above is a case where they found electric eels inside the lake. Other cases may be due to different reasons.
There was a lake in southern california where several teenagers have drown and died. The reason for the drowning are based on couple of things. First of all, the lake is way too cold in the middle. Even if the temperature is 100 degrees in the city, the middle of the lake's temperature is about 20-30 degrees. Some of them die of heart frozen or something. Secondly, in the middle of the lake has thingly weeds. Most dead teenagers probable got panics when their feet got tangled by the weeds and lost air breathe and drown. Lastly, the lake is a still lake and it does not have little waves to push you abroad. If you're not a good swimmer it's kinda hard to swim to shore because water molecules tend to hold onto you unless you're a good swimmer and break that kinda water draggings.
The bottom line is, don't blame every death at lakes or rivers because of different forms of Dragons.. NO such thing as ZAJ.