River temperature.

[L.Z]

Who knows the river temperature the revision.

The horizontal plane measuring point downward each 1m, how many can the temperature drop ?

Who knows that revision the numeral ?

Because I saw some rivers the temperature, in certain months is the high temperature.

I suspected the temperature can change along with the depth.

In fact is not such high temperature.

http://www.unb.br/ig/hibam/campanhas/Xingu97.htm Xingu'97

[Silurus]

Because a river is a moving body of water, a distinct temperature gradient is not established (unlike in a lake). Therefore, the temperature is more or less the same throughout the entire depth of the river.

[Shane]

There can be depth gradients in certain environments and at certain times of the year. The other week I went swimming in a large black water lake. Actually it is not a lake right now as it is the wet season and everything is basically connected. Anyway, the water felt very strange as the top nine inches was hot (around 85 F) while my feet six feet down were chilly at about 75 F. These temperature gradients, as Heok Hee pointed out, are most noticable in tropical lakes. Fishing is good in the early morning and evening when the fishes, especially Cichla spp., come to the surface to feed on the tetras. By 10:00 am the fishing is horrible as all the fish have dived down deep to stay cool. I have measured surface temperatures at over 93 F in Lake Camatagua, Venezuela. Even tropical fishes are much more accustomed to temperature changes than most aquarists believe.
-Shane

[L.Z]

Thanks Silurus and Shane opinion very much.

Has the help to me.