What can influence water quality in a lake or river?

Question

I can only think of- pollution from farming

-turbulence

-having a dam,

-how about the amount of sunlight???

Im so not sure about this. Help!

Any suggestion would be great with links to a site that explain what factors can change the water quality in a river/stream or lake.

Answer 1

salinity or soil erosion

Answer 2

nitrate and minerals  are some other things. i would imagine the surrounding rock type would be one also and wildlife

chemicals and snice u have mentioned waterflow i need not add it

http://en.wikipedia.org/wiki/Water_quali...

Answer 3

- quality of groundwater

- bacteria and chemicals from cities/towns

- flow speed

- type of aquatic vegetation

- surrounding soils

- nearness to ocean/sea