Streams in peaty areas are brown, because peat is partially broken-down plant matter containing high levels of plant tannins, which leach into the water.
What causes river water to turn brown?
Erosion from river banks brings soil into the river, changing its color. After heavy storms, many rivers run brown from all the runoff flowing into the river. Clay can cause rivers to be murky muddy brown, or yellow.Why are Scottish rivers brown?
Iron and manganese Occasionally, in northern and western parts of Scotland, a reddish-brown colour in the water is apparent and is due to high concentrations of iron and manganese. The acidic upland surface waters tend to dissolve these metals from soils and rocks in the local area.What is the brown slime in the river?
Iron BacteriaThe iron-loving bacteria combine iron and oxygen, producing dense masses of orange- brown slime in and around stagnant or slow moving water. There may also be a rainbow-colored, oil-like sheen visible on the water. Quite often, an unpleasant odour is evident when iron bacteria masses are disturbed.