Hey, Tortuga Tex, What are Runs, Riffles and Pools?What's a Run? A run is part of the river with water that is moving kinda fast but pretty calm. Runs usually have sand, gravel or stone substrates (bottoms) but seldom have silt or mud. They don't have mud substrates because the water is moving too fast for silt or mud to sink down to the bottom and it gets washed down stream. What's a Riffle? A riffle is a shallow part of the river with fast water and lots of little waves and splashes at the surface. Riffles can have sand, gravel or stone bottoms but not silt or mud for the same reason runs don't have silt or mud substrates. The water in riffles moves too fast and washes silt and mud downstream. What's a pool? A pool is part of the river that is deep and slow with calm water. Pools usually have silt and sand substrates (bottoms) but can have gravel and stone substrates too. Because water moves slowly over them, silt and other particles carried by flowing water tend to settle or sink to the bottom of pools. [top] |