rainy day reading

[Norm M]

Paths of Precipitation to a Stream

A stream is considered to be the downhill movement of water, dissolved substances and

suspended particles. These components are mostly derived from the stream's watershed. The

watershed is the total land area draining into a given stream channel. The hydrological, chemical

and biological characteristics of a stream reflect the climate, geology and vegetational cover of

it's watershed.

Water from precipitation, i.e, rain and snow, can follow different paths while moving toward a

stream it may first go to the vegetation, then into the litter on top of the soil and then into the

soli. The water will only flow over the top of the ground to the stream after the soli reaches it's

saturation point. However, most of the water that does soak into the soil remains there and

never makes it to the stream.

Different soil types can store water in differing amounts. Depth, structure and composition of

the soil are the main factors in determining the storage capacity. The storage capacity is

continually being lessened by the processes of evaporation and transpiration. These processes

return the water to the atmoshere to continue the water cycle there. Only when the storage

capacity of the soil is exceeded , is water released to help form a stream.

Water moving through the soil to a stream can move through cracks in the soil, worm or

animal burrows and root channels. The water moving downward into the soil can be halted by

impermeable layers at which point it will move laterally over the impermeable layers toward the

stream.

The surface of the saturated zone of permeable soil is called the water table. Vadose water is

the water in the soil above the water table. Ground water is the water in the soil below the

water table. Ground water provides the relatively stable base flow component in a stream

through seepage into the stream channel. Overland flow [ above ground water flow ] and excess

water flowing through the soil [ vadose water ] to a stream channel after storms are the main

components of peak flows and floods. The overland flow is the runoff that enters the stream

directly while the vadoe water enters through seepage into the stream channel.

None of this information will probably be of direct help to catching fish. It never hurts to have

some background information on how streams are formed though. I learned this stuff while

researching current and thought it would be of interest to some of you, so I'm passing it on.

[JOHN SCHENCK]

Pretty cool stuff thanks Norm!