term watershed is frequently used to refer to the entire area
that water flows across, under and through on its way to a common
body of water. In hydrologic terms, a watershed is a land area that
delivers runoff water, sediment and dissolved substances to a major
river and its tributaries. A watershed includes atmospheric, surface
and subsurface water.
of the main functions of a watershed is to temporarily store and
transport water from the land surface to the water body and eventually
on to the ocean. In addition to moving water, watersheds and their
water bodies also transport sediment and other materials (including
pollutants), energy, and many types of organisms.
can be large or small. Every stream, tributary, or river has an
associated watershed, and small watersheds aggregate together to
become larger watersheds. It is a relatively easy task to delineate
watershed boundaries using a topographical map that shows stream
channels. The watershed boundaries will follow the major ridge-line
around the channels and meet at the bottom where the water flows
out of the watershed, commonly referred to as the mouth of the stream
refers to the physical connection between tributaries and the river,
between surface water and groundwater, and between wetlands and
these water sources. Because the water moves downstream in a watershed,
any activity that affects the water quality, quantity, or rate of
movement at one location can change the characteristics of the watershed
at locations downstream. For this reason, everyone living or working
within a watershed needs to cooperate to ensure a healthy watershed.
Each one of us can make a difference within our own watershed.
most important thing to understand about the concept of a watershed
is that activities on land can very easily affect water quality
downstream. That water quality can affect people, along with everything
that relies upon that water--from micro-organisms to plants, from
aquatic insects to fish.