How to determine the watershed area

Civil engineering job is not only focused on buildings and highways.
But it also includes the construction of water buildings, such as
irrigation networks, dams, Harbor, and so forth. The work is called
work hydro-engineering , was civil engineering work associated with
water.

In planning and building a network of irrigation, hydrological data
need to be reviewed. The earliest hydrological data required is to
determine the watershed area, to determine the amount of water
(discharge water) available. The amount of watershed area determines
the amount of discharge that generated by a river.

Step by step in determines the watershed will be presented by the following:
Provide a topographic map.
Topographic maps that is used to determine the watershed area is a
topographic map with a scale of 1: 50000. This map can be obtained
from the Agency for Survey and Mapping Coordination Agency, or can
also be obtained from the local irrigation of an area.
Determine the desired catchment area.
Desired broad watershed catchment area means necessary to meet water
discharge in accordance with the needs of irrigation.
Consider the Main River.
The main river is a large river which is connected with several
tributaries. Tributaries will help drain the water into the main
river.
Drawing watershed
Describing watershed begins with knowing that the form of a watershed
in the form of a large pot. This means that watershed is an area to
accommodate the water to be channeled into the river. Describing the
watershed preceded by finding the end of the little river, then follow
the contour line drawn on topographic maps. Within a watershed may not
have mountains. Then a watershed bounded by mountain ridges.
Determine the location of the weir.
In accordance with the desired catchment area, the location of the
weir can be determined. Weir located on the main river.