Geoscience Reference
In-Depth Information
7.1.2.
Water flows at the outlet of a drainage basin
We have seen that the work of a hydrologist involves examining flows for a
particular area for which improvements need to be made. These improvements are
not made to any area, but rather to sites in which water flows are concentrated. In
other words, the improvements are made to sites that are part of the hydrographic
network. Such sites may be permanent or temporary, and are more than likely to
include points located in the outlet of a drainage basin. A drainage basin is defined
as being the area in which water discharge is transferred to the basin's outlet.
Figure 7.1.
The drainage basin and its components
The drainage basins included in this study range in size from a few hectares
(urban hydrology) up to several million square kilometers. The data available that
provide information on flows are sometimes not enough for a statistical study to be
carried out; therefore, the hydrologist uses climatological data because this type of
data provides a larger temporal distance. Therefore, the drainage basin acts as a
filter between climatological data and the transformation of this data which can be
used to measure water flows.
The different elements of the drainage basin, as well as the geographical
information used to generate these different elements, are maintained by the use of
Digital Elevation Models (DEM) for topographic elements, and by the use of
Geographical Information Systems (GISs) for other elements, such as land-use type,
vegetation type, geology, and pedology.
