Water resources are among the most important natural resources on
Earth and proper monitoring is important all over the world. Many
parameters in the water balance can be estimated using remote sensing
and GIS data. This is especially an advantage in places where in situ
data are scarce. In these cases, the temporal archives of remote sensing
data can be used to extract information on agriculture, snow cover,
reservoirs and even estimates of precipitation and
Remote sensing data are
excellent for identifying temporal changes in the water balance.
Satellite image archives date several decades back in time and in this
way it is possible to analyse temporal trends. Seasonal differences can
also be analysed very efficiently based on satellite data.
Water resource parameters
Remote sensing data can
be used to extract information that can be used for hydrological
models. Land cover type and maps of agricultural crops and irrigated
areas indicate the surface roughness and water retention capabilities of
the area. This information can easily be extracted from remote sensing
data. Similarly, volume changes in lakes and reservoirs and changes in
the water storage of ice and snow can be estimated using satellite data.
Precipitation can be estimated directly using historical microwave
satellite data. Back to the beginning of the 1980s changes in
precipitation can also be assessed from analyses of vegetation greenness
as these two parameters are highly correlated. Evaporation from free
water surfaces and evapotranspiration from crops and natural vegetation
can also be estimated.
Water resource analyses are highly
relevant for natural resource management and conservation projects.
However, it is also very important for reservoir and hydropower
projects, irrigation etc.