It is necessary to appreciate that the rainfall, though an aerial event, is measured
as a point sample over large area. The conversion of the point values to the aerial
estimates is a complex process. Many a times, it is observed that the point estimates
are directly used for making assessments of precipitation available for an area. Such
estimates have a strong probability of falling off the rational range over which
reliable planning can be performed.
While cumulative precipitation over seasonal time periods is good for working
out the yields, but the same is not adequate for flood risk and disaster management
purposes. Much better sampling frequencies are required for assessing the flood risk
in monsoon period. All these lead to requirements of sampling, transmission and
processing turnarounds.
2.2 Resource Yields
Once the precipitation hits the ground, the resource yield in its utilizable form takes
shape in form of surface water. Some of the surface water is absorbed by the ground
and becomes groundwater in varying quantities depending upon the infiltration
capacity of the ground and the rate at which the rainfall occurs. Since the opportunities of management and utilization of resource are different, they are treated as
two different resources as far as technological and management regimes are concerned though they are dependent upon each other. In an overall water management
scenario, they are like two verticals of a business where both may support each
other, and the internal management and implementation mechanisms operate
independently and come together at the time of finding final outcomes of the effort.
Therefore, the policy planners have the tendency to lump them in one basket, and
the operational strategies require them to operate in their own domains.
2.2.1 Surface Water
Surface water basically occurs in the form of flows in the natural rivers of different
magnitude and order and eventually connects to the sea where the water which has
not evaporated through evapo-transpiration process or consumptive evaporative
processes of industries and other societal activities or has been regenerated out of
surpluses of groundwater goes at the end of land phase of hydrological cycle. Flows
are also generated out of snow melt which is another form of atmospheric precipitation. Being a largely tropical country, the contribution of snow melt in
non-Himalayan basins is non-existent and even in Himalayan basins, varies greatly
depending upon the topography and elevation ranges being drained. It is observed
that the contribution of snow melt yield as a proportion to rainfall-based yield goes
on decreasing along the river basin as we progress towards the alluvial reaches of
the river.
Data Usage for Development, Management of Water Resources
135
as a point sample over large area. The conversion of the point values to the aerial
estimates is a complex process. Many a times, it is observed that the point estimates
are directly used for making assessments of precipitation available for an area. Such
estimates have a strong probability of falling off the rational range over which
reliable planning can be performed.
While cumulative precipitation over seasonal time periods is good for working
out the yields, but the same is not adequate for flood risk and disaster management
purposes. Much better sampling frequencies are required for assessing the flood risk
in monsoon period. All these lead to requirements of sampling, transmission and
processing turnarounds.
2.2 Resource Yields
Once the precipitation hits the ground, the resource yield in its utilizable form takes
shape in form of surface water. Some of the surface water is absorbed by the ground
and becomes groundwater in varying quantities depending upon the infiltration
capacity of the ground and the rate at which the rainfall occurs. Since the opportunities of management and utilization of resource are different, they are treated as
two different resources as far as technological and management regimes are concerned though they are dependent upon each other. In an overall water management
scenario, they are like two verticals of a business where both may support each
other, and the internal management and implementation mechanisms operate
independently and come together at the time of finding final outcomes of the effort.
Therefore, the policy planners have the tendency to lump them in one basket, and
the operational strategies require them to operate in their own domains.
2.2.1 Surface Water
Surface water basically occurs in the form of flows in the natural rivers of different
magnitude and order and eventually connects to the sea where the water which has
not evaporated through evapo-transpiration process or consumptive evaporative
processes of industries and other societal activities or has been regenerated out of
surpluses of groundwater goes at the end of land phase of hydrological cycle. Flows
are also generated out of snow melt which is another form of atmospheric precipitation. Being a largely tropical country, the contribution of snow melt in
non-Himalayan basins is non-existent and even in Himalayan basins, varies greatly
depending upon the topography and elevation ranges being drained. It is observed
that the contribution of snow melt yield as a proportion to rainfall-based yield goes
on decreasing along the river basin as we progress towards the alluvial reaches of
the river.
Data Usage for Development, Management of Water Resources
135