way, flooding can be prevented.
Precipitation in the form of snow would spend longer time on the land as it flows into channels
only when they melt. Knowledge of the volume of water contained in the snow and the time
taken for the melting would help assess if the area has the capacity to hold the water formed
from snow melt. Flood can be prevented by attempting to melt some of the snow 1 during the
winter time and allowing greater discharge during the season so that when summer comes, the
discharge do not increase too much suddenly.
An understanding of the stores available to hold back water before they drain into a channel
can be helpful as these components would eventually determine the lag time of the drainage
basin. Deforestation removes interception storage and urbanization (which increases the area
of concrete pavements, roads and walkways, would remove the soil moisture storage and the
catchment area for groundwater store. Both of these activities would result in shortened lag
time within the drainage basin. Thus, understanding these features in the hydrologic cycle
would allow us to reverse these developments and take actions to prevent flooding that may
result because of increased surface run-off due to lack of exposed land area to capture water
in the groundwater stores.
Afforestation projects may be undertaken to raise interception storage in barren areas so that
precipitation is intercepted and do not reach the channels that quickly. Large urban areas can
be planned with more parkland so that there are spaces between covered ground that can
accommodate the precipitation and would allow percolation so that groundwater stores are
utilized efficiently. This would also provide the opportunities for groundwater recharge. Urban
drainage systems can also be designed to allow water to seep into the ground rather than to
deliver water efficiently to a central channel. All these measures that are derived from an
understanding of the components of the hydrological cycle would help prevent flooding through
the increase in lag time of the drainage systems on land.
The understanding of the flows within the hydrologic system would also help devise measures
for flood prevention. By studying the discharge patterns of the river in concern, and the flood
events, the capacity and pattern of flooding can be worked out. This way, developments of
settlements can be guided in a way 2 that avoids the areas more prone to flooding. Assessing
flood peaks can also help making decisions on how much flood space to allow when building
artificial levees. Artificial flows can also be created through river engineering and knowledge
of the flows and behavior of the river can also help determine the potential negative impacts
of the river engineering or any chance that the engineering would backfire and worsen flooding
downstream.
While this essay has broken down the hydrological cycle into parts where knowledge of certain
components of the cycle can be used to devise flood prevention measures, in reality, the entire
hydrological cycle must be taken into consideration as the relations between the precipitation,
flows and stores are complex and these variables and interdependent. The precipitation would
influence the flows and this in turn can change the natural capacity of the rivers. At the same
time, the knowledge of infiltration capacity of the area inferred from local geology needs to be
combined with knowledge of precipitation patterns to assess the flows in the area and thus
work out the necessary measures to prevent flooding.
1 Effect of this method unknown because I made it up
1 Effect of this method unknown because I made it up
2 Not directly addressing the question of flood prevention (this is a mitigation measure)