Hydrological Cycle: What Is Water Cycle As It Relates To Engineering?

The hydrological cycle is a conceptual model that describes the storage and movement of water between the biosphere, atmosphere, lithosphere, and hydrosphere. It is also known as the water cycle. It is a continuous process whereby water evaporates from water surfaces like seas, oceans, etc, and moves inland as moist air masses, and produces precipitation if the correct vertical lighting conditions exist.

Water moves from one reservoir to another by way of processes like evaporation, condensation, precipitation, runoff, sublimation, infiltration, transpiration, melting, and groundwater flow. The ocean supplies most of the evaporated water found in the atmosphere. Of this evaporated water, only 91% of it is returned to the ocean basins by way of precipitation. The remaining 9% is transported to areas over land masses where climatological factors induce the formation of precipitation. The resulting imbalance between rates of evaporation and precipitation on land and ocean is corrected by runoff and groundwater flow to the oceans.

The hydrologic cycle

The hydrologic cycle is a model of movement of water through the earth system. It is also a pathway through which energy is transferred between the surface of the earth and atmosphere. The unequal distribution of water leaves its imprints on the surface of the earth through the mosaic of biomes and landforms. Human survival requires adequate and safe water resources. The future of those resources hinge on our understanding of delicate balance of water in our earth system.

The water balance is an accounting of the inputs and outputs of water. The water balance of a place can be determined by calculating the input and output of water. The major input of water is from precipitation and output is evapotranspiration.

Not only is the hydrologic cycle a cycle of water, it is a cycle of energy as well. There are six major components of this cycle viz:

a) evapotranspiration

b) condensation

c) precipitation

d) infiltration

e) percolation

f) runoff

This cycle operates continuously and receives energy from the sun. The hydrologic cycle consists of inflows, outflows, and storage. While inflows add water to the different parts of the hydrologic system, outflows remove water from the system. Storage is the retention of water by parts of the system. Because water movement is cyclical, an inflow from one part of the system is an outflow for another.

Looking at an aquifer as an example, percolation of water into the ground is an inflow to the aquifer. Discharge of water from the aquifer to a stream is an outflow to the aquifer (also an inflow for the stream). Over time, if inflows to the aquifer are greater than its outflows, the amount of water stored in the aquifer will increase. Conversely, if the inflows to the aquifer are less than the outflows, the amount of water stored decreases.

Inflow and outflows can occur naturally or result from human activity.

Also Read:

CONDENSATION: What Is Condensation As It Relates To The Water Cycle?

Evaporation In Relation To The Water (Hydrologic) Cycle

Precipitation: Definition, Importance, Uses, Process