Ground water Vs. Surface water: Few points to think about water use
a] Some reasons why ground water is often more desirable than surface water:
- Avaibility: Ground water storage is often orders of magnitude greater than the surface water. This is particularly true for alluvial aquifers (shallow aquifers comprised of unconsolidated sediments) and sedimentary basins. In some arid locations, streams are ephemeral (do not flow all year) making ground water source more important for water use.
- Uniform chemical composition: The chemical composition of ground water is often less variable than the surface water.
- Temperature: The temperature of ground water is nearly constant making it desirable for certain industrial applications – notably cooling methods.
- Turbidity: Ground water is typically less turbid than the surface water.
- Diseases: Ground water is often more free of water borne pathogenic organisms (malaria, salmonella, “river-blindness disease”, etc) and hence needs less water purification than surface water. These water borne deceases are by no means “in-control” and still represent a huge threat to large populations throughout the world.
b] Some reasons why Surface water is often more desirable thanGround water:
- Cost: This is the most important factor. Surface water typically costs much less per gallon to use than ground water as expensive drilling is not required for surface water.
- Availability: Some regions underlain by impermeable rocks will not yield significant volume of ground water. Example: unfractured basalt, granite and some metamorphic rocks.
- Quality: Ground water typically has more salts than surface water and in some regions the salinity of ground water makes the water non potable. The salinity of ground water increases with depth due to increased solubility of most minerals at higher temperature.
- Visibility: Surface water is visible while ground water is not.