Question

1.) What role, if any, do aquifers depletion overdrawing of surface waters, and salinization of irrigated soil play in the water problems associated with the High pLAINS AQUIFER AND THE COLORADO RIVER BASIN? How are these issues affected by drought and by development?

2.)Explain whether each of the following represents the point or nonpoint source pollution: fertilizer runoff, thermal pollution from a PowerPoint plant, urban runoff, sewage from a ship and erosion sediment from deforestations. Which is more difficult to control nonpoint source or point source pollution? Why?

Answer 1

High plains- High Plains of America are associated with intensive grain cultivation. Long term unsustainable groundwater use is depleting the extensive Ogallala Aquifer. Entire High plain region relies on the aquifer for the water supply. Irrigation forms the prime component of intensive water use. Apart from agriculture, industries, households owe their sustenance to it.

Colorado basin- The Colorado river basin owes its sustenance to the humongous Lake Mead formed due to damming of Colorado river. The basin is the source of sustenance for around seven states and million households. Coupled with over-extraction of water, unsustainable use of the existing resources and extensive irrigation practises, the basin is undergoing a tough time. The region is facing a continuous drought for the last 14 years in succession and hence the amount of groundwater has continuously depreciated with time.

The effect of the water depletion can be summed up in manifestation of following problems in these regions-

• Sustenance of the High Plains and Colorado basin region- Entire region is moderately populated and consist of lands of prime importance for Agri. purpose. Absence of water for irrigation can lay waste entire cities whose economies are dependent on the water from the aquifers below it. Moreover, the populated cities can be facing a severe crisis if the groundwater runs out in the future.
• Food security of the world- High plains have been nicknamed as the breadbasket of America and granaries of the world. Shortage of water for irrigation purpose can lead to a catastrophic decrease in Agri. production thus endangering food security.
• Land subsidence- Overdrawing of surface water and underground waters disturb the dynamic equilibrium of the land. This often leads to land subsidence when excessive water is withdrawn from underneath and land caves in.
• Extinction of fish in the region- Rivers and streams depending on Aquifers for water source are drying up due to over-pumping of the groundwater. There was a general trend of extinction of large river fish and were replaced by small stream fish which leads to bio homogenization.
• Water salinization and deterioration of water quality- Excessive irrigation of the agricultural lands often leads to accumulation of salt on the surface of fields (capillary effect). Under the impact of excessive irrigation, the soluble salt is carried to nearby water bodies which increases the salinity of the surface water. This makes it unfit for drinking and other purposes.

These issues are aggravated by the drought ad development factors in the following manner.

Drought- High plains lies in a semi-arid climate. Being in a semi-arid climate, the region receives less precipitation and hence the percolation and recharge of the ground aquifers are also less. On account of unscrupulous extraction of the groundwater and the surface water, the crisis is set to happen. Similar is the case with the Colorado basin which is facing consecutive drought for the 14 years in succession. Lack of rains meant the lowering of groundwater table and lowering of Lake Mead. At present, the lake holds water at its lowest level ever since it was constructed.   

Development- The major issue of the water-related problem is unsustainable development. Exaggerated water extraction, over-irrigation through modern tube-wells, water-intensive industries, water pollution all work combinedly to create an anthropogenic shortage of water. The extraction of water far exceeds the percolation and seepage of water which is exceedingly low since both the regions come under semi-arid condition. Unless unscrupulous development is replaced with sustainable development, the doomsday is all set to come.