Human Impacts on the Sustainability of Groundwater

This paper constitutes a lab report that investigates the impact of human development on groundwater and whether continued human development will affect the sustainability of groundwater. Time progression of industrialization and human development are the two key factors that have been used to collect data and to come up with the following table:

Part 1:

Time period	Impact to Forest	Groundwater Levels	Saltwater Intrusion	Farming	Industrial Development	Population
1800s	Associated with large forests	Groundwater levels were high	No occurrence of saltwater intrusion	Farming was done on small farms	Cities were not developed	The population was low and had limited housing
1900s	Forest cover was reduced by 50%	Groundwater levels were reduced by 50%	Ocean water begins to move into groundwater	Farms became larger, but are not numerous	Cities and towns began to develop. Industries also started developing	The population grew rapidly and housing developed substantially
2000s	Forest cover was reduced by 90%	Decreased by 90%	Increased movement of ocean water into ground water	Farms remained the same but the size of the farms were reduced	Development of industries reduced by 10-15%	Housing development was reduced by 10-15%

About 70% of the earth’s surface comprises of water. The oceans hold about 96 per cent of the water on planet earth; about 68 per cent is contained in ice and glacier and 30 per cent of freshwater is located underground (Gleeson, et al., 2010). Water exists on the surface of the earth as lakes, oceans, springs or rivers. Water also exists in the atmosphere as vapour; it also exists underground in aquifers. Water is characterised by continuous motion as a result of the hydrological cycle also known as the water cycle. 

The hydrological cycle refers to the continuous movement of moisture on the surface of the earth, below the surface of the earth and above the surface of the earth (Pandey, Shrestha, Chapagain, & Kazama, 2011). This cycle varies depending on climatic factors. The movement of moisture on, above or below the surface of the earth takes place through the following physical processes: surface runoff, evapotranspiration, infiltration, percolation, precipitation, condensation and subsurface flow (Pandey, Shrestha, Chapagain, & Kazama, 2011). This cycle’s pace is set by the radiation of the sun. Once the sun heats the atmosphere, the temperature rises. This causes the various water bodies to heat up due to the solar radiation. The water converts into vapour and is released into the atmosphere, plants transpire and release the moisture as vapour into the atmosphere, ice and glaciers once heated directly sublime and turn to vapour which is also released into the atmosphere. The vapour in the atmosphere moves upwards but as the vapour continues to move upwards, the air pressure reduces causing the temperature to reduce hence leading to condensing back of the vapour to moisture which later falls back to the surface of the earth as rain, sleet or snow. These processes enable moisture to convert into dissimilar stages liquid, solid and vapour. 

The processes responsible for the existence of groundwater are infiltration, percolation, plate tectonics and subsurface flow (Mays, 2013). According to Hubbert (1940), infiltration refers to the movement of water from the surface of the earth into the ground. Once in the ground it is referred to as ground water or soil moisture. Subsurface flow refers to the movement of water underground. This process can cause groundwater to make its way to the earth’s surface or to continue to move downwards into aquifers or seep directly into oceans. Percolation refers to the movement of groundwater that has already been infiltrated downwards in a vertical motion as a result of gravity. Plate tectonics, once the tectonic plates move by subduction water enters the mantle.

Hypothesis 

The following hypotheses will be proven or disproved based on the findings from the lab data:

Human activity in the form of agricultural development through irrigation or use of agricultural chemicals, housing development, global warming, urban development and clearing of natural vegetation among others, has led to reduced levels of groundwater.

The levels of saltwater intrusion have increased as a result of the high usage of groundwater. 

Construction of levees has led to raising the level of the water table. 

Atmospheric deposition has led to increased acidity in groundwater.

Method 

The methods used to obtain this information are through examining the time progression of industrialization and human development. The method used to collect information was researching from books, online journals and state websites. Information on population was obtained from the World Bank United States Census Bureau.

Results 

The following results were obtained: in the 1800s the earth’s surface had a large forest cover. Therefore, the earth’s surface then was characterised by high levels of groundwater. There was also no saltwater intrusion since most farms were small and the industrial development at the time was low. In the 1900s the forest cover on the earth’s surface was reduced by 50%, the levels of groundwater was also reduced by 50%, the rate of saltwater intrusion began to increase whereby ocean water began moving into the groundwater. Farming began to take place on bigger farms. Industrial development began to take place at a very fast rate. In the 2000s the forest cover was decreased by 90%, the groundwater levels were reduced by 90%, the rate of saltwater intrusion increased rapidly, agricultural development began to drop and industrial development also began to drop.

Discussion/Analysis 

The results obtained are providing proof to the hypotheses that were made. Evidence suggests that the removal of natural vegetation such as forests and wetlands leads to lower levels of groundwater. This is because forests play a very crucial role in the hydrological cycle; forests are responsible for most of the moisture that converts to vapour through evapotranspiration. This vapour later on condenses and precipitates back on the surface of the earth whereby some of the moisture infiltrates the surface and into the ground where it becomes groundwater. Hence, if there are no forests then there is no vapour which causes no rain to fall and thus no infiltration takes place. 

As seen from the above data, urban and industrial development relies on groundwater. For urban centres to develop they require a lot of water, some of which is usually obtained from groundwater. Therefore, it follows that if groundwater reduces this will slow down development. Additionally, industrialization is a large benefactor of groundwater. Nonetheless, most of the contaminants from the industries in fact contaminate groundwater, making it salty and unsuitable for the optimum growth of plants and vegetation. This occurs when industries pour their wastes directly into rivers and lakes this waste contaminates the water which then seeps and percolates and joins the rest of the pure groundwater which then leads to contamination. According to the data obtained and Wright and Borse (2010), the levels of saltwater intrusion have increased over time this is a clear indication that the levels of groundwater in aquifers are reducing. This is brought about when aquifers opening into the ocean begin to be drained. The pressure exerted by the groundwater in the aquifers against the ocean water reduces. Once this happens, a subsequent entrance of the ocean water into the aquifer follows and contamination occurs. 

Agricultural development is also dependent on groundwater. More than 40% of the world’s agricultural produce is produced through irrigation. Irrigation obtains water from groundwater as it uses most of the groundwater. If the levels reduce, this will lead to less irrigation and eventually the lack of food sustainability (Candela, Elorza, Jiménez-Martínez, & Von Igel, 2012). As a result, all the hypotheses have been proven by the data in the table. 

This lab report clearly shows that humankind through their actions such as the clearing of vegetation, excessive agricultural activities, industrial growth and construction are negatively affecting the levels of groundwater. It is clearly evident that groundwater is essential for human’s sustainability. Measures should be put in place to try to restore groundwater.

References

Candela, L., Elorza, F. J., Jiménez-Martínez, J., & Von Igel, W. (2012). Global change and agricultural management options for groundwater sustainability. Computers and electronics in agriculture, 86 , 120-130.

Gleeson, T., VanderSteen, J., Sophocleous, M. A., Taniguchi, M., Alley, W. M., Allen, D. M., et al. (2010). Groundwater sustainability strategies. Nature Geoscience, 3(6) , 378-379.

Hubbert, M. K. (1940). The theory of ground-water motion. The Journal of Geology , 785-944.

Mays, L. W. (2013). Groundwater resources sustainability: past, present, and future. Water resources management, 27(13) , 4409-4424.

Pandey, V. P., Shrestha, S., Chapagain, S. K., & Kazama, F. (2011). A framework for measuring groundwater sustainability. Environmental Science & Policy, 14(4) , 396-407.

Wright, R. T., & Boorse, D. F. (2005). Environmental science: toward a sustainable future. White Plains, NY: Pearson/Prentice Hall.