Water Provision in Arid and Semi Arid Areas - Essay Example

Water Provision in Arid and Semi Arid Areas Introduction In areas where there is water shortage it is important to introduce methods that can make adequate water available for community and also for ecological purposes. In some of these regions the water that is available is salty and so desalination is important to ensure that the water is fit for human consumption. Availability of water is important in boosting the economic growth of the community. In this paper I will discuss three methods of water provision in arid and semi arid areas. They are;- 1. Desalination 2. Ground water harvesting 3. Rain water harvesting The essay will discuss the available options, the needs for using each of the methods, the environmental and social impacts of each and the cost to use the method. The factors that determine the use of each of the methods include the topology and geographical orientation o0f the land, the amount of rain that is received in the area, the cost of installing each of the methods and the social and environmental impacts to the society. For example in ground water harvesting the environmental hazards must be considered through g round water modeling to ensure that the water that will be harvested will be fit for human and livestock consumption. In ground water harvesting the methods used include the drilling of well and boreholes (Taylor and Francis, 2003). These require capital investment and so without enough money it would not be prudent to use them. The level o the ground water also serves as a great determinant when it comes to harvesting of ground water. In some areas the ground water is close to the surface while in other areas it is far below. The position of ground water will determine the costs of drilling and the length of the pipes that will be used. If it is far below the cost will be high and if it is near the surface the cost will be less. In rain water harvesting, the main factor that is considered is the amount of rain that is received in the given region. In arid and semi arid areas it is logic that the amount of rain is minimal and so there is the need to ensure that the available rain is utilized in the best way possible. This is done by increasing the surface area of the harvesters. The storage is done in tanks and the water can be used for human consumption, irrigation and also for giving livestock. Rain Water Harvesting Rain water harvesting refers to the collection of water before it reaches the ground surface. The water is used for subsistence purposes and also for other purposes like irrigation. Rain water harvesting has been used for a long time in many regions and it has been applied lately in arid and semi arid areas to take advantage of the little amount of rain that is received in those regions. The rain water received is usually preferred over the collected ground water because it is considered soft and lacks the minerals unlike ground water which is hard and contains minerals which are associated with a number of problems like failing to foam while cleaning and changing of teeth colour when drank without boiling (Baron and Salas, 2009) In collection of rain water, the method that has mainly been used by many people is the collection of rooftop water. The buildings that are built in the arid and semi arid areas are fit with gutters which are directed to a tank for storage of the water. The type of tanks includes plastic tanks and metal tanks (Baron and Salas, 2009). However in few regions concrete tanks have been used though they are highly discouraged due to environmental aspects. The concrete tanks are discouraged because the cement that is used often dissolves into the water and after consumption causes long term effects to the user. Aluminum and plastic tanks have therefore been proposed as the ideal materials that should be used to make the tanks. The cost of the tanks is fair though it ranges from one region to the other. This method has been proposed as the best over the other in places where there is abundant rainfall. However in arid and semi arid areas other methods of water harvesting take preference as the amount of water available is less and so the little that is available is not enough. It is common to use more than one method of water harvesting when collecting water in the arid and semi arid areas to maximize the amount of water collected. In the recent past the collection of rain water has been faced by criticism due to acid rain which is caused by the acidic gases such as nitrogen IV oxide, Sulphur Dioxide and others reacting with the water to form acidic rain. This has been an environmental and social concern which has been in debate in the past to address the issues in relation to the adversities of industrialization. Desalination Desalination is the process in which salts and other minerals are removed from water. The fresh water that is produced after desalination is ft for human consumption and for other purposes which include irrigation. In some of the arid and semi arid areas there are water bodies which surround them which have salt water. The water is mainly got from the water bodies by use of pipes and then desalination is done. The pure water that is got can be stored and used in the various purposes in the society. The cost of water desalination is high and this makes it a non-popular method of water harvesting when compared to other methods like ground water harvesting and rain water harvesting (Committee on Advancing Desalination Technology, Water Science and Technology Board, Division on Earth and Life Studies & National Research Council, 2008). The main method that is used in distillation is vacuum distillation. Vacuum distillation essentially involves the boiling of the water and then using distilling tubes it is collected in another container or cylinder and it can be fit for consumption. Using the skills in physics, different compounds have different boiling points, water vaporizes at an average temperature of 100 0C. Because the minerals that are in the salty water have a higher boiling point the water boils first and forms steam. The steam rises and gets into another tube that is connected to the distillation chamber and directed to another container. The water cools due to the fall in temperature and can be used for the purposes needed. In large scale desalinization columns a large amount of water is put in the distillation chamber and the collection chamber is also as large. This is an efficient way of getting a large volume of pure water. However the cost of producing large amount of pure water is high and so the method is used in small frequencies when compared to other methods of water harvesting in arid areas (Maliva and Missimer, 2012). The environmental concern that is associated with this method is the disposal of the precipitate or the solid that is left after the water vaporizes and is collected in another container. The minerals usually change the pH of the soil when disposed without care and so they affect the productivity of the land (UN – HABITAT). This therefore calls for better methods of disposal. Another environmental concern in the use of desalinization as a method of water harvesting is the death of aquatic life which leads to it being disapproved in many regions. For example there was a ruling in the US in 2011 governing the intake of water from the ocean. This was aimed at reducing aquatic mortality which was associated with the method. Beach wells were used in place of the intake and the water was desalinized and used for various purposes. This method is recommended in places where there is enough capital to lay down the required structures that can then be used in the harvesting. Ground Water Harvesting Ground water harvesting is the collection of water below the aquifer. This is an ideal method of water harvesting in arid and semi arid areas. The method involves drilling of holes that go straight to the position of the aquifer where ground water is found. The water can be harvested from wells and boreholes. The cost of drilling to get the water is determined by the depth to get the water. This differs in different regions. In some regions where the water is far deep in the ground surface electricity or alternative power is important to pump the water to the surface. This method has been used in many arid areas as the rainfall is little ruling out rain water harvesting and there is no water body close so ruling out the use of pipes to get the water from them (Kumar, 2009). The water that is collected is hard and so methods of breaking water hardness are used. Hard water has high amounts of minerals. They include compounds like calcium carbonate and magnesium carbonate. Distillation is mainly used in breaking water hardness. However, other methods can be used like displacement method where the calcium or magnesium is replaced and therefore breaking water hardness. The main environmental concern is the fitness of the water for drinking as some of it is usually contaminated. Recommendations The use of a particular method in water harvesting is determined be a number of factors. The factors include the cost, the level of the aquifer in case of ground water and the availability of rainfall. Environmental concerns should also be addressed before concluding on the method to use. Multiple methods can also be used to maximize the amount of water collected. Conclusion In arid and semi arid areas the method of water collection used can mean the difference between survival and failure. The methods discussed above can be used to get the maximum from the little water available in the regions. Bibliography Baron, J., Salas, J. C., Stockholm Environment Institute & United Nations Environment Programme., 2009. Rainwater Harvesting: A lifeline for Human Well – being. UNEP/Eartprint. Committee on Advancing Desalination Technology, Water Science and Technology Board, Division on Earth and Life Studies & National Research Council., 2008. Desalination: A National Perspective. National Academic Press. Kumar, M. D., 2009. Water Management in India: What Works, what doesn’t. Gyan Publishing House. Maliva, R. & Missimer, T., 2012. Arid Lands Water Evaluation and Management. Springer. N.a., n.d. BlueDrop Series Rain water harvesting and Utilisation. UN – HABITAT. Taylor & Francis Group., 2003. The Middle East and North Africa 2004. Psychology Press. Read More