1. Introduction
Fresh water supply plays an essential factor in a country, such as development of agriculture, industry and tourism (Khalil, 2001:57). Nevertheless, potable water only constitutes nearly 3% in the world water sources. It means that approximately a quarter of world’s population cannot access a sufficient high quality water including Egypt (Karagiannis and Soldatos, 2008: 448). Egypt suffers from water scarcity due to United Nations (2012) states that water scarcity means less than 1000 m3/year/person, while the figure in Egypt is about 963 m3/year/person.

Although, from the geographic perspective，there are adequate water resources in Egypt, such as Mediterranean Sea, Red Sea and Nile River (CIA, 2012), the Nile water level is decreasing due to the result of evaporation, rainwater supply, hot and dry climate, vast desert and global warming . According to Kashef (1983: 163), comparing with entering water in Nile (35.69 km3/year), the losses are 29.29 km3/year. Thus, Egypt needs to seek some methods to alleviate the problem of water scarcity. Overall, this report offers two alternative measures, desalination and dams respectively.

Generally, this report will analyse and compare the feasibility and differences between desalination and dams from three viewpoints: cost, environmental problems and social impact, by this means attempt to find the most effective and economical method to address the dilemma (water scarcity) in Egypt.

2. Background
Egypt, an agricultural country, is located in the northern Africa (CIA, 2012) with three main water resources, namely Nile water, groundwater and rainwater (Abdel-shafy and Aly, 2002: 4-5). However, the desert region occupies more than 96% in Egyptian total land (Fouly and Khaill,1979:205-206) and the average annual rainfall seldom surpass 200mm (Allam et al, 2002:20). It seems that the geographical feature puts further pressure on water resources.

Desalinating water is an indispensable part in the majority of Arab countries, specifically using plants of Multi-Stage Flash (45%) and Reverse Osmosis (RO) (42%), and it have experienced about 100 years since the first desalination plants introduced in Egypt (El-Sadek, 2010: 876-877). It makes desalination more profitable in terms of coastal country. Historically, there were three different types of Electrodialysis established in Egypt since 1975 (El-Sadek, 2010:878). Nowadays, Egypt not only engages in public sector actively but also encourages private sector to find the most suitable desalination technologies.

High Aswan Dam (HAD) is a giant project which costs the government 11 years to build (Strzepek et al, 2008: 119). It impacts the economy and energy of Egypt, for example the hydropower support and the floods or drought defence. Although it contributes to the development of agriculture, it may break the fragile eco-system and reduce the quantity of Nile water. According to (Abu-Zeid and El- Shibini, 2010:215), the TDS (total dissolved solids) rises at 185 mg/l after construction of the HAD and surrounding environment suffered from increasingly growth of aquatic weeds.
3. Requirements
The first consideration should be cost. According to World Bank (2012), the income level of Egypt is defined as lower middle income. The cost plays one of the most significant factors in water provision.

The second requirement is environment. As bordering Mediterranean Sea and Red Sea (CIA, 2012), the methods took in Egypt should be focused on the eco-system. Environmental problem could influence life of human beings and balance of nature. The authorities cannot implement it at the cost of environment.

The last factor is social impact. Because of complex process and giant project, constructing desalination and dam may cause some social impact. Thus, these methods should consider this indispensable influence.

4. Presentation of option
4.1 Desalination
Younos (2005:1) points out that desalination is a process to remove salts and other substances from seawater so that it can be used as potable water. Some desalination plants use electrical energy, while majority of them use fossil fuels which are associated with CO2 (greenhouse gas) emissions (Lamei: 2007: 1748).

4.2 Aswan Dam
New Hamoshire (2009) claims that “a dam is any artificial barrier which impounds or diverts water which has a height of 6 feet or more”. Precisely, Aswan Dam is a giant project which is constituted by key dam, spillway and power station.

5. Comparison of Options
5.1 cost
The most influential factor affecting the total cost in desalting water system is the consumption of energy (Lattemann et al, 2010:15). It is also claimed that the main energy used in RO is electricity. Nevertheless, RO is more economical than Electrodialysis Reverse in a high salinity water area, and the surface salinity in Red Sea is very high (42,000-47,000 ppm). Thus, Egypt became the second biggest user of desalted water RO in Red Sea region (Lattemann et al, 2010:19). Specifically, according to GWI (2006, cited in Lamei et al 2008: 1749), the total capacity of RO in Egypt is around 130,000 m3/d. Moreover, as one of the main technologies, RO is a much less-energy ($0.23 m3) and less-costly ($0.46 m3) plant (Lattemann et al, 2010:15).

Due to the development of desalination technology, the cost of desalination plants is much cheaper and become more competitive choice than traditional measure, such as water conveyance (as shown in Figure 1 and Figure 2) (Allam et al, 2002:24). Additionally, renewable energy (solar, wind and wave) which combines with RO may decrease the consumption of energy (Charcosset, 2009: 215). It means that in the future the cost of construction and production may fall more.

Figure 1: capital cost (Cc) versus long-distance piping from capacity and pipe length (Lamei et al, 2008: 10)

Figure 2: production cost (Cp) versus long-distance piping from capacity and pipe length (Lamei et al, 2008: 10)

Figure 1 and Figure 2 show clearly in comparison between capital /production costs and water conveyance. Specifically, the capital cost of RO desalination is much cost effective when pipelines are longer than 140km and the production cost of RO desalination is much economical when pipelines at least 300km with 2000m3/d capacity. In Egypt, the water supply of most northern cities such as Sinai and Sharm mainly come form the Nile which means high costs, while some tourist cities may relay on desalination (Sanchez, 2007: 69).

The HAD is located 7.3km upriver from the old one (Low Aswan Dam) was constructed from 1960 to 1971 in £ 500 million (Egypt Pounds) (Strzepek et al, 2008: 119). According to WCOD (2000:11), during the 1990s, the annual expenditure on large dams was between $32 and $46 billion and throughout the 20th century it peak to $2 trillion on some dams. Thus, due to the high cost, Egypt experienced great difficulty in that time. The government had to loan some funds form the USA. The further problem such as evaporation is also a severe challenge for Egyptian government. Even though it can afford firm store 55.5 billion m3, the evaporation is 10 billion m3 (Strzepek et al, 2008: 119). Overall, it seems that desalination plants ($ 0.46 m3) is much cheaper and effective than HAD if the government decides to build a new project.

5.2 environmental problems
Even though desalination performs better than HAD in cost respect, it is high likely that it triggers many environmental issues. Firstly, although in many African countries have abundant solar resource, most of RO tends to widely use non-clean energy (Lamei et al., 2008 :1749). With the high capacity of RO which use fossil fuel in Egypt or other Arab countries, they may damage the environment. To be precise, 1m3 transformer in RO plant will produce 3kg CO2. Secondly, over-intake of seawater and groundwater may affect water quality, for instance changing the salinity and temperature of seawater, increasing pollutants and sediments, damaging to aquifer and spreading seafloor (Lattemann et al., 2010:26-31). All of these oceanic changes will influence maritime environment and marine lives. Thirdly, as a tourism-dominated nation, if Egyptian establishes plants near the shoreline and seashores it may affect the marine environment and recreation or tourism atmosphere (Einav et al., 2002:143). It seems that the Egyptian government should balance the environment and profit.

Thanks to the HAD, the Egyptian overcame the great flood in 1964, 1975 and 1988 and drought in 1978 (Abu-Zeid, 1997: 210-211). It is reported that with this water support, the crop yield increased dramatically, specifically from 92,000 acres to 275,000 acres in 1952. It also promotes the development of tourism and industry. However, the silt accumulation drives up the river-bed which increases the potential floods. After the construction of HAD, it changed remarkable the balance of Nile River system. Therefore, desalination may lead to a less environmental degradation than HAD, if it could change to use eco-friendly energy.

5.3 Social impact
Even though both of two measures can cause unavoidable environmental degradation, it seems that desalination have lower negative social impact. According to Water Corporation (2009), the most frequently negative social impact is noise to locals, beach problems and temporary increased population. Specifically, the operation of these high capacity desalination machines may generate noises to the locals. Furthermore, as a tourist resort, building the desalination plants at the nearby beaches may impact the tourism and aesthetics (Monterey Bay, 2006). When establishing a plant, the local services and facilities cannot provide a temporary increased workforce. In addition, another possible impact of society is health aspect. To be precise, during the desalinating water process, it should require chemical in pre-treatment and need to be re-mineralized in post-treatment which may corrode pipes and water (Schiffler, 2004: 9). Thus, the desalinated water exists potential safety hazard.

Even the HAD has an indelible contribute to Egypt, there are some possible social and health impact. Many Egyptians who used to live in a strip of Nile had to move a new place far away from Aswan because of flood causing by increased river-bed (NMMU, 2006). It is reported that the death rate increased from 1.36% (1963) to 2.36 (1965) due to the HAD (NMMU, 2006). Due to the silt accumulation, the river flows slowly which leads the schistosome (blood-flukes disease) increased. Furthermore, Abu Simbel temple had been mover to a high ground gathering in an enormous human, financial and material resources cause of the rising water of Lake Nasser (UNESCO, 2009). Hence, it is more likely that desalination has lower social impact than HAD.

6. Conclusion
From the information provide above, the following conclusions can be: 1) Desalination is more feasible than HAD. 2) It seems that desalination has a slight advantage than HAD in cost respect. 3) Both desalination and HAD have essential environmental problem, but the latter one is more severe. 4) In terms of social impact, desalination has less influential than HAD.

7. Recommendation
Considering the three requirements, desalination method is more likely to be recommended as the main water supply to Egypt. Although it still have problem to environment and society, the scientist have been trying to use renewable energy instead the unclean energy. The relatively better energy is solar energy because El Nokrashy (2005, cited in Lamei, 2008: 1752) pointes that Egypt has abundant solar resource (3000kWh/m2/year). Thus, the cost effective plants should be PV-RO, which has installed in Gran Canaria (Herold et al, 1998 cited in Charcosset, 2009:219). When the government choose site to build a plant, it should consider various factors, such as good electrical network and transport system, low population density and natural disaster, nearby power station.

Word Count: 1800

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