By Michigan Universality
Human Impacts on the Nile River
The past one hundred years have marked a period of incredible human advancement. However, these advancements have wrought enormous negative impacts on the environment. One such region that has been impacted is the Nile river. The Nile is a crucial resource for all of the surrounding communities, and the pollution of the area does not only affect the natural landscape, but the African people also. Being used by humans for so long has changed this noble river in many ways, and it is these changes we will be looking at for our presentation. We shall look into the history of human life along this river and see what the human presence has wrought.
Human developments along the river have, as noted before, been going on for millennia. All cultures that have moved through the area have left their mark upon the river. Whether they wish to use it for transportation, take the fish that dwell in its depths, or even try to harness its mighty power, humans have indelibly made their impact on the river for better or for worse.
The fishing industry has made a heavy impact on the river, and the introduction of the Nile perch to the river and Lake Victoria is one of the most harmful events that have occurred in the waterways to date. The carnivorous fish was introduced to the river ecosystem sometime in the mid-1900s, though the precise date is not known. The species originates from Lake Turkana, and was introduced to the area primarily to support the fishing industry. Lake Victoria is home to an incredibly diverse fish population, but the fish that lived in the lake were mostly small-bodied and did not provide the burgeoning fish industries with all that they needed, so the heftier Nile perch seemed like a godsend. The perch adapted quickly to the environment, and its population grew exponentially during the 1970s and 80s. The fish, being carnivorous, swiftly consumed vast quantities of the lake’s native species, and many varieties of fish went extinct as a result while others experienced population fallouts. The Nile perch has since become a dominant species in the river, and the once diverse ecosystem has been simplified.
Another problem that the Nile ecosystem faces is that of pollution, and the majority of this comes from human activity. There are many sources of this pollution. In rural areas, sewage is dumped into the river as a result of poor sanitation conditions. This is a problem because citizens of Egypt, for example, “Consumed more animal protein during the second half of the 20th century than they did previously. As food is metabolized, phosphorus and nitrogen are released as waste products in feces and urine” (Nixon, 1). These increasing amounts of phosphorous and nitrogen, when dumped into the water can create algal blooms which can lead to the suffocation of fish. Many industrial establishments do not follow the law, and drain untreated wastewater into the river or even inject it into the groundwater. Usage of pesticides and fertilizers also pollute the river, as agricultural practices near the river use a lot of chemicals. Most of the river’s water is considered fairly high quality, with only a few “black zones,” and efforts to reduce the number of pollutants entering the river are underway.
The Aswan High Dam, constructed in 1899, prevented the Nile River from flooding every summer. This flooding provided necessary nutrients and minerals, enriching the soils, but as increasing numbers of people migrated along the river, control of the floods became necessary. Although the dam was principally encouraged, the dam has resulted in many problems such as, “sediment that once accumulated to form a shield against saltwater intrusion is scarce,…commercial and residential sprawl has sealed priceless soil underneath miles of concrete, the discharge of chemicals into delta lakes poses a threat to fishing and drinking water, and the Mediterranean coast is eroding” (Theroux, 25). All of these problems have serious impacts on the environment and on the communities that rely on the Nile River form their livelihoods, for example, the Nile flooded southern Egypt, relocating about 90,000 people.
Overall, there is overwhelming evidence that both past and present human activities have affected the Nile River. When the Nile River is affected, all of the plants, animals, and humans that depend on the river are also negatively affected. Human activities such as introducing exotic species, pollution the natural land systems, and damming a river that provided essential nutrients and minerals, all have made the Nile River a place of concern. Hopefully enough people will take action to make an improvement, and to undo the adverse effects that humans have created over the past century.
Many peasants and valuable archeological artifacts were forced to move as a result of the threat of a possible flood from Lake Nasser. Matt Rosenberg explains this tragedy, “Over 90,000 Nubians had to be relocated. The government was also forced to…dig for artifacts before the future lake would drown the land of the Nubians” (Rosenberg, 1). In addition to the negative effects of relocating people and artifacts, the dam has also had negative affects on the environment.
No More Annual Floods
Since the annual floods from the Nile River no longer occur, the sediments and silt that were carried all throughout the region are trapped, and as one scientist explains, “Sediment is primarily retained in an extremely dense network of irrigation and drain channels, and also in wetlands in the northern delta” (Stanley, 1). This lack of natural fertilizer has resulted in an increase in erosion of the river and Nile Delta, and an increase in the use of chemical fertilizers, which is evidenced by Figure 2. Chemical fertilizers have to be imported and thus cost money for the farmers that grow their crops, and it also causes pollution of the surrounding environment due to runoff. The chemical fertilizers contain high levels of Nitrogen and Phosphorous which are harmful because they flow from the cropland to the water. Both of these elements are known to cause an increase in algae and algal blooms; algal blooms and the increasing erosion present a problem to fish because both contribute to an increase of particles in the water, which can occasionally clog the fish’s gills, suffocating them. Also, Lake Nasser has experienced an increase in the growth of plant life in its stagnant waters; this plant life supports the snails that carry the debilitating disease schistosomiasis. Despite the initial fall in population and the recent rise in pollution and plant life, fisheries have managed to revive themselves over the past forty years.
Figure 2. Consumption of Nitrogen, Phosphate and Potash Fertilizers in Egypt.
As evidenced by Figure three, the sardine fishery near the Egyptian coast declined after the Aswan Dam was built, however, since the 1980’s, it has been gradually increasing. Sayed El-Sayed explains the affect that the dam had on the fish populations after the dam was constructed, “The average fish catch declined from nearly 35,000 tons in 1962 and 1963 to less than one-fourth of this catch in 1969… Since the late 1980s, the total fish catch off the Egyptian coast has grown to levels comparable to those that existed before construction of the dam” (Sayed, 1). The reasons for the revival of the fisheries are unknown, but whatever the reason, they are very encouraging.
Figure 3. Total fish and sardine catches off the Egyptian coast between 1962 and 1992.
Lake Nasser is experiencing alarming rates of evaporation because the Lake was formed over a region that is very dry and hot. The water loss from the lake is, “…one of the national problems, because the lake is the water bank of Egypt and the evaporated water range between 10 to 16 billion cubic meter every year, which represent 20 to 30% of the Egyptian income from Nile water” (Shalhout, 1). Egypt and other northeastern countries in Africa, as evidenced by Figure 4 are already water stressed, and since Egypt is experiencing further population growth, the need for freshwater will become an even greater problem, Figure 5. How Egypt will cope with the increasing population and the demands from the surrounding countries to use the freshwater from the Nile River will become one of the most important concerns in the future.
Figure 4. Amount of freshwater Figure 5. Amount of freshwater available
available per capita/year in km3 in per capita/year in km3 in 2025
Along with direct human impacts, there exist some natural impacts that have altered the Nile River in some way. Scientists have suggested that rising sea levels coupled with more extreme weather events as a result of global warming have the potential to negatively affect the Nile River Delta. Figure 6, from the United Nations Environmental Program shows the impact of both a 0.5 m water rise and a 1.0 m water rise on the Delta. In the future, with the best case scenario, large areas from this area could be underwater. Since the Nile River Delta is one of the most fertile regions in northern Africa, the loss of cropland will be devastating for farmers.
Iceland’s Laki Volcano
Another natural affect would be Iceland’s Laki volcano event, in which the volcano experienced ten eruptions from 1783 through 1784, “…led to unusual temperature and precipitation patterns, including a significant reduction in the amount of rain that fell over much of the area surrounding the Nile River and led to record low river levels” (Unknown, 1). Finally, the annual floods from the Nile River, although they supplied the region with sustaining silts and sediments, resulted in a loss of land and livelihood of many Africans living along the river. Since the flood waters would stagnate on the land, this increased the breeding ground for mosquito populations, and increasing the spread of malaria. All of these natural impacts are significant, yet the problems that humans are reaping on this ecosystem greatly outweigh the natural impacts that have occurred throughout history.
Figure 6. Future projection of the affect of 0.5m and 1.0m sea level rise on the Nile Delta
Human Impacts on the Nile River
River and smog in Cairo. <http://www.wademan.com/VisionQuest/Cairo_Nile.jpg>
Water and air pollution continue to be a problem for the river. As development in the spheres of agriculture, industry, and urbanization have progressed among the human population, so too have the side effects associated with these practices increased, namely in the form of various pollutants. These pollutants range from agrochemicals to heavy metals to human waste products.
In the cities that we are used to, the water going down our drains goes through various treatment processes to make it as healthy as possible before it is finally released back into nature. Treating water keeps the by-products of everyday human water use from negatively affecting the environment it eventually winds up in. Unfortunately, these treatment facilities can be expensive, and for the more impoverished cities along the banks of the Nile, impossible to afford or maintain. The water that the people living here use can only be dumped into the river untreated (Said et al., 1999).
Human wastewater is largely comprised of pathogens, nutrients, oxygen demanding compounds, and suspended solids (Ezzat et al., 2002). Diseases and parasites are common in such wastewater. Oxygen demanding compounds are also present, and they leech the oxygen from the water. This, of course, has consequences on living organisms in the water that need oxygen for their natural processes.
Finding ways to treat municipal wastewater is a pressing challenge. While social programs are being set up in many districts along the Nile to increase their capacity for water treatment, as population in the area continues to rise even these facilities will be unable to meet the demand. See the “Projections of Wastewater Treatment Coverage” table by Ezzat et al. for a look at one projection on the effectiveness of this strategy.
Even as water treatment capabilities rise, future projections show that the population will continue to increase beyond those capabilities. Wastewater from the majority of people will be left untreated. (Ezzat et al., 2002).
Runoff from the agricultural sector frequently contains pollutants that may have an adverse effect on the river. Pollutants such as salts, nutrients like phosphorus and nitrogen, and pesticide residue can be found in this runoff (Ezzat et al., 2002). Agricultural runoff often is a “non-point” pollutant, in that it can come from anywhere in a region, and not from a specific drain. This can make it difficult to There are also problems associated with agricultural runoff seeping into the groundwater as well.
There has been some success in mitigating the effects of agricultural runoff as a pollutant. This is a result of increased regulation concerning the use of agrochemicals. A decrease in the use of these chemicals has tended to make the wastewater from this sector considerably healthier.
Being a highly urbanized region, the Nile river has its share of industry, and with that industrial pollution. There are about 700 industrial facilities along the river (Ezzat et al., 2002). Industrial wastewater is often highly toxic, containing heavy metals that can combine with the suspended solids in domestic wastewater to form hard to manage sludge. Besides water pollution, industry has been linked to air pollution, and is responsible for much of the smog cloaking major cities such as Cairo and Alexandria.
Though pollution in the Nile river is certainly a large concern, it should be noted that much of the river water is acceptably healthy and free of toxins. It is only in “black zones” near major drains that the water becomes unhealthy. Still, future measures should certainly be sought out to solve this problem before it does develop into a crisis.
Figure 1 shows the BOD (Base Oxygen Demand) of pollutants from domestic, agricultural, and industrial sources. These levels are shown over the course of the year 1995. It should be noted that data for the industries is not complete, and is missing a lot of information from different companies. As can be seen, domestic sources are the main absorbers of the river’s oxygen.(Said et al., 1999, pp. 7).
In Egypt, as shown in Table 1, the highest concentrations of NO^sub 3^-, SO^sup 2^^sub 4^-, K+ and PO^sup 3^^sub 4^- ions have been detected in ground waters of the Nile Aquifer, Nile Delta, and Nile Valley. Concentrations greater than their permissible limits in drinking water have been linked to health problems, especially in infants (Spalding an
The Nile perch. <www2.dpi.qld.gov.au/fishweb/2374.html>
In recent history, and especially during the last one hundred years, the Nile River ecosystem has seen a radical decrease in the diversity of its fish populations (Getabu, Tumwebaze, & MacLennan, 2002). This oversimplification of the river’s and its various lake’s fish populations has, of course, ramifications that threaten not only the stability of the ecosystem, but perhaps the human populations around the river as well. This section of our research delves into what the likely causes are for this decrease in biodiversity, as well as what effects this may have further on into the future.
Biodiversity in the Past
The Nile, and especially Lake Victoria, were once home an extremely diverse population of fish species, with more than 300 different variants (Ogutu-Ohwayo, 1993). These fish were by and large haplochromine cichlids, but other species of fish including mormyrids were common as well. More than 99% of the haplochromines were endemic to the region, making this population not only diverse but unique to the area as well.
Introduction of a New Species
Despite the wide array of fish, the region’s fishing industries struggled to grow because the fish that did live in the river and lakes were predominately small-bodied and bony, not the best sort of fish for commercial enterprise (Kitchell, Schindler, Ogutu-Ohwayo, & Reinthal, 1997). A larger, more commercially viable fish was clearly needed if the fishing economy was to expand. This fish was the Nile perch, Lates niloticus. The Nile perch can grow far larger than many of the other Nile fish, and was perfect for commercial fishing purposes. In the eyes of the human fishers, it was seen as “the saviour.”
Introduced at an undetermined time during the middle of the twentieth century, the Nile perch adapted to its new home extremely successfully. Its population grew slowly at first, but soon exploded into exponential growth during the 1960s and 70s (Kitchell, Schindler, Ogutu-Ohwayo, & Reinthal, 1997). Yields for the fisheries increased up to four times their previous maximums.
Impacts on Biodiversity
The Nile perch, while a boon for the fishing industry, proved to be devastating on the varied fish population. Being a carnivorous fish, the Nile perch made the smaller native fish its prey. As the population of the Nile perch grew, the populations of the other species plummeted. Many of the endemic species went extinct entirely, with many specialists saying that 150-200 of the native species have vanished entirely (Kitchell, Schindler, Ogutu-Ohwayo, & Reinthal, 1997). The Nile perch quickly ascended to become the dominant species in the Nile by a wide margin.
Presently, this system that was once so diverse has now been simplified to an extreme degree. Nile perch constitute most of the fish population, and their growth is only encouraged by local humans. Based on the impacts of foreign species seen in other waterways worldwide, this simplified ecosystem cannot remain stable indefinitely.
Limited Benefits at what Price
The Aswan High Dam
The Aswan High Dam was the second dam constructed in the Nile River. The first Aswan dam, constructed in 1889, insufficiently held the water, and was raised in 1912, and again in 1933. When the dam threatened to overflow for a third time in 1946, it was decided that a second dam was to be built a few miles upstream. For the first time in history, man has the ability to control the annual Nile River Flood. During the rainy season, the water is captured by the dam, stored until times of drought, and then released as needed. The necessity to control the annual flood arose from two principal concerns. Since the soils surrounding the Nile were so fertile, many more people were migrating to the region. Over a seventy year period, “The population of Cairo grew from 2 million to over 16 million people” (Nixon, 2004). With the increasing population came the concern that the flood would become increasingly dangerous. Also, the annual flood was unreliable, as one scientist explains, “One year, the floods might be low, resulting in weak soil that produced few crops. The next year, the floods might be high, destroying buildings, homes, roads, and washing away important features of the land” (Rose, 7). Because of the increasing population, the unreliability of the flood, and various other factors, the Aswan High Dam was built, and man now can control the water flow of the Nile River.
The High Aswan Dam had a positive impact on the rapid growing development of Aswan province, especially for the tourism industry, and the fishing success that occurred after a brief decline in fishing stocks (Osman 2000). The majority of the Egyptian population lives in close proximity to the river, which means that the majority of the population depends on the river for irrigation, drinking water, electricity, or transportation. The dam allowed for irrigation systems to be built, thus increasing the amount of land that farmers could utilize to cultivate their crops. Many farmers depend on the dam to irrigate their farms and as you can see from Figure one, Egypt irrigated 3.3 million hectares in 1997, and that number is only going to increase as the population continues to grow.
FIGURE 1. The graph represents Irrigation in Africa – Countries estimated to have the largest irrigation systems in Africa (1997)
Energy in Egypt
Egypt also relies heavily on the dam as one of its primary sources of energy, and according to Chris Rose, “By the mid-1970s, the Aswan High Dam was producing half of Egypt’s electrical supply. The new electrical production allowed many villages to have electricity for the first time. The Aswan High Dam…produces about 15% of the country’s needs each year” (Rose, 7). Despite the fact that the dam has provided many benefits for Egypt and various other surrounding regions, numerous disadvantages have occurred since the construction of the dam.
ArcGIS map examining modern day fish biodiversity. At one point, countries along the Nile may have had over four hundred different species of fish living within their borders. While they are still fairly diverse today, it can be seen that the diversity no longer reaches those lofty heights.