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Science in Africa
Human Interactions and Water Quality in the Horn of Africa
Lakes are one of humanity's most important resources, especially in the tropics, where they are often viewed as highly productive biological systems. They provide water for consumption, fishing, irrigation, power generation, transportation, recreation, disposal of wastes, and a variety of other domestic, agricultural, and industrial purposes. However, not all of these uses are necessarily compatible. Some uses, like waste disposal, are often difficult to reconcile with other uses. In spite of the fact that freshwater bodies are very limited and sensitive resources that need proper care and management, they are probably the most abused of resources. Therefore, accelerated eutrophication of lakes because of human activity is a concern throughout the world. However, most research on this problem has been done in the temperate zone, with little information from tropical Africa, especially Ethiopia and the countries in the Horn.
In Africa human factors, in combination with the natural conditions of climate and geology, may influence water quality to a large extent. Ethiopia does not have the industry that flourished in the developed countries, and pollutants are not produced in large quantity. However, pollution resulting from human activities, such as land use and modification and other practices associated with rapid population increase, has caused or accelerated many changes in the lakes. The major degradation problems that these lakes are facing at the moment have, to some extent, been studied over the last ten years (Zinabu and Elias, 1989; Elizabeth et al, 1992 and 1994; Brook, 1994; Zinabu, 1994). Based on available data from these previous studies, I intend in this paper to evaluate the human activities that are the possible causes of the water quality changes in the Ethiopian lakes, and to propose some corrective measures of management. I am also convinced that the issues raised here can be related to other countries in the Horn of Africa.
Ethiopia is gifted with a variety of aquatic ecosystems, especially a number of lakes that are of great scientific interest and economic importance. The total area of inland waters in Ethiopia is 8,800 square kilometers, representing 0.72 percent of the total surface area of the country (Greboval et al, 1994). The Ethiopian rift-valley lakes and the Bishoftu crater lakes are among the most studied water bodies in Ethiopia, if not in the Horn of Africa, and most of this paper is based on studies made in these lakes. Therefore, it is appropriate to say a few things about these lakes at this juncture.
The rift-valley lakes are a chain of permanent lakes lying entirely in the southern part of the Ethiopian rift valley. Most of the Ethiopian rift-valley lakes are very productive, containing indigenous populations of edible fish and supporting a variety of aquatic and terrestrial wildlife. Some of these lakes are being used for commercial fisheries, irrigation, recreation, and some industrial purposes. Although there is increasing use of these resources, they are not yet as permanently altered, damaged, and depleted as some other water bodies in the developing countries. However, there seems to be little awareness of the risks of overexploiting and degrading these lakes.
The Bishoftu crater lakes are a group of volcanic explosion craters in the vicinity of an emerging city, Debre-Zeit, which is situated 47 kilometers southeast of Addis Ababa (the capital of Ethiopia). The impacts of this fast-growing city on these lakes in recent years, and the extent to which the lakes have changed in the last three decades as a result of human interference and/or natural causes, have been recently studied (Zinabu, 1994). Compared to changes observed in the Ethiopian rift-valley lakes, the changes in most of these crater lakes are minimal, and the lakes have been well preserved.
Data from recent studies made on these and other Ethiopian lakes have been used in this paper to evaluate the human activities that are possible causes of water quality changes in the Ethiopian lakes. I have also attempted to relate my assessment of human interactions and water quality changes in Ethiopia to other countries in the Horn of Africa (i.e., Somalia, Djibouti, and Eritrea in this context). However, this assessment is limited by the lack of available data from these countries in the Horn. To my knowledge there is no published work on lakes in these other countries in the Horn; therefore, this evaluation is based on facts from the Ethiopian lakes alone. Although water quality problems may vary from one country of the Horn to another, the basic facts would probably be similar, given that the countries in the Horn share much with respect to their geology, climate, and socioeconomic development. Therefore it is my hope that the issues raised and recommendations given in this paper for the Ethiopian condition will apply to the countries in the Horn as well.
Water Quality Changes and Links to Human Interaction
The exponential growth of human populations and the attendant agricultural development (which demands more clearing of forests, irrigation, fertilizers, and pesticides) and industrialization are the main causes of water quality deterioration on all scales. Such impacts of human activities on freshwater lakes have existed for quite some time in Ethiopia and have contributed to the continuous degradation of their pristine qualities (Zinabu and Elias, 1989). The most important human activities that can be related to water quality changes in the Ethiopian lakes are described in the following few pages.
Land Use and Modification
Human activities in drainage areas are potential causes of pollution of lakes. Even without human interference, lakes change over time because natural factors, such as soil erosion, sediment loading, deposition of animal and plant debris, solution of minerals in the basin, and so on, are always at work. Human activities like land use and modification greatly accelerate some of these changes.
Clearing of forests, animal grazing, and other reductions in the vegetation of the catchment areas of the Ethiopian lakes, which have expanded considerably during recent years (Hillman, 1988), increase the silt and nutrient load of the water. Given the present level of deforestation in Ethiopia (about 150,000 to 200,000 hectares of forest per year), which results from the usage of wood for fuel and construction and from the population-driven need to increase cultivable land, forest clearing currently poses a serious problem. Most of the factors that encourage soil erosion (depleted forest, inadequate plant cover, organically poor soils, improper farming methods, etc.) are very common in Ethiopia, and some of its lakes have suffered from the consequences of the linked processes of plant cover removal, erosion, and sedimentation. When erosion takes place, the torrents, carrying soil particles, usually rich in nutrients, may end up in lakes. The result of such increased nutrient loading is eutrophication. This phenomenon in turn can lead to fish-kills caused by decreased oxygen concentrations, algal blooms, and other interrelated consequences. Such events have already been reported in some of the Ethiopian rift-valley lakes. Fish-kills, algal blooms, and the associated death of wildlife in Lakes Chamo (Amha and Wood, 1982) and Abijata (Kassahun, 1982) are attributed to the human impact in the catchment areas of these lakes.
Small-holder farming and state farms in the drainage areas of the Ethiopian rift-valley lakes have modified the catchment areas of the lakes and have contributed to enhanced nutrients and particulate run-off, especially when the grasslands are overgrazed and the fields are tilled or fertilized. It is hard to say how much of the soluble fertilizers and pesticides used remain on land, and how much of it passes to the water bodies. The new extension package that encourages Ethiopian farmers to use fertilizers may inevitably increase the nutrient load into lakes. So far there has been no study made with respect to impacts of pesticides and fertilizers on the water quality of the Ethiopian lakes. However, it is certain that such practices, aimed at increasing food production, also result in harmful long-term effects on the water bodies and in the accumulation of toxic chemicals in the bodies of fish.
Irrigation is the most obvious response to water scarcity in agricultural areas, which explains why a lot of effort is being made to use irrigation in Ethiopia. Ethiopia has been repeatedly plagued by drought, reflected by the declining water levels of some lakes. This situation by itself could be a major threat to the very existence of the lakes. On top of this threat there has also been a great increase in the extent of irrigation during the past few years.
The irrigation scheme that is being used for farms around Lake Zwai has had a considerable effect on the water level. Since the irrigation in this area is a year-round process, its effect on the water level is magnified, especially during times of low precipitation and high evaporation (Zinabu and Elias, 1989). Several rivers that flow into one or more of the rift-valley lakes have been diverted for irrigation. The rivers Meki and Katar and the Bulbula and Gogessa rivers, which flow into Lake Zwai and Lake Abijata, respectively, are being used for irrigation. This practice has caused water level subsidence in both lakes because of the reduced inflows. A similar phenomenon seems to have taken place in Lake Chamo as a result of the diversion of the rivers Kulfo and Sile for irrigation.
Fish production has become a victim of this decline in lake water levels. The decline damages the breeding grounds of fish species that spawn in shallower parts of the lake (e.g., Oreochromis niloticus, the most important species commercially). These effects are magnified in shallow lakes like Zwai, where a higher rate of water level fluctuation has been observed.
Diversion of Rivers into Lakes
Another important human impact is the diversion of rivers into lakes in order to increase the water volume of the lakes for irrigation. The drastic changes introduced into one of the Bishoftu crater lakes (Kilole) best exemplify this phenomenon. The chemistry of this lake was completely altered as a result of diverting the River Mojo in 1985 in order to fill the crater to its rim and use it for an irrigation scheme (Brook, 1994; Zinabu, 1994).
The drastic water quality changes include a three-fold increase in the concentration of nitrate, a more than 200-fold drop in phosphate-phosphorus concentration, a conductivity drop by 30-fold, and a 94 percent decline in the concentrations of the total anions and cations. In fact what used to be the most concentrated lake (on the basis of total electrolytes) is now the most dilute of the Bishoftu crater lakes. We no longer have the very productive soda lake that was of scientific interest at one time (Prosser et al, 1968; Talling et al, 1973). In addition to the changes in water quality, some morphometric changes have also occurred in this lake (Brook, 1994).
Although the River Mojo has stopped flowing into the lake now, the water that had already flown into the lake stagnates. All the substances that were carried into the lake with the water (e.g., silt, nutrients, or toxic substances) tend to be trapped in the lake sediments or in the bodies of the lake organisms. Changes in the species composition of the phytoplankton and the zooplankton have been reported in Lake Kilole as a result of the diversion of the River Mojo (Brook, 1994).
Urbanization and Human Settlement
Urbanization and human settlement in close proximity to the Ethiopian lakes are among the greatest potential causes of changes in water quality and quantity. Although there is very little indication of acute cultural pollution in the Ethiopian lakes at the moment, the potential problems deserve some attention here.
Most of the fast-growing cities, like Zwai, Awassa, and Arbaminch, are in the neighborhood of the rift-valley lakes, and the Bishoftu crater lakes are in the vicinity of the flourishing city of Debre-Zeit. The growing population and industrialization of these cities can have potentially serious consequences on the lakes. It is possible that domestic and industrial wastes may find ways into the lakes. The effluents from the textile factories in Awassa and Arbaminch are likely to end up in Lakes Awassa and Abaya, respectively. Septic tank leachate may also reach the lakes and cause eutrophication.
Industrial Uses of Water
There are not many industrial projects on the Ethiopian lakes at the moment. It is, however, possible that such ventures will soon start and their impacts may be severe. The soda ash extraction plant on Lake Abijata is a good indicator of what can be brought about by industrial uses of water from the lakes. I have already mentioned that the water level of Lake Abijata has declined as a result of the diversion of its inflows for irrigation. This loss of water from Lake Abijata has been exacerbated by certain activities of the soda ash extraction plant, such as pumping of water from the lake or the discharge of effluents. The relatively shallow depth and terminal position in the drainage area make Lake Abijata rather vulnerable. The fish and wildlife populations supported by the lake have already been affected.
Although the direct and immediate benefits of such development activities are demonstrable and not in question, one must question the ecological impacts of initiating undertakings like the one on Lake Abijata. I feel that the value of what is lost could be greater than what is gained, especially when the preservation of nature is inherently valued.
Introduction of Fish into Lakes
Remarkable changes have occurred in the trophic status of Lake Hayq, in Wollo, following the introduction of tilapia (Oreochromis niloticus). This area of northern Ethiopia is among those that have been severely affected by drought and famine over the last three decades. The lake was stocked with tilapia from a crater lake near Addis Ababa (probably Lake Hora) in 1978 to provide food. The major change in this lake has been increases in plankton biomass, the major symptom of eutrophication, which has resulted in reduced water clarity and oxygen levels, taste and odor problems, and loss of fisheries (Elizabeth et al, 1992).
Lake Hayq has changed greatly in its phytoplankton biomass and transparency since it was described in the 1960s (Baxter and Golobitsch, 1969). The available evidence implicates the introduction of planktivorous fish, which released the phytoplankton from grazer control. The fish-kills that occur in the lake are almost certainly because of anoxia. Although the introduction of fish is undoubtedly a major success in terms of the local economy, its negative effects on water quality should be considered with caution.
Comparison of long-term water quality changes in several Ethiopian rift-valley lakes with differing exposure to human influences may further illuminate some of the issues raised so far. A very good example would be to compare the changes that have taken place in the lava-dam lake Metahara (with little human impact in its catchment) with those in the terminal Lake Abijata, which has been affected by different sets of human activities as noted above.
A study of Ethiopian rift-valley lakes (Elizabeth et al, 1994) has shown that Lake Metahara, a relatively isolated lake with respect to human interference, decreased in its total ionic concentration by about a factor of 10 over the last 30 years. This change in ionic concentration appears to have been accompanied by a shift in the phytoplankton community: Spirulina platensis, the characteristic blue-green algal species found in African soda lakes, was reportedly dominant in 1961 (Wood and Talling, 1988), but totally absent in 1991. Instead, the phytoplankton community was composed of a mixture of green and blue-green algae. Lake Metahara has also increased in size over the past 20 years, possibly due to a combination of subterranean seepage from the basin and spillage from the nearby river Awash (Elizabeth et al, 1994).
On the other hand the terminal lake Abijata has shown a considerable increase in ionic concentration since 1961. Changes in phytoplankton composition also seem to have taken place in Lake Abijata: A dominant population of Spirulina species reported from Lake Abijata in the 1960s (Wood and Talling, 1988) was not observed during this study; instead, Anabaenopsis abijatae was the dominant phytoplankton (Elizabeth and Willen, 1996). Anecdotal information from local people and close observation of the shore line of Lake Abijata suggest that the water in this lake has receded significantly in the last three decades. Although the soda ash extraction plant on Lake Abijata may have increased the evaporation rate of the lake water in the last 10 years or so, diversion of the inflows for irrigation purposes and flushing from deforested and heavily grazed catchment may also have contributed to the decrease in the water level and the increase in the concentrations of ions (Zinabu and Elias, 1989).
Another study on the Ethiopian rift-valley lakes indicated that three different trends in the salinity of the Ethiopian rift-valley lakes have occurred in the last three decades. According to this study, two lakes (Zwai and Shalla) have maintained the same salinity they had in the 1960s, two other lakes (Langano and Awassa) have become more dilute, and the salinity of the soda lake Abijata as well as that of Lakes Abaya and Chamo has increased over the last 30 years. The changes that have taken place in the conductivity of the Ethiopian rift-valley lakes in the last three decades suggest a similar trend. My assessment of this scenario is that, although these changes in salinity can take place due to evapotranspiration and/or solute inputs, the intensity of the human activity in their catchments must have contributed to the contrasting trends in their salinity. In the catchment areas of the lakes that have become more saline, human activity has been much more intense than in those that have not. Thus it is possible to conclude that human interference in the lake basins is a major cause of water quality changes in the Ethiopian lakes.
Water Management Problems
Human activity has been identified as a major source of water quality changes in the Ethiopian lakes. However, there are other contributing factors that are a result of human "inactivity," i.e., water management problems. The following situations pose water management problems in the Ethiopian context.
Lack of Information
Most of the Ethiopian lakes have not been adequately studied; hence the information we have about them is scanty. Despite the studies conducted on the Ethiopian rift-valley lakes and the Bishoftu crater lakes so far, much is still to be done in Ethiopian limnology. The data we have on most Ethiopian lakes, besides being very old, are incomplete. They do not, therefore, give us a sufficient base of knowledge of the lakes, although the lakes may vary from season to season and from year to year (Wood and Talling, 1988). Without basic information on the physical, chemical, and biological aspects of the lakes, it is difficult to evaluate any qualitative and/or quantitative changes. Therefore, it is possible that degradation of the systems could go unnoticed for a long time and eventually bring disastrous effects.
Until very recently, Ethiopia did not have native limnologists or fisheries biologists, and only short-term visitors studied the lakes. Most of these visitors did not stay in the country long enough to make detailed studies; nor did they make repeated visits. In the last ten years, however, several studies have been conducted by graduate students and staff from the departments of biology at Addis Ababa University and the University of Waterloo, Canada. Although these efforts have produced a few highly trained and capable aquatic specialists, the studies have focused on only a few lakes because of logistical problems. Thus the information remains incomplete.
Difficulty in obtaining research funding is one cause of this lack of information on Ethiopian lakes. This problem applies to both local and international funding. Another problem related to lack of information is poor dissemination of results. There is only one local journal where research findings related to aquatic sciences, and all other physical and life sciences, can be published. Therefore it is more time-consuming and difficult to publish a research finding than it is to perform the research work itself. A lot of research findings based on Ethiopian lakes are rejected by international journals for being of only local interest; if they are published in international journals they often become unavailable to the local reader.
Absence of Lake Monitoring Systems
Monitoring is the continuous or periodic collection, organization and analyses of data and information for purposes of effective management of lake waters (Biswas, 1991). Both physical and socioeconomic data are required for proper management and optimum use of lake resources. However, for a large number of Ethiopian lakes, regular monitoring of essential water quality parameters (physical and chemical) is not generally carried out, or if carried out, the data are not available to users of such information. The situation with socioeconomic factors is even worse. Impacts of lakes on the lifestyles of intended beneficiaries, like farmers, fishermen, and domestic water consumers, has not been evaluated at all for Ethiopian lakes; thus monitoring in this regard is almost nonexistent.
Absence of Water Use Policies
For a long time Ethiopia did not have sound legislation or water use policies directed toward conservation of lakes or aquatic organisms. Even those lakes that were said to be protected under the national parks had been significantly affected by human activity. For instance, the two soda lakes in the Ethiopian rift valley, Abijata and Shalla, are of particular interest since they provide feeding and breeding grounds for over 360 migratory and local bird species. These lakes have been integrated within a national park since 1970, but no conservation was promoted because of enterprises, like the soda-ash extraction plant, whose activities were associated with domestic economic interests (Hillman, 1988). Although the Ethiopian Parliament has recently approved legislation on environmental protection, and an Environmental Protection Authority (EPA) has been established, no actions that warrant protection of the lakes have been taken as yet.
Conclusions and Recommendations
It is evident that human activity and catchment mismanagement have accelerated water quality changes in some of the Ethiopian lakes. Water resource in Ethiopia (and the larger Horn of Africa ) are of great importance given the nature of water availability in this area. It should be noted that much of the Horn of Africa has low rainfall, and the greater part of the land surface has been under moisture stress. Furthermore, there is significant variability in seasonal precipitation, placing many regions in a vulnerable position. In the face of the growing population, intensified land use, and the associated water quality changes discussed in this paper, immediate actions have to be taken to change the present approach of water utilization and management. Unless corrective measures for reducing degradation of the lakes are worked out and the existing problems are tackled soon, severe ecological crises are inevitable.
I propose the following corrective measures to prevent further water quality degradation in Ethiopian lakes.
Recognition of the Problem
In the absence of enough information on Ethiopian water bodies, scientists, policymakers, and the public at large seem to believe that water quality changes are not among the problems of the country. Probably the water scarcity problem in some parts of the country, which is more seriously considered, has caught the attention of the public so much that quality issues are not raised. Yet the evidence of water quality changes in the Ethiopian lakes is already strong enough to call for immediate corrective measures. The first and foremost corrective measure is to acknowledge the continuing degradation of these lakes and to be determined to act vigorously.
Limnological Research and Education
Limnological research in Ethiopia and the other countries in the Horn lags behind other areas of research, creating the information gap that now exists. It is, therefore, important that basic limnological research should be carried out in Ethiopia in order to generate baseline data so that the water quality of our lakes can be monitored regularly to detect any changes. Ethiopia now has a trained group of scientists who can carry out research in various fields of aquatic sciences. There are well-equipped laboratories for limnological studies at Addis Ababa University (AAU) and Awassa College of Agriculture, and a small specialized library at AAU. However, research in aquatic sciences is not a priority for funding. Research in food production and health is given so much importance that other fields of research, including limnology, are almost forgotten frontiers. Limnological research must be given attention in Ethiopia, and policymakers and funding agencies should be prepared to consider limnological research as an important area of research.
The limnological knowledge that researchers have already acquired concerning Ethiopian lakes and rivers, however limited, should be disseminated so that the information can reach students, researchers, and the public at all levels. Environmental education, which is not part of the school curriculum in Ethiopia, should be considered at various levels of education. Sadly, even the university education system in Ethiopia does not accommodate courses on environment, with the result that a university graduate lacks basic awareness of environmental issues that any ordinary citizen ought to have. Unless educational improvement is undertaken we will continue to have graduates with strange ideas, e.g., the engineers that still maintain the old notion that "dilution is a solution to pollution." Such engineers are at the moment designing and approving major construction projects to be built along lakesides, with the waste to be directly dumped into the lakes. This is becoming more common with resort hotels that are being built on lakesides. The same lack of awareness on environmental issues applies to economists, planners, development workers, agriculturists, etc. This situation calls for interdisciplinary curricula in Ethiopian higher educational institutions that deal with environmental concerns. A university course integrating environment and development should be an important priority.
Consideration of Environmental Problems with Developmental Planning
Ethiopia has in recent years been initiating a number of agricultural and other development projects that are of immediate importance to meeting the population's food needs and establishing self-sufficiency. The recent changes in economic policies in Ethiopia, i.e., the newly adopted free market economy, are leading to industrial activities that will necessarily exploit water resources. It is also expected that substantial changes in farming, e.g., large-scale mechanization of agriculture, fishing, extensive use of pesticides and fertilizers, and range development, will take place. Infrastructure development, e.g., the building of roads, bridges, and airports, is already in progress. In addition to these activities, changes in lifestyle, such as the proliferation of consumer products that generate significant wastes and effluents, have begun to produce environmental impacts. Therefore, the factors that brought about changes in the waters of developed countries are already at hand and serious problems are just around the corner. The fact that many well-intended development projects have adverse repercussions, including eutrophication and disruption of freshwater ecosystems, presents conflicts that need to be handled with care. It is clear that many environmental problems arise from the process of development itself. Therefore, although all the development programs that the country is planning to carry out appear to be indispensable, their ecological impacts should be considered before any of the development programs are launched; and their negative impacts should be minimized where and when possible. Increased emphasis should be placed on preventive planning based on environmental impact assessment.
Local Environmental Legislation
Management of Ethiopian lakes is now in the hands of a public that views water as an abundant "free good" always at hand. This view should be changed, and comprehensive water use policies should be established and maintained. There must be a legal body responsible for protecting aquatic systems. An environmental authority should develop appropriate policies and guidelines that can be adapted nationally and locally to bring about environmentally sound management of the lakes.
It is a known fact that lakes are integrated parts of the entire watershed and should be considered as portions of the drainage basin that supply them with water, sediment, and allochthonous material. Still, integrated management of lakes and lake basins seems far from being realized in Ethiopia. For instance, deforestation/reforestation of a catchment area is always viewed independently of the lake ecosystem. Those who are concerned about water quality changes are indifferent to the reforestation programs in the catchment of a lake, and vice-versa. Another example is the situation where DDT is indiscriminately used to control the insect vectors of malaria during rainy seasons. It is likely that a large part of this banned chemical contaminates water bodies following run-off. No efforts are being made to consider the impact of DDT on Ethiopian lakes. It appears that the government institutions concerned with food production, reforestation, and health are unaware of or indifferent to the effects of their policies on the health of the lakes. In Ethiopia the concept of integrated management, i.e., the management of lake water itself and the management of the whole catchment land area, should be introduced at different levels and emphasized. One must convince the educated fisheries personnel of the Ministry of Agriculture as well as the uneducated fishermen that deforestation in the catchment area of the lake is crucial to the fish.
Certain human activities, like building resort areas, washing cars and clothes, gutting and filleting of fish caught from the lake, etc., tend to be concentrated on the shores of lakes. The effects of using detergents for washing clothes at lakeshores, for example, may look very insignificant. However, given the number of people that live near the shores or go to the lakes to wash clothes and do other cleaning activities, the impacts can be significant indeed. Harrison and Hynes (1988) reported that such human activities were possibly responsible for the elimination of freshwater crabs and the reduction in numbers of some fresh water insects from an Ethiopian water body. It is, therefore, important to note that careful management of the lakeshore is a condition for the sustainable utilization of lake resources.
Participatory Approach to Water Management
Management of Ethiopian lake resources should not be left to a certain government organ alone. Both the inhabitants and the government establishments should be equally concerned. Active participation of the rural population is especially desirable in lake management. Indeed the participation of the inhabitants, who contribute to the damage of the catchments, is essential. It may be difficult to interest the public in lake management, but certain issues that concern the public can be emphasized. For instance, the importance of the relationship between the local inhabitants and the lake, which is not always beneficial, can be raised. Heavy rain in the rainy season can suddenly raise the water level of a lake, causing flooding over fields and houses at the lakeside. Recent incidences in lakes Koka and Awassa are very good examples to cite. It is possible to make this emphasis a tactical point of entry to convince the local inhabitants that water not only fulfills their basic needs but also poses considerable dangers, and hence managing the catchment (in this case abating deforestation to reduce over-flooding) is a matter of safety to the local inhabitants. Since environmental awareness is a contributing factor that makes the public participate in lake management programs, it is important to raise the level of awareness of the public through appropriate public channels, including the media.
Finally, the picture I have tried to portray of the existing conditions of the Ethiopian lakes, albeit incomplete, should serve the same purpose for the lakes in other countries in the Horn. I don't intend to alarm, but rather to alert all the countries in the Horn of Africa to the degradation problems their waters may be facing, and to warn them of potentially irreversible changes that presently seem inevitable. Of course, the "developing countries" are in a way fortunate in having fewer environmental problems than "developed countries," but we are not secure. We should learn valuable lessons from the problems of the industrialized countries and take the appropriate precautionary measures as soon as possible. My final remark: Now is the time to start proper management of our aquatic resources to protect them for future generations.
I thank Elias Dadebo, Hailu Yohannes, and Yosef Tekle-Giorgis of Awassa College of Agriculture for their comments on the draft manuscript.
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