Learning from other lake ecosystems as a development and policy guide

4.3 Learning from other lake ecosystems as a development and policy guide

Global research evidence show that the majority of lake ecosystems across the globe are under severe pressure. According to the World Preservation Foundation (as cited in Smith, 2012) one third of the world’s major rivers and lakes are drying up, and the groundwater wells for 3 billion people living around the Lakes are being affected. The loss of rivers, lakes and underground water reserves are impacting the livelihoods of millions of people. While climate change is playing a role, the building of hydropower and irrigation dams, over extraction and mismanagement of water and over-fishing are all playing a part in the disappearing of the world’s lakes and rivers (Smith, 2012).

An international synthesis that investigates the state of the Earth’s ecosystems (the Millennium Ecosystem Assessment) reveals that, over the past 50 years, humans have changed ecosystems more rapidly and extensively than in any comparable period of time in human history, largely to meet rapidly growing demands for food, fresh water, timber, fiber and fuel. This has resulted in a substantial and largely irreversible loss in the diversity of life

Irrigation

Ribb 19,925 172-220 146-187 233.7 Under construction since 2008

Megech 7,300 63-98 54-83 181.9 Under construction since 2008

Gumara A 14,000 115 98 59.7 Feasibility studies completed

GilgelAbbay B 12,852 104-142 88-121 563 Feasibility studies ongoing

Jema 7,800 57 48 173 Feasibility studies ongoing

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on Earth. Global ecosystem conditions and trends show that 50-80 per cent of original mangroves have been lost in the coastal ecosystem (Burke et al. 2000), and fifty per cent of world’s wetlands lost during the 20^th century in freshwater ecosystem (Revenga et al. 2000).

Some 60 percent (15 out of 24) of the ecosystem services examined in the Millennium Ecosystem Assessment-including fisheries and fresh water- are being degraded or used in ways that cannot be sustained. These problems will substantially diminish the benefits that future generations obtain from these CPRs; unless human attitudes and actions change, the pressure and degradation of ecosystem services could grow significantly worse during the first half of this century and is a barrier to reducing global food shortages and achieving the Millennium Development Goals (MDGs) across nations (MA, 2005; 2006).

Experiences learned from the Global Environment Facility (GEF) project which studied 28 lakes in the world, also show that development intervention of resource values for lake ecosystems typically take place in phases. Even stakeholders may not recognize the progress in the lake ecosystem. In early stages of resource development at ‘A’ (see Figure 4.3), they may be limited only to construction of lakeshore facilities for fisheries, navigation and small scale water supplies. As the population increases, the need for water for domestic, hydropower, industrial and agricultural uses increases, generally leading to construction of large scale flow control facilities. Through time the number of stakeholders involved and their interests also increases.

The commercial interest, development of tourism and recreational facilities may then grow, perhaps sufficiently to exploit the lake’s cultural and natural heritage assets. As the resource values peak at ‘B’, the resource development activities are inevitably associated with infrastructure development and landscape alterations in and around the lake basins which, together with wastewater discharges from cities and industries, gradually accelerate degradation of resources, water quality and ecological integrity, usually without being noticed when they began at ‘C’ (ILEC, 2007). As a result conflict over resources among stakeholders is inevitable.

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Figure 4.3: Changing resource values of a hypothetical lake Source: (ILEC, 2007)

The progression of degradation inside a lake often takes place on a wider and deeper scale than is apparent. If the seriousness of a lake problem is realized in time by scientific means, resource conservation and restoration measures may produce some promising results. Often, however, the symptoms of degradation remain unnoticed for a long period of time because of their incremental nature, and the introduced conservation and remedial measures may be too little too late. The level of ecological and water quality degradation may have already reached crisis proportions, suddenly leading to instant loss of ecosystem sustainability (ILEC, 2007).

Figure 4.4: The resulting environmental state of a hypothetical lake Source:(ILEC, 2007)

E

F G

H A

B

C D

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The same is true for Lake Tana ecosystem, where enormous development activities have been taking place since the 1990s. Without noticing what is going on inside and outside the Lake surroundings, there might be a serious degradation in the Lake ecosystem. There is research evidence that shows the overall progression of the Lake and its critical problems (Dargahi and Setegn, 2011; McCartney et al. 2010; Setegn, 2010; Vijverberg et al. 2009).

However, minimal or no effort has been done so far at policy/higher governance level to reverse the situation. Unless protective measures are put in place, there might be a disastrous effect on the Lake ecosystem. As seen from Figure 4.4, once a lake ecosystem reached a serious environmental degradation (at F), recovery is slow (at G) and full restoration is rarely possible (at H).

Especially for poor nations like Ethiopia where economic, institutional and technological capacity to reclaim the environment is limited, it will be very difficult to preserve valuable environmental resources effectively. According to the Environmental Sustainability Index (ESI, 2005), which evaluates a country’s potential to avoid major environmental deterioration, Ethiopia ranks 135^th out of 146 countries with a score of 37.9 which is the least score among the 40 NEPAD (New Partnership for Africa’s Development) member countries just above Sudan (with ESI score of 35.9). Even when compared with the 21 countries that are more than 50% desert, 15 countries scored from 39.8- 56.7. The ESI score quantifies the likelihood that a country will be able to preserve valuable environmental resources effectively over the period of several decades (Esty et al. 2005).

4.3.1 The Lake Haromaya Demise, Ethiopia

The then Alemaya now Haromaya lake in the Ethiopian Eastern highlands originally covered more than 1,751 km² but had shrunk to 879 km² (which is 50% of the original) in 1985 and to a mere 586 km² (33.5% of the original) in 2002. It is now believed that the lakes have all but completely dried up. The loss of the lakes, which were a source of drinking water, irrigation and fisheries, has affected the livelihoods and well-being of more than 550, 000 people in the Ethiopian towns of Haromaya and Harar. Preliminary research seems to suggest that serious siltation has been a major factor in the destruction of the lakes. A

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dramatic increase in urban and rural settlements is also believed to have put tremendous pressure on natural resources in the area, including water resources (RCMRD, 2005).

Increasing irrigation and domestic water use, change in the local climate, and changes in the surrounding land cover are believed to be the causes of Haromaya’s demise (Setegn et al.

2011).

4.3.2 Lake Chad, Africa

Lake Chad, once one of Africa's largest freshwater lakes, shared by Nigeria, Chad, Cameroon and Niger has shrunk dramatically in the last 40 years. In 1963, the lake covered about 25,000 km². Today it is one-twentieth of that size. The size of Lake Chad has gone from 30,000 km² to 3,000 km² in 40 years, according to some sources - from 25,000 km² to less than 1,500 km² in almost 30 years between 1966 and 1997(Coe M.T et al. 2001).

According to Smith (2012) global warming, with steadily reducing rainfall, and water extraction have seen it diminish around 80% of the lake in the last 30 years. Major irrigation projects built in the 1980s, which made use of the two main rivers, Chari and Longone, which supplement the lake, were believed to be the causes of the drastic change in the lake ecosystems. According to Noury (2009), increased irrigation demands are said to have significantly decreased the flow of water into the lake; some speculating that the irrigation demands, which increased a phenomenal four times between 1983 to 1994, have accounted for a 50% decrease in the lake's water level.

4.3.3 Aral Sea, Asia

The Aral Sea, formerly one of the four largest lakes in the world with an area of 68,000 km², has been steadily shrinking since the 1960s. In 1965, the Lake had lost over 75% of its volume. By 2007 it had declined to 10% of its original size. The major reason for the Aral Sea demise was the two major rivers (Amu Darya and Syr Darya) that fed it were diverted by a Soviet Union irrigation project (Philip et al. 2008; Smith, 2012). Fish stocks-previously a stable diet for those living around have diminished, drinking water is saline and disease is rife. The region's once prosperous fishing industry has been essentially destroyed, bringing

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unemployment and economic hardship, totally closing an industry that had employed 60,000.

The Aral Sea region is also heavily polluted, with consequent serious public health problems. The retreat of the sea has reportedly also caused local climate change, with summers becoming hotter and drier, and winters colder and longer (U.S. Geological Survey, 2007; Smith, 2012).The shrinking of the Aral Sea has been called ‘one of the planet's worst environmental disasters’ (Daily Telegraph, 2010).

What can be learnt from those lake ecosystems which have disappeared completely (Lake Haromaya) and/or are partially endangered and under reclamation program (Lake Chad), is that it is an alarm bell for other lake ecosystems across the globe and the Lake Tana ecosystem in particular. It is therefore essential that key stakeholders should be aware of the potential threats of the Lake ecosystem so that for any hydropower and irrigation development in and around Lake Tana appropriate lessons can be learned from the above cases.

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4.4 Case study of the fish commons: Overview of the Lake Tana fishery