Land Degradation In The Nile River Basin Environmental Sciences Essay

Per capita availability is generally calculated by dividing total annual renewable water resources with population. While this could provide an accurate picture for countries with no dependency on external water resources, it does not provide an accurate depiction for countries with trans-boundary water resources. Taking into account the dependency ratio of the countries provides a much more realistic depiction of future water resources. For instance, Uganda has a 40.9% dependency ratio for its total annual renewable water resources (Rwanda, Burundi, Tanzania, DRC and Kenya contribute runoff into Lake Victoria). This will be impacted when increased water demand in upstream nations results in reduced water runoffs into Uganda. Egypt which originally had a 98% dependency ratio has been able to bring down its dependency by increasing alternate water resources but still has a 76% dependency ratio (55.5 BCM out of 73 BCM).

Chapter 4

Land degradation is one of the challenges faced by several countries in the Nile River Basin. Land degradation comprises of any negative or undesirable change in the texture, content, moisture of land due to a combination of natural hazards and man-made activities. The African continent is characterized by 46% of extreme desert and 11% of land mass that is humid. Presently, in Africa around 250 million people are directly affected by land degradation while, worldwide 1 billion people in 100 countries are at risk of land degradation.

The causes of land degradation are a combination of changes in the natural ecosystem, and the impact of the human social system, including human use and abuse of sensitive and vulnerable dry land ecosystems.

Land Degradation in the Nile River Basin

In Rwanda, around 71% of total land area is facing severe degradation and about 60% of its forest cover has been lost in the last two decades partly due to genocide, displacement and repatriation. Similarly, more than 30% of Burundi is severely or very severely degraded.

In Tanzania, widespread land degradation is found in the highlands, especially on the slopes of Mt. Kilimanjaro. Kenya faced about 30% land degradation in 2002 and around one third of its population was directly dependent on degraded land by 2008. Also, land degradation is widespread in Kenya, affecting 20% of all cultivated areas, 30% of forests, and 10% of grasslands.

Uganda faces land degradation and erosion covering 60% of its total land area, the majority of which is in the highlands of the South-west. Ethiopia also faces land degradation mostly in its highlands, especially in the Amhara region. It is estimated that Ethiopia loses 4% of its GDP due to land degradation.

In Sudan, approximately 1,200,000 km2 of land has degraded in varying degrees. The most degraded zones are the arid and semi-arid regions in the Northern half of Sudan where 76% of the country’s population resides. In Egypt, the North-western delta faces highest degradation due to contamination and increased salinity.

Common Causes of Land Degradation in the Nile River Basin

Some of the causes for land degradation in the Nile River Basin are as follows:

Population Pressure: Growing population in the Nile River Basin countries puts immense pressure on land and its resources leading to severe degradation and reduced outputs. For instance, the majority of the population in Egypt and Burundi, 98% and 58% respectively, live in the Nile Basin. In Kenya, 70% of the population lives in 12% of the country’s land area which is suitable for rain-fed cultivation, thereby putting immense stress on its resources.

Deforestation: The most common cause for land degradation in the Nile River Basin is deforestation. To adhere to the needs of growing population, forests are cleared and there is immense pressure on its resources.

In Rwanda, the forest area was reduced to 4700 km2 from 7000 km2 post the genocide in 1994. Deforestation also took place due to increased need for wood to construct makeshift shelters for displaced people and for cooking. Bushfires have also become common especially in the dry seasons in the Eastern and South-eastern regions of Umutara, Kibungo and Bugesera.

In Burundi, the rate of deforestation in high due to increased dependency on wood for fuel. The forest cover declined from 11.3% in 1990 to 5.9% in 2005. In Tanzania, deforestation is severe in areas populated with refugee populations. Also, wild fire is common in its grasslands.

Between 1990 and 2005, Uganda lost one-third of its forest area due to deforestation. It is estimated that at this rate, Uganda will not have any forests by 2055. Uganda loses around $ 200 million annually due to deforestation.

Deforestation is a major factor for land degradation in Ethiopia. While the forests once covered 65% of the country and 90% of the highlands in Ethiopia, by 2001 they were reduced to 2.2% and 5.6% respectively. The Blue Nile basin faces such severe deforestation that very little forest cover remains in the region. The forest coverage fell from 16% to 2% in the 1980s itself.

Over Grazing: The demand for livestock is high in the Nile River Basin. Cattle farming leads to over grazing in fertile lands, depleting its quality and productivity.

In Rwanda, over grazing is observed in range-lands especially in the North-west parts of Umutara. In Tanzania, over grazing is witnessed mostly in the Lake Victoria Zone and parts of Northern Tanzania. Over grazing accounts for 75% of the total degraded land in Sudan.

In Uganda, the cattle corridor has most of its land degraded due to over grazing – from Moroto and Kotido in the North-east through Luwero and South to Masaka and Mbarara. Leaving aside the North, most of the Corridor is seriously degraded.

Lack of Awareness: Improper farming practices, poor soil management policies due to lack of awareness also lead to land degradation in the Nile River Basin. For instance in Rwanda, only 36.6% of the total land had soil protection structures in 2005 as compared to 83% in 1998.

Climate Change: Climate change is another factor due to which there is immense land degradation. Increasing instances of floods and droughts lead to wide spread land degradation.

There are various forms of land degradation. These include

Soil erosion and sedimentation

Surface runoff and floods

Desertification and loss of natural vegetation

Sand encroachments

Sedimentation and Soil Erosion

Sedimentation has three stages. It starts with soil erosion which is essentially the removal of top soil which is then transported and deposited in different locations depending upon the flow of water or wind or gravity. Some of the causes of sedimentation include deforestation which reduces water retention thereby increasing soil erosion; floods and droughts; and changes in river flow. Sedimentation in the Nile River Basin is witnessed the most in the Nile Equatorial Region, Blue Nile catchment and the coastal belts.

Wide spread deforestation has a detrimental impact on the sedimentation levels in the Nile Equatorial Lakes and leads to increasing soil erosion. The siltation of the Nile Equatorial Lakes if combined with unusually high rainfall could lead to a rise in the lake levels which could in turn lead to flooding. The key problem sites for soil erosion in the Lake Victoria Basin are the Kagera River and the Nyando River in Kenya.

Due to its topography and torrential rainfall, the Blue Nile catchment faces high rates of sedimentation as compared to the White Nile, whose sedimentation is largely retained in the Equatorial Lakes and the Sudd region. While the Nile catchment runoff is estimated at a low rate of 5.5%, the ratio of the runoff of the Blue Nile catchment on its own is 20%.

Sedimentation has a negative effect on reservoirs built along the Nile River Basin. It clogs the area thereby reducing the amount of water that can be stored.

Rwanda

Around 40% of land in Rwanda is at high risk of erosion, 37% requires soil retention measures before cultivation, and only 23% is erosion free. Data from field research stations report soil losses between 35 – 246 tonnes per hectare annually, amounting to losses costing about 3.5% of Rwanda’s agricultural GDP. The Nyamitera River delivers 567,000 tonnes of particles in a matter of five flood days to Rwanda, of which more than half is the annual suspended sediment yield of its Nile Basin region.

Increasing use of land for tea cultivation is also leading to sedimentation in Rwanda. The Mulindi tea plantation in Gicumbi district uses fertilizers that cause soil degradation, water pollution and deforestation, which in turn results in soil erosion, floods and sedimentation in the valley.

Burundi

Deforestation, over grazing and agricultural expansion into marginal lands are the main factors leading to soil erosion in Burundi. The sediment yield of Burundi and its contribution to the Nile basin is presently unavailable. Sedimentation causes many problems in Burundi including blocking inlet channels of pump irrigation schemes, clogging hydropower turbine areas, corroding pumps among others.

Tanzania

The main type of erosion witnessed in the Lake Victoria Basin in Tanzania is sheet erosion where a uniform thin layer of top soil is washed away. In Tanzania, 61% of land area faces soil erosion with a topsoil loss of 100 tonnes per hectare per annum.

Highest soil loss within the Lake Victoria Basin is from cropland which loses 93 tonnes per hectare annually, followed by rangeland losing 52 tonnes per hectare each year. Additionally, there has been soil loss in Shinyanga, Dodoma, Morogoro, and Arusha. Also, Kagera Basin is vulnerable to soil erosion and leaching of nutrients due to its high population and poverty levels.

The Masalatu Reservoir constructed on Simiyu River receives an annual sedimentation yield of 406 m3/ km2 or 1.43 tonnes per hectare.

Kenya

The Nyanza province bordering Lake Victoria is undergoing rapid catchment deterioration due to frequent droughts, deforestation and old agricultural practices. This results in Kenya’s high sedimentation load contribution to Lake Victoria Basin through its tributaries. 61% of the basin area contributes to soil sedimentation at a rate of 43 tonnes per hectare each year, whereas the rest of the basin forms a sink area where sediments are collected.

Due to high sedimentation on the bed, the rivers Nyando, Nzoia and Sondu, and other tributaries emptying into Lake Victoria are prone to flooding. Surface runoff in wet season causes sheet, rill and gully erosion. Wind causes erosion in dry season. Nyando River experiences severe gully erosion due to heavy water runoff. The removal of the top soil is very high ranging from 90 tonnes per hectare annually in degraded areas, to 67 tonnes per hectare elsewhere.

Uganda

Major source of soil erosion to the Lake Victoria Basin is the Kibale River at 0.06 tonnes per hectare annually. Runoff in sub-catchment of Bukora is the main reason for causing soil erosion. Soil loss rates are the highest on bare soils, followed by annually cultivated land, degraded range lands and perennially cultivated land.

Lake Albert is also under threat of siltation due to inflows from Kyoga Nile, as well as Semliki River which carries sedimentation from DRC. It is estimated that 4% – 12% of GNP is lost from environmental degradation, of which 85% is through soil erosion, nutrient loss and crop changes. Also, the rate of soil fertility depletion in Uganda is one of the highest in Sub-Saharan Africa.

Ethiopia

There is high erosion in the Ethiopian Highlands. Around 1900 million tonnes of soil is eroded annually at an average of 100 tonnes per hectare. Also, up to one billion tonnes of top soil is lost each year. The Highlands face severe types of soil erosion including sheet, rill, gully and wind. It also witnesses stream bank erosion, biological, physical and chemical degradation

Blue Nile is the major contributor of sedimentation during the flood season, contributing approximately 125 million tonnes, while the Atbara contributes roughly 50 million tonnes. The flows of the Blue Nile are unregulated until they arrive in Sudan leading to an enormous amount of sedimentation at the Roseires Dam. With increased deforestation and agricultural activities along the banks of the Blue Nile, there is a substantial amount of debris added to the flow which is carried downstream.

The proportion of runoff to sedimentation is higher for the Atbara River which is due to its geographic location in a drier region than the Blue Nile and also due to a relatively longer period of dry season followed by heavy rainfall in a relatively short period. Sedimentation peaks three weeks before rainfall peaks as rainfall washes away soil loosened due to loss of moisture during the dry season.

A decline in crop yields has been witnessed at a rate of 1 to 3% on cropland and 2.2% in Ethiopian highlands. It is estimated that the cost of land degradation due to soil erosion to Ethiopia could be about $2 billion in 25 years or $80 million each year. About 80% of the losses are from reduced crop production and 20% from reduced livestock production. Soil nutrient depletion reduces crop production by 885,330 tonnes annually amounting to losses of around 14% of agricultural contribution to Ethiopian GDP.

Sudan

Soil erosion is leading to rapid siltation and loss of functionality of reservoirs and irrigation schemes in Sudan. The small reservoirs get silted quicker. Irrigation schemes are witnessing major damage due to siltation which is leading to a reduction in water transported to crop lands. For instance, crop water requirements are no longer met in the Gezira and Rahad irrigation schemes.

River band erosion along the Blue Nile River has been witnessed with most affected areas lying downstream of Roseires Dam, Singa to AlSuki. River widening in the region also leads to bank erosion where irrigable land is lost as has been witnessed in the main Nile and Atbara River sections. Around $1.5 million worth of economic losses have been witnessed via the loss of mature date palm trees as a direct result of bank erosion.

Egypt

The Nile Bank is witnessing bank erosion due to the corrosive action of sediment free waters as witnessed in Sudan past Roseires Dam. Agricultural land is depleting at a rate of 13,000 hectares on an annual basis due to bank erosion. Increase in coastal erosion and extensive erosion of the Nile Delta is being witnessed due to lack of sedimentation and increase in salinity levels.

Sedimentation in Reservoirs

Sedimentation is the single greatest problem reservoirs face in maintaining their functionality for water storage, as well as for hydropower generation. Hydropower generation is reduced during peak sedimentation periods as debris gets caught in the turbines and need to be shut down for cleaning. Sedimentation stuck in the cooling mechanism of the hydropower plant leads to loss of efficiency in energy generation and also requires shutdown for repair. Also, silt adds to the wear and tear of the plant which decreases the lifespan of the machinery, depending on the abrasiveness of the mineral content in the silt. Hydropower generation is often stalled during floods to clean turbines and prevent damage resulting in very low power generation during flood season.

Sedimentation also leads to reduced water storage capacity which results in less water for irrigation and cost of construction to raise the dam to maintain storage capacity. Currently, the cost of clearing sedimentation is prohibitive at $625 million ($5 to clear 1 m3 of silt, about 125 MCM is being cleared per year).

Roseires Dam

The primary mandate of the Roseires Dam is to ensure that runoff levels are maintained to meet irrigation and water storage requirements. The Roseires Dam is losing considerable parts of dead water storage capacity, as well as live storage capacity. In 1966, its storage capacity was 3,329 MCM which has been reduced to 1,920.89 MCM as of 2007, leading to a 37% decrease in storage capacity. The Roseires Dam’s height has been elevated in order to mitigate losses in functionality and another elevation project is being currently discussed.

Aswan High Dam in Egypt

Aswan High Dam has 100% trap efficiency of sedimentation which means that waters are almost perfectly sediment-free beyond the Aswan High Dam. Sedimentation transported to the reservoir and deposited there is practically negligible from December to June, peaking from July to September, reducing in October and November to none in December. Aswan High Dam is losing considerable part of live storage capacity, as opposed to dead storage capacity which was designed to absorb sedimentation. The reservoir’s total operational span has been reduced to 362 years from an initial estimate of 500 years as a result of sedimentation.

Desertification

The African continent, with the Sahara desert in the North and the Sahelian belt below, is vulnerable to desertification. This condition is exemplified with increasing instances of drought and famines. The causes of desertification are complex, including both direct and indirect factors such as:

Cultivation, inappropriate agricultural practices and overgrazing

Unsustainable animal husbandry and pastoralism

Climate change including reduced rainfall

Population growth pressures

Poor land use and management practices

Lack of soil and water conservation structures;

Removal and loss of vegetation;

Deforestation and land clearing;

Total dependency on natural resources for survival;

Human activities comprising technological agents (water pumps, boreholes, dams) and institutional mechanisms and policies.

Desertification in the Nile River Basin

East and South-east regions of Rwanda show increasing desertification trends due to increase in population and migration leading to over exploitation and degradation of land. People from densely populated provinces in the North, for instance Ruhengiri, Gisenyi and Byumba, and Butare and Gitarama in the South, are moving towards the least populated provinces in the East including Umutara, Kibungo, Kigali and Ngali in the South East.

In Burundi, the area of Imbo witnesses long dry spells leading to a gradual decrease in water resources, especially in the levels of Lake Tanganyika with a tendency towards desertification. Since 1999, there has been a strong variability of rainfall with a tendency for a long dry season from May to October (6 months) in the lower altitude outlying areas like Kumoso, Bugesera, and Imbo.

In Tanzania, the main reason for desertification is expanding agriculture rather than overgrazing by pastoralists. Around 33% of Tanzania is affected by desertification. The coastal areas face pressure from intensive cultivation and fuel wood gathering.

In Kenya, 80% of its area is estimated to be threatened by desertification with up to 30% of the population affected by desertification and drought. Drought and increasing population are key factors that enhance desertification in Kenya. The Nyika Plateau and the Coastal Region are affected and threatened most by desertification. Also, the woodlands are prone to drought and desertification, primarily due to slash and burn methods of land preparation. Kenya’s drylands occupy 88% of the land surface area, and have a population of 10 million people. Approximately 50% of livestock and 70% of wildlife are located in these drylands.

In Uganda, the North-east, especially the Cattle Corridor has been witnessing overgrazing, soil compaction, erosion and the emergence of low-value grass species and vegetation which have subdued the land’s productive capacity, leading to desertification. Some dryland districts like Moroto, Nakasongola, Karamoja and Kakuuto in Rakai are experiencing desertification.

Around 71% of Ethiopian land is prone to desertification including its highlands and lowlands. The Rift Valley suffers immense desertification and land degradation. Desertification threatens Ethiopia’s agricultural productivity, wherein more than 80% of the population depends on various forms of agricultural production. Also, 95% of the farms are small-scale and depend on rain-fed agriculture. Ethiopia suffers a loss of $139 million per year due to reduced agricultural productivity.

Sudan and parts of Egypt are more prone to desertification in the Nile River Basin. Egypt has experienced accelerated desertification of rangelands in the last few decades. Presently, 45% of rangelands are severely degraded, 35% are fair, 15% are good, and 5% are excellent. It is reported that 11,000 hectares of land has been lost due to desertification. Parts of Western Egypt fall into the Sahara and are hot and dry areas which are extending into the mainland. Increasing evaporation has also led to drying out of one of the Toshka Lakes.

Egypt witnesses various forms of desertification such as:

– Degradation of irrigated farmland due to low quality water in irrigation

– Degradation of rain-fed farmland (Northern coastal belt and Northern Sinai)

– Degradation of rangeland (Northern coastal belt) through overgrazing, plant covers degradation

– Sand Encroachments from the Western desert on the Nile Valley land (Southern Egypt) and on the High Aswan Dam reservoir (in Egypt and Sudan).

Desertification in Sudan

In terms of desertification, Sudan is the largest and most seriously affected country in Africa. The arid and semi-arid lands cover an area of 1.78 million km2, constituting around 72% of the total area of the country. There is moderate to severe land degradation in the desert and semi-arid regions in the Northern half of Sudan. The Western part of Sudan (in the Sahel region) is most prone to drought and increasing desertification, especially the states of Darfur, Kordofan, Khartoum and Kassala. The total desertification between Darfur and Kordofan is 22% i.e. 200,000 km2. A decline in precipitation has caused a stress factor on pastoral societies in these two regions, thereby contributing to conflict.

There is a very strong link between land degradation, desertification and conflict in Darfur. In northern Darfur, increasing population growth, lack of resources and environmental stress led to conflicts which were further sustained by political, tribal or ethnic differences. As a consequence of desertification in Darfur, there has been increased mortality due to famine and disease, a decrease in total water and land availability, quality of water and land (including fertility), production of major staple foods, and deaths of domestic animals.

It is estimated that since the 1930s, there has been around 50 to 200 km Southward shift of the boundary between semi-desert and desert. This boundary is expected to continue to move Southwards due to declining precipitation. The remaining semi-desert and low rainfall savannah, which represent 25% of Sudan’s agricultural land, are at considerable risk of further desertification and could lead to a 20% drop in food production.

Sand Encroachment

Instances of desert encroachment in Sudan are increasing, whereby the entire strip of the country along the Nile especially between Delgo and Karima in Northern Sudan is threatened. Sand dunes on the Eastern bank of River Nile in Sudan and encroachments in North-central regions can threaten the river’s course. Sand encroachment is also affecting the productivity of soil which has been witnessed extensively in the Gezira scheme and also in some areas of North Kordofan, North Darfur and Kannar in the Northern State, Sudan.

In the Dongola-Merowe region of Sudan, the area covered by sand dunes increased from 51.2 km2 to 61.2 km2 between 1976 and 1996 and decreased to 35.1 km2 in 2000. This decrease could be attributed to an increase in the area covered by gravel and/or coarse sand. In Egypt, active sand dunes and encroachments occupy more than 16.6% of the country’s total land area. Sand encroachment in Egypt is further enhanced by the erratic rainfall, active winds, and scarcity of plant cover. Some inactive sand accumulations have been noticed in the Eastern side of the Nile delta and in the Sinai Peninsula.

Types of Desertification Processes Underway in Sudan

Climate-based conversion of land types from semi-desert to desert

The least drought resistant vegetation fails to survive and reproduce. For instance, in Northern Darfur and Northern Kordofan, this is manifest in the widespread death of trees during drought events which are not followed by recovery. The desert climate is estimated to move Southward by approximately 100 km over 40 years.

Degradation of existing desert environments, including wadis and oases

At least 29% of Sudan is desert, within which there are hundreds of smaller wetter regions resulting from localized rainfall catchments, rivers and groundwater flows. It was discovered that all these areas were moderately to severely degraded, primarily due to deforestation, overgrazing and erosion.

Conversion of land types from semi-desert to desert by human action

Activities such as deforestation, overgrazing and cultivation result in habitat conversion to desert, even though rainfall may be sufficient to support semi-desert vegetation. One of the problems is the conversion of dry and fragile rangelands into traditional and mechanized cropland.

Chapter 5

Water Quality

Several factors pollute Nile waters, in particular faecal coliform bacterial contamination caused by lack of sanitation facilities and a high dependence on pit latrines, leading to presence of animal and human waste alongside open water bodies. Additionally, agricultural fertilizers and pesticides discharge high concentrations of nutrients and phosphates that runoff and leak into ground and surface water. Also, chemical pollution from industrial waste, mining activities and domestic sewage are released into water bodies without any effective wastewater treatment. Furthermore, sedimentation and siltation caused by deforestation, land degradation and soil erosion impact overall water quality. Lastly, poor planning practices, weak infrastructure and inadequate wastewater treatment systems add to the untreated water discharge.

Some of the impacts of water pollution are death and destruction, loss of livelihood and income, and health hazards.

The problem with a transboundary water resource in terms of water quality is that, polluted water from one area flows into the other area. This is specially witnessed in the Lake Victoria Basin. Water Hyacinth is another transboundary issue between the countries as it has a tendency of spreading fast and also leads to increased evaporation. Pollutant loads are washed away along with runoff and sedimentation loads which lead to water quality deterioration further downstream, rendering it non-viable for drinking purposes.

Rwanda

The main sources of water pollution are domestic, commercial, industrial, agriculture, water hyacinth and mismanagement of wetlands. Due to increased population and agricultural practices, inadequate sanitation facilities, there is an extensive use of fertilizers and pesticides. Also, wastewater from rural towns and villages containing faecal pollution are left untreated, giving rise to water borne diseases.

In River Nyabugogo, there have been high rates of Iodine at 7.62m per litre. Additionally, there are large concentrations of Copper at 1.3mg per litre, Fluoride at 1.85mg per litre, Ammonia at 1.7mg per litre and Sodium at 105.3mg per litre. Also, Hexavalent Chromium was found ranging between 0.09 to 0.28 μg per litre.

Although the Rwandan Ministry of Lands, Environment, Forest, Water & Mines (MINITERE) and ELECTROGAZ have laboratories in place for water monitoring, the data is insufficient. The water drinking standards have been defined but have not been adopted yet.

As a result of eutrophication by water hyacinth and agricultural pressure, Lakes Mihindi and Muhazi in Southern Rwanda are diminishing in size.

Burundi

There are several types of water pollution including bacteriological pollution from animal waste, organic pollution due to waste effluent from coffee processing plants, and industrial pollution via chemical fertilizers such as nitrates, phosphates and pesticides. Some of the causes of pollution are high demographic density, lack of latrines and waste dumping, and mining activities resulting in discharge of heavy metals and arsenic, especially in River Kanyaru’s tributary, Nowgere.

Bujumbura accounts for 90% of industries in Burundi. However, data regarding industrial pollution is unavailable and not much has been achieved in monitoring and managing water quality due to under-resourcing of laboratories.

Tanzania

The water quality in Tanzania is affected by natural factors and human activities. The former comprises high fluoride concentrations and salinity in natural waters. The latter includes discharge of municipal and industrial wastewater, run-off from agricultural lands, and erosion encompassing high concentrations of nutrients, pathogens, BOD and COD levels. Additionally, gold mines in the Lake Victoria Basin consist of heavy metal pollution.

Tanzania has no comprehensive national program for monitoring the quality of water or pollution even though water utility companies are required by law to monitor the water source and quality of water they supply.

Kenya

Water pollution in Kenya is caused by point and non-point sources such as agricultural activity, urbanization, industry, leachates from solid waste tips, sediments, salts, fertilizers and pesticide residues. Additionally, municipal sewerage plants discharge untreated wastewater into surface watercourses, causing significant health hazards and localized eutrophication. Tanneries, pulp and paper mills, coffee processing factories, breweries and sugar cane processing facilities do not have effective wastewater treatment plants and their effluents contribute organic loads, heavy metals and other toxic substances.

The point pollution sources include sugar, paper, and fish industries, and also municipal sewage, oils and lubricants, marine workshops, petrol stations, human wastes and refuse from market and urban centres and fishing villages. The main non-point pollution sources comprise high nitrate, phosphate and pesticides from poor application of agricultural chemical and soil erosion.

The Kenyan Lake Victoria Basin has a population of 12 million people and a low depth of approximately 6 meters, thereby causing an inability of catchment areas to perform purification of water. Although only 8% of Lake Victoria falls into Kenyan territory, tributaries such as Sio, Nzoia, Yala, Nyando and Mara are already severely polluted and contribute further to the lake pollution.

Uganda

The increased demand and use of pesticides, fungicides, herbicides and fertilizers is impacting the water quality in Uganda. Agricultural practices account for 50% of nitrogen and 56% of phosphorus into the Lake Victoria Basin. Additionally, the exploitation of petroleum threatens the overall ecosystems of Lake Albert and Edward Basins. The Northern end of Lake George, Uganda, and its associated wetlands receive localized metal pollution from a former copper mine and tailings left after metal extraction. There is a concentration of zinc, copper, cobalt and nickel in the lake.

The point pollutants comprise domestic and industrial effluents, sewage and municipal effluents, and effluents from mining activities and breweries. The non-point sources include agricultural run-off and atmospheric deposition. The urban centres in Uganda contribute 77% of the pollution into Lake Victoria. Kampala alone contributes about 65% of Biochemical Oxygen Demand (BOD), 73% of nitrogen and 73% of phosphorus from all urban centers around Lake Victoria.

Some of the primary concerns for water quality include siltation, atmospheric deposition, industrial effluents, agricultural run-off, eutrophication, water hyacinth, discharge of heavy metals and residues from chemical herbicides and pesticides, wetland degradation, limited water quality assessment and monitoring, population pressure, and heavy metal discharge from copper mines.

Between 2000 and 2003, all the rivers monitored had high total coliforms and e-coli, due to faecal contamination. During this period, alkalinity levels in the rivers feeding Lake Victoria fell between 20-200 mg per litre. Above 100 mg per litre could indicate that the rivers have a self-cleaning capacity but high alkaline levels make water non-potable and limits irrigation use.

If the present treatment plants in Kisumu performed optimally, the BOD loads could be brought down by 50 per cent. Water supply to both municipalities and villages is also affected by water hyacinth. In municipalities, water hyacinth interferes with the water-intake points causing blockage, which lowers the quantity of water pumped – in Kisumu the water supply has dropped from 20,000 m3 to 10,000 m3 per day. The Kagera sub-catchment has a total of 33% discharge into Lake Victoria, thereby accounting for the highest total phosphorus and nitrogen concentrations into the Lake. Also, there are significant pollution loads from urban establishments.

The Mining Act 2003 prohibits mining activities from discharging toxic waste into water bodies. According to the Water (waste discharge regulations) Act of 1998, all industries are required to hold a waste discharge permit which requires them to install wastewater treatment equipment, monitor effluents by environment inspectors, and pay waste discharge fees. A statutory instrument dated 1999, defining the standards of water effluents to be discharged into water bodies, is also in place. All developments along the wetlands, lakeshores and river banks require environment impact studies to ensure water catchment conservation according to the National Environment (Wetlands, River Banks and Lakeshore Management) Regulation of 2000.

Ethiopia

In Ethiopia, the main industries are textiles, soft drinks, food, metals and tannery; however, most of these industries do not have any waste treatment facilities The notable point pollutants are chromium, hydrogen sulphide, dyes and caustic soda. The non-point pollutants include domestic solid waste and effluents. Additionally, faecal pollution from cattle, pesticide and fertiliser run-off also contribute significantly.

Ethiopia has no national water quality monitoring scheme or national laboratories monitoring the Nile. Data regarding heavy metal concentrations and nutrient levels that cause eutrophication are unavailable. Available data on water quality is spatially and temporally limited but shows that water quality is generally satisfactory with the exception of high potassium and fluoride content. Ethiopia contributes 140 million tonnes of sediment to the Blue Nile annually owing to torrential rainfall over a short period, highly erodible terrain and increased agricultural activity and habitation related deforestation in the Ethiopian Highlands.

Sudan

In 2002-04, a survey along the Blue and White Nile and their confluence in Khartoum was conducted to identify sources of water pollution. The results of this survey indicated the following:

1. There were high BOD values at the Blue Nile and the confluence.

2. There were high oil and grease values at the power stations on the Blue Nile.

3. There was an alarmingly high chromium (Cr+6) level in the White Nile

4. The White Nile is more bacteriologically polluted than the Blue Nile.

5. Ethiopia contributes approximately 140 million tonnes of sediment load into the Nile which causes siltation of reservoirs and irrigation canals and blockage of hydro-electrical turbines.

6. Since 2004, Sudan has being using neo-nicotinoids for agricultural purposes, thereby causing problems related to pesticides.

In 1974, Sudan passed an Act on the application of pesticides; this act was updated in 1994. Unfortunately, the law is not carried out by small and poor farmers, who often cause incidents of pollution due to unsafe application of pesticides. Several parts of the country have serious water quality problems; for instance, the Gezira region, Lake Nubia, and Eastern and Western parts of Sudan. Additionally, urbanization in cities like Khartoum and Wad Medani enhance pollution in the Nile, especially via sewage.

The Sudanese Ministry of Irrigation and Water Resources and the Irrigation Department conduct regular studies on sedimentation. The Permanent Joint Technical Commission for Nile Waters (PJTC) is responsible for co-ordination between Sudan and Egypt in Nile water management. The National Water Corporation under the purview of the Ministry of Engineering Affairs caters to drinking water supplies and is supervised by the Minister of Irrigation and Water Resources. The Natural Water Directorate under the Ministry of Irrigation and Water Resources runs the Ground Water Wadi Directorate (GWWD) and Nile Water Directorate. GWWD’s laboratories conduct tests from eight stations at three sites on Mongolla, Soba, and Dongolla thrice a year. Generally, water quality at the sites are satisfactory though high rates of Ammonia (1.29) and turbidity due to total suspended solids (upto 26950 mg/l) was found. A chemical analysis of industrial effluents and pesticide survey is needed to better understand these contaminants in the Sudanese context.

Egypt

Generally, the Nile waters that pass through Egypt undergo a process of cleansing as they pass through the reservoir of Lake Nasser. However, water quality is still a cause of concern because of changing practices along the Nile valley. The primary causes of water pollution are increase in population, agricultural drainage, industrial development, domestic and wastewater pollution.

Presently, the annual industrial water usage is 5.9 BCM, of which 550 MCM is discharged untreated into the River Nile. There are approximately 125 major industrial plants within the Nile Valley, of which 18% encompass existing industries, and 15% consist of heavy metal loads.

As a consequence of excessive use of fertilizers, that is almost 6.5 million tonnes each year, there is runoff and seepage into surface and ground water.

Also, upward seepage of sea water is leading to high salinity levels in the Delta. In the Delta region, the Rosetta Branch receives a higher concentration of organic compounds, nutrients and oil and grease than the Damietta Branch.

Currently, there is no toxicity study available but BOD levels are found to be highest from sugar and other agro-processing industries and chemical industries. It is well known that chemical, iron and steel industries dump toxic wastes but specific information regarding the effluent concentrations is unavailable.

In 1962, the Egyptian Ministry of Water Resources and Irrigation introduced a law catered to water quality management. The ministry set up 290 surface water locations for water monitoring purposes. It issues licenses for domestic and industrial discharge but the compliance inspections are under the purview of Minister of Health and Population. Furthermore, a ministerial committee was formed to intensify water pollution management and recommend remedial procedures, including industrial and domestic wastewater projects, networks for monitoring and controlling water quality, canals and agricultural drains management in the form of five year plans. In 2000-01, 34 industrial plants were monitored closely to prevent untreated discharge of about 100 MCM per year directly into the Nile to combat industrial pollution of the river.

Water Hyacinth

Water hyacinth, an aquatic weed found in tropical and sub-tropical regions is a cause of concern in the Nile waters. This is because in addition to creating physical obstacles to irrigation, navigation and hydro-electric inlets, they also increase evapotranspiration. Generally, water hyacinth causes water to evaporate thrice as much as native vegetation does. The reasons for its rapid growth and survival are sedimentation, and domestic and industrial waste.

Most of the Nile Basin countries witness cases of uncontrolled water hyacinth, especially Lake Victoria. In addition, Rwanda and Burundi’s Kagera River, Tanzania’s Pangani and Sigi Rivers, Kenya’s Naivasha River, Uganda’s Kyoga and Kwania Rivers, Sudan and South Sudan’s White Nile River, and Egypt’s main Nile River and Northern lakes also suffer from water hyacinth infestation.

The most serious incident of water hyacinth infestation was observed in the late 1990s. In 1995, 90% of Uganda’s coastline was blanketed by weeds. In 1998, approximately 20,000 hectares of Lake Victoria was covered in water weeds. In 2010, water hyacinth receded to cover 518 hectares of Lake Victoria due to conscientious efforts made by the Lake Victoria Environment Management Project. However, Lake Victoria’s waters will always be at threat due to the inflow of water hyacinth through Kagera River and the presence of favorable nutrients that enhance the growth of the weeds. In sum, the flow of River Nile is reduced by one-tenth due to water hyacinth in Lake Victoria.

Some of the consequences of water hyacinth include breakdown of hydroelectric stations due to choking of coolers and generators; decline of fishing industry because of lack of access to fishing grounds; health hazards such as spread of malaria, bilharzia, cholera and filariasis; economic impacts comprising high costs for manual removal of weeds; clogging of canals and rivers reducing water flow and increasing evapotranspiration; and difficulty in navigation on rivers.

Chapter 6

Groundwater

Some countries of the Nile River Basin have several alternate sources of water, while others are heavily dependent on the Nile Waters. Other than the surface water from lakes and rivers of the Nile Basin, groundwater is a very important addition to the total availability of water. While the Nile Basin countries are still negotiating their share of surface water, they are yet to begin the debate on groundwater sharing. The average ground water recharge in the Nile River Basin is around 400 BCM a year while the seasonal storage and soil moisture averages 100-150 BCM and 30 BCM per year respectively.

Factors that Impact Groundwater

The availability of groundwater depends on three main factors:

Morphological factors: Some land structures are more suitable to capturing groundwater than others. While extremely flat structures may also lead to evaporation, they also help the infiltration of rainwater for storage and ruptured structures cause surface runoffs. Hence, groundwater levels depend on the land form.

Climatic factors: Groundwater levels are dependent on the amount and the intensity or rainfall and its ability to reach the surface area after hitting intersections. Another variable among the climatic factors is the rate of evaporation and evapotranspiration which in turn depends on winds and temperatures.

Geological factors: Geological factors are most essential in terms of storing the groundwater and making it available for usage. The soil needs to have pores to hold the water and allow circulation and it is important that there are no toxic substances in the soil which may make the stored water unusable.

The main problem with forecasting groundwater potential in the Nile River Basin is absence of data and the involvement of different variables to calculate it. Other than the non-renewable ground water which exists due to tectonic factors or fossil fuels in aquifers, renewable ground water can be measured by interaction of various climatic features on the soil column. Factors to consider include the water retention capabilities of the soil column, groundwater runoff and its interaction with surface water.

Variables related to Groundwater in the Nile River Basin

The Need to Address Trans-boundary Aquifers: Most of the countries get their groundwater through direct precipitation/rainfall which recharge their aquifers or from fossil waters stored in their deep aquifers and through seepages or interaction with surface water. These aquifers extend across various countries. Currently, there is no law governing groundwater, specifically which is derived from these shared aquifers. This issue might crop up in the future as dependency of an aquifer of one country might affect the groundwater levels of the other countries involved. Also, pollution by a country might affect the groundwater in the shared aquifer.

Table 1: Trans-boundary Aquifers in the Nile River Basin countries

Aquifers

Countries

Nubian Sandstone Basin

Egypt, Sudan, Chad, Libya

Baggara Basin

Sudan, Central Africa – South Darfur, Kordofan, Unity States

Sudd Basin

Sudan, Ethiopia, Eritrea

Gedaref Basin

Sudan, Chad

Disa Sandstone Basin

Sudan, Uganda

Sedimentary Aquifers

Uganda, Kenya, Tanzania

Ogaden (Juba)

Ethiopia, Kenya, Somalia

Kilimanjaro Aquifer

Kenya, Tanzania

Merti Aquifer

Kenya, Somalia

Kagera

Tanzania, Uganda

Ruvumu

Tanzania, Mozambique

Precambrian Basement

Tanzania, Burundi, Rwanda, Northern DRC

Crystalline Aquifers

Uganda-Rwanda-Tanzania, Uganda-Kenya-Sudan, Uganda-DRC

Understanding the Interaction between Surface Water and Groundwater: It is essential to understand the overlap between the groundwater and surface water and their effects on each other.

Surface water pollution may also lead to groundwater pollution. This has been noticed in Lake Victoria where polluted water from the lake had seeped in as ground water which was of poor quality and unsuitable for drinking purposes.

In the coastal regions this overlap may lead to high levels of salinity.

Over abstraction of groundwater may lead to reduction in the surface water levels. For instance, surface water from Lake Alemaya, located in the Ethiopian highlands is rapidly shrinking due to abstraction of groundwater from adjacent aquifers.

Weak Groundwater Infrastructure in the Nile River Basin: Groundwater infrastructure requires a lot of improvement in the Nile River basin. This infrastructure needs to be planned and regulated, while existing systems need to be maintained and repaired from time to time. In Tanzania, over 90% of piped systems failed due to unavailability of fuel to pump water out. In Kenya, Transparency International found cases where water was unaccounted for and meter readings were being tampered with. Groundwater monitoring systems are very new to these countries. Kenya installed 100 of these for the first time in 2003. Also, many countries lack deep wells and pumping systems and rely on shallow wells and boreholes. For example, Ethiopia till the last decade had only shallow, community-built wells and boreholes.

Country Profiles on Groundwater

Rwanda

Rwanda has many lakes and springs with total renewable surface water amounting to around 9.5 BCM. The total groundwater availability in Rwanda is estimated to be around 7 BCM which completely overlaps with its surface water.

Rwanda shares the crystalline aquifer with Uganda and Tanzania and hence it has rocks with comparatively low levels of permeability but does have groundwater potential which needs to be studied. Pollution levels have not specifically been studied in terms of groundwater but it is understood that pesticides from cultivated lands, garbage dumping and industrial waste do lead to pollution of groundwater.

In the extremely flat lands of Rwanda water is supplied by gravity systems which are expensive due to the usage of long pipeline and PVC. According to the WHO and UNICEF’s Joint Monitoring Programme for Water Supply and Sanitation, there has been 65% improved access to water as of 2010 of which 77% is through groundwater.

Abstraction of groundwater in Rwanda could help the agriculture sector which is mainly rain-fed by providing yearlong, continuous supply of water for crops. Also, groundwater is not as badly hit as the surface water levels during the dry periods and could be used to mitigate drought.

Burundi

Burundi is a highly mountainous country with an exception of Ruzizi river plain near Lake Tanganyanika. The aquifers in Burundi are really deep and do not have a great yield. Burundi has 7.47 BCM of water, all of it which merges with its surface water.

Tanzania

Tanzania has three major lakes – Victoria (northwest), Tanganyika (west) and Lake Nyasa (Eastern rift valley), which it shares with other countries. Nile only forms a part of Tanzanian waters in the Western part of the country.

Over 75% of Tanzania has an underlying basement of crystalline rocks, mainly Precambrian which form the base for groundwater. Other kinds are the coastal sediments of limestone and sandstone as well as volcanic rocks. Around 30 BCM of groundwater is available in Tanzania out of which 26 BCM overlaps with surface water. Groundwater contribution to the basin is through river base flow entering Lake Victoria and Tanganyika from the South. The major rivers are the Kagera on the Western side and Mara River on the Eastern part which flow into these lakes.

Groundwater is accessed through bores, shallow wells and springs and these contribute towards 25% of total domestic water supplies and 4% of other uses with the 50% of the usage from the rural sector. Many of the heavily populated industrial urban centres also depend heavily on groundwater. Many industries have constructed private wells to get supplies. Singida, Mtwara, Lindi and Dodoma get 70 to 80% of their water from groundwater.

To meet the Millennium Development Goals (MDG), the Tanzanian National Rural Water Supply and Sanitation Programme aims to provide access to safe water for 74% of the rural population by mid-2015. For this an additional 14.5 million people need to be added to the water supply coverage by 2015 at a cost of $533 million.

The threat to groundwater in Tanzania is from over-exploitation and failure of groundwater infrastructure at many places. With severe drought conditions in Dar-es-Salaam in 1996-97, 200 bore wells were constructed as an emergency measure, of which only 92 are in service now. Also, due to gold mining, mercury levels in the water nearby have been deemed high.

Kenya

There are three main aquifers in Kenya – the Merti aquifer bordering Kenya and Somalia, the Kilimanjaro aquifer shared with Tanzania and the Lake Victoria Basin. Lake Victoria accounts for 50% of water available in Kenya and has the highest amount of groundwater storage. The total ground water availability in Kenya is estimated to be around 3.5 BCM out of which 3 BCM overlaps with surface water.

In terms of utilization of groundwater in Kenya, agriculture utilizes 24.17% of the water extracted, while public supply uses 19.45% and 6.04% is used for domestic purposes.

Groundwater quality is affected by man-made activities in Kenya. Groundwater is found in shallow aquifers in Kenya and surface level pollution affects it. The industrial waste disposal in Lake Victoria, fertilizers and pesticides used by agriculture are some of the examples of rampant pollution. Also, Kenya is a water scarce country in terms of surface water and hence there have been cases of over-abstraction of groundwater in certain areas. Many boreholes either require repairs or are abandoned due to low quality of water or low yield.

The Kenyan Water Act of 2002 brought changes to the water sector where distribution of water was decentralized to many service providers and the Water Services Regulatory Board (WASREB) was put in place. Groundwater could be accessed in Kenya through bore wells for public use and piped water from where it merges with the fresh water. Records of the Water Resources Department suggest that boreholes were drilled in Kenya since 1920 and by 2006 Kenya had around 15,400 of them. Of these, 53% are for public water supplies, 24% for agriculture and 6% for industrial purposes.

The problem in Kenya is of access to the available water resources. The distribution of water is not balanced and extraction infrastructure is either non-existent or needs repairs leading to expensive supply of water.

Groundwater could be utilized to improve irrigation facilities in Kenya where 17.05% of the land is cultivable while only 6.4% of it is cultivated with only 0.12% having access to irrigation.

Uganda

The total estimated groundwater available in Uganda is around 29 BCM which completely overlaps with surface water. 90% of the land area is covered with ancient crystalline rocks which are covered with a ‘regolith layer’ consisting of weathered rocks on the surface and solid rocks below. Other rocks are found near the Eastern Rift valley which contains volcanic material or crater lakes which have fractured surfaces.

Groundwater is extracted from both the fractured rocks, as well as the Regolith layer. There is immense potential to extract more groundwater from the regolith layer which is also considered cost effective as it is available close to the surface. It is also renewable as water first settles in this layer before it percolates downwards.

Land area in Uganda is mainly rural with agriculture as the most important factor of the economy, with groundwater as the most important source of potable water. Groundwater is estimated to supply around 80% of water requirements in the rural areas. Water supply in Uganda stands at 61% for rural supply and 68% for urban supply. Groundwater is extracted by deep boreholes, shallow wells and protected springs approximately 20,000, 3,000 and 12,000 in number respectively, mainly constructed for domestic water supply. Supply in the urban areas is mainly through piper waters.

Rural Water and Sanitation Strategy and Investment Plan 2000-2015 was formulated in Uganda with a goal to increase water supply to 95%. It is estimated that to achieve this, the number of hand pump bores and shallow wells are to be increased to 40,000 and 30,000 respectively. In the Urban Water and Sanitation Strategy Plan, the supply is planned to be increased to 80% (40% private connection and 40% public connections). There is also a plan to increase access to piped water to 250 more towns where 50% of the water will be based on ground water reserves.

The threat to groundwater in Uganda is due to lack of access to the water resources. In many places the hand pumps and bores are broken. More than availability, the distribution of water is a problem area. Also, water quality suffers at various places especially renewable groundwater which is close to lakes and wetlands.

Eritrea

The Setit river course bordering Ethiopia is Eritrea’s most important river although 90% of its catchment area lies outside. Hence, groundwater resources have the most pressure on them to cover this gap and provide water to Eritrea.

Eritrea shares a part of the Nubian Aquifer which extends from Egypt towards Saudi Arabia which has deep levels of groundwater storage linked to fossil waters. Most of the area is covered with Precambrian basement rocks which have undergone metamorphosis and collected sedimentary and volcanic rocks which collect water in their fractures.

There is 0.5 BCM of groundwater in Eritrea of which 0.4 BCM overlaps with surface water. According to a report on development and management of groundwater in Eritrea, “the available water resources hardly cater to around 15% of the requirement of the people”. Also, there are high levels of fluoride content found in groundwater in rural Eritrea leading to extensive dental fluorosis from drinking water.