This study will use the mixed methodology since it is an assessment on the impacts of climate change on water resources in west Africa. It will be a combined qualitative and quantitative study. This study will benefit from the qualitative methodology because climate change is a very complex topic and the qualitative research design offers a flexible structure as the design can be constructed and reconstructed to fit the objectives of the study (Maxwell, 2012). The qualitative method offers a thorough and appropriate analyses of the climate change issue making it easier to understand (Flick, 2014). As a result, the complex issues can be understood easily. As for the quantitative methodology, its data analysis is less time consuming as it uses the statistical software such as SPSS (Connolly, 2007). In this study, the researcher will primarily need secondary data coming from reputable sources and the statistical formula of correlation or ANOVA will be used to find out the relationship between different water resources variables and climate change. This study will use data on variables related to water resources, coming from reputable organizations like the United Nations as well as from the websites of the different government departments of Ghana and Senegal. By using that secondary data, the researcher will be able to present an objective assessment on the impacts of climate change on the water resource systems in Senegal and Ghana. The quantitative method also allows the measurement of variables and its relation to the issue being studied (Kauber, 1986). Furthermore, the other pertinent secondary data that will be presented in this research is derived from previous work done by various authors on similar topics across the world. Data from authors in Africa, will also be used to meet my research objectives.
Data acquired from such sources will be analyzed by using a number of software like excel, sigma plot, GIS and other relevant software that might be useful to meet the set objectives. The results derived will be presented in Tables, GIS maps, Bah and pie-chat respectively. Authors, co-authors and all reference journals will be properly cited. In a situation where the researcher won’t be able to find data of the sample countries due to lack of in-depth research information, data or information from the United Nations and its agencies will be used as a representative data. The timeline of the data to be used in this study will be from 2000-2019.
Chapter 4
Interpretation and Analysis of Data
The Situation in Ghana
A Regional Picture of Climate Change Impacts on Ghana’s Water Resources
Climate change has been identified as a major problem in managing the water resources of Ghana. It is expected to aggravate the problem of diminishing water resources in the Volta Basin. Figure 1 below shows a map of the Volta Basin. One can see that it traverses, in varying degrees, the area of six different countries - Benin, Burkina Faso, Ghana, Côte d’Ivoire, Mali, and Togo. However, for purposes of this study, the discussion here will be limited to Ghana only. The map shows that more than 84 percent of the basin area lies in Burkina Faso and Ghana.
Figure 1: The Volta Basin
The Volta Basin occupies the central part of Ghana covering about 45% of the country’s total land surface. In the north, at the upper part of Lake Volta, it rises to a height of about 150 to 215 meters above sea level. In the west, the elevations at the Konkori Scarp as well as the Gambaga Scarp in the north reach from 300 to 460 meters. In the south and southwest, the basin is less than 300 meters and it is marked by the Kwahu plateau. The basin has poor soil called the Voltaian sandstone. Annual rainfall averages between 1000 and 1140 mm. The area is mostly savanna and the woodlands usually contain red ironwood and shea, depending on the local soil and the climatic conditions (Owusu, 2015).
Several rivers feed into the basin. Among them are the Black Volta; the White Volt which is a major tributary of the Red Volta; the Main Volta, which is formed below the confluence of the Black and White Volta; the Oti; and the Lower Volta below the Akosombo and Kpong hydropower facilities in Ghana. The major landmark in the basin is the 8500 km2 Volta Lake, which was formed from the damming of the Main Volta at Akosombo for hydropower production in Ghana.
The water resources in the Volta Basin is under serious strain due to poor climatic conditions and the competing demands for the resource by the different countries that traverse it. The temporal distribution of rainfall or the time duration of the rainfall event and the spatial distribution of rainfall or the extent of the area that experiences the rainfall event is highly variable thus affecting the streamflow in the basin. This means that most streamflow only happen in just a few months of the year with almost or little flow throughout much of the year, particularly in the northern regions of the basin.
The rainfall decreases from the south to the north. It stands at 1600mm per annum in southern Ghana to less than 500 mm per annum in the northernmost parts of the basin in Mali. Consequently, the evapotranspiration, increases moving northwards. Rainfall is unimodal in the northern and middle sections of the basin, meaning, there is no alternation of humid and dry months within the wet season. It is then bimodal in the southern part of Ghana, meaning, it has a wet season with two rainfall peaks, separated by at least one dry month.
The drainage system of the basin moves water from the more arid regions in the north to the wetter regions in the south of the basin. Mean annual observed streamflows for the main sub-basins of the Volta is at its maximum annual flow through the turbines at Akosombo running at 1200 m3. It constitutes the Lower Volta streamflow. It is followed by the Main Volta at 500m3, while the Oti, Black, and White Volta have streamflows ranging from 200m3 to 280m3. The southwestern and the coastal (SWC) basins are the river basins in Ghana outside the Volta system and they encompass roughly 30 percent of the country. The southwestern river system is composed of the Ankobra, Bia, Pra and Tano rivers and it is the wettest in the country. The coastal system is composed of the Amisssa, Ayensu, Densu, Kakum, and Nakwa rivers and they are drier in average terms than even the part of the Volta system in Ghana. All of the nine sub-basins in the SWC basin system are stand-alone basins as each discharge directly to the sea.
The Climate Change Impact on Ghana’s Agricultural Sector
One sector of the economy that is dependent on water resources is agriculture and because of the variability of the availability of water, it is the sector in the economy of Ghana that is the most at risk if the country’s water resources are affected. Right now, 30% of Ghana’s GDP is dependent on the agricultural sector, employing around half of the population. Although annual growth is expected in this sector, its vulnerability to the country’s water resources may affect it. Another factor affecting the availability of water for agricultural needs is the presence of hydraulic infrastructure. These hydraulic facilities can be found in northern Ghana and they have been used primarily for agricultural purposes especially during the long dry season. Moreover, there are large-scale irrigation systems like those in Botanga, Tono, and Vea in northern Ghana. Furthermore, there is the huge Volta Lake in the country, powering the nearly 1200 MW hydropower generation facilities at Akosombo and Kpong in the Lower Volta with turbine flow of up to 1200 m3/s. Although these facilities help in the irrigation and the provision of electricity in the country, their use of the country’s limited water resources also affects other sectors like agriculture.
The Situation in Senegal
A Regional Picture of Climate Change Impacts on Senegal’s Water Resources
Figure 2: Senegal River Basin
Long-term observational records and climate projections done in Senegal have shown that the freshwater resources in the country are vulnerable and can be strongly impacted by climate change. Several impact studies in the country have shown that its water resources are significantly impacted by climate change. The focus for the water resources in Senegal is in the Upper Senegal Basin (USB). Its source is in Guinea and the Senegal River flows through the western Sahel region in Mali, Mauritania and Senegal and has a catchment size of about 289,000 km2. The Senegal River has three main tributaries – the Bafing, Bakoye and the Faleme and they provide over 80% of its flows and are within the upper basin. The basin occupies a large north-south precipitation gradient ranging from 200 mm/year in the north to more than 1800 mm/year in the south. The end result of the precipitation can be clearly seen in the natural vegetation of the region. In the north is the semi-arid savannah which gives way to a sub-humid forest in the south.
The flow rate of the river is determined mainly by the rainfall in the upper basin. The high water season lasts from July to October while the low water season begins in November and lasts till June. The high water season peaks at the end of August or beginning of September and ends quickly by October. Another vital characteristic of the Senegal River is the inter-annual irregularity of its flow volume. This has been a big problem for the valley for a long time because it lowered the possibilities for much needed agricultural production due to the slim geographical area. The arable land that could be farmed after the flood varies from 15,000 ha to 150,000 ha, depending on the gravity and time duration of the flood (National Academy of Sciences, 2003).
Bakel is considered to be the reference station of the Senegal River due to its location below the confluence with Faleme, the last major tributary. At this station, the average annual discharge is about 690 m3/sec, which corresponds to an annual input of around 22 × 109 m3. The annual discharge ranges between a minimum of 6.9 bm3 and a maximum of 41.5 bm3.
The Climate Change Impact on Senegal’s Water Resources
Both surface and groundwater are relatively in large supply in Senegal. Ditto for the people’s access to improved water sources across the country. In fact, more than 93 percent of urban Senegalese and 67 percent of rural Senegalese populations have adequate access to clean water. However, the country also has many challenges like increasing demand for clean water, sharing the water resources with its neighbors resulting in disputes regarding access to quality water, water pollution and inadequate infrastructure in the transport of clean water make the availability of the country’s fresh water resources quite sensitive to heightening climate variability and future climate changes. The amount of rainfall – its temporal and spatial distribution – affects the amount of groundwater and surface water. The country is no stranger to these situations. Between 1981 to 1989, the country’s fresh water resources decreased by around 36% due to droughts and rainfall deficits. Even the groundwater levels were affected, going down 5 meters to 10 meters in the north and 15 meters to 20 meters in the south. Moreover, the poor rainfall rates and its erratic variability can lead to the reduction of the aquifer recharge rates, making it more difficult to avail of clean water. Even now, coastal communities, including Dakar will experience saltwater intrusion into their coastal aquifers affecting the availability of clean water. Salinization can also make arable land useless and this increased salinity will be exacerbated by rising sea levels and lessened rainfall. The lack of rain will increase demand for irrigation. For now, the agricultural sector of the country consumes more than 90 percent of its water resources, and with only 4 percent of the land currently irrigated. The increased evaporation rates of retention in ponds and dams, along with the poor rainfall will also affect the country’s electric supply as hydropower production provides more than 10 percent of the country’s needs.
Researchers have pointed out three major climate stressors and the risks that come with them. First climate change stressor are the rising temperatures. Among its consequences are the lessened supply of freshwater resources, which means fresh water from ponds, lakes, rivers, and streams and even groundwater is reduced. This also means faster evaporation of surface water and reduced recharge of groundwater which means the water table will be too low for access, consequently making people drill deeper into the water table to access more water. Another climate change stressor can either be reduced or variable rainfall or an increase of heavy rainfall events. This could lead to increased salinity of groundwater affecting the amount of available natural drinking water sources. There is increased flood risk and associated erosion as well as soil salinization which can affect the agricultural produce of the country. Sedimentation may also happen leading to the destruction and loss of aquatic environments, wetlands and coral reef communities. Furthermore, due to the lack of rainfall, the demand for irrigation will increase, further adding stress to the availability of freshwater resources. The third climate change stressor is rising sea levels. This can lead to reduced hydropower production or reduced potential for future investment in hydropower. This could affect the economy of Senegal, especially if the power needs of business investors are not met.
The Climate Change Impact on Senegal’s Agricultural Sector
Agriculture employs more than 70 percent of the Senegalese workforce and is the backbone of the rural economy. Cereals like millet and sorghum are key subsistence crops, while groundnuts, a main cash crop, are grown on 40 percent of cultivated land and employ up to 1 million people. Smallholder agriculture, which is predominantly rainfed, is already stressed by overexploitation of land, degraded soil and limited extension services. Climate change is expected to magnify most of these challenges. Groundnuts are sensitive to both rainfall variability and higher temperatures, and crop models project a 5–25 percent decrease in yields. Rainfall has been inadequate and decreasing in some areas, affecting important growing regions near Thies and Dioubel. While clear evidence does not yet exist, climate factors may also increase the frequency of Desert Locust infestations, which cause significant crop losses throughout West Africa.
There are two main climate change stressors that can have an impact on Senegal’s agricultural sector. The Earth’s rising temperatures can lead to reduced crop quality and yields particularly for maize, sorghum, millet and groundnuts, all rainfed plants USAID, 2016). This is due to increased demand for water, water stress and reduced soil moisture. Water stress happens when the demand for water exceeds the available amount during a certain period. This causes the deterioration of fresh water sources in terms of quantity and quality. The quantity problem pertains to aquifer over-exploitation and dry rivers while the quality problem refers to eutrophication, organic matter pollution and saline intrusion (Morgan, 2017). Another consequence is reduced available land for the growing of ground nuts. Ground nuts play a major part in Senegal’s economy, currently producing one percent of the world’s output. The groundnut sector directly and indirectly employs 1 million Senegalese people or about seven (7) percent of its population. In fact, the country has a “groundnut basin” where this product grows. It covers a large tract of land in central and western Senegal. The product requires between 500 and 70 mm or rain to achieve good yields but droughts have affected the harvest in recent years (Adama, 2017).
Another climate change stressor is reduced or variable rainfall which have led to several catastrophic consequences (USAID, 2016). This has led to increased occurrences of locust infestations. This lack of precipitation reduces the habitat of the locusts. The high locust density causes the locusts to enter the gregarious phase where they form swarms and migrate, often wreaking havoc to the grain and grass vegetation in their path (Pribyl, et al, 2019). This can also lead to heat stress and reduced water and feed supplies to livestock. Heat stress affects livestock health causing metabolic disruptions, oxidative stress, and immune suppression leading to infections and death (Lacetera, 2019). Finally, it can cause food shortages and problems in food security. This is because climate change affects food production and availability and the stability, utilization, quality and access of food systems (Mukerji, 2019).
The Climate Change Impact on the Catchment Runoffs
Water harvesting is the collection of runoff for productive use. Runoff is generated by rainstorms and its occurrence and quantity are dependent on the characteristics of the rainfall event (temporal and spatial distribution).
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Monday, April 27, 2020
An assessment of the impacts of climate change on water resources of Senegal and Ghana - Research Methodology
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