Inflows into lake Chad

The Komandugu-Yobe River is providing the northern pool of the lake Chad. As I already pointed out in an earlier post, the total inflow to the lake is just about 5% and in the dry seasons, the river sometimes not even reaches the lake.

Figure 10: Wikipedia

On the first view, the situation looks quite dramatic, just seasonal inflow, several irrigation and damming programs and large wetlands upstream. Not to mention the planed Kafin Zaki Dam, which would be the largest dam in this area. But if you look closer, there could be an opportunity as well. For example, by using water more efficiently. Thomson and Hollis (1995) are naming in their paper a study from Barbier et al (1991), in which he proofed that the traditional usage of the wetland is generating more benefit than the usage of irrigation schemes.

At the moment, there are two main damming projects, which are the reducing the river flow. The Tiga Dam, which is connected to the Kano River Irrigation Program and the Challawa George Dam, which is connected to the Hadeija Valley Project. According to Barbier and Thomson (1998) these projects are causing more harm to the wetlands downstream, including lake Chad, than bringing benefits. Just by comparing the economical (agriculture, fishing, livestock) aspects and not even mentioned the ecological ones, like destroying the ecosystem of the wetlands and the ecosystem of lake Chad.

Barbier and Thomson (1998) are proposing a regulated flood release to revitalize the wetlands and increase at least temporary the river flow. I think this proposal could be a possibility for lake Chad to gain more river inflow. Especially, if the LCBC would build an alliance with the other stakeholders, who are negatively affected by the large damming projects, they could force them to do that.

Figure 11: Wikipedia

But more important for the inflows into lake Chad is the Chari Logone River, which is providing up to 95% of the inflows to the lake. Again it is a large river system, like the Komandugu-Yobe, with several damming projects. The most important one is the Maga Dam, which is connected to the SEMRY project, one of the most important rice cultivation projects in central Africa. The project was founded in the 1960s, but caused a lot of damage to the environment in the floodplain area. Therefore, the WWF and the UICN launched a project named Waza-Logone to revitalize and recover the floodplain and use the Maga Dam more sustainable. (Mouafo et al 2002)

There are lots of studies to restore the Waza Logone floodplain and the connection to the Maga Dam, but they are mostly not mentioning the affects on the lake Chad. (Loth 2004) In addition, there is a good case study concerning the river discharge, made by the BGR in 2013. But they just measured current situation, therefore it is not possible to make a statement regarding the impact of the damming to the inflow into lake Chad. Furthermore, they are trying to recover the environment, which is harmed by the dam nearby. Hence, the lake Chad is most likely the only one who gets damaged through the process of damming. For this reason, I don’t see many opportunities for the LCBC to get more water from the Chari Logone River.

To conclude, maybe there are some possibilities to increase the river inflow, the best would be at my opinion the support of a regulated flood release. This could be just a step in the right direction of saving the lake, but it is by far not enough.

Potentialities!?

Hitherto, I explained on the one hand water management solutions, which were mostly quite small and may not have the power to rescue the lake. Or on the other hand solutions, which were most likely too big to realize, for example the Inter-basin Water Transfer Project. Therefore, I want to concentrate in this post again on the causes of the drying and in particular which causes could be changed.

The effects of climate change may be important for this area, but cannot be solved from the local people. Hence, I will more focus on the man made factors, which could be changed from the local people. For instance, agriculture and irrigation and how they influences the river recharges of the lake. Which are according to Rititingar et al. (2012) on of the most important causes for the shrinking of the lake.

But not only the dropping of water levels are a problem, which are generated by irrigations schemes. In addition, if you look at the Southern Chad Irrigation Project (SCIP), which should provide 67,000 hectares with water, you will a different kind of problems. Because the project ran out of water, the canals dried up and were taken over by an invasive plant species. (Rititingar et al. 2012)

By looking at the geographical position of the lake, in particular by looking at the two main rivers, which are providing the lake with water. The Komandugu-Yobe River and the Chari-Logone River are both coming from relatively tropical and therefore rainy areas. Both rivers are providing, before ending in the lake Chad, many cities and wetlands with water. On account of that could be a potential in just increasing the river flow.

Figure 9: Tschierschke, K. 2002

In general, an even more complicated solution, because more stakeholders are involved, but with the trans boundary organisation LCBC, it could be the most powerful stakeholder. I am going to verify or falsify this personal idea in my next post by looking more specifically on the wetland areas of the Chari-Logone River and the Komandugu-Yobe River.

Inter-basin Water Transfer Project (IBWTP)

As I already wrote in my previous posts, the current situation of Lake Chad is alarming. On that account, there is a massive need for alternative solutions, which could be an inter-basin water transfer.

The idea of an inter-basin water transfer arose first in the 1960s. A water transfer, which would deliver water from the Ubangi River to the Chari River and therefore, would provide the Lake Chad with additional water. The reasons for this project were to revitalize the lake and increase agriculture and fishing. (Ifabiyi 2013)

This project stayed just an idea till 1988, where the first scheme was created by an Italian firm named BONFICA and the National Electricity Corporation of Nigeria. The goals behind this project (TRANSAQUA scheme) were mainly economical.

·      “Ensure river transportation in order to transfer goods from east to west across Africa

·      Produce electricity

·      Develop irrigation and agro-industry in the region“ (FAO Water 2009)

In 1994 the LCBC started to think about an inter-basin water transfer. Hence, a few years later in 2009 they ordered for 5.5 million USD a first feasibility study a bit modified TANSAQUA scheme. Their main goals were:

·      “Stop the drying up

·      Restore lake level

·      To facilitate the navigation and transportation of goods as well as tourism

·      Generate 700mw of electricity through hydropower

·      Regulate the Bangui river flow

·      Clear the region of land lockedness nature and achieve regional integration, cooperation and security

·      Act as catalyst for the establishment of fishery and irrigation activities

·      Promote poverty alleviation, drought mitigation and control desertification“ (Ifabiyi 2013)

The first idea to build a navigable channel from the Ubangi River to the Chari River was proven economically not reasonable. In addition, the study revealed that the channel might create problems with invasive plants and sediment transportation. But they came up with another option for an inter-basin water transfer. By using the Kotto River, the Palambo dam and the Bria dam. This scenario would be feasible and economical reasonable by creating energy. Moreover, with this scheme the Lake Chad would increase up to 5,500 km2, with 1m sea level rise. (LCBC)

An inter-basin water transfer could better the situation of Lake Chad. But the approximate costs of this project are 15 billion € (Ifabiyi 2013). Therefore, it is going to be a long way for the LCBC to conduct this project. In addition, it is a massive intervention in the environment and in the society. As you can see in many other projects the theoretical success doesn’t directly implicate that a project is going to be successful. For example, there are many damming projects in Africa, which failed. (International Rivers)

Groundwater pollution

As I pointed out in my last post, the groundwater recharges dependents on the surface water inflows and the river recharges from upstream. And at the same time it is a closed system, on that account the vulnerability for pollution could be immense, because every contamination will accumulate over the time. In particular, because of a growing population, there is a growing demand for food, therefore more production and more fertilization. Which implicates a great threat to the groundwater. While working on the project ‘Advice on groundwater resources for the Lake Chad Basin Commission’, the BGR published several reports on the quality of water in this area. I will give you a brief summary on that.

In their most recent report (Nr. 4, 2012), they used data from 441 water samples, 19 from surface water and 422 from groundwater. They looked at the anion and cation species and trace elements by measuring temperature, pH and electric conductivity. In general, groundwater quality depends on the paste of infiltration. To put it simply, fast infiltration means less minerals and less filtering than slow infiltration. The paste of infiltration depends on the flow features and thickness of the unsaturated zone. As you can see on the figure below the light-colour areas are characterized by direct recharge and therefore low in minerals, whereas the dark-colour areas are marked by low flow velocity, so the water had time to mineralize.

Figure 7: BGR Nr. 4, 2012

The danger of pollution is immense higher with a direct recharge of water than with a long time of filtration through the ground. Therefore, hand dug open wells are a particular threat to the groundwater. The next figure is showing the nitrate pollution, a pollution, which is caused by agricultural fertilizers and human or animal faeces. With more than 50mg/l nitrate (US and WHO limit, the European limit is 25mg/l) the water can harm the health of a human body. In 59 samples of water were the limit exceeded.

Figure 8: BGR Nr. 4, 2012

To conclude, there is a punctual pollution of nitrate in some areas. Mainly caused by livestock and farming and open contact to the groundwater. On that account, the BGR strongly recommend a better protection of the groundwater, especially concerning open hand dug wells. But in general the pollution of water is at the moment not the greatest threat for this area. More important is a constantly water supply to save lake Chad from drying and keep a basis of existence for all the people living there.

Advice on groundwater resources for the Lake Chad Basin Commission

Following an idea from a comment at one of my last post, concerning the groundwater availability, I found the next project at the lake Chad.

"Advice on groundwater resources for the Lake Chad Basin Commission" Again a cooperation between the LCBC and the BMZ (GIZ), but this time with the additional help of the BGR. The project runs from July 2011 to June 2017 with a budget of 4 million €.

First of all, for a better understanding of the importance or potential of groundwater, I start with a quotation from the LCBC website; “The Lake Chad Basin is one of the largest sedimentary groundwater basins in Africa“ (LCBC).

But at the same time it is also one of the largest “closed” groundwater basins, which means there are just inflows and no outflows. The inflows are provided from mainly two river systems the Chari-Logone River, which provides up to 95% of the inflow and ends into the southern pool and the Komandugu-Yobe River, which ends into the northern pool. But most time of the year, the Komandugu-Yobe River doesn’t even arrive at the lake and runs dry kilometres before. (GIWA regional43)

The groundwater basin is divided into three main aquifers, “the upper Quaternary (alluvial aquifer), the Lower Pliocene and the ‘Continental Terminal’ (Oligocene – Miocene) (both sands and sandstone)” (LCBC). The main recharge to these aquifers is provided by surface waters and by the lake. Therefore, the vulnerability is quite high.

Figure 6: BGR

„The groundwater quality of the Quaternary phreatic aquifer is suitable for domestic consumption of the local population and livestock. The Lower Pliocene Aquifer, found at depths of about 250 m with average thickness of 60 m, is an artesian aquifer intensively used in the Nigerian part of the basin. Although the reserve of the Lower Pliocene Aquifer is unknown, the exploitation of this aquifer is estimated at about 3 million cubic meters per year.“ (BGR)

The project aims to provide knowledge of sustainable use of the groundwater and the trans boundary exchange of collected data between the member states of the LCBC. The project is divided into two stages; the first stage is all about collecting data, groundwater levels and the quality of the water. The second stage concentrates more on creating a groundwater database and giving the knowledge from stage one to LCBC experts, so that they can move on by themselves. The project will finish by creating integrated water resources management strategies. (LCBC)