TOO MANY INTERACTIONS: Water, Climate Change and Transboundary Context

We saw in the previous posts that climate change has had an huge impact on Africa, in general. I find it relevant to stay on the same region as in previous posts because it illustrates a lot of contrasts that this continent faces.

-Actual situation:

The continent of Africa is tremendously touched by climate change through extreme events like droughts and floodings, driving its natural environment to be degradaded, particularly in the form of desertification. In this way, we will see that various aspects of north-west of Africa can be characterized as interacting each other.

Hydrology interactions:

African hydrology is changing from these last decades. The global rate of precipitations in the northern regions of North Africa have demonstrated a significant decrease (Isabelle Niang et al., 2014) and the african climate is now characterized by extreme events.

Succession of droughts and floodings leads to the degradation soils, driving them to increase the amount of run-offs. Thus, the way that watertables, as well as watercourse flows operate is modified.

Decrease of water infiltration in soils

Source: Wikipedia 

According to H.H.G. Savenije et al. (2008), the close relationship between watersurface and groundwater is a very important aspect of hydrology and has a crutial impact on water supply.

Interaction between groundwater and water surface

Source: SouthEast Texas Water 

Transboundary interactions:

As previously mentioned West Africa is characterized as an 'interzonal' freshwater transfer area, understandably as a hydrological link between arid and wet areas IUCN Regional Office for West Africa establishing a water distribution between groundwater and precipitations is quite distinct.

Complementary distribution of groundwater and precipitations

(post1)

Also, as hydrological system goes through different climate areas, national boundaries do not reflect the boundaries of african hydrology. Unlike land, water allows countries to be interdependent. The interaction between upstream and downstream causes many issues for governments. Environmental changes are becoming a big challenge in this aspect.

This Map can help the understanding of interzonal fresh water dimension, as well as the transboundary aspect.

Source : IUCN Regional Office of West Africa

-Consequences on water resources

According to IUCN Regional Office of West Africa, water resources are vastly threatened by climate change. Because of the increasing extreme events, the availability of the water resource is highly uncertain and more often not usable.

GROUNDWATER RECHARGE

With regards to groundwater recharge, there are two main threats;

Decrease of precipitations:

First, the decrease of precipitations is the principal issue. As watersurface and groundwater are closely interlinked (G.Mahe, 2009) less precipitation leads to a lower recharge and decrease of its' quantity.

Degradation of soils:

Second, I understand that the watertable recharges are compromised by the capacity of soils to permit water to penetrate in the ground. Instead of going down on the ground to apply watertables, water is more likely to run-off on surface, or even evaporate because of vegetation degradation. 

Both reasons dramatically jeopardize the reliability of this source of water -which is used in both urban water management (S.M.A. Adelana et al., 2008) and rural water use, mainly agricultural activities (Mark Giordano, 2005).

Installing a water pump

Source: International Water Management Institute

WATER SURFACE:

Dams and reservoirs: Most dams and reservoirs are highly impacted by climate change. Two principal causes are responsible for the recent inefficiency of dams in Africa.

Instability of flows:

First instability of flows in rivers dramatically affects african activities that rely on reservoirs and dams for their water supply. This instability due to the tendancy of extreme events (floodings and droughs) is responsible for the decrease of water availability in term of quantity and quality.

For instance, in 2002 and 2003, Ouagadougou has been touched by a tremendous water supply shortage because of the decrease of the level of water in reservoirs supplying the entire city (IUCN Regional Office of West Africa).

On the other hand, just three year before, three dams in Nigeria were opened because of the extreme floods (IUCN Regional Office of West Africa) leading to enormous consequences on population, and water supply.

After dam opened in 1999

Source: Safer Nigeria Resources

Siltation:

The second cause of degradation in efficiency of dams is the siltation of river basins (NICHANE M et al. , 2015) generated by consequences of desertification: wind erosion due to lack of vegetation cover, and water erosion due to the bad capacity of water penetration in the ground (land degradation) and increase in run-offs and floods.

Siltation of river

Source: Wiz Science

TRANBOUNDARY:

The transboundary disposition is another cause of issues of this region and how environmental change raises the magnitude of its impacts.

Basically, tranboundary river basins are difficult to manage. The interaction between upstream and downstream are not often taken in account for big dams projects. This is particularly observable in floodplains regions (W. M. Adams, 1992) with large-scale water management established after independance.

Also, environmental changes are likely to increase this complexity. "Water grabbing" leads to water scarcity downtreams during droughts. In the same way, opening dams because of floodings upstreams (Nigeria for instance, as I explained above) drives to shift the problem downstream.

-Other consequences:

Except water availability, these issues also affect other aspects :

Energy :

Besides, the effects of hydroelectric dams which jeopardize the energy supply in transboundary context (NICHANE M et al. , 2015). That's what happened in 1988 in Ghana. Decrease of water level in Lake Volta had huge consequences on operating of Akosombo dam that provide energy in three countries leading to a serious crisis in economic activities (IUCN Regional Office of West Africa).

Pollution:

We also can mention another environmental issue that affects this transboundary aspect of this region: pollution. Pollution in rivers made in upstream can dramatically drive the ecological modifications downstream crossing boundaries and leading to political conflicts.

To conclude, the complexity of interactions between hydrological components and also between countries combined with climate changes generate a lot of conflicts. First between countries themselves, but also between governments and citizens. Water supply being highly affected drives the unequal distribution of geographical and social segregation.