Dams vs. Floodplains

This blog post is another example of the importance of indigenous agricultural approaches in Africa and how the intrusion of experts from the global north have disrupted these approaches and the damage it has brought in economic and social terms. 

The Senegal river is the second longest river in West Africa, 1800 km (Degeorges and Reilly, 2006). The Sahelian drought in 1970 resulted in the creation of the Senegal River Basin Authority in March 1972 (‘Organisation Pour la Mise en Valeur du Fleuve Sénégal’) by the governments of Mali, Senegal, and Mauritania with two main goals: to promote irrigation and power generation (Degeorges and Reilly, 2006). This was followed by the construction of 2 dams, Diama Dam (1986) and Manantali Dam (1988), both inaugurated in 1992 (Degeorges and Reilly, 2006). Diama dam is located on the Senegal and Mauritania border and was built with an intention to avoid the salinisation of water during the dry season; Manantali Dam was built mainly for hydroelectric production and agricultural purposes (Poussin, Bossa, Ndiaye, Cisse, Martin, Bader, Sultan and Ogilvie, 2020).  In 1997 it was approved by the World Bank to offer a loan of $US38 million to help finance the installation of turbines for HEP despite several environmental and socio-economical concerns raised previously (Degeorges and Reilly, 2006). 

The problem with building these two dams has been on the traditional flood-recession farming, which is practiced in almost all West African countries. The installation of dams has reduced flooded areas and the duration of the flood and therefore affecting the practices of flood-recession farming. The geomorphological, hydrological, and ecological processes going on in the wetland area allow water retention, flood control, be used for agriculture, but also for fishing, grazing, and water supply (Adams, 1993). Around half a million people depend on agriculture for food (Degeorges and Reilly, 2006), and directing the floodwater away from these wetlands also affects the economic benefits provided for the local communities. 

Map to show Diama and Manantali dams on Senegal river

The two main areas affected by interrupting the traditional flood-recession farming have been fisheries and agriculture. 

Fisheries 

Normally, the floodplains offer a habitat for breeding for various fish species, but during the dry seasons the fish have to leave the floodplain and move to the main channel until the next flood season (Degeorges and Reilly, 2006). All the fish caught from the floodplain were sold and/or consumed, but while the dams have disrupted the floods, it has forced families to start eating imported fish. The main fishery areas in Senegal and Mauritania have completely collapsed and fish production has dropped by 90% (Degeorges and Reilly, 2006). 

Food 

One of the main crops grown in floodplains is rice. It has become important in culinary traditions and food security strategies (Poussin, Bossa, Ndiaye, Cisse, Martin, Bader, Sultan and Ogilvie, 2020), but is limited by the unpredictability of floods due to dams. The consumption of rice increased from 163,000 tons in the 1960s to 1.5 million tons in 2015 (Manikowski and Strapasson, 2016). At the same time, the population of Senegal grew from 3.2 million to 15 million including the per capita consumption of rice, which increased from 51 kg per person per year to 100 kg per person per year (Manikowski and Strapasson, 2016) throughout in which the Senegalese government began to promote and encourage rice production schemes and joined the program for the constructions of dams (Manikowski and Strapasson, 2016). However, after the dams were built it became clear that their benefits were not as initially expected. 

Thus, the problems the dams have created in agriculture and fishing has resulted in a socio-economic crisis, where young males have migrated out of the country to find a job in other countries to get money (Degeorges and Reilly, 2006) and caused conflicts between farmers and for scarce water (Pearce, 2017). The dams which were supposed to bring economic development have instead caused the poorest in the region to risk their lives and leave. 

Ngadda River in Nigeria

Despite the negative impacts of the dams, the government of Senegal has taken limited actions to try to improve the situation. Before the dams were built the government and stakeholders should have conducted more hydrological and economic analyses for the downstream impacts, especially on floodplains, as it has greatly affected the local communities. 

Another important idea as a solution to save floodplains is the opportunity for artificially controlled floods to control the unpredictability in flooding. However, a previous study done on the Senegal river in 1988-1990, the engineers argued that there were more advantages coming from maximising HEP generation (Adams, 1993). Even if artificial floods can be demanding as it requires an understanding of downstream floodplain hydrology and effective real-time monitoring systems (Adams, 1993), with the years of work and the experience of experts who manage the dams on the Senegal river there is no reason why they should not be capable of handling that.