Hydrology in Senegal: Navigating diversity and sustainability

Senegal, situated on the Western coast of Africa, boasts a highly diverse river network which provides lifeline for it’s population.

Located on Africa’s western coast, Senegal is home to a hydrological network that is essential to the survival of local communities, agriculture, and ecosystems, in addition to its storied cultural legacy. Senegal’s hydrology offers a variety of opportunities and problems, ranging from the renowned Senegal river basin to the lush Casamance region. We explore the importance and intricacies of Senegal’s main river basins in BWI’s latest blog post.

Senegal’s Hydrological Diversity

Senegal’s hydrological network, which includes its lakes, rivers, and coastal wetlands, is essential to the country’s economy and population. The most notable river in the nation, the Senegal River, originates in Guinea and flows through Senegal, creating a hydrological border with Mauritania along the way. The river is of great importance when it comes to agriculture, fishing, and energy generation, as do other smaller bodies of water like the Gambia River.

Seasonal Dynamics

Senegal has very distinct rainy and dry seasons because of the monsoon season in West Africa. The rainy season, which runs from June to October, usually replenishes the rivers and groundwater rivers in the country. Variability in rainfall patterns, however, can cause floods or droughts, which have an impact on water availability and agriculture.

River Basins: The building blocks of Senegal’s Hydrology

Senegal’s hydrology is centered around several key river basins, each playing an essential role in the country’s water management and utilization.

The Senegal River Basin

Location: Northern Senegal

The Senegal River Basin is Senegal’s largest and most economically valuable hydrological resource. The river, which has its source in Guinea, naturally divides Senegal and Mauritania. Spanning 1086 kilometers, The Bafing, Bakoye, and Faleme rivers are some of the principal tributaries of the basin.

Did you know: The early Mediterranean civilizations were aware of the Senegal River’s existence! It was named Nias by Claudius Ptolemy and Bambotus by Pliny the Elder. It was even referred to as ‘the river of gold’ in ancient times.

Significance: The Senegal River Basin is the lifeline for irrigation, farming, livestock grazing, and hydroelectricity in the country. The Manantali Dam, located in the basin, is a major source of hydropower for Senegal and surrounding countries. Additionally, the river basin is an integral part of several ecosystems, including wetlands and floodplains.

Challenges: The Senegal River Basin faces difficulties with regard to water availability and quality due to sedimentation and upstream dam development. Furthermore, successful intercountry cooperation and management are needed to resolve disputes over the distribution of water.

The Casamance Basin

Location: Southern Senegal

Casamance enjoys a more humid temperature than the rest of Senegal, which is conducive to lush flora and a wide variety of animal species. The river is 320km long, with a basin area of over 20000 square kilometers.

Significance: The Casamance Basin is essential to agriculture because it supplies water for cash crops like cashews and peanuts, as well as for rice farming and orchards. Since the river sustains aquaculture and numerous fisheries, fishing is also a major economic activity. Furthermore, the wetlands and mangrove forests in the Casamance basin provide crucial habitats for marine species and migratory birds.

Challenges: Water management and sustainable development activities have been hampered by political unrest in the Casamance region. Additionally, the biological integrity and water quality of the basin are threatened by deforestation, pollution, and excessive land use.

The Saloum Basin

Location: Central Senegal

The Saloum River and the wetlands that surround it, notably the Saloum Delta, a UNESCO Biosphere Reserve, are all part of the Saloum Basin. Freshwater marshes, tidal flats, and mangrove forests constitute the basin’s topography. The river is 250 kilometers long and located in the Sine-Saloum natural region. Furthermore, it forms a delta with the Sine and flows into the Atlantic Ocean.

Significance: The Saloum Basin facilitates a wide array of commercial functions, such as fishing, farming, and tourism. Creatures like fish and crabs use the mangroves in the delta as breeding grounds, which in turn aid in sustaining local economies and preserve biodiversity. The basin is also significant culturally, with historical sites and traditional fishing communities scattered around its borders.

Challenges: Pollution, excessive fishing, and habitat destruction pose a threat to the Saloum Delta’s biological equilibrium. These issues are made worse by the effects of climate change, such as rising sea levels and altered precipitation patterns, necessitating the use of adaptive management techniques.

The Gambia River Basin

Location: Eastern Senegal

The Gambia river flows in Senegal and Gambia before reaching the Atlantic Ocean. The basin’s main tributaries include the Falémé and Bao Bolong rivers. The length of the river is over 1100 km with a basin area of approximately 80,000 square kilometers.

Did you know? The Gambia river, during the 14th century, played an important role in the West African trade network, where exchanging goods such as salt, shellfish, iron was quite common.

Significance: The floodplains of the Gambia River Basin, where rice farming is common, are crucial for agriculture. Along with being a means of transit, the river empowers trade and business between Senegal and Gambia. In addition, the basin supports savannas and gallery forests, two ecosystems essential to the preservation of biodiversity.

Challenges: The ecological integrity of the Gambia River Basin is in jeopardy due to deforestation, soil erosion, and land degradation. Furthermore, the construction of dams upstream, especially in Guinea, may modify river flow and sediment movement, affecting communities and ecosystems downstream.

The Need for Sustainable Water Management

Sustainable water management techniques are critical as Senegal deals with issues including urbanization, climate change, and population increase. Monitoring and decision-making related to water resources can be improved by utilizing technology such as remote sensing and hydrological modeling. BWI‘s discharge forecasts help analyze water flow patterns, thereby contributing to better water resource management, and overall sustainable development. 

Read more about HydroSpace4Senegal Project, for which SAED, MEOSS, and BWI are working together. 

Hydrology in Senegal