[Spécial Magal] : Inondations à Touba : Nappe phréatique et fuites d’eau, un cocktail explosif !
In Touba, several neighborhoods are wading through rainwater just days before the 2025 Grand Magal. The holy city is facing a cycle of flooding exacerbated by a rise in the water table caused by leaks in the drinking water supply network.
Since the dawn of time, people have prayed to God to send them rain so that it would fertilize the earth and provide them with abundant harvests, because water is the source of all life. In Touba, the holy city, where the vital liquid has turned into a source of devastation, people hold their breath every time the sky turns gray. Here, the consequences of torrential rains exacerbated by the rising water table have transformed the daily lives of the inhabitants into a veritable nightmare. A few days before the Grand Magal, the flagship event of the religious city which is preparing to welcome millions of Mouride faithful and guests from all over the world, torrential rains fell on Touba on Saturday, August 2 and Friday, August 8.
These intense rainstorms hit the holy city with heavy rainfall of 140 mm in Touba and 118 mm in Mbacké. It's a deluge on the eve of the Magal! In Ngiranène, Keur Niang, or Ndamatou, neighborhoods located on the outskirts of the great mosque of Touba - the beating heart of the Mouride city -, the populations live in apnea, praying ardently that this ordeal - accentuated by climate change - which has lasted for more than a decade will be definitively averted or at least mitigated before August 13, 2025, the date of the 2025 edition of the great Magal.
The aerial images are chilling. They reveal the extent of the damage and reveal the complexity of the flooding equation in Touba, which the government has been struggling to resolve for several years at a cost of tens of billions of CFA francs. The difficulty of the task lies in the fact that anthropogenic factors have, through a domino effect, created a chain reaction, thus producing increasingly serious consequences. This includes, among other things, the rising water table in the low-lying areas of Touba (around the great mosque, Ndamatou, Keur Niang, Ocass Market), which are today the most vulnerable to flooding.
This phenomenon of groundwater rising to the ground surface causes submersion and prevents rainwater from infiltrating. It is usually caused by prolonged heavy rains that overload the soil, but in this case, it is mainly soil sealing caused by uncontrolled rampant urbanization in Touba that prevents water runoff and infiltration. This, combined with leaks in the drinking water supply network.
Furthermore, the topography of Touba's soil does not help matters, as it reveals that the city was once crossed by a valley with low-lying areas and basins where thousands of people settled. This topography shows a sandy-clay soil that is very vulnerable to underground saturation, which presents the image of a completely soaked sponge.
These stagnant surface waters pose a danger to populations in that they threaten the safety of buildings in the affected areas. The phenomenon in question was detected in May 2021, according to Abdoulaye Cissé, project manager at the Senegalese Directorate of Water Resources Management and Planning (Dgpre) at the Ministry of Water and Sanitation. The then-supervisory minister, Serigne Mbaye Thiam, had also alerted the National Assembly in December 2021 during the vote on the budget allocated to his department.
Rising water table threatens building safety
"We were informed of the problem in May 2021. The State of Senegal had funded a rainwater drainage and surface water pumping project. The Senegalese National Sanitation Office (ONAS) had begun work in the holy city. The population alerted the technicians to this problem of rising water levels. The latter informed the ministry, then headed by Serigne Mbaye Thiam, and the authority contacted the Dgpre," reveals the hydrologist, returning to the genesis of the problem that is worsening the flooding in Touba.
A team from the Directorate General of Public Health (DGPRE) was therefore dispatched to the religious city to diagnose the problem and find solutions. "On site, we observed a rising water table phenomenon around the great mosque, the old cemeteries, and at the Ocass market. For example," he confided, "at the Ocass market, the underground passages where traders keep their stock were completely flooded. We took samples. Based on the results, we reported to the minister, who requested that further studies be conducted to better understand the phenomenon and find lasting solutions."
Thus, in July 2021, a mission from all the ministry's services and civil protection was sent to Touba. Geophysical studies, chemical analyses, water leak detection and mapping were carried out. These studies revealed that: "the quality of the water that surfaces is the same as that of the deep water table, that is to say the same that is distributed for the drinking water supply. We were therefore able to conclude that these are leaks in the water network."
More than 350 leaks detected in the water supply network
Worse still, Mr. Cissé points out: "Since we were with OFOR, we realized that the water supply network is at 50% of its capacity in Touba. That is to say, if OFOR produces 100 liters of water, it is the 50 liters that reach the taps. This means that all the other 50 liters of water are lost. These are either water leaks or uncontrolled clandestine connections that can also be subject to leaks."
This revelation was corroborated by a ministry technician who spoke to Seneweb on condition of anonymity. According to him, during a recent assessment meeting, authorities announced that more than 350 leaks had been detected in the water supply network, and the list is far from exhaustive since the study had not yet been completed. The resulting recharge was around 2,655 m3/day, according to Mr. Cissé.
Drawdown drilling, an emergency solution that drags on
In an emergency to relieve the inhabitants facing this imminent danger, drawdown boreholes were drilled, pumps installed, microbiological analyses carried out to better understand the origin of the water, the rainwater drainage and wastewater collection network reinforced, an assessment of the resistance of the buildings and precautionary measures taken to protect the population, but the problem persists.
Indeed, 22 drawdown boreholes associated with 8 piezometers (boreholes used to monitor the level to see the effect of pumping) are operating at full capacity. They are connected to the rainwater drainage network in the Touba Mosque area, around the old cemeteries, in Ndamatou and at the Ocass market. The water pumped daily is poured into the Nguélémou basin and then discharged into the Darou Rahmane basin. This solution is far from sustainable because the water rises to the surface as soon as the boreholes stop pumping.
The urgency of finding a lasting solution
A new, more in-depth study was therefore carried out in 2023, under the direction of the Dgpre, consisting of hydrogeological modeling to detect leakage areas and see the volume and level of the water table in order to find sustainable solutions. "This is a modeling of scenarios capable of definitively resolving the phenomenon of rising water tables which accentuates the flooding of Touba," says Mr. Cissé. Three scenarios were modeled and simulated: "pumping without repairing leaks; repairing leaks without pumping; both combined."
"Simulations have shown that repairs alone cannot solve the problem, nor can pumping alone. We must therefore combine the two because if we repair all the leaks in the network and the boreholes continue to pump, we could have water table drawdowns of 3 to 4 meters. So the water table will no longer be at the surface, allowing rainwater to infiltrate," says the hydrologist, who points out that a renewal of the water supply network is recommended.
"The solution," he insists, "is to continue pumping and repairing the leaks. If the two measures are combined, over a year, the problem will be solved. This will also reduce the flooding phenomenon." However, this renewal of the water network in Senegal's second largest city certainly requires significant resources and months of work, but Touba, given its size, is worth it.
Commentaires (12)
Bi dé nawétou macky sall. thieye macky boula akhou sénégalais yi dallé...
au lieu d'appeler a l'aide a la solidarité nationale ils se versent dans la manipulation semant ainsi la confusion sur la population leurs armées de tiktokeur pondent des vidéos de montages affirmant qu'il n'y'a plus d'eau a touba ils sont sans coeur ses gens la vraiment lii métina.
Tu es un idiot et tu le sais
Avec l'enfouissement les panses d'animaux issues des abattages pour le Magal et les restes de repas, les restes de proliférations bactériennes et virales, les risques sanitaires sont énormes.
Le gouvernement gagnerait à accélérer les autoroutes de l'eau
@kGB tu as parfaitement raison comme on dit chez nous la vérité sort dans la bouche des idiots je préfère l’être plutôt qu’un doué malhonnête wassalam.
C’est un échec et surtout un avertissement pour Cheikh Tidiane Dieye.
Vous ne pouvez pas espérer des résultats en vous entourant des mémés incapables suceurs de Francs.
Pour moi, vous êtes sans doute le plus volontaire de ce gouvernement. Mais…:
L'assainissement c'est une affaire Sérieuse! On ne donne pas ça à un sociologue médiocre qui ne sait que parler. C'est un émotif ce soi disant ministre dou sama nawét ! L'assainissement concerne plusieurs corps de métier à regrouper et à faire travailler ensemble pour avoir des résultats...le topographe, l'urbaniste, l'ingénieur génie civil, l'hydraulicien...et tant d'autres! Ces gens brillent par leur Incompétence et leur Populisme! Pauvre Sénégal!
Quel èchec ? Arrètez vos mensonges là . Vous n'avez que cette de merde en ligne là maintenant pour raler. Nous , on travaille et nous ne volons pas l'argent du peuple .
Tu veux quoi ? qu’il s’entoure des 4000 cadres qui ont écrit le livre solution pour régler le problème ?
Touba est mal barré alors.
Serigne MBaye Thiam s’est glorifié que la renégociation a été faite par les personnes qu’il avait mis en place…:
Vous ne réglerez rien à Touba avec eux
Touba la ville sainte sois disant directement connecté avec dieu sous le déluge, mais la ligne directe à un gros beugg. Et puis c'est pas quelques centimètres d'eau qui vont empêcher des dizaines de milliard de Sénégalais d'aller faire bombance et de faire la fête, puisque dans ce pays c'est la chose la plus importante, si on mettait les cons dans un panier, il y en aurait beaucoup qui resterait sur le couvercle !
Stp nul besoin d'lnsulter
Nos lumières pastouffe vont régler ça, no souci c'est une broutille....sinon RV en....2050
Ce qui m’étonne moy que tout le monde sait que la ville était construite sans canalisation et s’est agrandie ainsi et au fur et à mesure et tant que le Magal tombera en saison des pluies ,ça sera ainsi.Soyez honnête et arrêtez de le politiser.L’année prochaine ça sera pareil.Wasalam
Cette ville est sur une ancienne vallée aquatique, elle doit donc être évacuée, sinon le contribuable y perdra des milliards sans résultats.
En plus, même si par miracle les ingénieurs parvenaient à faire baisser le niveau de la nappe, les bâtiments commenceraient à s'effondrer du fait d'un sol devenu mouvant.
Cette ville subit l'insouciance de ses guides religieux et des régimes précédents qui ont toujours fermé les yeux sur ces fuites du réseau d'eau potable et sur l'absence d'assainissement.
J’étais tellement fier quand SONKO est allé inaugurer les orages,
On dirait que c’est pire que l’année dernière
On devrait convoquer en garde à vue tous les responsables du projet
Tant qu’on ne rend pas compte des milliards de dépenses on aura pas de résultats
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