Saturday, October 10, 2009
Senegal: Diama Dam On our way back to Dakar we stopped at the Diama Dam, built in 1984 near St. Louis at the mouth of the Senegal River. This dam now traps manatees in the river and although they have well over 600 km of river to use, as well as Lac de Guiers and much more area during the rainy season when the river floods the plains, these manatees are isolated here with no way to leave or breed with other manatee populations. In the dry season, food plants can be scarce, and although there doesn't seem to be much targeted hunting, manatees do get caught in fishing nets and drown fairly frequently. And of course they get caught behind smaller dams near Matam and Kanel. At the southeastern end of the river they are hemmed in by a hydroelectric dam in Mali. So there are many challenges for this population.
The dam in Mali provides power far into the interior of Senegal; these power lines near Kanel are over 200 km away from the dam.
But there's good news too. There is very good habitat in Lac de Guiers (a huge man-made lake which provides the drinking water for all of Dakar and water for farm irrigation for hundreds of miles surrounding the lake) with lots of the manatees favorite food plants. Dams keep the water in Lac de Guiers high year round and the manatees have learned they no longer need to migrate back to the river during the dry season.
Lots of water lilies and grasses in Lac de Guiers
And as I mentioned in my previous post, they have lots of food on the flood plain during the rainy season. From what I've seen so far, I think the Senegal River supports a fairly healthy manatee population, and I'm happy that many people, government agencies and private organizations here are interested to conserve them.
Downstream and seaward of the Diama Dam is the Senegal River delta, and it is unknown if manatees still use this area as well. It will be interesting to try to find out!Water flowing out of the Diama Dam towards the ocean.