TITLE:
Evolution of the Physico-Chemical Quality of the Water in the Manantali Dam Reservoir from 1989 (One Year after Impoundment) to 2022
AUTHORS:
Joseph Mbeur Faye, Saïdou Ndao, Louis Eugène Victor Sambou
KEYWORDS:
OMVS, WQI, Senegal River, Physicochemical Parameters
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.11 No.9,
September
28,
2023
ABSTRACT: The Manantali dam is located on the Bafing River in
the Kayes region of Mali. It is the main tributary of the Senegal River. The
water released from the dam provides year-round access to water for drinking,
irrigation and livestock watering. The
Manantali dam regulates the river’s flow, generates energy and supports
agricultural development in all three countries (Mali, Mauritania, and Senegal). The aim of this article is to
monitor changes in the physico-chemical quality of the water in the
dam’s reservoir from 1989 (one year after the dam was impounded) to 2022. In order to carry out this work, we analysed the evolution of physico-chemical parameters in Stations 1 and 3 of the dam, on the basis of fluctuating water levels in the
reservoir. The results obtained show a similarity
in the parameters measured at the two stations, except for iron content,
which is higher at Station 3. The average pH is weakly basic (7.44 at Station 1
and 7.29 at Station 3) and the average water temperature is between 26.5°C at Station
1 and 26.2°C at Station 3. The average conductivity of the water at Station 1 is 38.8 μS/cm and 39.8 μS/cm at Station
3, attesting to low mineralization of the water. The oxygen content of
5.75 mg/L at Station 1 and 5.00 mg/L at
Station 3 shows good oxygenation of the water, which is favorable for the development of most fish and aquatic
plant species. Ammonium levels of 0.02 mg/L at Station 1 and 0.06 mg/L at Station
3 show that the water is not contaminated.
In addition, the Water Quality Index (WQI) was calculated, showing excellent water quality at Station 1 and
good quality at Station 3. Overall,
the results obtained show that the water is of good quality, enabling the authorities of the Organization for the
Development of the Senegal River (OMVS) to achieve their development objectives.