TITLE:
Modelling of the Hydrogeological Behaviour of the Tassette Aquifer: Study of the Possibilities of Exploiting This Aquifer as an Alternative against the Limestone Problem in the Commune of Thies
AUTHORS:
Saidou Ndao, Famara Seydi Ba, Papa Babacar Diop Thioune, Diadioly Gassama
KEYWORDS:
Modelling, Tassette, Hydrogeological Model, Aquifer, Aquifer
JOURNAL NAME:
Natural Resources,
Vol.14 No.10,
October
31,
2023
ABSTRACT: Senegal’s drinking water supply comes on the one hand
from groundwater and mainly from Maastrichtian and Paleocene aquifers. The
Tassette area included in the Thies region has such potential that the
Paleocene is currently exploited to cover a certain part of Dakar’s important
water needs. In addition, the city of Thies
is itself confronted with the problems of limestone present in its
drinking water and generally creating problems of scaling pipes. A water
transfer is therefore a possible option to deal with this situation. This study
will consist of modelling the Tassette aquifer to determine if it will cover
Thies’ water needs over a period of 20 years. To assess the responses of the
groundwater to pumping at this level and the changes that may occur, a
numerical hydrogeological model is necessary. In order to have a better
overview of the area, boreholes and piezometric tests were carried out,
highlighting the different characteristics of the aquifer and the water it
contains. Based on these, the model was
developed according to a mesh system and more precisely by
discretization and simulation according to the finite difference method from
the Visual Modflow Flex software. The results observed for this modelling show
that the city of Thies cannot be supplied as a whole. This mining model also causes brackish water
intrusion. On the other hand, the additional withdrawal of a certain quantity
of water compared to the current situation does not have as great negative
impacts and would still partially meet the expectations of this modelling.