Water and Construction - Hydrogeology: Objectives, Methods, Applications - page 235

C HAPTER D1
Water and Construction
Groundwater plays an essential role in most projects undertaken by
humans, and the hydrogeologist holds a more and more important place
within the teams studying and following civil engineering operations.
The hydrogeologist must, indeed, specify the infl uence of the projected
construction on the behavior of the aquifer, evaluate environmental effects,
and defi ne the eventual modifi cations or compensatory measures to be
adopted.
Diffi culties linked to groundwater can concern all types of construction
or development, whether during their construction or during their use, and
whatever their nature, their size, or their degree of permanence. Problems
are resolved by setting up a classic hydrogeologic study, obviously adapting
to the natural context and the particularities of the development under
consideration. This also requires that historical data and surrounding
installations be taken into consideration, enabling a solid understanding
of the piezometric fl uctuations of the aquifer over time, and the impact of
the construction on the natural and human environments of the site.
The reciprocal infl uences of construction on groundwater and vice
versa is principally determined by their respective positioning, as well as
by groundwater fl ow conditions and the inter-seasonal and inter-annual
variations of the aquifer.
1 NATURAL FLUCTUATIONS IN THE AQUIFER
The piezometric surface of an aquifer is directly influenced by the
pluviometric conditions in its environment and shows permanent variations
that regulate the state of its infl ows and its drainage possibilities.
The amplitude of variations changes signifi cantly, depending on the
nature of the aquifer, but also from one point to another within the same
aquifer. It can refl ect as a signifi cant rise in the water table during periods