Environmental Engineering Reference
In-Depth Information
8
Water: Surface and Subsurface
8.1
Introduction
8.1.1
General
Hydrology and Geohydrology
Hydrology
is the science that deals with continental water, its properties, and its distribu-
tion on and beneath the Earth's surface and in the atmosphere, from the moment of its pre-
cipitation until it is returned to the atmosphere through evapotranspiration or is
discharged into the oceans.
Geohydrology
or
hydrogeology
is the science that is concerned with subsurface waters and
their related geologic aspects.
Chapter Scope
This chapter describes the conditions of engineering significance pertaining to surface and
subsurface water (groundwater), analytical procedures, groundwater and seepage control,
and environmental planning.
Exploration methods are described in
Chapter 2
and the measurement of water tables
and pore-water pressures in
Chapter 4.
Permeability, its measurement, and typical values
for the coefficient
k
are presented in
Section 3.3.
8.1.2
Engineering Aspects
Surface Water
Flooding
is a geologic hazard that occurs naturally; however, its incidence is increased by
human activity.
Erosion
of the land is also a natural occurrence detrimental to society; its incidence is also
increased by human activities.
Water supply
for human consumption is stored in surface reservoirs created by the con-
struction of dams.
Subsurface Water
Water supply
for human consumption is obtained from underground aquifers that must be
protected from pollution, especially since the water is often used without treatment. As
groundwater is a depletable natural resource, its extraction, conservation, and recharge
require careful planning.
