4.3.3.2
Establishing Horizontal Flow Direction and the Horizontal Component
of Hydraulic Gradient
After the water level data and measurement procedures are reviewed to determine that
they are accurate, the data should be used to:
Construct potentiometric surface maps and water table maps that are based on
the distribution of total head, such as the example in Figure 4. The data used
to develop water table maps should be from piezometers or wells screened
across the water table. The data used to develop potentiometric surface maps
should be from piezometers or wells screened at approximately the same
elevation in the same hydrostratigraphic unit;
Determine the horizontal direction(s) of ground water flow by drawing flow
lines on the potentiometric surface map or water table map (i.e., construct a
flow net); and
Calculate value(s) for the horizontal and vertical components of hydraulic
gradient.
Methods for constructing potentiometric surface and water table maps, constructing
flow nets, and determining the direction(s) of ground water flow, are given by USEPA
(1989c) and Freeze and Cherry (1979). Methods for calculating hydraulic gradient are
provided by Heath (1982) and USEPA (1989c).
A potentiometric surface or water table map will give an approximate idea of general
ground water flow directions; however, to locate monitoring wells properly, ground water
flow direction(s) and hydraulic gradient(s) should be established in both the horizontal and
vertical directions and over time at regular intervals (e.g., over a one year period at three 
month intervals).
4.3.3.3
Establishing Vertical Flow Direction and the Vertical Component of
Hydraulic Gradient
To adequately determine the ground water flow directions, the vertical component of
ground water flow should be evaluated directly. This generally requires the installation of
multiple piezometers or wells in clusters or nests, or the installation of multi level wells or
sampling devices. A piezometer or well nest is a closely spaced group of piezometers or
wells screened at different depths, whereas a multi level well is a single device. Both
piezometer/well nests and multi level wells allow for the measurement of vertical variations in
hydraulic head. To obtain reliable measurements, the following criteria should be considered
in the evaluation of data from piezometer/well nests and multi level wells:
November 1992
4 42






footer




 

 

 

 

 Home | About Us | Network | Services | Support | FAQ | Control Panel | Order Online | Sitemap | Contact

quality web hosting

 

Our partners: PHP: Hypertext Preprocessor Cheap Web Hosting JSP Web Hosting Ontario Web Hosting  Jsp Web Hosting

Cheapest Web Hosting Java Hosting Cheapest Hosting

Visionwebhosting.net Business web hosting division of Vision Web Hosting Inc.. All rights reserved