| Survey Mode |
Applications |
Typical
Sensitivity |
Typical
Accuracy |
Advantages |
Limitations |
| Wading Survey |
Bottom of
impoundments,
sumps |
0.001
square inch
|
1 inch |
Most
sensitive,
tests under
load, can be
for in-service
testing |
Geomembrane
must be
flooded with
water |
| Towed Sensor
Survey |
Impoundments
with deep water
or side slopes |
0.001
square inch |
24 inches |
Deep or
foul water
surveys, can
be for in-service
testing |
Accuracy of
leak position,
geomembrane
must be
flooded with
water |
| Long Probe
Survey |
Side slopes of
impoundments |
0.001
square inch |
2 inches |
More
accurate
than towed
survey |
May require
second
mobilization |
| Surveys with
Soil |
Landfills, landfill caps, and
heap leach pads |
0.01 square
inch |
Half of
thickness
of soil
cover,
leaks are
uncovered
and exactly
located |
Detects
leaks under
soil, detects
construction
damage
after high
potential for
damage is
gone |
Soil must have
some moisture |
| Bare Liner
Survey |
Bare liners |
0.001
square inch |
Leaks are
exactly
located |
Does not
require
flooding
liner with
water, can
be done as
construction
progresses |
Not as reliable
for patches or
tortuous leak
paths, or for geomembranes
with wrinkles,
bridging, or
desiccated
subgrade |
| Electrical Leak
Imaging and
Monitoring
System (ELIM) |
Pre-installed
monitoring
system
|
0.1 to 1
percent of
electrode
spacing
|
10 percent
of
electrode
spacing
|
Detects
leaks under
waste,
continuous
monitoring
|
Must be
installed
during liner
installation,
higher cost |
