Environmental Engineering Reference
In-Depth Information
Requires
wading or
retrieval
during high
fl ows
High
percentage
of channel
width
sampled
Large
opening
relative
to grain
size
Physical
sample
obtained for
sieving
Relatively
long
sampling
duration
Bed-load
sampling
technology
Stream
excavation
required
Disruptive
to fl ow
fi elds
Status of
development
(2003)
Potential use
as calibration
standard
Relative
ease of use
Stream type
Pressure-
difference
samplers
(large
openings)
Gravel bed
channel
Yes
Yes
No
Yes
No
No
Depends on
fl ow
condi-
tions
Highly
Additional
verifi cation
Additional
verifi cation
needed
Baskets
(suspended or
instream)
Gravel bed
channel
Yes
Yes
Depends
on
design
Depends
on
design
Yes
No
Depends on
fl ow
condi-
tions
Depends on
experi-
mental
setup
Completed
Moderate
Bedload traps
Gravel bed
channel
Yes
Yes
Depends
on
number
of traps
deployed
Yes
Yes
Minor
Depends on
fl ow
condi-
tions
Slightly
Completed;
testing of
modifi ca-
tions
Moderate
with
additional
verifi cation
Tracer particles
(painted,
magnetic,
signal emitting
rocks)
Gravel bed
channel
Possibly
No
Depends
on tracer
place-
ment
N/A
Yes
No
Easy
No
Additional
verifi cation
Low
Scour chains;
scour monitor;
scour core
Sand-gravel
bed
channel
Possibly
No
No
N/A
Yes
Yes
Easy
No
Completed
Low
Bedload
collector
(Streamside
Systems)
Sand-gravel
bed
channel
No
Yes
Depends
on
number
and size
of
devices
deployed
Depends
on
design
of
device
Yes
Yes
Operation is
easy once
installed
Unknown
Needs
verifi cation
Needs to be
tested
3. Surrogate technologies
ADCP - acoustic
Doppler
current
profi ler
Sand bed
rivers,
experi-
mental in
larger
gravel
bed
channels
No
No
Yes
N/A
Continuous No
Logistics
and data
reduction
are
complex
No
Moderate
(sand
systems)
early (gravel
systems)
Additional
verifi cation
for gravel
bed
systems
