Environmental Engineering Reference
In-Depth Information
Table 2.1
Comparison of characteristics of different bed-load sampling technologies (Ryan et al. 2005). See the original table for all annotations.
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
1. Instream Installations
Birkbeck sampler
(weighable pit
trap)
Narrow
gravel
bed
channel
No
No,
automati-
cally
weighs
mass in
stream
Typically
not;
depends
on slot
width
Depends
on slot
width
Continuous Yes
Easy
May change
with fi ll
level
Additional
testing and
modifi ca-
tions
High
Vortex sampler
Gravel bed
channel
No
Yes
Yes
Yes
Continuous Yes
Depends on
fl ow
condi-
tions
Depends on
experi-
mental
setup
Additional
testing and
modifi ca-
tions
High
Pit traps,
unweighable
Gravel bed
channel
Yes
Yes
Typically
not
Possibly
Possibly
Yes, small
scale
Depends on
fl ow
condi-
tions
Slightly
Additional
testing
Probably not
Net-frame
sampler
Gravel bed
channel
Possibly
Yes
Yes
Yes
Yes
Depends on
experi-
mental
setup
Can be
diffi cult
Depends on
experi-
mental
setup
Completed
Possible
Sediment
detention
basins/weir
ponds
Sand-gravel
bed
channels
No
Periodically
Yes
Yes
Yes
Yes
Relatively
easy
No
Completed
High
2. Portable/physical devices
Pressure-
difference
samplers
(small
openings)
Sand-gravel
bed
channel
Yes
Yes
No
No
No
No
Depends on
fl ow
condi-
tions
Slightly
Additional
verifi cation
Additional
verifi cation
needed
