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69th SWCS International Annual Conference “Making Waves in Conservation: Our Life on Land and Its Impact on Water” July 27-30, 2014 Lombard, IL
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Unit Source Area Monitoring with Grade Control Pipe
InstrumentationSeth Dabney, Glenn Wilson, J.R. Rigby, and James Bonta
USDA-ARS National Sedimentation Laboratory
Oxford, MS, US
Goodwin Creek Experimental Watershed•Area - 21.3 sq. km
•Operation 1981-pres.•Instrumentation:
30 rain gauges13 supercritical flumes5 pump sampler sites3 edge-of-field sites
Land Use Change by Decade
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
1975 1980 1985 1990 1995 2000 2005 2010 2015
Fractio
n of W
atershed
Area
Year
Grassland
Forestland
Cropland
Edge-of-field sample locations
Timber 29 acres
Cropland 3 acres
Pasture 11 acres
Station #2 4420 acres
Primary Research Objectives
• Assess hydrologic, sediment, and turbidity responses to land management and scale.
Instrument “sled” fabricated from stainless steel, slips into grade control pipe
Turbidity
Sampler intake
Depth and velocity
Weir
y = 1.035xR² = 0.982
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
Discharge from
Con
tinuity (cfs)
Discharge from V Notch Weir (cfs)
1 on 1
+‐10%
1.5% Slope
3.5% Slope
5.5% Slope
Linear (all data)
Station #16 Cropland
Station #16 Cropland
Station 15 Forest / Timber
Station #17 Pasture
Station #17 Pasture
Supercritical grade control flumeStation #2 (as built)
Turbidity gauge deployed on a strut from catwalk at Station #2
0
50
100
150
200
250
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500
0
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1000
1500
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2500
3000
6/12/2014 19:12 6/12/2014 21:36 6/13/2014 0:00 6/13/2014 2:24 6/13/2014 4:48 6/13/2014 7:12 6/13/2014 9:36 6/13/2014 12:00
Trub
idity
(mV)
Discharge (cfs)
Discharge fines Turbidity
y = 7.028x ‐ 501R² = 0.980
0
500
1000
1500
2000
2500
3000
0 100 200 300 400 500
Fine
s Con
centratio
n (ppm
)
Turbidity (mV)
Station #2, 12‐13 June 2014
0
1000
2000
3000
4000
5000
6000
Feb-82 Aug-87 Jan-93 Jul-98 Jan-04 Jul-09
Fine
s C
once
ntra
tion
(ppm
w)
Date
Dec to Mar
Aug to Nov
Apr to Jul
Four-month average concentrations of sediment < 53 µm at Station 2
CEAP
0
500
1000
1500
2000
2500
3000
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
6/12/2014 19:00 6/12/2014 21:24 6/12/2014 23:48 6/13/2014 2:12 6/13/2014 4:36 6/13/2014 7:00 6/13/2014 9:24 6/13/2014 11:48
Concen
tration (ppm
)
Discharge (in
/hr) and
Sed
imen
t Disc
harge (to
ns/acre ho
ur)
Discharge
Fine Sediment Discharge
Concentration of Fines
Fines Sample Concentration
y = 3.4468x ‐ 71.889R² = 0.9353
0
100
200
300
400
500
600
0 20 40 60 80 100 120 140 160 180 200
Fine
s Con
centratio
n (ppm
)
Average Turbidity (mV)
Station 15, 16, 17 combined
Station 17
Station 15
Station 16
Linear (All Data)
y = 7.0275x ‐ 501.01R² = 0.9803
y = 3.4468x ‐ 71.889R² = 0.9353
0
500
1000
1500
2000
2500
3000
0 50 100 150 200 250 300 350 400 450
Fine
s Con
centratio
n (ppm
)
Average Turbidity (mV)
Edge of Field Sites and Station 2
Station 2
Edge of Field Sites
Linear (Station 2)
Linear (Edge of Field Sites)
4 % of sediment from upland sources
96% of sediment from gully and
channel erosion
Station Drainage Area (acres) Drainage Area (sq_ft) NOTES1 5266.8 2294218082 4421.6 1926048963 2145 934362004 893.7 389295725 1033.3 4501054813 303.4 1321610414 411.9 1794236415 28.859 1257098 Original estimate for Andrea Bowen's work16 2.87 125017 This is an estimate based on Darlene's work with an area removed by Mick Ursic based on what is known from the field.17 11.01 479595.6 This is an estimate from Darlene's work
April 2005 Simon site
2006
1513
14
3
4
2
Steady Pond Construction
y = ‐0.0145x2 + 58.82x ‐ 59375R² = 0.9947
y = 0.4192x ‐ 811.18R² = 0.9877
0
5
10
15
20
25
30
35
40
0
15
30
45
60
75
90
105
120
1930 1940 1950 1960 1970 1980 1990 2000 2010
Pond
Surface Area (ha)
Num
ber o
f Pon
ds
Year
NumberArea
Conclusions
Instrumentation to measure depth, velocity and turbidity, sample runoff, and quantify sediment yield from grade control conduits was described.
Turbidity was well correlated with concentrations of sediment <53 µm.
Runoff from cropland and grassland areas was flashier than from a timberland source areas.
Analysis suggests that most (>90 %) sediment originated from channel and gully sources.
QUESTIONS?
y = 0.911xR² = 0.977
y = 0.204xR² = 0.298
0
500
1000
1500
2000
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3000
3500
0 5000 10000 15000 20000
Fine
s sed
imen
t con
centratio
n (ppm
)
Total sediment concentration (ppm)
Station #15Station #16Station #17uplandStation #2Linear (upland)Linear (Station #2)