2017 SWCS Annual Conference July 30-August 2, 2017 Monona Terrace Convention Center

1. F. Ghidey, C. Baffaut, R. Lerch, and E. J. Sadler

2. Goodwater Creek Experimental Watershed
(GCEW)
#*
#*
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Salt River Basin
GCEW
Weir 1
Field 2
Field 1

3. Goodwater Creek Experimental Watershed (GCEW)
 GCEW is a 7263 ha (17946 ac) located in the claypan soil
region of north-central Missouri.
 It’s mainly an agricultural area: 75% cropland, 14%
pasture, 7% forestland, 5% urban, and 1% water.
 Major Soil type is Mexico Silt loam characterized by
naturally occurring argillic claypan horizon located 15 to
45 cm below the surface. The clay content of the argillic
horizon is > 50%.
 Claypan soils are considered to be poorly drained.

4. Watershed Scale Data
 Flow data from 1971 to present.
 Water quality monitoring at GCEW started in 1992:
 Dissolved nutrients
 Herbicides
 Suspended Sediment

5. Field Scale Data
 Field 1 – (1993 – 2002)
 34.4 ha (84.9 ac) area
 Mulch tillage corn-soybean rotation.
 Herbicide and fertilizers surface applied and incorporated during the corn
years.
 Flow, herbicides, dissolved nutrients, and suspended solids measured during
the study period.
 Field 2 (1997 -2001)
 7.8 ha (19.2 ac) area.
 No-till corn-soybean rotation
 Herbicide and P fertilizer surface applied and not incorporated.
 N injected.
 Flow, herbicides, dissolved nutrients, and suspended solids measured during
the study period.

6. Objective
 To analyze and link runoff and water quality
measured from field and watershed scales
located within the Goodwater Creek
Experimental Watershed (GCEW).

7. How do we analyze and link measured field
and watershed data?
 Percent of herbicide and fertilizer applied
lost to runoff.
 Flow and load duration curves.

8. Annual loads and Percent Losses
 Runoff, herbicide and nutrient concentrations are
measured on a sub-daily basis.
 Daily, monthly, and annual loads (g/ha) are computed
based on the measured runoff and corresponding herbicide
and nutrient concentrations.
 Annual load data are analyzed to estimate losses as
percent of total fertilizer and herbicides applied during the
study period.

9. Average Annual Runoff (1997-2002)
Growing Season (GS, Apr-Oct) Non-Crop Crowing season (NCGS, Nov-Mar)
F1 Mulch F2 No-Till GCEW Surf GCEW Total
Runoff(mm)
0
50
100
150
200
250
300
• During the GS, average annual flow between the fields and GCEW was not significantly
different (p=0.1).
• During the NCGS, average annual flow between fields and GCEW was also not
significantly different, however, Baffaut et al. (JEQ, 2015) showed there was a significant
difference between runoff from the no-till field (F2) and tilled field (F1) at the event
scale. F2 flow was 20% less than F1 flow.
a a
a
a
F1 Mulch F2 No-Till GCEW Surf GCEW TotalRunoff(mm)
0
50
100
150
200
250
300
a
a
a
a

10. Applied Atrazine Lost to Runoff (1997 – 2001)
Growing Season (GS, Apr-Oct) Non-Crop Crowing season(NCGS, Nov-Mar)
F1 Mulch F2 No-Till GCEW
AtrazineAppliedLosttoRunoff(%)
0
1
2
3
4
5
6
7
F1 Mulch F2 No-Till GCEWAtrazineAppliedLosttoRunoff(%)
0
1
2
3
4
5
6
7
• Atrazine loss from the no-till and GCEW was ~ 4 times greater than from the mulch tillage
system.
• This implies that, overall in the watershed, atrazine was broadcast and not
incorporated.
• Almost all atrazine losses occurred during the GS.
a
a
b

11. Applied Nitrogen Lost to Runoff (1997 – 2001)
Growing Season (GS, Apr-Oct) Non-Crop Crowing season(NGS, Nov-Mar)
F1 Mulch F2 No-Till GCEW
NitrogenAppliedLosttoRunoff(%)
0
2
4
6
8
10
12
14
F1 Mulch F2 No-Till GCEW
NitrogenAppliedLosttoRunoff(%) 0
2
4
6
8
10
12
14
• Nitrogen –Dissolved N (88 - 94% NO3-N, 6 – 12% NH4-N).
• Most losses from the fields occurred during the GS.
• Average annual N loss from Mulch tillage (F1) and GCEW was 3 times greater
than from the No-till system (F2). N was injected at F2.
a
b
c
a
bb

12. Applied Phosphorus Lost to Runoff (1997 – 2001)
Growing Season (GS, Apr-Oct) Non-Crop Crowing season(NCGS, Nov-Mar)
F1 Mulch F2 No-Till GCEW
PhosphorusAppliedLosttoRunoff(%)
0
2
4
6
8
F1 Mulch F2 No-Till GCEWPhosphorusAppliedLosttoRunoff(%)
0
2
4
6
8
• Phosphorus was not applied at F1 (1997 – 2000) because soil P was high.
• During the NCGS, average annual dissolved-P loss from F2 was significantly
less (p=0.1) than from GCEW.
• At the watershed level, dissolved-P loss during the GS and NCGS was similar.
a
b
a
a

13. Average Annual Sediment Yield (1997 – 2001)
Growing Season (GS, Apr-Oct) Non-Crop Crowing season (NCGS, Nov-Mar)
F1 Mulch F2 No-Till GCEW
SedimentLoad(T/ha)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
F1 Mulch F2 No-Till GCEW
SedimentLoad(T/ha) 0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
• Average annual sediment load from the tilled field was 3 times greater than form
the no-till field.
• Average annual sediment load from GCEW was also low compared to field 1
probably due to several processes that happen between the edge-of-field and the
watershed outlet: sediment deposition, stream bank erosion.

14. Load Duration Curves
 Estimating percent of applied fertilizer lost to runoff does
not include the contribution of point sources in a
watershed.
 Load duration curves can help identify possible point
source-contributions.
 Load duration curves can also be used to separate surface
and subsurface herbicide and nutrient losses.

15. How do we develop load duration curves?
 First we develop the flow duration curve.
 Next we plot daily loads against daily flow duration.

16. Flow Duration Curve
 Relates daily flow values to the frequency at which these
values have been met or exceeded:
 Rank measured daily flow from highest to lowest
 Compute frequency using the formula
 𝑝 = ((𝑀 − 0.4)/(𝑁 − 0.2))*100
 Where:
 p: frequency at which a given flow will be equaled or exceeded
 M: rank of the event
 N: total number of events
 Plot flow duration curve: daily discharge versus frequency of
exceedance (flow duration interval).
 Plot load duration curve: daily load versus frequency of the
corresponding daily flow.

17. An Example of Flow duration curve for GCEW
Date Rank Frequency Runoff, mm Nitrate g/ha Dissolved_p
2/21/1997 1 0.016462 63.31199354 881.0208132 142.553319
5/24/1995 2 0.043898 59.65162086 220.1953212 70.25217957
9/23/1993 3 0.071335 59.44457893 51.7507174 89.85975796
5/18/1995 4 0.098771 54.82831095 446.8900301 63.98812325
4/11/1994 5 0.126207 51.84280873 644.8829597 91.32177026
8/24/2000 6 0.153644 46.7014137 178.7126397 65.23956295
6/6/2001 7 0.18108 42.08176259 576.2484652 54.49760983
. . . . .
. . . . .
. . . . .
12/13/2002 3641 99.884767 0 0 0
12/14/2002 3642 99.912204 0 0 0
12/15/2002 3643 99.93964 0 0 0
12/16/2002 3644 99.967076 0 0 0
12/17/2002 3645 99.994513 0 0 0

18. Flow duration curve for GCEW (1993-2002)
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailyDischarge(mm)
0.0001
0.001
0.01
0.1
1
10
100
1000
High
Flow
Moist
Conditions Mid-range Flows
Dry
Conditions Low Flows

19. Dissolved N load duration Curve for GCEW (1993-2002)
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailyNitrogenLoad(g/ha)
0.0001
0.001
0.01
0.1
1
10
100
1000
10000
Daily Load
Median
0.1X Median
10X Median
Point Source
Contributions
Dilution Conditions
• Point Source Contributions:
• Flow duration interval > 30%
• Loads above 10X median band.
• Dilution Conditions:
• All daily loads that fall below the 0.1 X median band.

20. Field1 and GCEW flow duration curves (1993-2002)
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailyDischarge(mm)
0.0001
0.001
0.01
0.1
1
10
100
1000
Weir 1
Field 1
Surface
Flow
Inter+Base
Flows
Base Flow
% of Total Flow
Flow Field 1 GCEW
Surface 97 84
Inter +
Base
3 11
Base 0.0 5
Total 100 100

21. Atrazine Frequency Curves
• The 10X median band did not apply to atrazine load frequency curve,
because almost all the atrazine loads above the 10X band are possibly non-
point source contributions.
• The median load values for F1 are smaller than those for GCEW.
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailyAtrazineLoad(g/ha)
1e-6
1e-5
1e-4
1e-3
1e-2
1e-1
1e+0
1e+1
1e+2
1e+3
Daily Load
Median
0.1X Median
10X Median
Field1 median
GCEW(1993-2002) Field 2 (1997-2001)Field 1 (1993-2002)
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailyAtrazineLoad(g/ha)
1e-6
1e-5
1e-4
1e-3
1e-2
1e-1
1e+0
1e+1
1e+2
1e+3
Daily Load
Median
0.1X Median
10X Median
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailyAtrazineLoad(g/ha)
1e-6
1e-5
1e-4
1e-3
1e-2
1e-1
1e+0
1e+1
1e+2
1e+3
Daily Load
Median
0.1X median
10X Median

22. Dissolved N Frequency Curves
• The Median values for Field 1 were approx. 10 times lower than those for GCEW.
• Almost all the loads were contributed by non-point source.
GCEW (1993-2002) Field 2 (1997-2001)Field 1 (1993-2002)
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailyNitrogenLoad(g/ha)
0.0001
0.001
0.01
0.1
1
10
100
1000
10000
Daily Load
Median
0.1X Median
10X Median
Field1 Median
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailyNitrogenLoad(g/ha) 0.0001
0.001
0.01
0.1
1
10
100
1000
10000
Daily Load
Median
0.1X Median
10X Median
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailyNitrogenLoad(g/ha)
0.0001
0.001
0.01
0.1
1
10
100
1000
10000
Daily Load
Median
0.1X median
10X Median

23. Dissolved-P Frequency Curves
• Only few loads were suspected to be contributed by point sources.
• Median load values for Field 1 were lower than GCEW.
GCEW (1993-2002) Field 1 (1993-2002) Field 2 (1997-2001)
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailyDissolved-PLoad(g/ha)
0.0001
0.001
0.01
0.1
1
10
100
1000
Daily Load
Median
0.1X Median
10X Median
Field1 Median
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailyDissolved-PLoad(g/ha)
0.0001
0.001
0.01
0.1
1
10
100
1000
Daily Load
Median
0.1X Median
10X Median
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailyDissolved-PLoad(g/ha)
0.0001
0.001
0.01
0.1
1
10
100
1000
Daily Load
Median
0.1X median
10X Median

24. Sediment Yield Frequency Curves
• Most low concentration events were not analyzed for sediment. In those
cases, a sediment concentration of 34 ppm was assumed.
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailySedimentLoad(g/ha)
0.0001
0.001
0.01
0.1
1
10
100
1000
10000
Daily Load
Median
0.1X Median
10X Median
Field 1 Median
GCEW (1993-2002) Field 2 (1997-2001Field 1 (1993-2002)
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailySedimentLoad(g/ha) 0.0001
0.001
0.01
0.1
1
10
100
1000
10000
Daily Load
Median
0.1X Median
10X Median
Flow Duration Interval (%)
0 10 20 30 40 50 60 70 80 90 100
DailySedimentLoad(g/ha)
0.001
0.01
0.1
1
10
100
1000
10000
Daily Load
Median
0.1X median
10X Median

25. Contributions of Surface and Base flows
Good water Creek Experimental Watershed (GCEW)
Flow % Atrazine % Nitrate % Dissolved-P % Sediment
Surface 84 84 87 93
Inter+Base 12 12 10 6
Base 4 4 3 1
Total 100 100 100 100
Field 1
Flow % Atrazine % Nitrate % Dissolved-P % Sediment
Surface 95 96 96 100
Inter 5 4 4 0
Base 0 0.0 0.0 0.0
Total 100 100 100 100
Field 2
Surface 92 96 96 100
Inter 8 4 4 0
Base 0 0 0 0
Total 100 100 100 100

26. Summary and Conclusion
 Watershed and field flow duration curves were consistent  Field scale
runoff can be scaled up to watershed scale in this watershed.
 Field and watershed flow duration curves provided information to
divide flow into three categories: Surface flow, interflow, and base flow.
Stream constituent loads through these pathways were calculated.
 Field scale load duration curves were not a good indicator of what
happened in the watershed:
 Different soil vulnerabilities across the watershed.
 A range of management in the watershed (planting times, fertilizer and
herbicides application dates).
 Load duration curves can be useful to compare between fields.
 The upper boundary that distinguishes between non-point and point
sources is likely to be different for different constituents.

27. Thank you!