This document discusses hydraulic conductivity, emphasizing its significance in various fields like agricultural soil management and hydrology. It outlines the factors affecting hydraulic conductivity, differentiates between saturated and unsaturated conductivity, and includes case studies on land-use impacts and measurement techniques. Additionally, it offers insights into improving measurement efficiency and understanding spatial variability in soil properties.

2. HOW TO INTERPRET
HYDRAULIC CONDUCTIVITY DATA
PART I
Leo Rivera, MS
Director of Scientific Outreach, METER Group, Inc.

3. • Crop production
• Irrigation and drainage
• Hydrology (native and urban)
• Landfill performance
• Stormwatersystem design
• Soil health
It impacts almost everything soil is used for
HYDRAULIC CONDUCTIVITY
WHY DO WE CARE ABOUT IT?

4. • Soil texture
• Soil structure
• Biopores
• Compaction/bulk density
• Water content/potential
HYDRAULIC CONDUCTIVITY
WHAT FACTORS DETERMINE ITS VALUE?

5. HYDRAULIC CONDUCTIVITY
SATURATED VS UNSATURATED

6. Hydraulic Conductivity
A measure of the ability of a porous
medium to transmit water
HYDRAULIC CONDUCTIVITY
THEORY
K
i
so
dz
dh
time
long
at
dz
dh
dz
dh
K
dz
dh
K
dz
dh
K
i
m
g
g
m

→
=
+
=
=
0
1
so
at a long time

7. For two ponding depths, we can write:
Solving to eliminate l, we get:
SATURO OPERATIONAL THEORY
MULTIPLE PONDED HEAD ANALYSIS

8. SATURO OPERATIONAL THEORY
MULTIPLE PONDED HEAD ANALYSIS
Head
-25
-20
-15
-10
-5
0
5
10
15
20
0 20 40 60
Pressure,
cm
Time (Min)
Flux
0.00E+00
5.00E-03
1.00E-02
1.50E-02
2.00E-02
2.50E-02
3.00E-02
3.50E-02
0 20 40 60
Flux,
cm
s-1
Time (Min)

9. DATA DEEP DIVE

10. SATURO OPERATIONAL THEORY
IDEAL SATURO FLUX DATA
0.00E+00
2.00E-03
4.00E-03
6.00E-03
8.00E-03
1.00E-02
1.20E-02
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 97 101105109113
Flux
(cm/s)
Time (min)
Kfs =
D(i1 -i2 )
D1 - D2

11. SATURO DATA EXAMPLES
IDEAL PRESSURE HEAD DIFFERENCE?
0.000E+00
2.000E-04
4.000E-04
6.000E-04
8.000E-04
1.000E-03
1.200E-03
1.400E-03
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81
Flux
(cm/s)
Time (min)
Flux (cm/s)
Flux (cm/s) 5 per. Mov. Avg. (Flux (cm/s))
0.00
2.00
4.00
6.00
8.00
10.00
12.00
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81
Pressure
(cm)
Time (min)
Pressure(cm)
Pressure (cm)
Kfs (cm/s) 0.0002506
Kfs Error (cm/s) 0.00003963

12. SATURO DATA EXAMPLES
DEEPER LIMITING LAYERS
0.000E+00
1.000E-03
2.000E-03
3.000E-03
4.000E-03
5.000E-03
6.000E-03
7.000E-03
8.000E-03
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81
Flux
(cm/s)
Time (min)
Flux (cm/s)
Flux (cm/s) 5 per. Mov. Avg. (Flux (cm/s))

13. SATURO DATA EXAMPLES
UNSTABLE PORE STRUCTURES
0.000E+00
2.000E-03
4.000E-03
6.000E-03
8.000E-03
1.000E-02
1.200E-02
1.400E-02
1.600E-02
1.800E-02
2.000E-02
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65
Flux
(cm/s)
Time (min)
Flux (cm/s)
Flux (cm/s) 5 per. Mov. Avg. (Flux (cm/s))

14. SATURO DATA EXAMPLES
UNSTABLE PORE STRUCTURE OR TEMPERATURE?
15.00
16.00
17.00
18.00
19.00
20.00
21.00
22.00
23.00
24.00
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74
Flux
(cm/hr)
Time (min)
Flux (cm/hr)
Flux (cm/hr) 5 per. Mov. Avg. (Flux (cm/hr))

15. SATURO DATA EXAMPLES
HOW CAN I SPEED UP MY MEASUREMENTS?
y = 0.0366e-0.014x
R² = 0.8966
y = 0.0352e-0.019x
R² = 0.9261
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0 10 20 30 40 50 60 70
Infiltration,
cm/s
Time, min
Extrapolating Steady State
Flux high 1.04E-02cm/s
Flux low 6.37E-03cm/s
Pressure high 9.73cm
Pressure low 5.16cm
Hold time 15min
Insertion depth 5cm
Ring radius 7.5cm
D 9.3cm
cm/s cm/hr in/hr
Kfs 8.16E-03 29.4 11.6

16. CASE STUDIES

17. • Graduate research
• Developed semi-automateddouble-ring
infiltrometer system
• Made ~200 Kfs measurements
• Evaluate land-use impacts on soil
hydraulic properties
• How soil hydraulic properties change
across landscape positions (catena
effect)
CASE STUDY 1
LAND-USE & LANDSCAPE IMPACTS

18. Comparing the effects of landscape & land-use on
hydraulic properties of the same soil type
• Improved pasture—grazed
• Conventional tillage (corn/corn/wheat)
• Tall grass native prairie
CASE STUDY 1
LAND-USE & LANDSCAPE IMPACTS

19. Located in the USDA-ARS Riesel
Watershed in the Blackland prairie
Soils are predominantly mapped as
Houston Black and Heiden Clay
CASE STUDY 1
LAND-USE & LANDSCAPE IMPACTS

20. CASE STUDY 1
LAND-USE & LANDSCAPE IMPACTS

21. Tillage vs no-till impacts on the Palouse
• Cook Agronomy Research Farm
How do lab vs field measurements compare
• KSAT lab measurements
• SATURO field measurements
CASE STUDY 2
TILLAGE EFFECTS VS
LAB & FIELD MEASUREMENTS

22. CASE STUDY 2
TILLAGE EFFECTS VS LAB & FIELD MEASUREMENTS

23. Accounting for spatial variability
• Representative Elementary Volume (REV) - The smallest volume of soil that can
represent the range of microscopic variations
• For water flow processes, REV is based on soil structure
Time domain or seasonal changes
• Antecedentsoil moisture
• Changes in vegetation
• Land-use impacts
OTHER CONSIDERATIONS

24. • Optimize measurements for your location and application
• Learn from past mistakes
• Comparing lab vs. field measurements can be challenging
TAKEAWAYS

25. QUESTIONS
Leo Rivera, MS
Director of Scientific Outreach
METER Group, Inc.
2365 NE Hopkins Ct, Pullman, WA USA 99163
T: +1 509 332 2756
E: leo.rivera@metergroup.com
W: www.metergroup.com