72nd SWCS International Annual Conference July 30-August 2, 2017 Madison, WI

1. Soil Vulnerability Index in
Mark Twain lake Watershed,
Missouri: the restrictive layer
effect
Claire Baffaut, Sapana Lohani, Allen Thompson
Symposium on SVI evaluation SWCS Annual Meeting, Madison, WI, Aug 2, 2017

2. Location
• 6,417 km2
• Sub-watersheds range
from 271 to 1579 km2

3. Hydrologic Soil Groups
Most soils are in group D
(in undrained conditions),
with a small fraction in
group C.
Claypan found at 5 - 60 cm
depth.
Poorly drained soils across
the whole watershed.

4. Slope categories
Runoff categories
Leaching categories
Leaching categories

5. Land use
Pastures and woodland
replace cropland wherever
slope > 4%.

6. SVI
Runoff potential Leaching potential

7. Zoom-in Goodwater Creek
• F1 in moderate area.
• F1 has ~ 1 t/a measured
sediment loss. Tillage is not as
intense as in the SVI baseline
scenario used for SVI
development.
SVI, Runoff potential
F1
SVI risk
Sediment loss (t/a)
Low Moderate Moderately
high
High
SVI
development
< 2 2 – 5 5 – 8 > 8