69th SWCS International Annual Conference “Making Waves in Conservation: Our Life on Land and Its Impact on Water” July 27-30, 2014 Lombard, IL

1. Watershed
Physical
Processes
Measuring erosion on irrigation
reservoir levees
Daniel G. Wren, USDA-ARS-Watershed Physical Processes
Research Unit, Oxford, MS
Yavuz Ozeren, University of MS, National Center for
Computational Hydroscience and Engineering
Michele Reba, USDA-ARS-Delta Water Management Research
Unit, Jonesboro, AR
UM NCCHE

2. Acknowledgements
Carlos Alonso USDA‐ARS(ret.)
Dennis Carman White River Irrigation District
Keith Admire NRCS National Water Mgt.
Center
Watershed
Physical
Processes

3. Introduction
• The Mississippi/Arkansas Delta region is one of
the largest agricultural production areas in the
United States—about 7.1 million irrigated acres
• In spite of receiving around 55 inches/year of
rainfall, irrigation is needed to both maximize
yields and reduce risk
• Excessive groundwater withdrawals have
exceeded recharge rates for some time
• Surface water storage in irrigation reservoirs is
one strategy that is being used for reducing the
use of groundwater

4. Problem: severe levee damage

5. Waves in an irrigation reservoir

6. Study site: Fisher Reservoir

7. Fisher reservoir in high wind

8. One season of erosion from a south‐facing levee
in Fisher Reservoir

9. One season of erosion from a south‐facing levee
in Fisher Reservoir

10. Pin erosion measurements
Erosion pin

11. Levee erosion
measured
using LIDAR

12. Soil losses at
Fisher Reservoir

13. Maximum lateral losses by levee

14. Loss of levee volume
• About 1800 yd3 lost in one season
• At $2/yd3 for repair, this is about $3,600
• If this is typical, then 5 year maintenance
would be $18,000

15. Where do we go from here?
• Levee erosion mechanics—field and
laboratory research
– Relationship between wave energy and
erosion
• Reducing fetch
– Interior levees
– Floating barriers
• Assess existing reservoirs for useful
patterns
– Effect of reservoir shape and orientation on
erosion

16. Laboratory work

17. Floating wave barriers

18. Floating wave barrier in laboratory flume

19. Interior levees
Inner levee
system

20. Levees at Hunt’s reservoir

21. Questions?