DEPARTMENT OF THE ARMY
ETL 1110-2-569
U.S. Army Corps of Engineers
CECW-EG
Washington, DC 20314-1000
Technical Letter
No. 1110-2-569
1 May 2005
Engineering and Design
DESIGN GUIDANCE FOR LEVEE UNDERSEEPAGE
1. Purpose. The purpose of this document is to provide interim guidance for design of levees to
minimize the adverse effects of levee underseepage. This ETL recommends exit gradients and
associated minimum acceptable factors of safety. Use of this guidance should minimize
emergence of adverse levee underseepage and initiation of sand boils along flood-control levees
with a landside top stratum. EM 1110-2-1913, Design and Construction of Levees, currently
contains design recommendations for levee seepage control. Except for the changes
recommended in this ETL, all other definitions, design equations and procedures recommended
in EM 1110-2-1913 should be followed. Where changes are recommended, the specific EM
reference is noted in brackets. Currently, EM 1110-2-1913 is in the process of being updated to
incorporate these recommendations and other changes. This ETL will be rescinded when the EM
is revised.
2. Applicability. This ETL applies to USACE commands having civil works responsibilities.
3. Distribution Statement. Approved for public release; distribution is unlimited.
4. References.
a. EM 1110-2-1913, Design and Construction of Levees.
b. Biedenharn, D. G., and Tracy, F. T. 2000. Finite Element Method Package for Solving
Steady-State Seepage Problems, Technical Report TL-87-6, U.S. Army Engineer Waterways
Experiment Station, Vicksburg, MS.
c. Brizendine, A. L., Taylor, H. M., Jr., and Gabr, M. A. 1995. LEVSEEP: Analysis
Software for Levee Underseepage and Rehabilitation, Technical Report GL-95-10, U.S. Army
Engineer Waterways Experiment Station, Vicksburg, MS.
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