THE TETON DAM
FAILURE
INTRODUCTION
• June 5th 1972: Teton Dam Collapses.
• Teton Dam is located on the Snake River Plain in
southeast Idaho
• Total damage cost reached as high $2 billion.
• 11 people died, 200 left homeless and 13000
cattle were destroyed.
SITE HISTORY
• United States Bureau of Reclamation (USBR) studied 16
different sites between 1932 and 1961.
• Settled on Teton canyon and began inspecting site in
1957.
• Over 100 borings were taken on site and a report on
the geological and seepage conditions deemed the
site suitable for dam construction.
• USBR awarded Morrison-Knudson the contract to begin
construction.
• The main aim of the dam was to provide irrigation to
surrounding farmlands and HEP.
FOUNDATIONS
• Section 1: 21m deep trenches with steep sides
on the abutments of the 1550m elevation.
• Section 2: A cutoff trench to the underlying
rock below the 1550m elevation.
• Section 3: A grout curtain that ran along the
foundations itself.
• Section 4: The extraction of the rock located
beneath the abutments.
DAM COMPOSITION
•
•
10 million m³ of material needed to construct Dam.
There were 5 main sections to the Dam:
• Section 1:
Core: Moisture content 1.5% dry
of optimum permeability 0.3
metres/year.
• Section 2:
Compacted Sandy Gravel:
Overlies Section 1.
• Section 3:
Miscellaneous Fill: Similar
composition to that of Section 1.
• Section 4 and 5: Rock Fill: Compacted on outer
surface of dam.
FAILURE
• June 3rd 1976: Small leaks discovered in
northern section of the abutment.
• June 4th 1976: Areas of dampness and small
springs appeared in the right section of the
abutment.
• June 5th 1976: Major leak with flow rate of 500800 litres/second. Seepage occurs 40m below
dam crest.
• June 5th 1976: A few hours later a whirlpool
forms in the reservoir. Shortly after, the Teton
Dam Collapses.
TETON DAM TAKING A LEAK
HOLEy CRAP
God DAM that’s a lot of water
FLOODING
• Over 300 million m³ of water passes through
broken Dam.
Rexburg, Idaho
CAUSES
• Piping failure proved to be main reason
for Dam failure.
• Piping Failure = “The development of
tubular leak-causing cavities”
• Poor geological surveying.
• Poor construction: Grout Curtain failed
thus allowing underlying materials be
swept easily downstream
CONSEQUENCES
•
•
•
•
11 people dead
200 people homeless
13,000 cattle destroyed
Surrounding farmland and towns ruined
through flooding
• Up to $2 billion in total costs through
damages and compensation
REMAINS OF
TETON DAM