Macchu dam

this is about dam burst in Gujarat,INDIA in 1973

1. 1

REPORT
ON
“FAILURE OF MACHCHHU DAM IN GUJRAT ”

SUBMITTED TO:
PROF. RENJI REMSON
(SCHOOL OF WATER RESOURCES)
SUBMITTED BY:
VISHVJEET THOLIA
M.tech First Year
(17WM60R01)
(2017-2018)
SCHOOL OF WATER RESOURCES
INDIAN INSTITUTE OF TECHNOLOGY KHARAGPUR

2. 2

1. INTRODUCION
Machchhu dam was built near Morbi district in Gujarat, India, on River Machhu in August,
1972, as a composite structure. It consisted of a masonry spillway in river section and earthen
embankments on both sides. The embankment had a 6.1 m top width, with slopes 1 V : 3 H
and 1 V : 2 H respectively for the upstream and downstream slopes and a clay core extending
through alluvium to the rocks below. The upstream face had a 61 cm small gravel and a 61
cm hand packed riprap. The dam was meant to serve an irrigation scheme. Its, storage
capacity of 1.1 * 10
3
m. The dam had a height of 22.56 m above the river bed, a 164.5 m of
crest length of overflow section, and a total of 3742 m of crest length for earth dam.

The Failure Tragedy
The dam failed on August 1, 1979, because of abnormal floods and inadequate spillway
capacity. Consequent overtopping of the embankment caused a loss of 1800 lives. A
maximum depth of 6.1 m of water was over the crest and within two hours, the dam failed.
While the dam failed at a peak discharge of 7693 m3 /s, the figure was revised to 26,650 m3
/s after failure, with a free board of 2.45 m given, providing also an auxiliary spillway with a
full capacity of 21,471 m3 /s. The observed actual flood depth over spillway crest was 4.6 m
with an observed 14,168 to 19,835 m3 /s, while the design depth over spillway crest was 2.4
m. The Machchhu dam failure has been listed as the worst dam burst in the Guinness book of
record. The failure is also known for being officially termed as an “Act of God”. However,
the claims were debunked by the book ‘No One Had A Tongue To Speak’ by Tom Wooten
and Utpal Sandesara. It pointed out the structural and communication failures that led to the
occurrence and also exacerbation of the disaster.
Causes of Dam Failure
Reason of failure - abnormal floods and inadequate spillway capacity leading to the
disintegration of the earthen walls of the 4 km long Machchhu dam.The actual observed flow
following the intense rainfall reached 16307 m³/s, thrice what the dam was designed for,
resulting in its collapse .Some claims that design of flood gates was impropriate and
miscommunication.The earthen dam overtopped and collapsed inundated the low-lying areas
of Morbi town.

3. 3

Effect of Dam Failure
There was great economic loss. The flood damaged the farmland, leading to a decrease in
productivity of crops. According government report 1800 people lost their lives but some
media reports death of nearly 25000 people. Huge capital for rehabilitation of people and
reconstruction of dam.

Tragic tale of the Commission of Inquiry-
After the disaster, revelations were made about the government failures before and after the
Machhu dam disaster. The independent judicial Commission of Inquiry set up by the State
Government. The tragic tale of the commission of inquiry tasked with uncovering the
truth about the flood. For 18 months in the 1980s, the commission's members collected
evidence on the technical causes of the dam's failure and on the adequacy of the efforts
to warn downstream citizens of the impending danger. Then, as the investigation honed
in on flawed design practices in the irrigation department, engineers complained to then
Chief Minister Madhavsinh Solanki. The CM wound up the commission before it could
complete its work. District Collector A R Banerji had scrambled to coordinate immediate
relief operations, only to lose his position several months later after writing a damning
(and subsequently hidden) report about the government's handling of the flood.

Reconstruction of Machchhu Dam
Machchhu dam was rebuilt in the end of the 1980s. A public interest group sued the
government on behalf of the people and won a judgment in the Gujarat High Court, but the
Supreme Court overturned the ruling, ensuring that the full lessons of the Machchhu dam
disaster would not come to public light.
Some other Dam Failures in INDIA
Kaddam Project Dam, Andhra Pradesh, India
Built in Adilabad, Andhra in 1957 - 58, the dam was a composite structure, earth fill and/or
rock fill and gravity dam. It was 30.78 m high and 3.28 m wide at its crest. The storage at full
was 1.366 * 108 m3 . The observed floods were 1.47 * 104 m3 /s. The dam was overtopped
by 46 cm of water above the crest, inspite of a free board allowance of 2.4 m that was
provided, causing a major breach of 137.2 m wide that occurred on the left bank. Two more
breaches developed on the right section of the dam. The dam failed in August 1958

4. 4

Nanaksagar Dam, Punjab, India
Situated in Punjab in northwestern India, the dam was constructed in 1962 at Bhakra, with a
reservoir capacity of 2.1 * 106 m3. An estimated maximum discharge of 9,711 m3 /s had
occurred on August 27, 1967, due to heavy monsoon rains that were heaviest in twenty years.
This caused dam to fail. The water that gushed through the leakage created a 7.6 m breach,
which later widened to 45.7 m. The condition of the reservoir had worsened, causing a 16.8
m boil downstream of toe, which was responsible for the settlement of the embankment. As
the dam was overtopped, causing a breach 150 m wide. A downstream filter blanket and
relief wells were provided near the toe but were insufficient to control the seepage. The relief
wells each 50 mm in diameter were spaced at a distance of 15.2 to 30.4 m
Panshet Dam: (Ambi, Maharashtra, India, 1961 - 1961)
The Panshet Dam, near Pune in Maharashtra India, was under construction when the dam had
failed. It was zoned at a height of 51 m and having an impervious central core outlet gates
located in a trench of the left abutment and hoists were not fully installed when floods
occurred at the site of construction. The reservoir had a capacity of 2.70 million m3 .
Between June 18 and July 12, 1961, the recorded rainfall was 1778 mm. The rain caused such
a rapid rise of the reservoir water level that the new embankment could not adjust to the new
loading condition. The peak flow was estimated at 4870 m3 /s . Water rose at the rate of 9 m
per day initially, which rose up to 24 m in 12 days. Due to incomplete rough outlet surface
the flow through was unsteady which caused pressure surges. Cracks were formed along the
edges of the right angles to the axis of the dam causing a subsidence of 9 m wide. An
estimated 1.4 m of subsidence had occurred in 2.5 hours, leaving the crest of the dam 0.6 m
above the reservoir level. Failure was neither due to insufficient spillway capacity nor due to
foundation effect. It was attributed to inadequate provision of the outlet facility during
emergency. This caused collapse of the structure above the outlets.

Khadakwasla Dam (Mutha, Maharashtra, India, 1864 - 1961)
The Khadkawasla Dam, near Pune in Maharashtra, India was constructed in 1879 as a
masonry gravity dam, founded on hard rock. It had a height of 31.25 m above the river bed,
with a 8.37 m depth of foundation. Its crest length was 1.471 m and had a free board of 2.74
m. The dam had a flood capacity of 2,775 m3 /s and a reservoir of 2.78 * 103 m3 . The

5. 5

failure of the dam occurred because of the breach that developed in Panshet Dam, upstream
of the Khadkawasla reservoir. The upstream dam released a tremendous volume of water into
the downstream reservoir at a time when the Khadkawasla reservoir was already full, with the
gates discharging at near full capacity. This caused overtopping of the dam because inflow
was much above the design flood. The entire length of the dam spilling 2.7 m of water.
Vibration of the structure was reported, as the incoming flood was battering the dam. Failure
occurred within four hours of the visiting flood waters.
Dams at Risk of Failure in INDIA
Mullaperiyar Dam
Liquefaction of the materials used in the dam. Liquefaction in the foundation soil. Inability to
estimate performance of the dam and foundation characteristics by comparison with case
histories of dam failures .Slope failures induced by ground motions .Sliding of the dam on
weak foundation materials. Disruption of dam by major fault movement in the foundation
.Loss of freeboard due to slope failures or soil compaction. Piping failure through cracks
induced by the ground motions .Overtopping of dam due to slides into the reservoir.
Overtopping of dam due to failure of spillway or failure of dams upstream

Idukki Dam
The dam of Idukki is facing serious risks of failure on account of a variety of factors. These
include the precarious condition of the Mullaperiyar dam upstream, the inadequacy of the
spillways, slope instability in the catchment areas, siltation, earthquakes and lack of proper
instrumentation to monitor the Mullaperiyar, Idukki, Cheruthoni and Kulamavu dams.
Tamil Nadu has long been arguing that the Mullaperiyar dam could withstand a water level of
145 feet or higher. However, experts from Kerala dispute this. Last week, experts from both
Kerala and the Centre came across fissures and leaks in the dam body. A report of the Central
Soil and Materials Research Station is expected to be submitted in a week's time.

6. 6


CONCLUSIONS
Freeboard
The correct amount of freeboard will vary with the size of the dam, area of catchment and
likely wave action. Minimum freeboard should not be less than 1 metre . Even with good
compaction some vertical settling of the bank should be expected. Make a 10% allowance for
settlement.
Batters
For banks up to 3 metres (10 feet) high, the standard recommended slope of batters is 3:1 on
the upstream side of the bank and 2:1 on the downstream side. Before building batters steeper
than this, it is important to ensure that it is safe to do so.
Spillway
A correctly designed spillway is essential. Many dams fail due to faulty design or
construction of the spillway. It must be large enough to handle flood flows without water
overtopping the bank. Nor should the flows cause erosion of the spillway or disposal area
below the dam. If the spillway has a newly formed earthen surface to take overflows from the
dam, a heavy grass surface cover should be sown and established as quickly as possible. Do
not allow construction equipment or vehicles to travel on the spillway discharge area, the
vegetative cover is too important.
A rule of thumb for estimating the width of a spillway: it should equal (in metres) the square
root of the catchment area (in hectares). For example, a catchment area of 9 hectares would
require a spillway 3 metres wide. If trickle flows of water are likely to be produced from the
catchment during winter and spring, installation of a trickle flow pipe should be considered.
Topsoil
When construction is completed, the stockpiled topsoil should be spread over the bank.
Suitable grass species should then be sown to stabilise the bank and prevent it eroding. Trees
should not be used on banks because their larger root system can disturb the compacted mass.

7. 7

Another important feature of placing topsoil back over the bank is that, when grassed, it helps
prevent the clay bank from drying out and cracking.
Regular Monitoring
Dam site should monitored at regular intervals to prevent any mishappening. If any crack or
leakage is observed, it should be correctly immediately. No delay in maintenance work and
use of poor quality material should be checked. Monitoring should be done honestly because
any mistake cause huge loss of live and economy.

Warning & Quick Dislocation Facilities
The people living in the downstream areas are severely affected if any failure occurs. Proper
facilities of transportation should be available for shifting local people to safe sites. Warning
should be given in time, so that people can shifted and losses can be minimized.
References
Sandesara, U., Wooden, T., Farmer, M.D., 2011. No One Had a Tongue to
Speak: The Untold Story of One of History's Deadliest Floods. Kindle Edition.
Websites
 http://agriculture.vic.gov.au/
 https://en.wikipedia.org/wiki/1979_Machchhu_dam_failure
 https://www.scribd.com/document/126033660/machhu-dam-disaster-in-gujarat
 http://www.wrmin.nic.in/

8. 8