Dams and Impounded Rivers - River Dynamics and Integrated River Management - page 424

(Continued)

Economic loss
(million dollars)

Dam Country Time of failure Casualties

Vajont Italy 1963-10-9 3,000

Baldwin Hills U.S. 1963-12-14 3 50.0

Mayfield U.S. 1965 2.5

Vratsa Bulgaria 1966-05-01 600

Nanak Sagar India 1967-09-08 100

Sempor Indonisia 1967-12-01 200

Pardo Agentina 1970 20.0

Buffalo Creek U.S. 1974-02-26 118 65.0

Teton U.S. 1976-06-05 6 70.0

Machhu II India 1979-08-1 1,800 (deaths)

T able 7.13 Major dam failure events in China

Time of dam failure
(Month-day-year)

Casualties
(death toll)

Dam/Province Loss of properties Data source

25,942 houses, 14,210
ha of farmland

Lomngtun/Liaoning 07-21-1959 35,428 (707) Huang (1998)

Tiefosi/Henan 05-18-1960 1,662 (1,092) 7,102 houses Huang (1998)

67,721 houses, 1,587
ha of farmland

Liujiatai/Hebei 08-08-1963 (948) MWRC (1981)

Hengjiang/Guangdong 09-15-1970 (779) 66,600 ha of farmland Huang (1998)

1,133 ha farmland,
1,000 ha farmland

Lijiazui/Gansu 04-27-1973 (580) Huang (1998)

298 houses, 40 ha of
farmland

Shijiagou/Gansu 08-24-1973 146 (81) Huang (1998)

5.24 million houses,
1.13 million ha of
farmland

Banqiao and
Shimantan/Henan

10.155 million
(26,000)

08-08-1975 Song (2000)

18.5 million U.S.
dollars

Gouhou/Qinghai 08-27-1993 (288) Huang (1998)

7.3.1.2 Periodicity
Figure 7.23 shows the number of dam failure events in the period from 1954 to 2003. There are two peaks
of dam failure around 1960 and 1973. It seems that there are periodicities in the number of dam failure
events. Treating the series of dam failure events in the same way as turbulent fluctuations and using the
fast Fourier transformation a spectral density of dam failure events is calculated. Figure 7.24 presents the
distributions of the spectral density of dam failure events. The distribution of spectral density has three
peaks at frequencies of 0.04, 0.08, and 0.16 per year, which means periods of dam failure of 25 years,
12.5 years, and 6 years.
It seems that the periodicity of dam failure events is similar to the periodicity of solar activities. Figure
7.25 shows the distributions of the number of sunspots (maculas) and the number of dam failure events
in the period from 1954 to 2005. The distributions exhibit similar periodicities with a phase difference of
about 1/3ʌ. Peaks of dam failure events occur in the receding period of number of maculas. The dam
failure events lag about 4 years behind the solar activity. Thus, it could be a factor causing dam failures.