News letter Dam edition

Ingeokring Newsletter
A
WT
h
δh
H-h
WT-(h/H)(WT-WB)
WB
h
δh
H-h
α
b
τ = ah+b
A’
Front (upstream) elevation
Side elevation (cross-section A-A’)
w = W T[1-(h/H)(1 -W B/W T )]=W T [1-rh/H]
r = 1-WB/W T
Fig. 1 Model used to solve for overall membrane permeability k.
Fig. 2 Paradela Dam, Northeast Portugal (source: cnpgb.inag.pt/
gr_barragens/gbingles/ParadelaIng.htm).
Fig. 3 Salt Springs Dam, central California (source: concise.britannica.com/ebc/art-73277/Salt-Springs-Dam-a-rock-dam-ison-the-North).
Table 1 ‘Efficiency-permeability’ of dams with upstream reinforced concrete membrane cut-offs.
Dam
Height
[m]
Crest
length
[m]
Slope
(upstream/
down-
Geology
Fill
Type membrane/
foundation cut-off
Membrane
Thickness [m]
Crest
Base
Leakage
[l/s]
Permeability,
k [m/s] 1
Cethana (Tasmania,
110 213 1.3/1.3 Quartzite
1971) A
Rock, compacted
Reinforced concrete
(RC)/8 m grout curtain
0.3 0.6 35 2x10 -8
Paradela (Portugal,
110 525 1.3
1957) B
Granite, weathered
Rock, sluice
dumped
RC/30 m grout curtain 0.3 1.1 3020/315 2 1.3x10 -7
Salt Springs
100 396 1.3/1.4 Granite, sound
(California, 1931) C
Rock, sluice
dumped
RC/1.5 m wide 1 to 6 m
deep trench & 15 m deep
0.3 1.1 113/556 3 2x10 -7 /3x10 -7
Lower Bear 1 75 293 1.3/1.4 Granite, massive RC/no information 0.3-0.75 0.6 57 4.7x10 -8
Lower Bear 2
46 264 1.0/1.3 Granite, massive 0.3 0.6
(California, 1952) C
Vilar (Portugal) B 55 210 1.1/1.3 Granite and Rock, sluice RC/no information 0.3 0.6 130 7.4x10 -8
Quioch (Scotland,
38 320 1.3/1.4 Rock, sound
1955) D
Rock, rolled
sluiced
RC/2 m concrete wall & 12
m grout curtain
0.3 22 5x10 -8
La Sassiere (France,
30 300 1.4/1.4 Moraine Rock, dumped
1959) E
RC/2m wide, more than
15 m deep grout curtain
0.35 12 5.4x10 -8
1
Value for k is back-calculated; 2 Before/after repair; 3 partly filled/full reservoir
A
Wilkins (1973); B Da Palma Carlos, et al. (1973); C Steele & Cooke (1958, 1969); D Roberts (1958); E Destenay & Lemay (1961)
Dam edition | Double Issue 2007/2008 | 43