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13 Tunnel Flow and Erosion Processes …
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I (mm/h)
Rainfall
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Sc (g/l)
Q (l/s)
Tunnel 1
Flow discharge
Sediment concentration
Flow discharge
Sediment concentration
Flow discharge
Sediment concentration
Flow discharge
Sediment concentration
Flow discharge
Sediment concentration
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Sc (g/l)
Q (l/s)
Tunnel 3
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Sc (g/l)
Q (l/s)
Tunnel 4
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Tunnel 6
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Sc (g/l)
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Time (h)
Sub-basin
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Fig. 13.5 The Yangdaogou experimental catchment, tunnel connectivity and measurement sites
formed a second discharge peak for the same rainfall peak. The uneven peaks in the
flume hydrograph implied the slight difference in peak time among different tunnels.
In light and medium storms, tunnel flow duration showed only limited differences
among the tunnels, and was more or less comparable to the effective rainfall duration
(Table 13.1). However, in the heavy storms, such as on July 11, July 26, and August
28, 1990, Tunnel 3 and 4 had a considerably longer flow duration than the others.