Read Journal 1276 Volume 58 No 1 – Hydraulic model study of the blowback behaviour of the bottom outlet of the Berg River Dam, South Africa

CPD NO: SAICE/OJ/2025/58/1/43/2028
0.2 ECSA CPD points allocated

Course Content

Introduction – Blowback behaviour Berg River Dam
Journal – Blowback behaviour Berg River Dam

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ZAR 370.00

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CPD Points: 0.2

The Berg River Dam is equipped with the first multi-level draw-off environmental flood release outlet in South Africa and can release flows up to about 200 m3/s. The outlet is controlled by a radial gate at the outlet end, and is protected by a vertical emergency gate near the inlet end. Commissioning tests of the emergency gate in 2008 found that large volumes of air were expelled, instead of the expected air entrainment into the air vent, designed to reduce expected negative pressures in the conduit during emergency gate closure.

This paper describes the testing of a 1:14 physical model representing the outlet works of the Berg River Dam to determine the reasons for the unexpected release of air from the outlet work’s air vent, as observed in the field during the commissioning tests of the emergency gate in the outlet conduit.