2023-06-28 22:11:08
The grit traps at the Stafel water intake functioned as a degraver. Gravel up to 50 millimeters in diameter was then found in the grit traps, which reduced their efficiency, complicated the rinsing operations, and led to an increase in the quantities of sediments in the compensation basin. These problems were solved by changing the water intake to a degraver. All phases of the project, from study to completion, were managed by the civil engineering unit of HYDRO Exploitation.
Addition of a reinforced concrete spillway and elevation of the metal spillway
The work focused on the one hand on the design of a new reinforced concrete spillway located before the desilting basin, and on the other hand on renewing the intake purge system. The spillway at the bottom of the intake was raised by a system of cofferdams. These targeted measures have several advantages: the retention of water reduces the flow speed and allows the gravel to settle, with a view to being evacuated later by the bottom outlet, whose valve has been renewed.
An achievement carried out in the best conditions
The works were carried out by SULAG AG for the reinforced concrete spillway, and by Inauen-Schätti AG for the design and installation of the metal cofferdams. The works took place in October and November 2021, the only period that does not involve any loss of water, the pumping season ending on October 31.
The new spillway was concreted in November. To do this, the workspace had to be covered and heated. The weather was generally mild. Snowfall and flooding represented risks that had been anticipated: in the event of flooding, the site would have been immediately stopped, and the snow cleared in the event of a heavy snowfall. Some tasks, such as raising the metal spillway, were anticipated during operation by backfilling with sand on the water side.
Disclaimer
HYDRO Exploitation SA published this content on 29 June 2023 and is solely responsible for the information contained therein. Distributed by Public, unedited and unaltered, on 28 June 2023 22:09:55 UTC.
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#Stafel #water #intake #construction #degraver
