WORKING WEEK - May / June 2000

An early start .....
Although the Monday was a public holiday, the weather forecast suggested that we should make an early start to the working week early and so a large number of club members were press ganged into going up to the water tanks to carry out a day's maintenance work.

The Penwyllt water supply is dependent upon flow from the river into some settling tanks and over a period of several years the dam which diverts the water had reached a state of imminent collapse. The aim of the exercise was to install some gabions and fill them with rocks to stabilise the dam.

  Levelling the river floor at the dam base before installation of the new gabions

A team effort .....
With each gabion sized at 2m³, we needed rocks to the volume of about 9m³ to complete the job. Thanks to a team effort from about fifteen people and under the guidance of John Lister, four of the units were installed just in front of the existing, dam which has gradually been collapsing and preventing water from flowing into the collection tanks.

An estimated 16 tonnes of rocks were shifted from upstream into the gabions. Allan Richardson and Andy Amatt had a competition to see who could shift the largest rock, whilst others contented themselves with smaller items. Lastly, several barrow loads of pebbles were poured into each gabion to fill up the gaps.

Filling the gabions with rocks to stabilise the dam wall  

Digging out the water tank .....
We also had to set about digging out the top water tank. During floods, this tank fills with rocks and sediment, making it ineffective as the first stage of settlement. Dave Edwards, and Simon Amatt abetted by the dog, cleared the tank, Keith Goodhead cleared upstream blockages whilst Graham Christian and others worked downstream.

By the end of play, we had successfully restored the flow through the tank and reconnected the supply. Since we also had a vehicle up there, the opportunity was taken to tidy up the area and in particular to remove all the unsightly lengths of pipe which had been lying around the tanks for some years.

  Milo (the one with the biggest ears) supervises the clearing out of the top water tank

Improved protection .....
The water supply to the club is carried from the tanks by a 2" alkathene pipe which is for the most part buried underground for protection against mechanical damage and freezing in cold weather. In one or two places however, it has become exposed, one of these places being where the pipe crosses the river just downstream from the third settling tank.

Improved protection was achieved by placing a half-sized unit just in front of the exposed section of pipework so that it will then cover in with natural deposition of silt and rocks.

Clark Friend tries to collapse the downstream gabion