Feed on
Posts
Comments

Thanks to everyone who has contributed to this blog over the last few years. It’s been a great way to tell you all about the work that’s taken place at Chasewater, and we’ve been bowled over the the amount of public interest, involvement and support for the blog.

Now the the works are complete we are no longer going to be using the blog to communicate news about the dam or reservoir. News updates will be issued by the press office at Staffordshire County Council. To keep up to date on any news visit www.staffordshire.gov.uk

Thanks again to everyone who has commented, given their support (their moans or the ir groans) on this blog. We very much hope that the blog helped you to understand the works in hand and that you felt more informed as a result.

Kind regards

Lizzie & Neil.

Staffordshire County Council has announced that the major £5.5 million engineering project at Chasewater reservoir has now been completed.

The 200-year-old dam at the heart of Chasewater Country Park was drained of water in early 2010 amid concerns for the safety of the reservoir which dates back to 1797.

The plug went back in last October and water levels slowly started to rise once more, helping to restore Chasewater to its original position as a major regional leisure attraction, wildlife haven and key component of the Midlands’ canal network.

The last major milestone took place this February when 100 tonnes of concrete were pumped into the dam to create a weir which will control the flow of water when the reservoir is full.

County Councillor Mark Winnington, Cabinet member for Environment and Assets, said: “Chasewater is one of the Midlands’ most popular beauty spots so it was absolutely vital that the safety improvements were carried out and the site is now returning to its former glory.

“We appreciate the impact that this vital work has had on people who use the reservoir for activities ranging from sailing to angling and wildlife spotting. The county council’s expert engineers pulled out all the stops to get the work done as efficiently and effectively as possible so that local people as well as visitors from far and wide can enjoy the tourist attraction as we approach the summer months.

“The team has improved the overflow to safeguard nearby residents in the event of severe flooding, which will enable us to monitor the condition of the dam much more closely in the future.The drawdown culvert – the equivalent of the plughole in a bath – was located and inspected for the first time in over 200 years.”

A mystery brick-built chamber that does not appear on any plans was also discovered inside the dam, and will now be used as part of the monitoring procedures.

The original role of the reservoir was to regulate water in the Midlands canal network – in times of drought water would be drawn from the reservoir to ensure the economically vital canals were still deep enough to navigate.

Fears had grown that the earth dam was no longer safe to withstand major floods, was leaking, and could pose a danger to nearby homes.

Water does naturally seep through the dam. This is perfectly normal and acceptable as long as it is carefully monitored to spot potential safety concerns. It has also created a mini-ecosystem that has become a Site of Special Scientific Interest. The work has ensured this is safeguarded.

British Waterways is pumping water into the canal system from other sites and will continue to do this while the reservoir refills.

A hard task!

More than 100 tonnes of concrete is to be poured into Chasewater Reservoir to help support the 200-year-old dam.

The concrete will help control the flow of water when the reservoir is full. Repairs to the reservoir’s drawdown culvert (or plughole), have also been carried out.

County councillor Mark Winnington said: “This is the last major milestone in what has been a hugely successful and high profile project to restore one of the most popular country parks in the Midlands to its former glory.

“The county council has carried out vital safety improvements to the overflow to safeguard nearby residents in the event of severe flooding, which will enable us to monitor the condition of the dam much more closely in the future.

“The drawdown culvert – the equivalent of the plughole in a bath – was located and inspected for the first time in over 200 years. Vital improvements have now been made and the project is expected to be complete in the spring.”

Water levels have begun to rise again after the plug was replaced last October. It is expected to be refilled fully by spring 2013.

As you will be aware, due to the hazards associated with the construction works at the site, members of the public have been prevented access to most areas since November 2010 for their own safety.

However, because of the good progress that we have made, we are pleased to be able let you know that we are able to open Pool Road to pedestrians over the Christmas period. Galliford Try will be closing the construction site down for Christmas tomorrow (Wednesday 21 December) when they will be making arrangements for walkers to be able to cross the overflow bridge at the Nine Foot Pool, and so have access along the whole length of the eastern dam.

Unfortunately, we will have to close this access off again when we return to the site on Wednesday 4 January 2012 to enable us to complete the works in this area and will remain closed until completion of the works in the spring of 2012.

However, we hope that this temporary access will allow members of the public to enjoy use of the park over the Christmas break, and we ask that the safety requirements are again respected at the end of this Christmas period.

December update

It might be getting colder by the day and the snow getting ever closer, but on the whole the weather has been very kind to us since the last update in November, and we have made excellent progress with the works.

We’ve finished the main works at the northern end of the embankment and removed everything from the north shore that was being used as a storage area.  The grass seed that was spread on the dam embankment is now starting to grow, and last week a team of volunteers has spread cuttings over the area behind the dam to provide a seed bank to encourage the growth of a heathland habitat come the spring.

The work to extend the stop board grooves in the ‘hidden chamber’ which will allow improved maintenance access to the valve chamber in the future is finished.

Water levels continue to rise and the inlet chamber is now completely submerged. There is still a concrete cover slab to cast at the canal basin which will be done in the New Year – otherwise, our work in that area is complete.

That leaves the works in the Nine Foot Pool. The casting of the concrete spillway slab was originally programmed for the New Year. But we have taken advantage of the weather conditions and brought that forward and were able to cast the final section last week, completing that work.

Concreting work can be difficult in the winter as ideally, temperatures have to be above freezing and rising for new concrete to be placed, otherwise the frost can seriously damage the fresh concrete.

We can now be reasonably certain of completing the Redirock retaining walls around the spillway early in the New Year as this operation is not adversely affected by cold conditions.

The last items of concreting work on the project are the headwalls to the overflow pipes and the main weir in front of the spillway, all of which are planned for the New Year, weather permitting.

Finally, could we, the Chasewater project and site team, thank you all very much for your continuing patience and understanding over the past year. We would like to wish you all a very Happy Christmas and very much look forward to handing Chasewater back to you soon after the New Year.

FAQs ….

In response to various queries that we receive from time to time, we have included below a few FAQs relating to the reservoir and dam works:

  • When will we be able to walk across the dam?

If it is safe to do so, we are hoping to temporarily open the footpath along the crest of the dam to walkers over the Christmas period when the site will be shut down. This, however, depends on the stage that the works at the Nine Foot Pool and in particular, the overflow bridge, have reached at that time. Unfortunately, we will then have to reclose the access over the bridge in the New Year to enable us to complete the outstanding works and the path across the dam will then remain closed until the project is completed in Spring 2012.

  • When will the dam work be finished and the site cleared?

Subject to weather conditions over the winter which could delay progress, we are currently planning to complete the works and clear the site by late March/early April 2012.

  • Where does the water come from that feeds the reservoir other than rain water?

The reservoir has what is known as a “catchment area”, an area of land over which rain water, ground water and some drainage run-off collects into various streams and watercourses which ultimately flow into the reservoir.

The catchment area for Chasewater Reservoir is about 9 square kilometres and lies mainly to the north of the reservoir. The main dam was built across the valley of the eastern Crane Brook which rises in high ground in Burntwood and flows into the reservoir along Blackman’s Gutter and into the inlet where the sailing club is now sited.

The secondary, western dam retains streams such as the Big Crane Brook from Biddulph’s Pool and other ponds to the north which before disturbance by mining subsidence and open cast mining flowed into the River Penk to the west.

  • When will the sailing and powerboat clubs be back open?

This is entirely dependant on the water level in the reservoir and, therefore, the rate at which it refills. The reservoir level is currently around 144 metres above ordnance datum (AOD). Based on historical records and current rates of rainfall, it has been estimated that it may be the summer of 2013 before the reservoir starts to reach normal operating levels of between 150 and 152 m AOD. However, the sailing and power boat clubs can operate in lower water levels than this and so may be able to open a little earlier.

  • Will Pool Road be reopened, when the dam is finished? If not, why?

It is our intention to seek to close Pool Road to all traffic other than for access to the properties on Pool Road after completion of the works, however, this will be subject to a statutory consultation exercise.

  • Will there be a DVD released of the works involving the dam and of the hidden chamber?

We don’t anticipate releasing a DVD as such but video footage of the drawdown culvert and hidden chamber was included in an earlier blog update.

  • Will they remove all the debris and plants before it refills?

Some willow growth will be removed but other plant growth will not. This will die out naturally as the reservoir fills.
Debris will be removed where it might form a hazard to boat traffic or is regarded as waste. 

  • Will fish be put back into the reservoir?

There is no requirement or intention to put any fish back. We estimate that a small proportion of the total fish stock was removed. The majority of fish removed were predatory which may actually benefit the water body as smaller prey species may now be more prolific. In addition there will be a large flush of nutrients through re-fill which will ultimately facilitate the quick expansion of the fish populations.

  • Can you explain, ‘What is the plug that has been put back in?’

A critical part of the works was to ensure that the brickwork tunnel (the “drawdown culvert”) which runs under the eastern dam from the bed of  reservoir and which is the means by which water is released into the canal system was in good condition and fully functional.

Until this work was complete, water levels in the reservoir had to be kept down. Having completed these works, there is now no need to continue to release water from the reservoir and it can now be allowed to refill naturally.

  • Is there really a plug?

There is no actual plug but the valves that control the flow of water out of the reservoir are now shut.
 

 

Most of the main works to the north of the canal are now complete, although we still have to install drainage pipes through the sheet piles and carry out further landscaping works on the north eastern area next to pool cottages.

The repair works to the canal basin are also nearing completion, although the reconstruction of a concrete cover slab over the drawdown outlet is still to be done. This should be cast within the next few days.

Water levels in the reservoir are rising, albeit quite slowly at the moment. The water is now almost level with the top of the sheet piled dam around the inlet to the drawdown tunnel.

The two valves in the main valve house which are used to release water from the reservoir into the canal have been repaired – one of them had jammed shut and the spindle which operates it sheared away – if you watch our video Dam Cam Goes in Deep – you can see this in detail.

The maintenance regime that we have introduced for the valves will mean that we will have to open them briefly from time to time to ensure that they remain operational, but there is a secondary valve further downstream in the drawdown culvert which will make sure that we do not lose too much water from the reservoir during these tests.

Most of the construction activity is now concentrated on the Nine Foot Pool area. We recently completed the overflow bridge wing walls and started backfilling this and the sheet piled cut off wall.

Work is progressing well on the construction of the bases to the retaining walls which will run either side of the spillway area downstream of the weir.

Because of Galliford Try’s planned construction sequence and the need to have access through the whole of the Nine Foot Pool and spillway area, it is likely that the weir itself will be the last structure to be built in the New Year.

Thanks

The SCC team

The team at staffs county council have created a photo gallery to show the works they carried out to mend the entrance to the pipe/culvert through the dam, and also create a tower to help filter the water that flows through the dam in future.

The photos show:

  • Emptying of the area around the pipe.
  • Mending the pipe entrance and creating a concrete surround.
  • The top of and down the hidden chamber discovered by the camerabot (see previous post)
  • The team offering the first part of the concrete tower up to the existing pipe.
  • Cutting through the concrete tower.
  • Building up the concrete tower.
  • The top of the finished concrete tower.

 

To thoroughly investigate the pipe/culvert that runs through the dam, the engineering team sent a camerabot into the pipe and took what we believe is the first even film footage of the inside of the dam!

The footage reveals a hidden chamber the team was unaware of before, a working penstock and a broken penstock. Enjoy!

Lots of you have been asking (including Brownhills Bob) about whether Pool Road that runs across the top of the dam will now be open.

As I said to Stefan (a regular commenter on the blog), I need to refer to colleagues at the county council for answers to your questions, so sometimes they take a little longer to answer – so thanks to you all for your patience!

The county team has come back to me and explained that whilst the plug has gone back in, the road won’t be open til the works are complete (early/mid next year), and said to thank you for your patience.

The team at the county are also pulling together some information about the next steps (and dates in more detail) in the project to keep you all up to date on what to expect next.

Cheers and have a lovely weekend!

Lizzie

Older Posts »