The repairs are part of a wider conservation project to ‘Save The Finest View’ in England by dredging the Queen Pool and repairing the Grand Bridge, which has been postponed until 2021/22 due to COVID-19.
The maintenance work to the cascades, originally created by the famous landscape architect ‘Capability Brown’, involves the two main protective walls of the cascade, which funnel water into the dam to control the flow from the estate’s lakes.
The remedial repairs are being carried out by contractors Land and Water Services and are expected to take until the end of Summer to complete.
In total approximately 150 metres of the wall will need to be repaired. Wherever possible we will use the existing stonework, which is being retrieved from the lake bed, cleaned and then re-instated.
In order for the work to be carried out safely and to provide access to staff on the project, the level of the Great Lake and Queen Pool needs to be temporarily lowered by around half-a-metre. The work on the cascade we are currently conducting is essential work under the reservoirs act to repair leaks in the cascade.
The effect on wildlife
The works will affect wildlife, in particular nesting birds and Swans at this time of year, but with the support of West Oxfordshire District Council, our ecologists, Swan Support, the Queens Swan Marker and Natural England we have worked hard prior to the commencement of the project to protect wildlife during this time.
Blenheim is a Site of Special Scientific interest and has been a home to these amazing birds and many other species of wildlife for hundreds of years now. The future success of all resident species at Blenheim is dependant on this vital work happening.
Timing of the work
This is essential work under the reservoirs act to repair leaks in the cascade which pose an immediate risk. It is also 'low flow' for the river so safer for the works. If we do not carry out the essential repairs to the dam, and dredge the upper lakes in the next few years, the habitats of many species will disappear to a marshland before the end of the decade. This work is vital to protect our lakes for hundreds of years to come.
Provisions for nesting birds and swans during low water levels
From December last year, under the watch of our ecologists, we began clearing nesting habitat around the banks of the queen pool to deter wildlife from nesting. Most of the wildlife nested successfully further downstream. Our ecologists visited the site prior to the work starting and for those animals that remained they were happy for water levels to be lowered on the basis water remained nearby the animals. Many other birds have successfully nested in the lakes further down where the water remains, with many having hatched already.
Changing the water levels
From the 24th April we gradually dropped the water to reach the point where we are now, 600mm down. The water level may fluctuate slightly but it will then begin to be lifted, subject to flows, for the works to be complete by the middle of September.
One of Blenheim’s 10 goals to be delivered by 2027 is to spend 45 million on restoration projects to ensure we can protect and share the site with future generations. You can read all about our goals here.
Read more details on the wider project plans Read about the postponement
Should you have any further questions on this project or our restoration masterplan please email firstname.lastname@example.org