Planned improvements at Welbeck lakes

Planned improvements at Welbeck lakes

It is believed that the first lake at Welbeck estate, known as Carburton Forge Lake, was built in 1695. Ten acres of land were leased to John Wheeler of Worcester in 1695 by the Duke, on which he was empowered to build the forge, a dam pool and floodgates.

Lakes were added upstream under the design of Francis Richardson, and then Humphry Repton, during the 18th century. The largest of the lakes is Great Lake, which fronts the Abbey, and was extended to its current form during the latter part of the 19th century. The risk of flooding associated with the construction of large lakes has only become a serious consideration in the past hundred years or so.

During this time improvements have been made to the dams at Welbeck to keep them in a safe condition and minimise the risk to those living and working downstream. Most recently a detailed inspection of the lakes has identified the need for improvement works at three of the dams. These improvements will ensure the dams meet current reservoir safety standards, and will help ensure the integrity of these important features at Welbeck for the future.

Why:
The safety standards required for large bodies of impounded water have been raised
over the years. The recommendations for improvement works from the 2014 investigations
have been made with reference to current standards.

What:
During the time since the recommendations were made a number of studies have been carried out to help identify the most appropriate course of action to meet current standards within the setting of Welbeck estate. As well as the engineering requirements ecology, landscape and heritage studies have been undertaken to help ensure the proposed works are carried out in the most sympathetic way avoiding adverse impacts.

The works will be on the three dams that impound the lower three of the cascade of lakes, namely: Great Lake, Carburton Forge Lake and Carburton Lake. The proposals are:

Great Lake: New overflow culverts, to replace the existing, providing much greater capacity for flood flows, combined with raising of the dam crest by 50cm to 60cm on average. The existing stone cascade, forming the most notable feature of the dam will be retained in its current form. The southern bankside area just upstream of the dam will also be improved to protect the bank during flood events.

Carburton Forge Lake: The existing raised spillway structure is to be lowered by approximately 25cm to improve its performance during flood events, and a stone effect kerb will be installed to give a consistent level along the length of the dam crest.

Carburton Lake: The existing dam, which is known to have been overtopped by floods in the past, will be improved by marginally lowering the crest and constructing a concrete block protection system on the downstream face. The protection system will be covered with grass to help maintain the appearance of the dam.

When:
A planning application for the proposed works is due to be submitted in October 2019, subject to completion of supporting studies and reports. This should allow preparatory works to start during the early part of 2020, with the main construction activities due to be on site during late summer 2020. The works should be complete before the end of 2020.

The Environment and Amenity
Protecting the environment, and maintaining the amenity value of the lakes, for fishing, sailing and bird watching, are of the utmost importance. A careful consultation process has been undertaken with Natural England, with support from an expert ecologist, to ensure the scheme proposals have no long term adverse impacts. For instance, whilst the lake levels will need to be lowered temporarily to allow the works to be constructed safely, in all cases the levels will be unchanged once the works are complete. We also realise that noise can be an issue during construction, and this will be addressed by careful selection of an experienced contractor and the use of appropriate plant and equipment.