Little Malvern Court & Gardens, Worcestershire
De-silting lake and construction of overflow & cascades
Little Malvern Court is a 15th century Prior’s Hall, once attached to the 12th century Benedictine Priory, with its tower dominating the views. The house and its 10 acres of grounds and gardens are open to the public from April to July each year.
MJ Abbott were approached by Hugh Thomas, Head Gardener of Little Malvern Court, following a recommendation by Michael Balston of Balston Agius Architects. We were asked to prepare our recommendations and estimate for works required to remove an existing failed overflow structure, the formation of a new overflow structure and stream/cascade system and the cleaning out and de-silting of the existing lake.
The proposed cascade and overflow structure was to be built more in keeping with the rest of the estate and surrounding features, and not to follow the timber structure that had been constructed in the 1960s during a large renovation project to the Priory and grounds.
Following successfully pricing and winning the project, the works commenced in September 2014.
The existing overflow structure was removed to ease the draining down of the lake.
Once drained down, the existing silt and unwanted plants were removed by a combination of mechanical excavator and slurry tanker. The thinner silt was pumped into the tanker and spread over a large adjacent field, whilst the thicker silt and debris was loaded into dumpers and stockpiled in a silt bund for spreading in the summer of 2015 once it has been allowed to fully dry out.
Once cleared out, the proposed shape of the overflow cascades were cut and filled through the banks to form the profile of the proposed feature.
A new hollow block retaining wall was laid over a concrete foundation set into the solid clay base of the existing lake formation. This was overlapped onto the surrounding sheet piling and encased in concrete and puddle clay to prevent future wicking between the two structures. Once built, the hollow block wall was in-filled with concrete.
Once the overflow structure was constructed, works started on the cascade/stream feature. Large on-site rocks were collected and transported to their proposed positions within the stream bed. Once their locations were decided, the underlying clay was excavated to ensure the rocks were set into the surface so as not to appear to have been placed on top of the feature.
Once the positions of the larger rocks were decided upon, they were removed and placed to the side of the feature while a 3 layer liner was laid through the stream, over the retaining wall and into the lower pond to ensure the stream was watertight and to prevent erosion during severe flows.
The large rocks were then replaced over the liner prior to being set in concrete. Smaller rocks were then placed and set in between the larger rocks, haunched and bedded in concrete to provide a base to the stream and form a number of collection pools and cascades.
Two concrete pads were also constructed for the future installation of a timber bridge over the stream and a layer of imported puddle clay was placed over the wall, foundations and liner to ensure a water tight seal on the main lake.
The works were completed in early October 2014.
The gardens at Little Malvern Court will open again to the public in spring 2015, by which time the garden team will have completed the planting around the new feature and lake banks and installed a bespoke oak bridge crossing the feature.
Little Malvern Court & Gardens: littlemalverncourt.co.uk/index.html