Heaton Park Reservoir
Heaton Park impounding reservoir is located approximately 5 miles to the north of Manchester city centre and was constructed in 1928. It provided the City with 2,800,000 cubic metres of storage capacity for potable water conveyed from the Lake District via the Thirlmere and Haweswater aqueducts. The reservoir is no longer used for potable water storage but is needed to receive flushing waters during maintenance outages on the aqueducts.
The eastern embankments of the six-sided 31.4 hectare reservoir were assessed as having an “intolerable” risk of failure due to erosion of the soil foundations below the clay lining blanket. In order to achieve a safe “tolerable” failure probability level of 1 in 10,000 years, United Utilities decided upon remedial works to the reservoir consisting of a combination of improvements to the protect the clay liner and a reduction of the reservoir’s holding capacity.
Bethell Construction were appointed as main contractor to the scheme having taken part in a competitive tendering procedure and our work scope included the following activities:
- Emptying of the reservoir to scour level, clearance of silt and vegetation. Cleaning off stone pitching liner.
- Installation of over 150,000 square metres of lower protector geo-textile clay liner (GCL), a middle waterproof layer of 1.5mm thick MDPE liner and an upper protective blanket.
- Sealing of the blankets around the outlet tower.
- Structural repairs and modifications to the outlet structure to reduce the weir level by 3.5 metres to limit the reservoir’s capacity.
- Over 700 linear metres of anchor trench to secure the lining membranes at the top of the embankment.
- Removal and replacement of stone pitching, final landscaping and reinstatement works.