Construction of new water storage reservoir
The Bryanston Estate, Dorset
Project challenges
Historic water supply and storage infrastructure
Until recently, the estate relied upon a historic well to provide the water to a pair of old brick built reservoirs. The single pump in the well provided no back up to the estate should it fail, and the two old reservoirs were leaking heavily and were poorly sealed.
MJ Abbott was engaged by the estate’s land agents, Savills, to help find a solution to provide back up water and a reliable sealed reservoir system.
Our approach
Temporary water system to allow replacement of the old reservoirs
Taking the old brick reservoirs out of service would have left the whole estate without water while the new reservoir was being constructed in the same location. We therefore had to install a temporary water system to supply the estate for the duration of the 14 week project.
Our solution was to provide 3 no. temporary tanks for water storage. We adapted the existing pumping system and diverted the well pump to the temporary tanks, and installed a new twin pump variable speed booster unit to pressurise water to the higher properties. This allowed the old brick reservoirs to be demolished to clear space for the new reservoir.
To provide the back up water supply, the design included for a second borehole on the site to provide back up to the well system. A new 125m deep borehole was proposed adjacent to the existing well and, working with a local hydrologist and the Environment Agency, permission to drill and test pump was gained. Once the borehole had been constructed and tested, an abstraction licence was agreed and put in place.
The solution
New sectional reservoir with a divisional wall
The old reservoirs were demolished and, in their place, MJ Abbott designed and built a new 325,000 litre sectional reservoir with a divisional wall to allow one side to be shut down. A twin pump variable speed booster unit was installed in the adjacent well house which provided water to higher outlying houses, troughs and farm buildings. All associated pipework around the reservoir to the eight outgoing supplies was replaced with new 90/63mm pipework and all valves and meters replaced with ducting laid for future monitoring equipment to be installed.
The full scope of work comprised:
- Installation of a temporary water supply system to maintain flow to the whole estate
- Demolition of the old brick reservoirs
- Groundworks to clear the site and prepare for the new reservoir
- Traffic management and full safety management plan
- Construction of 325,000 litre Naylor Concrete sectional reservoir with divisional wall through centre for individual draining for cleaning and maintenance
- Bespoke twin pump control panel with variable speed and transducer in borehole to maximise water abstraction whilst maintaining water level in the borehole
- New 125m deep borehole with level transducer and digital water level display
- Grundfos fixed speed pumps installed in both well and borehole
- Twin pump variable speed Grundfos booster pumps for pressurising water to higher ground
- Water meters installed on outlet prepared for GSM telemetry for remote flow monitoring
- Replacement of all valves and external pipework
- Landscaping on completion of the works.
