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 This was the fourth day in our new house - the big dig had begun! The digger was provided by our old next door neighbours in Bournemouth, S Francis Groundworks and this was the first pond they have ever dug or built! As Andy knew what had to be done and at what stage he was on site all the time directing the progress - when not in the garden he was decorating!! The "swimming pool" in the background is the home for the fish for the time being - the grey tank above and to the side is a Nexus filter ("wheelie bin" as refered to by Peter Waddington) which will cope with the filtration of the pool for the time being. We seeded this filter with media from our old pond which meant the there was bacteria present as soon as we switched the system on allowing the biological side of the filtration it to mature just that little bit quicker. The topsoil was kept for a later date to the side of the garden ready for the landscaping at the end of the project.
The depth of the pond is to be about seven foot so allowing for the two layers of the thick concrete base, the pond was dug to about eight or nine foot using a laser level system to ensure a constant level was attained, as the garden slopes off towards the bottom of the garden (about two foot difference). Neighbours got a bit of a shock when they saw this gaping hole!
About halfway dug on the second day of digging. We were a bit worried about the root system from the large willow at the side but surprisingly enough there was only one small root branch off from the main stem which was cut back and will not cause a problem in the future. Normally one of the biggest expenses is getting rid of the earth, or in this case the mix of sand and clay as this would normally cast around £120.00 per 12 ton lorry to dispose of. We disposed of 12 lorry loads but managed to find someone local who was building a BMX course and needed the soil to built the jumps and mounds, so the only cost incurred by us was the cost of the driver and the hire of the vehicle - considerably less then dumping it! Some of the sub-soil was kept to level the garden off before the retained top-soil is put down and seeded.
Day four - digging now finished on the main pond area and in went the polythene membrane and the steel mesh to reinforce the concrete base of the pond prior to the ready mix arriving the next day. We had ordered two loads so that there was no way the base would not be thick enough. As the house is built on clay and sand we went a bit over the top on the strength side due to the contraction and expansion of clay based soils. We also had strengthening fibres added to the ready mix - just in case.
The first load of concrete is delivered and spread out over the steel mesh reinforcing the second load closely followed and the whole area was raked over to provide a good adhesion layer when the blocks are laid on top. The base of the waterfall was also laid with remaining concrete left over from the second lorry load. This can be seen just in front of the "swimming pool".
Day five - All set and ready for the blocks to be laid just waiting for the first delivery of blocks. We managed to get hold of the highest spec newton block (normally used in prison walls, bank vaults and lift shafts) these will be laid at the base of the wall where the pressure would be the greatest. These will be laid flat to add to the strength and depth of the walls. Single upright blocks would not be capable of containing the outward pressure of the tons of water the finished pond will hold.
The blocks are delivered directly into the pond base by one of our customers Brian Reed who is the owner/driver of the lorry. Thanks to his skill, this makes it much easier for the brickies to handle as they do not then have to pass the heavy blocks down to the pond base ready for laying.
The brickwork begins! Blocks are laid on their side to add to the strength of the walls and directly on to the base concrete. Laser level can be seen in the centre of the picture to ensure the walls are exactly the same level all round as the garden slopes towards the bottom. Andy has started to arrange and connect the pipework and bottom drains to go to the filters. The bottom drains and pipework will eventually be encased in the next layer of concrete in the base.
Pipes in place for the filter ready to connect to the bottom drains. Four filters will be fitted to cope with the approx 18,000 gallons of water to be able to work efficiently, hence four bottom drains and the four pipes.
Bottom drains in position and being connected to the filter pipes. Inlet pipes are now positioned on back wall ready to be bricked in. These are set at an angle so that the returned water from the filter will create a clockwise circular current of water at mid level allowing constant movement and flow around the pond, this ensures that there are no "dead" areas of water at all and also assists the bottom drains to work as efficiently as possible as any debris will be carried to them to go to the filters. The shape of the pond and careful positioning of the bottom drains were designed to allow this.
The walls are built and two places are left for the fitting of two skimmers which will situated at the surface of the water to collect any floating debris such as leaves and dust. These will not be working all the time and will only be used as needed especially in the Autumn as the leaves fall off the numerous trees around the garden.
Skimmer in position and final layer of blocks to finish the shelf around the top of the pond. This shelf will be below water level and landscaped natural rocks placed so they are sitting in the water creating a natural finish. This is still a long way off completion.
Waterfall has now been built and the shelf has been finished around the top of the pond. This has been plumbed in so that the flow can be turned off so as not to annoy the neighbours or can run like Niagra falls when you have a barbeque!!! Ladder was essential item as it was removed during the day so that the brickies could not escape until the required amout of work was done!
The whole pond has now been rendered after the final laver of concrete had been poured. The top of the bottom drains can now be seen and all the pipework had been covered and sealed in. The whole pond will be fibreglassed in the spring as we ran out of good weather to be able to get it done.
One job we needed to do was to put in some sort of soakaway to take care of the water discharged from the filter when it is cleaned out as we do not have any mains drainage and the quantities of water discharged would mean it would not be possible to be passed into the septic tank. A three metre chamber was built at the lowest point of the garden and three concrete rings were laid on top of each other with the gaps around back filled with coarse stones to allow an even distibution of water leakage. Not an ideal way of getting rid of the water but the only option open to us.
The "Naughty Boy" chamber in progress!
After putting in the chamber, a discharge pipe was run from the filters.
The final stage for this year was to get the base in for the filters as the weather was now closing in meaning we could not get any more work done as the downpours started!
The final view of 2009. Pond now filling up nicely!! Too much rain!
The first view of 2010 now follows. As the weather was so extremely cold we ordered some hay bales to put around the Koi's temporary home just to give some sort of insulation to the water as temperatures plunged to -8 degrees. We also lagged the external Nexus filter with polywrap and an old duvet, and put a tarpaulin over most of the top to keep the snow out. Ice on the pond which was now nearly half full measured about 4" thick note the water comes up to the inlet pipes!.
Heres to a decent spring and bumper hot summer!!!
PART TWO!!!
Now the better weather has returned and all the water has been pumped out of the pond and allowed to totally dry out we have had various quotes for fibreglassing the inside of the pond. We decided on buying the raw materials from GRPMS ourselves and getting a few lads from a well known local "Luxury Motor Yacht Company" to do the work! The Koi seem to have weathered the extremely cold temperatures of the winter and are now feeding well - must feel like a hot tub to them at the moment!
FLAMING JUNE! Literally!!
The pond was well and truly dry and any loose rendering which was affected by the ice was removed and patched over and the whole pond was literally "hoovered" to remove any loose material and dust (another use for a Dyson). We were all set for a weekend start with the preparations starting on the Friday night - delivery of the materials were in two parts on the Thursday and the remainder on the Friday. The forcast had changed for the weekend at the last moment with showers arriving on Sunday morning - not good news but they had been wrong numerous weeks before so the lads turned up at 7am on Saturday and began work in earnest.
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