The hole in the ground that was once Abbey Wood’s railway station is sometimes filled with water and at other times not, without any obvious correlation to rainfall. I asked the man in charge what was going on and why they had been digging the hole anyway.
The excavation is necessary to locate (and avoid) the piles that supported the old station because before long the site will be piled in connection with the diverted North Kent line and the new station.
Now that the old piles have been located, hardcore has been rolled in to support the massive piling machine which has become a familiar sight to Crossrail watchers.
Those who know the area will have assumed that the water is yet another indication of the high water table. The reason it is not linked very directly to rainfall is because it is in effect part of the Thames. The Network Rail engineers have noted that the water level goes up and down in perfect synchronicity with the tidal flow of the river very nearly a mile and a half away.
When the tide is in Crossrail’s pump has no chance of keeping pace with the inflow.
The ground further east is fortunately much more stable, hence the simpler ground preparation in that area and my own house is unlikely to float away at the next high tide.
More Crossrail related blogs.