The work began immediately following the Natwest series of one-day internationals between England and Australia in September and will be ready in time for the start of play next April.
It involves removing the existing turf from the outfield, stripping topsoil and the grading of subsoil.
This will be replaced to create improved levels that marry to the square and the existing boundary, especially upslope of the square.
At Durham water currently runs from the side of the ground onto the square and the aim is to eliminate this.
The clubs will install main, collector, lateral and sand slit drains as well as an automatic pop-up irrigation sprinkler system including a new storage tank and pump system.
This will be followed by the spread of rootzone material to provide a stone-free layer on the surface.
The decision to install the new system follows pioneering work done with irrigation at Lords.
It will bring the stadiums inline with other Test venues that have already had their drainage updated.
Edgebaston is now the only Test venue not to have undergone the improvements.
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