In some locations, during the digging of the foundation you might notice a lot of water appearing in the trenches. This could be due to the fact that the water level is quite high in that area.
As a rule, the foundation is dug about 3 feet below the surface. 1 ft of concrete is poured and then the foundation walls starts going up. It is obviously going to be a problem if the water level is high and your foundation is sitting in the water.
The solution could be a raised foundation. Either at 2 ft, 1 ft or even on the surface with the help of shuttering (which basically means a frame for the concrete to be poured into).
This could help stop any water or dampness entering the foundation level, but do remember that this has to be checked by your qualified engineer/architect and has to be accepted by the planning department.
* Please note: In some areas, the planning department may not accept the floor level of the house being raised, as this could effect the whole view of the house from the road.