water in heat ducts below grade

I have a question that I thought I would throw out for some feedback…We bought our home last Nov (Had the inspection done as well) at the time the home inspector and myself noticed a probable water pump that was installed in a sealed 10 inch vent line going from the furnace into the ground…This summer (which has been unusually wetter then usual) we discovered 12 inches of standing water in 4 basement vents below grade. I ended up pulling 600 litres of water out over a span of 3 days… (That probable pump did end up being a rusted out pump)

In the days that have followed I have noticed that there is water still seeping in and the musty smell seems to be everywhere now that I cut out the 10 inch vent line going straight into the floor from the furnace. There also appears to be a great deal of sand that is washing into the ‘now exposed area.’

Our house is sitting on a hill in such a way that half the house is on the high side and the other half is the low side. The low side of the house has the partial walkout basement and it is on this side that the 4 vents were flooded out.

I am not sure what my next move should be. On the one hand the an HVAC contractor suggested that we pour concrete in to seal the problem. Another suggested an interior weeping tile system. I am looking at redoing the landscaping to incorporate deeper grooves to channel water around the house but this will not be for some time. Any input would certainly be appreciated.