Just before Christmas, Ireland suffered a number of flooding instances. They did not all have the same cause and cannot all be termed “acts of God”. (Few events in Ireland would qualify in that category).
Dempsey v Waterford Corporation  IEHC featured a case of flooding causing, the Plaintiff alleged, an actionable nuisance. In the case the Defendant was found not to be liable, principally because it did not know of the existence of the sewer from which the flooding came. The law of nuisance requires that the nuisance be caused by the Defendant or be continued by the Defendant after gaining knowledge or means of knowledge of the nuisance. (In short, if the Defendant did not know of the nuisance but ought to have known of it, he will be liable.)
Nuisance does not require proof of negligence on the part of the Defendant. It does not require the Plaintiff to prove the Defendant caused it. It requires the use of land or adoption of use, detrimental to the Plaintiff’s use of his land.
The nuisance is complete if the “use” is complete; in short, the arrival of rain water is not necessary to complete the nuisance, just the conditions on the land that will and do cause the flooding. A blocked or inadequate culvert would qualify, for instance, as a nuisance.
When the Plaintiff proves the nuisance, the onus to exculpate himself falls on the Defendant.
The remedy for nuisance can extend beyond compensation to injunction. The compensation will be an amount sufficient to put the Plaintiff back in the condition he/she was before the wrongful event.