NEC3 ECC: 1 in 10 Weather Events and associated Ground conditions

I am currently working on an overhead line scheme which requires 100’s of different access requirements on 3rd party land. The contractor had ample opportunity to review the access and way leave requirements prior to commencement and provided a track-way based solution which was accepted.

I am now starting to see claims in and around weather and their effects. We are getting situations that due to the level of rainfall that we have experienced over the winter, the ground has started to saturate and therefore mean that extra track-way and prevention is required to stop damage to the land. The Contractor has raised a claim based around a 1/10 weather event 60.1(13) and the data supplied does seem to support the position that we have had a greater than average level of rainfall.

However, I always worked under the assumption that CL60.1(13) works on the basis that you calculate weather impact by time delay based on the averages of the stated weather station and then apply this to a disruption element to the programme. How do we deal with the consequence of the weather, I have so far raised that this is an event pursuant to CL60.1(12). If this is the case how do I make the assessment of what does and does not fall under additional claims. In my view unless the Contractor has detailed data at time of tender (which they do not have) showing ground water levels and saturation tests and this can be shown to differ from that encountered they do not have a case.

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Similar question has been asked within this platform so I copy the answer below here as well. The only thing to add is that weather date is not dealt with by “averages” but by recognised 1 in 10 year events from the Met Office using historical data - this subtly is not an “average”.

This is always a difficult one to assess and the contract only goes so far (but equally not sure how it could do it definitively better). The first test is to see if the one in ten year weather event has been exceeded. If it has, you then need to justify the impact that the extra over has had which is likely to be subjective rather than definitive. As you say there is unlikely to be specific saturation tests to call upon as historical data.

If the weather has made the ground conditions worse than they would have expected then it would seem that this would be a compensation event. Whether it is under 60.1(12) or (13) is of little relevance as once it has ticked the box as being a CE it then has to be assessed.

Seems like one you are just going to have to try to get a joint agreement on - and if you can’t you just have to make the fairest/most correct assessment as PM that you can - but recognise that this could be challenged by an Adjudicator if the Contractor does not agree and wants to take it that far.