NEC ECC: Assessing a rainfall 1 in 10 weather event

When the Project Manager assesses the compensation event due to rainfall, do they give only the number of days with rain above the 10 year average or consideration is given to the follow on days where production is greatly reduced due to excessive wet ground conditions?

The project is extensively earthworks and after a rainy day, the following 2 or so days ground conditions are such that little or no production at all is achieved. Is the Contractor not entitled to additional days due to conditions so caused by the rain?

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The last paragraph of clause 60.1 (13) determines the criteria for assessment of a weather compensation event, as the difference between actual weather conditions and up to the 1 in 10 year average. This is where the fun commences though as this appears pretty open ended with regard to how you assess the effect.

The compensation event is apparent when the officially recognised data is obtained, although it actually occurs when the ‘tipping point’ of the 1 in 10 year average is exceeded, which could be on the last day of the month. My view, however, is that you treat the entire month as the compensation event period for assessment, because that is the period of time that clause 60.1 (13) relates to and is averaged out across.

Personally I would take the Accepted Programme prior to the applicable month and update to the beginning of the month. Weather conditions are one of the instances where I believe the Accepted Programme is not actually updated to the point when the compensation event occurred, as it is assessed over the entire month. Assess the forecast progress, obviously including time risk allowances, including for weather conditions which are not a compensation event, and compare with the actual progress for that month.

Although this ‘re-measure’ approach includes an element of your own risks which do not relate to weather conditions, including Equipment breakdowns etc, it does at least provide a starting point for an assessment. Agree the programme effects with the Project Manager and then confirm any agreement in a formal communication.

The quotation assessment would also factor in other consequent measures, such as any additional de-watering equipment, temporary surfacing to access roads, additional excavation support and weather protection etc, which are a direct consequence of the compensation event,. Hopefully an early warning was previously notified which discussed the use of such measures anyway, so the Project Manager would have been aware of what was proposed.

I would generally agree with Andrew but my view is

The event occurs when the weather measurement is recorded and since the standard weather measurements are for each calendar month the measurement is for the month and if provided by the Met Office will not be available for some time after the month. The CE could be apparent during the month but can not be confirmed until the measurements are available.

I don’t believe there is a “tipping point” because the measurement is for the full month - who is to say that the rain on day 1 of the month is the Contractor’s risk, the risk is over the full month.

I would also suggest that the assessment of the event should include for the effect of the event on subsequent months and is not restricted to the month in which the event occurred (but only the extra over effect). Therefore any delay, disruption, additional work etc due to the event should be included.

Dave, thanks for your comments, much appreciated.

The main point I was trying to make is that the assessment is based over the entire month, so is not calculated on the actual day of excess rainfall days or the day where the total rainfall exceeded the 1 in 10 year average, which I referred to as a ‘tipping point’.

My assumption for a programme assessment based upon that month, does not preclude the effect on remaining activities, as you rightly point out, although was a suggestion of how to measure the time effect in terms of days of progress (or no progress as the case may be).

From my own experiences this not an easy compensation event to assess, both in terms of assessing time and a quotation with the usual round of ‘fun and games’ commencing when such an event occurs.