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BOC Immingham Dissolved Acetylene Project Environmental Statement: Vol. 2 Main Text
9.26 For the Humber Estuary, the standard reference station is Immingham where the Proudman
Oceanographic Laboratory (POL) operates two full-tide bubbler gauges. Table 9.2 58 summarises
the main tidal characteristics for the site.
Table 9.2 Predicted Tide Levels
m above Chart
Datum (CD)
Immingham
m above Ordnance
Datum Newlyn (ODN)
Highest Astronomical Tide HAT 7.97 4.07
Mean High Water Springs MHWS 7.19 3.29
Mean High Water Neaps MHWN 5.74 1.84
Mean Sea Level MSL 4.13 0.23
Mean Low Water Neaps MLWN 2.58 -1.32
Mean Low Water Springs MLWS 1.00 -2.90
Lowest Astronomical Tide LAT 0.11 -3.79
Ordnance Datum Newlyn ODN -3.9 -
Tidal Range
Peak Range (HAT LAT) 7.86
Spring Range (MHWS MLWS) 6.19
Neap Range (MHWN MLWN) 3.16
9.27 Extreme sea level analysis 59 has been undertaken for the EA for Immingham for the 0.5 and 0.1%
annual exceedence probability (AEP) using the POL methodology. The results for extreme sea
level analysis are provided in detail within Appendix 9A and are summarised in Table 9.3.
Return
Period (year)
Table 9.3 Extreme Sea Levels
AEP (%) Still water level (m
AOD)
Still water level with climate
change to 2063 (m AOD)
200 0.5 5.05 5.449
1,000 0.1 5.34 5.739
9.28 Studies 60 suggest that increased rates of sea level rise are resulting from climate change. The rise
in sea levels will change the frequency of occurrence of high water levels relative to today’s sea
levels, assuming no change in storminess. There may also be secondary impacts such as
changes in wave heights which would increase the risk from tidal flooding. The predicted effect of
climate change on extreme sea levels is provided in detail within Appendix 9A and is summarised
in Table 9.3.
5100935.404 Environmental Statement August 2011 133