In August 2015, a new tidal gauge was installed in The Wash, Lincolnshire, to help the Environment Agency measure tides, predict flooding and assess the impact of climate change more accurately. The installation completed a £6m project to create a national network of 44 gauges that record information on sea levels to provide more accurate forecasts.
The instrument is on a platform measuring approximately two meters wide and 11 meters above sea level. It is located 4km offshore in The Wash, close to the port of Sutton Bridge, Lincolnshire.
As well as collecting data for the Environment Agency during its projected 60-year lifetime, the gauge’s information on tide levels can also be used by the harbour authority to help boats navigate through The Wash.
Meteorological equipment onboard measures wind speed and direction, air pressure and temperature. The Eastern Fisheries and Conservation Association (EFCA) also has equipment on the platform to measure the water’s quality and salinity. The MoD uses this as a static marker of the end of its testing range, where previously it had used floating buoys.
The gauge unexpectedly stopped transmitting so Briggs Marine Contractors Limited was requested by the Environment Agency to undertake repairs.
Briggs Marine assigned Coastal Survey Vessel ‘Humber Guardian’ to the task.
A tidal gauge expert from Briggs Marine’s Aids to Navigation department, along with a Briggs Marine sub-contracted 3D sonar side scan operator were mobilised to the area.
On-site on day one, in good weather conditions, a side scan sonar survey providing underwater 3D imaging was carried out at high water. Because a charted wreck and debris close to the tide gauge is used as a live firing target by the Ministry of Defense, this meant the Humber Guardian’s officers and crew needed to take extreme care in the approach to the tide gauge.
The side-scan sonar operator who conducted the survey advised that all data was excellent, and the scour areas and reinforcing grout bags around the base of the structure could be clearly assessed.
Day 2 on site, an engineer climbed to and worked on the upper level units of the gauge platform. When the tide sensors became visible at low water, the engineer boarded the structure again and climbed to the lowest platform to clean the three tide sensor heads.
Once complete, the engineer confirmed that data was now being transmitted from the tide gauge and receipt was confirmed at the remote receiving station.
This was an example of Briggs Marine staff carrying out very successful collaborative work, utilising the vessel and crew, personnel from other Briggs Marine departments and subcontracted experts.