Being based in the South West of the UK we are blessed with beautiful beaches and a spectacular coastline. This has also made us all very aware of the more negative natural processes such as erosion, rising sea levels, and increasing frequency and severity of storms that affect our coasts.
Merrett Survey’s involvement with the geospatial inputs to help alleviate such processes include:-
Beach monitoring – Regular visits to survey beach profiles, as individual sections, or better still to laser scan the whole beach and make ‘difference map’ comparisons from year to year or after storm events. We are experienced at both of these methods.
Cliff monitoring / coastal stability – For 10 years we monitored the coastal town of Lyme Regis using a network of more than 100 permanent control stations that were monitored using GPS / GNSS tied in to stable structures inland. This enabled engineers to measure ground movements and design stabilisation works for the entire town. Boreholes were also monitored regularly measuring ground water and underground tilt / movements.
The cliffs along the south west and other coasts have been regularly monitored by us for movement and loss of material using laser scanning methods.
When the South West of UK was hit by a major storm that destroyed the sea defences protecting the region’s only rail link, Merrett Survey were engaged by Network Rail to scan and then monitor the slope above the railway line. This was achieved by a combination of aerial and ground based laser scanning / lidar.
Inter-tidal surveys – During the construction of DP World’s London Gateway port – the new container terminal at the mouth of the River Thames, Merrett Survey was engaged to fly aerial lidar every 6 months to monitor any changes in the inter-tidal zone. This was essential for environmental compliance during the dredging work associated with the new port build.
Bathymetric / Hydrographic skills – Whilst we specialise in land surveying we have skills in survey work on the water as well, providing bathymetric and hydrographic surveys as and when required for nearshore coastal and inland water way projects.
Ecological survey – We have been involved with innovative methods of surveying the extent of biotopes (extent of marine grasses) in inter-tidal zones to monitor changes over time. This was achieved using shore based laser scanning.
Of course all of the above includes the ‘marine environment’ but here we want to emphasise our experience with the man made connections to the marine / maritime world.
Ports and harbours – From UK to Oman we have provided all of the survey services required for the construction of new ports or development of existing ones. This has included the detailed scanning and modelling of roll on – roll off – RoRo ramps and pontoons, quay walls and dock facilities. Plus the sub-sea environment using ‘conventional’ echo sounding, multi beam and side scan sonar to map the sea bed and the sub-sea walls and piles/columns. Boat mounted laser scanning provides a good view of harbour walls and jetties that cannot otherwise be accessed.
Ship surveys – Merretts have provided high accuracy survey services for the calibration of ship board navigation equipment plus offset computations from the ship’s centreline / datum plate to GPS / GNSS antennae, roll and pitch sensors and submersible AUV equipment (autonomous underwater vehicles).
Ship / boat building and repair – Laser scanning can be used to rapidly survey and assess damage to vessels, plus to survey complex shapes when no existing design drawings are available.
Coastal construction – Merrett Survey Ltd has been involved in the setting out of pontoon piles and other waterfront construction – even the accurate placement of subsea anchors for a rowing course. During beach replenishment projects we have acted for the contractors and also for the client (UK local authorities) in surveying and measuring material volumes for accounting purposes.
Merrett Survey’s work for DP World on the
London Gateway project included 6 monthly
aerial lidar surveys of the inter-tidal zone
Scanning on board cable laying vessel
for calibration of all navigation aids, IMU
and GNSS antennae
We can survey above and below water
Coastal cliff and beach erosion surveys