Contact

The Liverpool ONE Pavement

29 September 2008

Liverpool ONE is a major development by Grosvenor Estates covering 42 acres in the heart of Liverpool. The development, which opened fully on 1 October 2008, is divided into six districts, one of which includes the former Chavasse Park. This was the site of the first Liverpool dock, known as the Old Dock.

Grosvenor have attempted to convey some of the history of the dock by outlining its boundaries in the walls and brickwork of the pavement of the new open space.

The partial outline of the Dock wall.

Black lines in the pavement indicating the boundary of the Old Dock.

Fountains in the development and a 'lunar pool' convey a tidal theme, while etched into the pavement alongside the fountains can be found a set of numbers which refer to measurements of the heights and times of high water made by William Hutchinson , the 18th century Liverpool privateer and dockmaster.

The only image thought to be of William Hutchinson. The original portrait is now lost but a copy survives at Liverpool Local Record Office.

Fountains in the development and a 'lunar pool' convey a tidal theme.

What do the numbers in the pavement mean?

Hutchinson measured the heights and times of high waters between 1764 and 1793. The numbers in the pavement refer to measurements that he made in January 1783.

Numbers in the pavement.

You will see a column starting Wednesday 01 then Thursday 02 and so on which refers to the dates of the days in that month.

The second column starts with (for Wednesday 1st January) '28'. This is the 'Age of the Moon' or the number of days since the last New Moon. Hutchinson would not have measured this - he would simply have noted the Moon Age from information in an almanac.

The third column starts with '8:55' which was the time of the morning high water on the Wednesday, as measured by Hutchinson, while the fourth column shows '14.1', the height of that morning high water in feet and inches as measured by him.

By 'morning' we mean the period from midnight to noon and the exact time noted by Hutchinson would have been what is called 'apparent time', which is the time one would infer from using a clock adjusted to correspond to a local sun-dial.

On the second row, but still for Wednesday 1st January, one sees the time and height of the afternoon tide, where 'afternoon' means the period from noon to midnight. In this case, we see that the afternoon tide occured at 9:25 (pm) and had a height of 15 feet 2 inches.

Why is there a 'no high water' occasionally?

Liverpool has one of the largest tidal ranges in the world. Most days there are two high tides, one in the morning and one in the afternoon. They are separated by, on average, 12 hours 25 minutes which is half of the length of the 'lunar day'. Ocean tides are primarily due to the Moon rather than the Sun and the lunar day is the average time between passages of the Moon over the longitude of a given location, such as Liverpool. Learn more about ocean tides.

Because of that extra 25 minutes, it can happen that when a high tide occurs just before a midnight (or noon) then the next high tide does not occur in the following morning (or afternoon) but in the early part of the next afternoon (or morning). Hutchinson noted this skipping of a morning or afternoon entry as a 'no high water'. It is an inevitable consequence of the main tidal period (the 12 hours 25 minutes) - it does not mean that he actually missed a high tide!

'No high water' as drawn on the pavement for the morning of Monday 20th January.

What are the strange characters in the Age of the Moon column?

As mentioned above, the numbers in this column usually indicate the Moon Age, or the number of days since New Moon. However, on the day when New Moon occurred you will see a symbol such as 'N7M' which is Hutchinson's code for 'New Moon at 7 o'clock in the morning'.

Hutchinson's code for 'New Moon at 7 o'clock in the morning'.

On other days there are other strange codes. For example, on Friday 10 January you will see 'Qr10M' (appearing in the pavement as '210M') which means 'Quarter Moon at 10 in the morning'. A quarter moon is when the Moon appears half full! That is to say it is a quarter of the way through its progress from New Moon to Full Moon and back to New Moon again.

Similarly, on Saturday 18 January one sees 'F2E' which means 'Full Moon at 2 in the evening' (i.e. afternoon). On these days, Hutchinson is providing 'extra information' for us - it is clear from the column as a whole what the Moon Age on these days was (e.g. age 7 days for 10 January). Another code is the '11 A' on 14 January which indicates a Moon Age of 11 days and that the Moon was then at its greatest altitude called its 'Apogee'.

More about William Hutchinson

Hutchinson made measurements like this from 1764 to 1793. It was an enormous achievement and provided the first extended set of tidal measurements in the UK. They were used to devise the first, accurate set of tide prediction tables by Richard and George Holden, and the Hutchinson data are still used in tidal research today.

Aside from tides, Hutchinson was a major figure in Liverpool's history. He was at various times a privateer (a licensed pirate), ship owner,businessman, inventor, author and philanthropist. It is excellent that some memory of him is preserved in the new Liverpool ONE development.

For a free CD containing all Hutchinson's tidal and meteorological measurements and many more details about him Click here. This CD has been produced for the Liverpool '08 celebrations by the Proudman Oceanographic Laboratory (POL) in Liverpool. The POL web site contains more information on Hutchinson and can provide you with tidal predictions for Liverpool (and other UK locations) for the next few days.

---

Notes

The Proudman Oceanographic (POL) scientific research focuses on oceanography encompassing global sea-levels and geodesy, numerical modelling of continental shelf seas and coastal sediment processes. This research alongside activities of surveying, monitoring, data management and forecasting provides strategic support for the wider mission of the Natural Environment Research Council.

As a public funded body it is part of our remit to inform the public of the science and research undertaken at the laboratory. Attending events like the 'Ocean Awareness Weekend' at the Blue Planet Aquarium offers the opportunity for our scientists to meet members of the public and present the laboratory's work.

The Natural Environment Research Council is one of the UK's eight Research Councils. It uses a budget of about £ 350m a year to fund and carry out impartial scientific research in the sciences of the environment. NERC trains the next generation of independent environmental scientists. It is addressing some of the key questions facing mankind, such as global warming, renewable energy and sustainable economic development.