SUNDERLAND POINT
Sunderland (locally known as Sunderland Point) is unique in the United Kingdom as being the only community to be on the mainland and yet dependent upon tidal access. Another example of a tidal affected area of the U.K. is Holy Island in Northumberland, however Sunderland is part of the mainland whereas Holy Island is not. The causeway to Sunderland Point runs below the high-water level and is flooded by the sea twice a day, preventing safe foot or vehicle access to the village.
The windswept peninsular lies between the mouth of the River Lune and Morecambe Bay in Lancashire. The village consists of around 30 houses and farms and can only be accessed by vehicle over a 1.5mile single track tidal causeway from Overton. During high tide the causeway is covered by water. Many people visit Sunderland Point to see Samboo's grave, a tribute to a slave who died here, as well as the remains of a cotton tree said to have been bought over with the slaves.
In this Earthcache you are going to observe the local tides and discover their effect on access to Sunderland Point.
TIDES
Tides are the rise and fall of sea levels caused by the combined effects of gravitational forces exerted by the Moon, Sun, and rotation of the Earth. Some shorelines experience two nearly equal high and low tides each day, called a semi-diurnal tide. Some locations experience only one high and low tide each day, called a diurnal tide. The moon causes tides by pulling on the ocean’s water. The sun also pulls on the water, but with about half as much force. During the full moon and new moon, the sun and moon work together to pull the water up at high tide, causing higher high tide and lower low tide. This effect is called a spring tide. During the first and last quarter moons, the sun and moon do not pull together and the high tides are a little lower and the low tides a litter higher. This is called a neap tide.
TIDAL BORE 
Tidal bores are a tidal phenomenon whereby the incoming tide forms a wave that travels up the river/bay against the direction of the river/bay's current. Worldwide there are only about 100 rivers that produce bores, of which about 20 are in the UK. They occur in funnel-shaped estuaries, and even then, decent sized bores only tend to occur in a handful of these rivers, and on a few days each year when there are the largest tides.
To observe the tidal bore at Sunderland Point you can sit on the bench outside First Terrace. You should be able to witness the bore and leave via the causeway in complete safely before it floods. To increase your chances of seeing the bore you should visit at spring tide rather than neap tide. Ideally Equinox spring tide for maximal range (late March or late September.)
YOUR TASKS: (include answers to 1, 2 and 5 in your log, please send other answers via email)
To claim this Earthcache, you are going to record a number of observations regarding tidal conditions on the causeway.
1. Record the time of your visit. Also, find a local tide timetable and state what time high tide is on the day of your visit.
2. What has a greater influence on tides, the Sun or Moon?
3. Use your GPS compass to find out how many metres above or below sea level you are.
4. Estimate the width of the causeway where the tidal warning sign is (at parking GZ).
5. Name the phenomenon which may cause this to change over time.
We will only accept logs where you have been able to visit Sunderland Point so you must check tide times in order to do this (hence terrain and difficulty rating being higher). As always with earthcaches, any photos are very much appreciated.