Bench marks

A bench mark is an Ordnance Survey arrowhead sign found on stationary objects such as walls, bridges, churches and specially erected concrete posts where the altitude above sea level has been accurately measured by surveyors and may be used as a reference point in tidal observations and surveys.

The arrowhead points to a horizontal line above it which marks the exact altitude. At places below sea level, the arrowhead points down. The marks are charted on the large-scale Ordnance Survey maps, such as the 6 in. and 25 in. to the mile.

When a surveyor takes another altitude measurement from the mark, an angle-iron is fixed at the level of the horizontal bar to form a temporary bracket or “bench” which supports the levelling instrument.

Bourne lies between fen and upland and therefore has a varying elevation above sea level. The ridge of Jurassic land which lies to the west overlooks the town with the reclaimed fen to the east but the area is not one of great altitude, rather a very gentle relief, the fen edge being at a height of about 23 feet while 1½ miles away, the highest ground in Bourne Wood is at about 190 feet. The town itself is built mainly between the 25 ft. contour line on the east side and the 50 ft. contour line on the west.

Bench marks may be found in the Bourne area but few survive in the town itself because of modernisation and drastic alterations to old properties.

There is a bench mark on the Abbey Church and it can be found at the foot of the tower on the southern face while one of the dark lines high up on the stonework is reckoned to have been left by the flooding in November 1571. The locality was hit by one of the worst storms in history and it was later recorded that the flood water in Bourne rose "to midway of the height of the church walls" during a tempest which affected the whole district, particularly houses and other buildings on the eastern side of the town.

Two others can be found on the front of the cemetery chapel in South Road and on the yellow brickwork of the commercial premises of No 2 South Street.

Other known bench marks are on the Town Hall, a private house at 101 on the west side of North Road and at the Abbey Primary School, all flush brackets. A flush bracket on the lodge house at Bourne Hospital in South Road disappeared when the premises were demolished in the summer of 2003.

The level shown for the old Market Place, now the town centre, on the 1891 OS map shows 34 feet above sea level and there is a flush benchmark on the Town Hall nearby. The other nearest benchmarks to the centre of the town shown on this same map are on the old railway bridge which crossed the Abbey Road east of the primary school, in West Street and in North Road on land where Wherry’s windmill once stood, now the junction with Mill Drove. All have disappeared. Known bench marks in Bourne:

 1. Woodland Nurseries off Exeter Street now demolished (incised mark)
 2. No 69 Woodview (incised mark)
 3. Building on the east side of Exeter Street (incised mark)
 4. No 63 West Street (incised mark)
 5. No 35 Woodview (incised mark)
 6. No 43 Stanley Street (incised mark)
 7. No 17 Woodview (incised mark)
 8. No 2 South Street (incised mark)
 9. Wake House, North Street (incised mark)
10. The Town Hall (flush bracket)
11. No 14 North Road (incised mark)
12. No 4 Harrington Street (incised mark)
13. No 1 Queen's Road (incised mark)
14. No 35 Queen's Road (incised mark)
15. No 1 Recreation Road (incised mark)
16. No 53 Recreation Road (incised mark)
17. No 46 Harrington Street (incised mark)

See also Flooding in Bourne