Tuesday, 30 January 2024

Mapping Mountains – Summit Relocations – The Fours – The 400m Hills of England

 

Wood Barrow (SS 716 425) 

There has been a Summit Relocation to a hill that is listed in the The Fours – The 400m Hills of England, with the summit height, col height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Wood Barrow (SS 716 425)

The criteria for the list that this summit relocation applies to are:

The FoursThe 400m Hills of England.  English hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main list are three categories of sub hills, with this hill being included in the 400m Sub-Four category, the criteria for which are all English hills at or above 400m and below 500m in height that have 20m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and the 2nd edition of the booklet containing this list was published by Mapping Mountains Publications on the 24th April 2018.

The Fours - The 400m Hills of England by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Wood Barrow, and it is adjoined to the Dunkery Beacon group of hills, which are situated in the counties of Somerset and Devon, and it is positioned with the A39 road to its north-west and the B3358 road to its south, and has the small community of Parracombe towards the west north-west.

When the 1st edition of the The Fours was published by Europeaklist in December 2013, the qualifying 400m Sub-Four hill was listed as Wood Barrow (SS 716 425) with 22m of drop, based on the 480m summit spot height that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and the 458m col spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map, with an accompanying note stating:

Although Chapman Barrows at SS 700 434 has a 480m map height, it is not listed as a twin Sub-Four as its 480.093m flush bracket height means ground at the base of the trig pillar will be below 480m. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

LIDAR image of Chapman Barrows (SS 700 434) and Wood Barrow (SS 716 425)

The height produced by initial LIDAR analysis to the high point of Chapman Barrows is 479.8m positioned at SS 70003 43472 and to the high point of Wood Barrow is 479.7m positioned at SS 71627 42506, resulting in the summit of the qualifying 400m Sub-Four being relocated from Wood Barrow to Chapman Barrows. 

LIDAR summit image of Wood Barrow (SS 716 425)

However, the latest available LIDAR analysis gives the high point of Chapman Barrows as 479.8m positioned at SS 70003 43471 and the high point of Wood Barrow as 480.0m positioned at SS 71627 42505, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to when the high point is positioned in a different field, to a different feature such as a conifer plantation, within a different map contour, a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is considered a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the height produced by the latest available LIDAR analysis to the summit of Wood Barrow is 480.0m and this is positioned at SS 71627 42505.  This position is adjacent to where the 480m spot height appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and is approximately 1.8km south-eastward from the summit of Chapman Barrows which LIDAR gives as 0.2m lower.

 

The full details for the hill are:

Group:  Dunkery Beacon

Name:  Wood Barrow

OS 1:50,000 map:  180

Summit Height:  480.0m (LIDAR)

Summit Grid Reference (New Position):  SS 71627 42505 (LIDAR)

Col Height:  457.7m (LIDAR)

Col Grid Reference:  SS 72621 42582 (LIDAR)

Drop:  22.3m (LIDAR)

 

Myrddyn Phillips and Aled Williams (January 2024)

 

 

 

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