Mapping Mountains – Hill Reclassifications – Humps

Moel Maenefa (SJ 087 744) – proposed Subhump reinstated to Hump

This is the fourty first in a series of Hill Reclassification posts that detail hills whose status has either been altered in the listing of the Humps (HUndred Metre Prominences) through map study, surveys or LIDAR analysis that I have been involved in, or it is the recommendation that their status is altered.

LIDAR image of Moel Maenefa (SJ 087 744)

Many preceding posts detailing these hill reclassifications are retrospective as they were initiated from studying the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map, or from surveying with the Trimble GeoXH 6000, or from LIDAR analysis, and for this proposed reinstatement that affects the Humps the email I posted on the pedantic@groups.io forum in relation to this hill was dated 09.01.25.

The listing of Humps was published in book format by Lulu in 2009 and entitled More Relative Hills of Britain, its author; Mark Jackson gives credit to a number of people who contributed toward the formation of this list, these include; Eric Yeaman, Alan Dawson, Clem Clements, Rob Woodall, Bernie Hughes, Pete Ridges and others.  When the list was published in book format there were 2987 Humps listed with their criteria being any British hill that has 100m or more of drop, irrespective of their height.  Accompanying the main list is a sub category entitled Subhumps, with the criteria being any British hill that has 90m or more and below 100m of drop.

More Relative Hills of Britain by Mark Jackson

The details for this proposed reinstatement appear below:

The name the hill is listed by is Moel Maenefa, and it is adjoined to the Moel y Gamelin group of hills, which are situated in the north-eastern part of Wales, and it is positioned with minor roads to its north, north-west and east, with the A55 road farther to its north and the B5429 road farther to its west, and has the small community of Rhuallt towards the north-west. 

Summit extract from the Ordnance Survey 1:25,000 Explorer map

When the list was first published this hill was classified as a Hump with 100m of drop, based on the 290m summit height adjoined to an old trig pillar and which appeared on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps of the day, and a 190m bwlch height, which upon first compilation was probably based on interpolation of 10m contouring.  The triangulation pillar stood on a plinth and this has now been removed from the summit, with the contemporary online Ordnance Survey 1:25,000 Explorer map giving an erroneous 286m summit height.

Bwlch extract from the Ordnance Survey 1:25,000 Explorer map

This hill was subsequently reclassified to Subhump status in January 2013 and listed with 98m of drop, based on the natural col being on the old minor road south of the A55 road cutting, which was supported by old maps.  This was also supported by a 191m spot height appearing on this minor road on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage 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.

In 2023 the team in charge of the listing of Humps first analysed this hill with LIDAR and it remained classified as a Subhump with 98.8m of drop, based on a 289.5m summit height and a 190.7m bwlch height, with a note stating; Natural col extant.

The hill was subsequently analysed using LIDAR by Myrddyn Phillips and his findings posted on the pedantic forum, this post appears below:   

 

I haven’t posted one of these in quite some time, so if not interested in numerical detail or Humps I’d suggest you skip this post.

Many years ago the status of Moel Maenefa (SJ 087 744) was under debate.  It’s currently listed as a Subhump with 98.8m of drop, having once been listed as a Hump.  However, its current status is dependent upon its natural col being intact. 

If prioritising an intact natural col over a cutting, and if the natural col of this hill is no longer intact, the hill would be listed as a Hump with 103.2m of drop due to the A55 road cutting to the north of the summit.

Having driven this road a few days ago in slushy conditions I thought it time to have a look at this hill’s details with LIDAR.  Something I’d been meaning to do for a long time.

A col just south of the A55 road cutting does exist and LIDAR gives this as 190.690m positioned at SJ 08701 75852.  This coupled with the LIDAR summit of 289.470m at SJ 08711 74413, gives its current listed drop of 98.8m.

But does the natural col still exist?

Old Six-Inch maps give a variety of bench mark heights just to the south-west of where LIDAR places the 190.690m col.  These include documented heights of 623.5ft, 626.43ft, 625.1ft and 625.2ft.  These were probably positioned on or near an old building and are periphery in deciding whether the natural col still exists.

Before the A55 road cutting, the area of the col consisted of minor roads forming a diagonal crossroad.  These ran north, south, north-east and south-west.  Three of these roads still exist, with the northerly now swallowed by the cutting.

The 190.690m position at SJ 08701 75852 is placed in the centre of the north-easterly and south-westerly roads as they are intersected by the southerly road.  LIDAR contouring hereabouts is stretched following the course of these minor roads.  This indicates terra-forming and therefore the natural col cannot exist at this point.  On a subjective note; these LIDAR col contours do not look natural, which isn’t surprising as the land hereabouts is terra-formed. 

Now you could argue that this doesn’t really matter as this road col is near enough.

Importantly LIDAR contouring also indicates that the 190.690m col is not where the natural col once lay, as the 191m contour is flattened from SJ 08711 75856 to SJ 08769 75878.  This indicates that prior to the A55 road cutting this contour would have extended and culminated at the old natural col.  The north-easterly road hereabouts has cut into the 191m contour, only slightly, but it still has.  This position is approximately 40 – 45 metres eastward from the SJ 08701 75852 position currently taken as the col for Moel Maenefa.

Conclusion; the natural col no longer exists and therefore this hill should be listed as a Hump with 103.2m of drop.

A LIDAR image is attached.  The thick yellow contour is at 200m.  The blue and green contours are at 1m intervals.  The thick red contours are at 10m intervals.  The thin red and white contours are at 0.1m intervals.  The intersection of one of the thin red contours is where LIDAR places the 190.7m position that is currently taken as the col. 

LIDAR bwlch image of Moel Maenefa

Therefore, the proposed reinstatement of this hill from Subhump to Hump status is due to LIDAR analysis, resulting in a 289.5m summit height and a 186.3m bwlch height, with these values giving this hill 103.2m of drop.

 

The full details for the hill are:

Name:  Moel Maenefa

OS 1:50,000 map:  116

OS 1:25,000 map:  264, 265

Summit Height:  289.5m (LIDAR)

Summit Grid Reference:  SJ 08713 74418 (as listed in the Humps, with LIDAR analysis giving SJ 08711 74413)

Bwlch Height:  190.7m (as listed in the Humps, as the natural bwlch no longer exists, LIDAR analysis gives 186.3m to the A55 road cutting bwlch)

Bwlch Grid Reference:  SJ 0870 7585 (as listed in the Humps, as the natural bwlch no longer exists, LIDAR analysis gives SJ 08948 76019 and SJ 08949 76019 to the A55 road cutting bwlch)

Drop:  98.8m (as listed in the Humps, as the natural bwlch no longer exists, LIDAR analysis gives 103.2m of drop to the A55 road cutting bwlch)

 

Myrddyn Phillips (February 2025)