Roads, Earth and Geological Engineering

Sapper Geologists: Roles in Planning for D-Day and Beyond

COLONEL E P F ROSE TD MA DPhil CGeol FGS FInstRE

Geologists served professionally as such in the Royal Engineers at the time of D-Day much as they do today: from the reserve army, in small numbers, and in relative obscurity. In describing geologist roles in planning for D-Day and the subsequent NW Europe Campaign, this article is intended to be:

• informative, to those readers who know little of the contribution of geologists to the success of the greatest amphibious assault in world history;

• useful, to serving members of the Corps, in that ways in which geologists have been used in the past can provide clues to potential uses in the future.

Initially, once Normandy had been chosen for the Allied invasion, a survey of possible temporary airfield runways  sites was essential.  To make the significance of the geology apparent to non-geologists on the planning staff, in mid-1943 King prepared a map that essentially interpreted ground conditions in terms of ‘go’, ‘no go’ and ‘slow go’ regions for the rapid construction of temporary airfields. From this map, whose regions closely match those of the bedrock ‘solid’ geology (Figure 2) or superficial ‘drift’ geology, it is evident that the Cotentin Peninsula was far less suitable than the Calvados coast to the east for this purpose. Geology and the advice of a Sapper geologist therefore helped to influence the decision finally to route the Allied invasion through Calvados (Figure 5) rather than the Cotentin Peninsula.

Shotton developed the airfield planning work begun by King. Twenty airfields were successfully constructed within the British sector of operations in Normandy between 7 June and 13 August 1944 (Figure 8) and a further 3 by the end of August. The Deputy Chief Engineer Airfields primarily responsible for their construction later recorded that the value of detailed topographical and geological study in selecting airfield sites in the beachhead area was fully proved. The most valuable forms of specialized intelligence were, in his opinion, ‘geological overprints for topographical maps prepared by the geologist staff officer at a scale of 1:100,000’ .  Moreover, geological study enabled calculated risks to be taken in forecasting the rate of airfield surfacing stores.

Two well-drilling units were deployed to Normandy in the build-up phase of operations, which followed the initial assault: No. 8 Boring Section RE arrived on 8 July 1944, followed by No. 6 on 11 August. (All Boring Sections RE were to be re-named Boring Platoons RE from September.) Each Section comprised three officers and about 90 other ranks, and could deploy as detachments to operate four percussion drilling rigs, two rotary rigs and an earth auger.  In Normandy the two units were in total to drill over 30 wells for potable water, plus numerous sullage holes for disposal of waste water, and shot holes to assist quarrying, before following the Allied combat troops as they advanced eastwards.

Amongst his many tasks, Shotton provided geological maps and later occasionally advice to the Quarry Group RE. This comprised a headquarters unit plus five Quarrying Companies RE: numbers 125, 853, 855, 856 and 858. Leading elements were in Normandy 12 days after D-Day, and the Group was essentially complete there by 7 August.  The Group (comprising about 900 men in total) provided the stone required for road widening and repair, and the construction of new roads. The movement of large numbers of troops and their copious supplies of food, fuel, ammunition and other stores required routes that provided an efficient infrastructure. However, military vehicles that accompanied the invasion force arrived in a region that had hitherto only experienced relatively light traffic. Their large number, the weight of many of them, and the passage of those equipped with caterpillar tracks, was predicted to make road maintenance a problem.  In total 670,075 tons (over 680,000 tonnes) of stone were delivered by the Group from quarries in Normandy (Table 1), before its companies moved on to Belgium and finally Germany as the Allied armies advanced.

At the end of hostilities, the Chief Engineer for 21st Army Group (Major-General Sir Drummond Inglis) thus had reason to record (in the Journal of the Royal United Service Institution, 1946, v.91, p. 177): ‘We had, fortunately, long appreciated the importance of geology in modern war’.

Quarrying Company RE

read the full article in the December 2019 Institution of Royal Engineers journal.