German Defense of the Volturno River Line, WWII Tactical and Technical Trends, No. 45, April 1, 1944 (Lone Sentry)

The enemy has so far made use of the river lines in Italy as delaying features rather than as defensive lines. On the Adriatic coast the rivers Trigno and Sangro have merely formed part of positions naturally suitable for defense and have not in themselves constituted defensive lines. On the Tyrrhenian coast the Volturno river constituted a sufficiently difficult obstacle for the enemy to take advantage of it to carry out a major delaying action. He did not intend to stand indefinitely on the river and make it a major defensive position. On 5 November 1943 his right flank was standing on the Garagliano river but this again forms part of a natural defensive system and has not dictated the choice of the position itself.

Thus, although he has not yet had the opportunity of standing behind a river line constituting in itself a natural defensive line and a major obstacle, the enemy has invariably employed the rivers either as an element in a defensive position or as a delaying feature.

[Volturno River Line - Map]

a. The Volturno River Position

The Volturno river line is divided at Capua into two sharply contrasting sectors.

Westwards from Capua to the sea the terrain on both sides of the river is completely flat (see figure 1) to a depth of at least six miles and is almost entirely devoid of cover. The whole of this area can be overlooked from the Monte Massico hills on the coast north of the river, and from the western slopes of the massif* northeast of Capua.

[Volturno River Line - Figure 1]

Eastwards from Capua there is hilly uneven terrain with considerable wooded cover (see figure 2) to a great depth on either side of the river.

[Volturno River Line - Figure 2]

The natural contrast between these two sectors of the river-line resulted in contrasting methods of defense.

b. The Enemy's General Intentions on the Volturno Line

The enemy's general intention in standing on the Volturno river-line was to impose maximum delay on the Allies within the limitations of the position and in accordance with the strategic policy at the time of slow withdrawal. To this end the defense was organized with a view to preventing the Allies from crossing the river. Once the river had been crossed in strength and as soon as its value as an obstacle was gone, the enemy did not apparently intend to fight to regain it.

He thus made no plans for counterattacking in strength and organized a planned withdrawal to fresh positions.

c. Characteristics of the Volturno Line as a Defensive Position

The key to the enemy's retention of the river line lay in the massif northeast of Capua. This was his main gun area and as long as this was held no crossing in strength between Capua and the sea was possible. East of the massif, however, the close nature of the country on either side of the river presented greater difficulties to the defense and was subject to infiltration. Thus, the main crossings were made by American forces at points east of Capua and the central massif with its vital gun area was turned. This operation forced a withdrawal from the center and thus opened up the coastal plain and enabled the British corps on the coast to cross.

d. The Withdrawal Behind the Volturno Line

Having withdrawn his main forces behind the river-line the enemy destroyed all road bridges across the river. Demolitions were complete, all spans being blown and all piers wrecked (see figure 3).** (In the initial stages of operations in Italy, the enemy simply broke the bridges, frequently leaving only from 10 to 15 feet to be spanned and, even in cases where more thorough demolition was effected, piers were left, thus facilitating the task of repairing.) Approach routes were blown at all culverts and all normal deviations were mined. This mining was however on a normal and routine scale and no special or unusual minefields were laid on the Allied side of the river.

[Volturno River Line - Figure 3]

Contact with advanced Allied elements was maintained by patrols after the enemy's main body had crossed the river. The function was observation rather than delay and they disengaged as the Allies approached. These patrols withdrew over the railway bridges at Cancello, Capua and Triflisco which were destroyed last. Removal of the railway tracks had enabled these bridges to be used by motor transport after the road bridges had been destroyed. It is presumed that the decision to demolish rail bridges last was on account of their greater strength and smaller vulnerability to bombing attacks. The enemy succeeded in timing the destruction of the three railway bridges so that his patrols were able to cross but before the bridges could be seized by the Allies.

e. The Enemy's Estimate of Probable Allied Crossings

The enemy had time to thoroughly reconnoiter the entire river—line. He therefore knew at exactly what places crossings were likely to be attempted. For the most part, certainly west of Capua, such places were at the original bridge sites. The defense plan provided for heavy concentrations of fire from all arms, including antitank guns, on the possible crossing points on both sides of the river. Mines and wire were laid at such points on the north bank.

f. Conduct of the Defense in the Plain West of Capua

West of Capua the enemy's defensive system was as follows:

A main gun area was established on the massif northeast of Capua and a subsidiary gun area on the Monte Massico feature north of the river in the coastal sector. There was little artillery emplaced between these two areas but self-propelled guns were given a roving mission in the intervening zone.

An uninterrupted line of company positions held the north bank of the river. Rifle platoons were sited on the reverse bank of the flood levee which runs parallel to the stream some 100 to 150 yards from the banks. Heavy platoons were in support in the rear. A series of small outposts were in positions on the river bank itself. Machine-gun and mortar positions were dug into the flood levee and the river bank (see figure 4). Warning of the Allied approach was by signal pistol. No patrols were maintained on the Allied side of the river. The enemy actually made no attempt to leave his own side of the stream except during two small nuisance attacks made when the Allies were themselves seeking to secure bridgeheads.

[Volturno River Line - Figure 4]

From his positions on the flood levee and from observation points in buildings and trees the enemy was able to observe very closely all Allied movement and our own patrols on the river-line and on the lateral road were at all times subjected to heavy small-arms and mortar fire. Any major movement south of the river drew heavy fire not only from the river bank but also from the commanding enemy artillery positions. Unobserved assembly within five or six miles of the river was almost impossible owing to the open nature of the country.

Battalion areas were organized about 1 1/2 miles in the rear of the covering company line. Communications with companies was by line telephone. Inter-communication between companies was by runner. Regimental support weapons and in some cases a small number of tanks were subordinated to battalion reserve or even to forward companies near likely crossing points. These were immediately employed in a counterattack role whenever small crossings were effected. There appears to have been no major regimental or general counterattack reserve. One battalion was placed in depth in the coastal area. Otherwise the position had no depth at all. This was, of course, due to the fact that the enemy regarded the Volturno as a delaying position only. Tank reserves were split up into groups and held in readiness for counterattack at the probable crossing points. Smoke was not used. Nebelwerfer and heavy mortars were concentrated forward of the main gun area to fire on the main roads. In the event of major crossings taking place, the enemy's plan was to withdraw the covering company line from sectors threatened by outflanking into the battalion areas and there to organize for counterattack.

g. The Defense in the Hills East of Capua

East of Capua the hilly and wooded nature of the terrain dictated a different form of defense and made the holding of a continuous river-line impracticable.

Observation of Allied movements was only possible to a limited extent and was obtained from commanding features overlooking the southern bank of the river. No attempt was made to cover the whole river-line. An estimate had been made of the most probable crossing points and the approaches and exits to these were mined, covered by antitank and artillery fire and supported by mixed counterattack forces. The enemy's defensive scheme consisted of a series of battle group positions organized in depth in order to counter and seal off penetration in the event crossings were effected.

h. Success of the German Defense

On the plain west of Capua the defense was entirely successful. The natural advantage of complete observation and the limited number of points suitable for crossings enabled the enemy to maintain control of the whole river-line. When eventually an Allied bridgehead was secured in the coastal sector the situation underwent little change as the forward enemy defenses fell back a short distance to a similar position on the Cancello canal. The Allied tanks landed from the sea had a moral and fire-power value only as the intersecting drainage ditches made their use as a mobile spearhead impossible.

East of Capua in the hills, the enemy succeeded in delaying the Allied advance but, in view of the more favorable terrain on the southern bank which afforded both observation and cover to the attack, he was unable to prevent the breaking of the line. The crossings secured by the Americans resulted in the turning of the central massif position, and the forced withdrawal of the main artillery group. This withdrawal removed the main pivot of the position. Crossings at Capua itself became possible and the firm line westwards to the sea became useless.

*Principal mountain formation
**Shown with American-built temporary bridge