Sere de Rivieres Line (1870-1914)
From the time of Vauban (1633-1707) until the Second World War (1939-1945), France had the reputation of producing the best fortifications and the best defensive systems in Europe. During this period, the long shared border between France and Germany had been crossed by hostile armies wany times as the two nations contested for the continental mastery of Western Europe. In most cases, these fortifications and barriers had not proven themselves equal to the hopes of their builders or of their owners during periods of actual combat. Despite this, the existence of such barriers often served as an unquantifiable deterrent against the initiation of hostilities, and as a strategic factor which altered the attacker's plans.
The Franco-Prussian War of 1870-71 was an unmitigated defeat for France and the French Army. One result of this French defeat was the plan for, and construction of, a defensive barrier to protect France against its more powerful German neighbor.
When the war of 1870-71 was over, the old French defences of the east had passed into the hands of the Germans, so a system of fortifications on the very largest scale was undertaken by France. The defeat of 1871 forced the very young Republic to sign the treaty of Frankfurt and to accept the annexation of Alsace and Moselle to the german empire. On several hundred kilometers, between Longwy and Belfort, the fortified barrier, designed by Vauban iwa destroyed. The road toward Paris was consequently wide open.
This barrier was named after its primary designer, Sere de Rivieres, an engineer general. The official objectives of this barrier, asstated by General de Rivieres in 1874, could well serve with minor modifications as the ideal statement of objectives for most such barriers. " [it is] to create a barrier stretching from Calais to Nice, and behind it a general defensive scheme in depth as far as Paris... for the purpose of providing a cover during the mobilization, concentration and formation of troops in battle order, of controlling the invasion routes and of providing strong defensive points behind the barrier which would increase the strategic possibilities of the area without impairing freedom of operations."
The French had long been masters of fortifications. The difference between earlier French defenses and that designed by Sere de Rivieres was the difference between isolated fortresses and a continuous barrier composed of mutually supporting strongpoints. General Séré de Rivières is nominated director of the Royal Engineers to the ministry of war. To him, it is absolutely necessary to recreate a fortification line along the new borders, between France and Germany. The low offers him 700 000 million gold Francs for the construction and the armament of 166 forts, 43 little works and more than 250 batteries. These works must be located along the new boundary with Germany, but also in the Alps, facing Italy. Thus he organised the construction of two defensive curtains. The first one along the costs of the high valley of Moselle, between EPINAL and Balfort. The second along the costs of la Meuse, between TOUL and VERDUN. From now on these two cities are border cities of the north-east.
He reinforced also the fortifications of the citadels of Langers, Dijon, Besançon, Longwy, Monymédy and Givet. They constitute background bases being able to stop the enemy if he eventually tries a breakthrough towards the gaps in Charmes on the Moselle or in Stenay on the Meuse.
The Belgian Frontier frontier presenting no natural obstacle, a line of strong works was constructed along it by the amelioration of the old fortifications. Detached forts were placed around the most important centres, converting them into intrenched camps. The first line of defence consists of four groups of works: Dunkerque, Lille, Valenciennes, and Mavbeuge. The first group comprises Dunkerque, Bergues, and Gravelines. and is being strengthened by the construction of detached forts. The second, Lille, was to have a cordon of forts, Aire and Douai. The third, Valenciennes, was to have a cordon of forts, Conde, Bouchain, and Quesnoy. The fourth, Maubeuge, had a cordon of forts, Landrecies, Ilirson, and Iiocroy. In the second line, on the river Somme, are the citadel at Amiens, and the fortresses of Peronne and Ham / farther south, the strategic triangle of La Fere, Laon, Soissons. This triangle, when the fortifications about these places were completed, was to form an immense intrenched camp ; the base of armies operating in the north of France. Iineims, further south, is also an intrenched camp with detached forts.
The defensive works along the German Frontier frontier were constructed along the river Meuse from Givet to Tout, and thence along the Moselle to Belfort. Givet is a small fortress of minor importance. Mezieres is a fortress which bars the valley of the Meuse, and occupies an important railroad junction. Verdun is an intrenched camp on the railroad from Metz to Paris. Toul is an intrenched camp on the railroad from Strasburg to Paris. Verdun and Toul are connected by a line of forts. Epinal is an intrenched camp on the upper Moselle. Belfort is a large intrenched camp near the frontier of Switzerland. Epinal and Bc1fort are connected by a line of forts. Montmedy and Lotu/wy are small fortresses along the railroad from Luxemburg and Thionville to Mezieres. In the rear of this frontier line are the intrenched camps of Langres, Dijon, and Jjesaneon. The intrenched position, Beljort, Epinal, Langres, Dijon and Besan^on, will form the base of an army operating from the south along this frontier.
On the Italian and Swiss Frontiers, the line of the Alps was defended by numerous small forts in the passes, supported in the rear by the intrenched camps of Besan^on, Lyons, and Grenoble. On the Spanish Frontier the line of the Pyrenees was defended by numerous old works which had been only slightly changed since the time of Vauban. The principal ones arc those at Perpignnn, on the Mediterranean side, and Bayonne on the Atlantic. The principal sea-coast works were, on the English Channel: Cherbourg, St. Malo, and Havre; on the Atlantic: Hochefort, Lorient, Brest, La Eochdle, Oliron, and Belle Isle; on the Mediterranean: Toulon and Antibes.
This system of Sere de Rivieres was designed as two continuous lines of sunken forts, these lines separated by a pre-planned 40-mile gap. Other portions of the French borders which were not fortified included those facing neutral nations like Switzerland and Belgium, plus those areas with terrain considered impassable, such as the Argonne and Ardennes regions.
The 40-mile gap between Epinal and Toul was designed to entice and channel any German attack into a desired corridor where it could be destroyed by the waiting French forces. It is unclear how well this planned breach in the French barrier would have performed, since Germany never obliged by attacking according to the French plan. In any event, in 1914, the Germans avoided these defenses entirely by attacking across neutral Belgium and invading France through an unfortified region.
The type of fort adopted developed from a combination of the redoubt at Paris fort and the forts of Metz. It was urgently necessary to protect their open frontier as soon as possible. The adoption of the type of fort admitted of their throwing up the front parapet on a field profile without any interference with the further progress of the construction. They thus obtained a certain amount of immediate protection, which increased in strength as the work continued. None of the new French fortresses were provided with enceintes. They were not objected to in principle, but it waa of the utmost importance to have the outer lines of forta fiuished as soon as possible, so that the enceintes were left to be done afterwards.
Each fort was provided with a high-level and a low-level parapet, ihe dwelling casemates being under the former and the latter defending the glacis, as at Metz. The trace was that of a simple lunette with a bastioned gorge, similar to the redoubt. The front and flank ditches were flanked by caponiers. Small emplacements for riflemen were arranged on top of the caponiers and at the shoulders of the work, so as to command more effectively the exterior slopes and the covered way. Protection was given to the guns against enfilade fire by numerous high traverses, which contained bombproof cover for the men on duty on the ramparts.
The guns were behind the low-level parapet, and the high-level one is organised for infantry. Sometimes the reverse arrangement was adoptod, but the guns behind the low-level parapet were better covered and saw the near ground better. Also the traverses, being projected against the cavalier, were not nearly so visible as when they are on the high-level parapet. In addition, the construction was more economical. On the other hand, the guns do not get such a large field of view as in the other case. One would think that shells bursting against the cavalier would throw back splinters against the low-level parapet, but the French appeared to have satisfied themselves that, with powder shells at all events, this was not to be feared. It was to be understood that the type of fort would be infinitely varied in detail in adapting it to actual conditions of the ground.
The distance of the forts from the town they had to defend was taken as preferably being about 5 kilometres, or 5,500 yards. The reason for this distance was that bombardment was not considered practicable beyond 7 kilometres, and that the bombarding batteries should not be possible within 2 kilometers of the forts. The interval between the forts themselves was governed by the desirability of giving one another mutual support with their artillery. Taking medium ranges for the guns, this would require intervals of from 3,300 to 4,400 yards, which were the best to adopt. Taking extreme ranges, the intervals were often extended to 6,600 yards. In these cases it was contemplated to construct intermediate works in time of war, the plans of which were carefully prepared beforehand.
In France a considerable number of "forts d'arret," or barrier forts, were built. These were isolated works, intended to close important lines of communication at points where it would be difficult to make an alternative route, such as mountain passes, important bridges, and railway tunnels.. Their design was difficult, as they are exposed to attack on all sides and must contain everything necessary for the garrison.
The works started in 1874 in Epinal with the forts of Uxegney, Parmont and Rupt and in Toul with the forts of Mont Saint Michel, Ecrouves, Dongermain and Villey-le- Sec. These works continued eleven years, until 1885. Victim of intrigues, the General Séré de Rivière retired in 1880, leaving a coherent and ambitious fortification system
The fortifications of General Séré de Rivière proved to be ineffective as far back as 1883, with the appearance of "mélinite". It is an explosive which gives new and strong capacities that Séré de Rivère could never have imagined.
In 1879, a new era in artillery commenced with the introduction of long guns and slow-burning powder, which may be considered to have culminated in 1885 with the introduction of shells containing high explosives into the French and German services. In 1883, french researchers developed a new explosive powder, calledmelinite. This allows them to load up shells, and make them explode,either upon clashing with the obstacle, or, with the use of a timer, beforeor after the obstacle. The experiences brought to the fortifications in theparisian region give overwhelming results. The stone vaults and walls do not resist this new shell torpedoes. It is therefore necessary to reinforce the majority of the forts of Séré de Rivière, by a thick concrete crust and to hide the artillery equipment, like it is used to be done in warships, in armoured cupolas and in dark turrets.
The change was as great a one as the introduction of rifled artillery. Its magnitude was so great that when it was first realised in France, there was a feeling that all the enormous sums which had been expended on the fortification of the frontier after the last war had been practically thrown away. This was an exaggeration of the real state of the case, but extensive works were undertaken both there and in Germany to restore to the defences their former efficiency.
Strategically this barrier had the effect of influencing the Germans to first invade Belgium in the process of attacking France. The execution of the German "Schlieffen Plan" almost achieved a rapid and decisive, defeat of France. Most observers believe it would have succeeded if it had, in fact, been executed according to the original plan. Since it did not work, however, the related strategic effect of the barrier system and the diversion of the German attack through Belgium was to bring Great Britain into the war against Germany. This created a balance of forces which led to prolonged stalemate and eventual German defeat.
Tactically, the sunken and mutually supporting fortifications performed very well when they were seriously defended and had been maintained properly. Verdun, for example, the strongest of the individual fortress complexes, withstood the German attack in 1914 and provided a strong point on which the defending French forces could rely firmly. The subsequent French defense of Verdun in 1916 was to prove one of the costliest episodes of the entire First World War for both the French and the Germans. This defense, successful only in a Pyrrhic sense, was made possible only because of the strength of the defensive positions. However, it was also severely jeopardized because of the neglect of those positions.
Long before the outbreak of World War I in 1914, the French had already begun to ignore defensive strategy. Thus, the magnificent system designed by Sere de Rivieres in response to the experience of 1870 was allowed to deteriorate. Prior to 1900, the French Army had become enamored with the need for an all-out offensive spirit. Thus, it was natural for France to neglect its defenses and favor investments in offensive forces.
Along the Western Front, World War I, of course, was to show overwhelmingly the dominance of the defense over the offense, and the errors in a total reliance on offensive strategy and tactics. Even after the war was well underway, however, and confirming daily the effectiveness of defensive weapons and defensive positions, the French military leadership demonstrated little capability to modify their offensive-oriented views. In battle after battle, this repeatedly caused unnecessarily high casualty rates for the French troops. More particularly, this offensive overemphasis was also manifested in the mindless weakening of the defenses at Verdun, the pride of the Sere de Rivieres Line.
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