British soldier daring trench with improvised pump. After the Battle of the Marne in September, 1914, the Germans were forced to retreat to the River Aisne where they carefully chose where to dig their trenches. The possession of the higher ground gave them a tactical advantage, but it forced the British and French to dig in areas rarely a few feet above sea level. Waterlogged trenches were a constant problem for soldiers on the Western Front. Frontline trenches were usually about seven feet deep and six feet wide. The front of the trench was reinforced with sandbags to absorb bullets or shell fragments. Trenches were not dug in straight lines. Duckboards were also placed at the bottom of the trenches to protect soldiers from problems such as trench foot. Soldiers also made dugouts in the side of the trenches to give them some protection from the weather and enemy fire. The front line trenches were also protected by barbed wire entanglements and machine gun posts.
