Editing Inner German border (section)

==River borders==
{{multiple image
| align    = right
| image1   = Sparnberg 1980s.jpg
| width1   = 200
| alt1     = View of a small village with houses and a church, located in a wooded valley, with a river in the foreground. A high concrete wall separates the village from the river.
| caption1 = [[Sparnberg]] on the Saale in the mid-1980s, enclosed behind a concrete wall
| image2   = Gdr river patrol boat.jpg
| width2   = 220
| alt2     = View of a small streamlined boat resting in a cradle out of the water. The boat is painted white and green, with "G 718" painted on the side. Two searchlights and a loudhailer are attached to the roof of its open-backed cabin.
| caption2 = High-speed GDR river patrol boat, equipped with searchlights to detect escapees
}}

The border also ran along part of the length of three major rivers of central Germany: the Elbe between [[Lauenburg]] and [[Schnackenburg]] (around {{convert|95|km|mi}}), the [[Werra]] and the [[Saale]]. The river borders were especially problematic; although the Western Allies and West Germany held that the demarcation line ran along the eastern bank, the East Germans and Soviets insisted that it was located in the middle of the river (the [[Thalweg]] principle). In practice, the waterways were shared 50/50 but the navigation channels often strayed across the line. This led to tense confrontations as East or West German vessels sought to assert their right to free passage on the waterways.<ref>[[#Cramer|Cramer (2008)]], p. 52.</ref>

The rivers were as heavily guarded as other parts of the border. On the Elbe, East Germany maintained a fleet of about 30 fast patrol boats and West Germany had some sixteen customs vessels. The river border was closely watched for escapees, many of whom drowned attempting to cross.<ref>[[#Shears|Shears (1970)]], pp. 90-91</ref> Numerous bridges blown up in the closing days of the Second World War remained in ruins, while other surviving bridges were blocked or demolished on the East German side.<ref>[[#Shears|Shears (1970)]], p. 173</ref> There were no ferry crossings and river barges were rigorously inspected by the GDR border guards.<ref>[[#Shears|Shears (1970)]], p. 138</ref> To prevent escape attempts, the East German river banks were barricaded with a continuous line of metal fences and concrete walls. At one location, [[Rüterberg]] on the Elbe, the border fortifications completely surrounded the village and sealed off the inhabitants from the rest of East Germany as well as the West.<ref>[[#Cramer|Cramer (2008)]], p. 51.</ref>