Why did Danish troops abandon the Danewirk in February 1864?

Danish troops abandoned the Danewirk on February 6, 1864, because the Prussian forces threatened to turn the flank of the entire Danish defensive line. Specifically, the Prussians successfully crossed the Schlei inlet to the northeast, rendering the fortifications untenable.12

Rather than engaging in a struggle they were likely to lose, the Danes withdrew without a fight. This retreat marked an inauspicious start to the German-Danish War, as the Danish defenders were consistently outnumbered and outgunned by the Austro-Prussian forces throughout the remainder of the campaign.12