From: Rabbi Moshe Sofer
To: Rabbi Moshe Katz
Rabbi Moshe Katz asks why the Chasam Sofer did not protest against carrying in Dreznitz, given concerns about the March River's sandbars, winter freezing, and a wide bridge. The Chasam Sofer rules leniently on all points: sandbar concerns are irrelevant where three walls already stand, ice retains water's halachic status, and the bridge itself constitutes a private domain.
Source: Shu"t Chasam Sofer OC §89