60 lines from JQ Johnson of Univ. As at other well-wired institutions, University of Oregon faculty make heavy use of email in instruction. Many classes have course-wide listservs.
Many faculty invite students to use email as an alternative to office hours.
So I think this is a manageable problem. For example, batch your processing of student email, and allocate a fixed amount of your day to that task. This depends, of course, on the email software in use at your institution, but as a general rule I find that most faculty don't make as full use of their email reader as they might. You'll still have to read the listserv and intervene occasionally to correct misinformation, but you'll be encouraging collaborative learning while taking some of the load off yourself. What works in a class of 50 isn't likely to work the same way in a class of 250.