For a 5-hour shift, the ddt° (desired dough temperature) for the Basic Levain is 76°F. With that in mind, the Mise en Place shows that Water should be at 84°F and the Culture at 70°F when you mix the Levain.
This is based on the observation that the Ambient Temperature in a bakery classroom averages 76°F. The Flour temperature is usually close to that, but it can be two or three degrees cooler.
Based on these assumptions, the Mise en Place specifies Water at 84°F.