1) If it’s permitted in the period from Rosh Hodesh Av until 10Av to drive to the Lake out of city for immersion in the Lake?
2) When it’s permitted for a woman to uncover her head? Can she do it when she is alone with her husband? Can she remove a head cover for swimming in the lake?
1) One should not go swimming in the Nine Days, but it is permitted to immerse in the lake for purposes of purity, with the exception of Tisha Be’Av itself. This year, it is permitted to do so even on Friday.
2) It is worthy practice for a woman to cover her hair even at home, even when alone with her husband (but not in times of intimacy) — but there is no obligation to do so. While a niddah, it is better to keep hair covered, even at home.
If the lake is a private place, it is permitted to be there with uncovered hair. Of course, for immersion there is no choice but to take off one’s hair covering.
For purposes of niddah, one should generally ensure to use a valid mikva, with an attendant who certifies the immersion.