A) Early in my stalking career I used to sit overlooking suitable pools, thinking that deer were bound to come trooping down at dusk like antelopes to a waterhole. Needless to say, my waits were in vain! Roe like damp spots and can be quite aquatic at times. I have seen them standing in a river in hot weather, enjoying the cool flow round their legs. Nor do they mind swimming, not only when chased but as a part of their normal movements, and they will swim strongly even in a river in flood. Even so, it is rare to see a roe actually drinking unless there is a severe and prolonged drought.
In the dry summers of 1975 and 1976, the deer in my area made use of drinking troughs, mainly at night. Otherwise their habit of feeding at dawn and dusk guarantees there is some moisture in the herbage. When stalking in the evening, look at the soles of your shoes. When they look dark because of dew forming underfoot, the chances of seeing a deer coming out to feed are increased. I also have an idea, but based only on a few observations, that when walking through dew-wet crops in the early morning, roe will brush through with open mouths and gather moisture in this way.