This somewhat confusing BBC article suggests that water voles are thriving. Or at least I think it does. It states that the number of sightings from a particular survey has doubled since last year, but also notes that this is the first year the survey has been held online and that the total number of submissions has gone up six-fold. So maybe water voles have declined to a third of what they were? Who knows – but the thrust of the article is that things are rosy, and if so then that's heartening.