About 100 water voles are to be reintroduced to a valley in a national park later this month. Forestry England is releasing the animals at Wild Ennerdale in the Lake District on 12 August, as part of a programme to rebuild the mammals' population numbers in the UK.

(NEXSTAR) — For one day only in August, you can get into any of our national parks for free.

The free entrance day celebrates the fifth anniversary of the Great American Outdoors Act, a federal law which helped pay for maintenance on public lands.

Here’s the lowdown on 10 parks that now require timed entries or permits and how to get yours without pulling your hair out.