Simplify the following text for a Grade 6 native English-speaking person.
Original: Chalk hills , known as chalk downland , usually form where bands of chalk reach the surface at an angle , so forming a scarp slope . Because chalk is porous it can hold a large volume of ground water , providing a natural reservoir that releases water slowly through dry seasons .
Simplified: Chalk holds water , so these chalk hills have a lot of water in them , and when the weather is very dry , water comes slowly from the chalk .