True Detective Season 2 Episode 7: Black Maps and Motel Rooms. Written by Nic Pizzolatto (airs Sunday, August 2nd) Ray (Colin Farrell), Ani (Rachel McAdams) and Paul (Taylor Kitsch) take precautionary measures to elude detection and untangle a dark mystery. Frank (Vince Vaughn) deals with the fallout of his betrayal.
The permeability of the rock samples is likely to be â permeable-sandstone, chalk; impermeable â clay, slate, marble, granite. This may vary according to the samples, e.g. some sandstones may have a mixture of grain sizes and may have poor permeability.
A demonstration of the features formed by water drainage in limestone areas, both at the surface and underground. Permeable and impermeable layers of rock in the Malham area give rise to intermittent drainage. We see features formed both at the surface and underground.Surface water passes over impermeable rock until it reaches permeable limestone. The water passes through the limestone and erodes it to form swallow holes.Gaping Gill is a swallow hole where water has eroded a cave to form the highest waterfall in Britain.The water continues to flow underground until the limestone meets impermeable rock at the valley floor. Here there is a resurgence where the water returns to the surface.Shake holes and water sinks are also formed by the flow of surface water.e see features formed both at the surface and underground. Surface water passes over impermeable rock until it reaches permeable limestone. The water passes through the limestone and erodes it to form swallow holes.