Why would the NW area of Monmouth Cave, KY have streams, and not the NE area?

Question

The entrance of the cave is near the NE corner of a topographic map of the area, and a series of ridges with nearly flat tops are dissected by streamless valleys. The NW area has valleys that are not as deep, but do contain streams.

I meant Mammoth Cave, KY!

Answer 1

The short answer is that the NW area drains over the surface, and the NE area primarily drains through underground cave systems. The rest of this is an explanation of why that happens.

First, Mammoth Cave drains into the Green River. The entire cave and its drainage are on the south side of the Green River. If the area you are wondering about is north of the Green River, then it is a very different area. One of the reasons there is a difference in both the morphology (shape and patterns) of both the surface features and the cave features between the north side of the Green River and the south side is that the bedrock in the area has a very slight dip towards the north. It is primarily for this reason that Mammoth Cave drains northward into the Green River. A large area to the south of the cave drains through the cave into the Green River. On the opposite side of the river (NW), the drainage is more complicated and while some surface streams and some underground drainage is southward towards the river, some areas do drain north away from the river. The drainage area that goes into the Green River from the northern side of the river is much smaller so erosional patterns are very different. The few caves on the north and northwest side of the river are very short and small because the natural tendency of the drainage there has been northward away from the Green River. This variation is related to the dip of the bedrock that is towards the north.

If you could look at a vertical slice (a stratigraphic section or column) through the rock around Mammoth Cave you would see that the top rock layer below the soil in the areas where there are ridges is a caprock of interbedded sandstone, shale, and limestone. This caprock is much more resistant to erosion and dissolution than the underlying rock. Beneath that caprock is are layer of limestone known as the Girkin Formation, the St. Genevieve Limestone, and the St. Louis Limestone. These limestone layers are about 150 m (approx 500 ft) thick.

Where the caprock has eroded away, the limestone has dissolved much more quickly and an area of sinkholes and karst drainage has formed that continues far to the south of the cave. Most of these karst sinkholes and landforms drain through the subsurface and there are only very short surface streams. In some places there are karst windows, where the surface has collapsed exposing an underground stream. Almost all of that area drains through several underground cave systems into the Green River.

Where the caprock has not yet eroded away, there is often cave passage underneath it, but it has formed protected ridges, containing large cave systems like Flint Ridge. Drainage over these areas of caprock is through surface streams. One interesting effect of this caprock is that often near the edge of the caprock, the water drains into joints in the limestone and sometimes forms vertical cave passages that intersect the lower levels of the cave.

References:
Palmer, Art N., 1985, "The Mammoth Cave Region and Pennyroyal Plateau", Chapter 7 form Caves and Karst of Kentucky, Kentucky Geological Survey, Special Publication #12.

White, William, and Elizabeth White, editors, 1989, Karst Hydrology Concepts from the Mammoth Cave Area. New York: Van Nostrand Reinhold. 346 pp.

Answer 2

gravity