The trip was really informative for all that I missed the pinnacle. Especially when seen from above, the Valley and Ridge region is obvious, the land crumpled like a rug. The push of tectonic plates from the southeast is tangible.
The gaps through those ridges, formed by creeks and rivers over millennia, became the primary paths for long hunters and settlers and remain the preferred routes for railroads and highways. Of course, the construction of those highways entailed some widening and straightening of the route and the exposed rock faces reveal the sharply slanted layers of rock beneath the surface.
Such layering is familiar to me from travels all through the southern Appalachians and I had assumed all the hills and mountains were essentially geologically the same. I was wrong.
What I hadn’t realized is that the Valley and Ridge region, geologically similar to the Shenandoah Valley in Virginia, is essentially made of limestone. Limestone is a sedimentary rock formed from the ancient remains of marine organisms like coral or diatoms. It’s mostly made of a type of calcium carbonate and is soluble in water and acids. This solubility leads to fantastic cave systems carved out by underground streams, full of stalactites and stalagmites. It also leads to surface erosion and the formation of the Valleys.
In contrast, the Plateau is made up of mostly metamorphic rock: shale, sandstone, quartzite, and coal. Creeks have cut through the softer sandstone, forming deep, narrow valleys, but harder quartzite formed capstones that protected the tops of cliffs and peaks. This topography is familiar to me from visits to my mother’s people in eastern Kentucky coal country. The difficulty they had in farming even the bottomland is no surprise after realizing that their farms were sitting atop such hard ground.
All of this new information is undoubtedly interesting and will make my trips to the mountains more meaningful, but how does it affect my professional practice? As environmental stewardship must form the backbone of any modern landscape architecture design, an understanding of the watershed is vital. When you realize that the limestone karst system lies under all the Valley and Ridge region, non-point source pollution issues become even more problematic. How can my designs eliminate the need for fertilizers, pesticides or herbicides? How can my designs mitigate storm water run-off? How can I help people make the best choices for their own actions? Practically, the soil of the Valley and Ridge is going to be high in calcium, quite alkaline and drain quite easily. I need to keep that in mind as I select plants. On the other hand, if I am designing for the steep and rugged portions of the Appalachian Plateau, I will need to accept that the soil will be thin and poor with the underlying rocks not too far away. The land is also likely to be steep so erosion control will be important.
Getting to know a particular region intimately is one of my anticipated joys. With the last two decades spent moving around the country, putting down my own roots, learning the language of a smaller region, and designing for its particular quirks will be heavenly. I’m thankful it is a focus of studio this semester and hopefully this attitude of regional respect will inform all of our work at university and professional practice.