|
|
 |
|
|
NATURAL FEATURESA shallow sea existed in which sand was covered by silica-rich waters. The silica provided the "glue" that gradually produced extremely hard sandstone rock layers in the earth. Then the ancestral continent of Africa collided with the ancestral North America. This collision caused the very hard standstone to crunch together like an accordian and push up new mountains. This mountain-building event called the Alleghanian orogeny created what today we know as the Appalachian Mountains stretching from Georgia to Maine.
Because the streams exposed the coal seams in outcrops, mining was relatively easy and some of our mine discharges now emerge on steep banks near streams that make treatment especially difficult. The Upper Conemaugh, Casselman and West Branch Susquehanna River watersheds are unique in Pennsylvania because they are sandwiched between the two most massive structures on the state's landscape -- Allegheny Ridge and Laurel Ridge. These long ridges are prominent features of the western Appalachian Mountains, and make up a sub-region of the Appalachian Pleateaus physiographic province known as the Allegheny Mountain region. This area has greater relief than the Appalachian Plateaus to the north and northwest, where glaciers shaved off mountain tops and deposited rubble in valleys, reducing the elevation contrasts (Check our topographic map). In the Appalachian Plateaus, all of the earth's surface pushed up and the rock layers remained relatively flat compared with the tilted rock layers typical in the Ridge and Valley province. The highest and most rugged part of the Appalachian Plateaus is the Allegheny Mountain section, where the Stony and Little Conemaugh flow. The Allegheny Mountains section also includes Pennsylvania's highest mountain, Mount Davis in Southern Someset County, just south of the SCRIP drainage area, and Pennsylvania's second-highest peak, Blue Knob, which is sort of a horn extending off Allegheny Ridge just east of SCRIP's drainage area. |
SCRIP generally focuses on the watershed upstream of Conemaugh Gap, which is about 1,560 feet deep and is the third deepest river gorge in Pennsylvania.
The Stonycreek Upper Gorge, Stonycreek Canyon and Little Conemaugh Gorge also provide dramatic beauty, but access to them is limited in most places to those willing to hike in or boat through rapids. Many streams flowing down off the ridges here attract kayakers from all over the Eastern United States. Our most popular whitewater boating areas are the Stonycreek Canyon and Upper Gorge, and Shade, Clear Shade, Dark Shade, Paint, and Bens Creeks. Paint Creek is especially dramatic because of its waterfalls.
Soils here were generally produced by the weathering of underlying rock stratta, mostly sandstone and shales that tend to be acidic. In higher elevations, the soils tend to be thin -- less than three feet thick. Valleys often have soil depths of more than five feet and the flood plain in downtown Johnstown has depths of 80 feet or more from soils deposited during floods.
Many areas, especially riparian areas along streams, have lost their native vegetation and been overtaken by Japanese Knotweed and the closely related Giant Knotweed. These are invasive species brought into the area by railroads, and SCRIP is supporting efforts to better control these species throughout the broader Kiski-Conemaugh River Basin.
The Upper Conemaugh is about 65 percent forested. Important game species include Ruffed Grouse, Wild Turkey, White-tailed Deer, Gray Squirrel, Eastern Cottontail and Black Bear.
The area lies within the Eastern Deciduous Forest Biome and, prior to European settlement, was almost entirely forested. Today, the ridges and highest elevations are dominated by Northern Hardwood Forest communities, including Sugar Maple, Yellow Birch, Beech and Eastern Hemlock. Mountain Laurel and Rhododendron are extremely common in the under story because they like the acidic soils.
Wooded areas at lower elevations are dominated by the Appalachian Oak Forest, with a lot of White Oak and Northern Red Oak, as well as Sugar Maple, Bitternut, Hickory, Beech, Tulip Poplar and White Pine.
Agriculture is still common in areas, especially in the
Stonycreek. Johnstown and its suburbs are the largest urban area, although
other urbanized areas include Portage, Ebensburg, Cresson, Windber, Jennerstown
and Boswell. More information is available on the watershed's rich
history of steel making and coal mining.
|
SCRIP PO Box 153 Johnstown PA 15907-0153 |
|
|
As the rock pushed upward very slowly over thousands of years, surface
water and precipitation needed to find a way to flow to the oceans. The
water carved down into the rock, creating such magnificent gorges as the
Conemaugh
Gap seen at right. The carving by water also exposed the many
layers of rock and minerals underneath, including the layers of coal in
our area.