Etowah+Indian+Mounds

Etowah Indian Mounds

​ Physical Properties: Water temp 65° Air temp 70° Soil temp 60° Soil texture: sandy, clay loam Soil pH: 6.5 very slightly acid

For the final stop, you travel downstream to the **confluence** of the Etowah River and Pumpkinvine Creek. Here you stop along the north bank of the river, leaving the shoreline and moving inland through a riparian zone.



On the back side you encounter three massive mounds, the tallest reaching 63 feet. Surrounding the three mounds is a grassy plain within which three smaller mounds lie unseen. It was in this fertile basin of the **Ridge and Valley** province that an ancient civilization once thrived. Oral tradition did not sustain the name of this Mississippian society of mound builders, but hundreds to thousands of Native Americans inhabited this area between 1000 A.D and 1550 A.D. [ 18 ]



The topography of the area was formed in Pangea when the northwestern corner of Africa collided with the east coast of North America. During this **orgogeny** period, intense thrusting, folding and faulting occurred; igneous and metamorphic rock overrode crumpled sedimentary rock causing the formation of the Appalachian Mountains. [ 19 ] Where the sedimentary rock folded, the Ridge and Valley topography was formed. Elongated, parallel ridges with narrow valleys between run directionally from the northeast to the southwest. Elevation ranges from 1,000 to 1,600 feet for the ridges and 600 to 800 feet for the valleys. [ 20 ] Because layers of sandstone and chert form the underlying rock structure of the ridges, wind and fluvial erosion have softened their tops and sent the sediment down hill. The valleys between, formed mostly of shale and limestone, have benefited from the **deposition** with a thick layer of eluviated minerals creating fertile ground. The soil type for the valley areas are categorized as **Alfisols**, while the soils of the ridges are mostly **Inceptisols** and **Ultisols**. These soils are “derived from heavily-weathered shale, siltstone, sandstone residuum and colluvium, cherty limestone, and limestone residuum.” [ 21 ]



The Etowah River has been divided into the Upper Etowah and Lower Etowah because its characteristics differ so immensely before and after the dam. The upper region has sections of long shoals, is relatively narrow, clear running, and quite scenic. As it enters the piedmont it begins to widen. After leaving the Allatoona lake area it becomes the lower region. This section of the river has been impacted significantly by the power generation at the dam. It has become much wider through bank erosion as volumes of water discharge regularly. Turbidity has increased leaving the river murky from sedimentation much of the time. The generating of power causes water temperature averages to cool and currents become quite dangerous as swift moving water flows downstream when the gates are opened. All of these changes have contributed to disturbances in the aquatic ecosystems of several species of fish, mussels, and turtles. [ 22 ] In defense of the dam, it has contributed to the stabilization of flood events in the area and supplies water and power to many residents. The Etowah River continues on, but your journey ends here.


 * Question 4: What is the reason for the fertile soil of the valleys?**