| Naperville Riverwalk Safari | Peter Chen |
|---|
| History: | |
| · | 400 Million years ago: this area was located just south of the equator, covered by a shallow tropical sea. Primitive marine animals with calcium-rich shells lived and died; their remains settled to the sea floor, forming layers of sediment that form the parent material of our bedrock: limestone and dolomite. Some dolomite outcrops are visible in the 3 quarries along Riverwalk, and limestone can still be seen on older buildings that date to the late 19th century. "Limestone" in the new Millennium Tower is simulated precast concrete. |
| · | 75,000-10,000 years ago: glaciers covered much of northern Illinois, leveling the topography and leaving behind soil rich in glacial till and wind-blown loess. Most of Naperville lies on the West Chicago Moraine left by the retreating ice sheet. Outwash from the melting ice also carved out the valley where the DuPage River flows. Pockets of ice potholes and slow-draining clay soils created marsh areas in Chicago region. Movement of Pottawatomie and other native peoples into the region brought human-caused fires that promoted growth of prairies and savannahs. |
| · | Joseph Naper settlement 1831: sawmill on Mill Street processed lumber from the woodlands along the river. By 1840 the trees have been cleared and the mill was converted to a grist mill. Examples of lumber use include log dam for mill pond, Pre-emption House at Naper Settlement, Plank Road. Drainage tiles and other farming activities led to rapid disappearance of wetlands and prairies. |
| · | Naperville Centennial, 1931: Centennial Park established on former Von Oven estate (Naperville Stone Company). |
| · | Sesquicentennial 1981: Riverwalk established; includes 45 acres park & forest preserve land, 80 acres total. |
| · | 1982: extension beyond Centennial Beach to Jefferson Avenue. |
| · | 2000: extension to Hillside Road; Fredenhagen Park. |
Human Impact on DuPage River: | |
| · | Burlington Park: dam created a lake for boating, skating, ice harvesting. |
| · | Sewage treatment: much improved water quality at Riverwalk. |
| · | Loss of wetlands, stormwater runoff in watershed. |
| · | Conservation Foundation: Riverbank Stabilization program. |
| · | Park District stocking and planting programs. |
| · | Forest Preserve District: Bass in Class program. |
| Flora: | |
| · | Floodplain trees: Box Elder Cottonwood Elm Hackberry Kentucky Coffee Tree Sycamore |
| · | Other natives: Ash Basswood Bur Oak Eastern Red Cedar Hawthorn Sugar Maple Sweetgum White Pine |
| · | Other: Austrian Pine Colorado Green Spruce Ginkgo Norway Maple Scots Pine White Mulberry Oak-leaf Hydrangea Bottlebrush Buckeye Arrowwood |
Fauna: | |
| · | Mammals:
|
| · | Birds:
|
| · | Fish/Invertebrates:
|