Southwestway Park is located approximately ten miles south of downtown Indianapolis within Decatur Township. Southport Road bounds the park to the North, with Mann Road to the West, the White River to the East and Morgan and Johnson Counties to the south. For a MapQuest location, query address 7550 Mann Rd, Indianapolis, IN 46221, US
Southwestway Park is a 587-acre regional park that includes natural and cultural landscapes. The park is the second largest park in the Indy Parks and Recreation system. The park amenities include a trail system used for hiking, running and horseback riding. Additionally, there are soccer fields, ball diamonds and an 18-hole golf course (Winding River Golf Course) used for recreational sports. Future recreational facilities to be developed on the recently acquired Mann property to the north will include a swimming pool, recreation and nature center, and additional athletic fields. Another recent acquisition to the south is Cottonwood Lakes. This oxbow floodplain property will be designed and restored for passive recreation.
Surrounding land use
Southwestway Park’s surrounding land use primarily consists of agriculture, sand and gravel mining, camping/fishing ponds, and recent residential development.
The Southport wastewater treatment facility is located northeast of the park on Southport Road. IDEM issued the renewal of the NPDES permit in 2001 to discharge 125 million gallons per day of treated sanitary wastewater into the West Fork of the White River, which is upstream from the park property. Due to municipal and industrial waste contamination within the White River IDEM has issued a fish consumption advisory. Boating is allowed on the river but it is unsafe for full body contact activities such as wading and swimming.
A 100-foot wide power line easement runs north and south across the park. Located east of Mann Hill, this easement area has been disturbed due to clearing for power line right-of-way but there are prairie plantings beneath the power lines made possible with partnership between Indianapolis Power and Light and Indy Parks and Recreation.
Prehistoric and historic Indian use
There are over seven prehistoric sites inside the park according to archaeological field reports. Several sites produced diagnostic artifacts from the Archaic period. Brown (1882) notes two Delaware Indian villages in Marion County upon the arrival of the first White Settlers. The largest was located on a high bluff west of White River at the Marion/Johnson County line. The Madison Rangers destroyed this village, the home of the Delaware chief Big Fire, during the War of 1812. The Rangers, seeking revenge for the killing of 24 settlers in the Scott County Pigeon Roost Massacre, mistakenly attacked the Delaware village and massacred the inhabitants.
Quakers originally inhabited the area around Southwestway Park and founded the town of Spring Valley in 1848, near Spring Valley Hill, which later became known as Mann Hill. Before it was abandoned in 1884, Spring Valley contained five businesses, a post office, a school, and residences. The land surrounding and encompassing the present-day Southwestway Park was farmed and pastured for many decades until it was purchased for use as a regional park. It should also be noted that Mann Hill was extensively used for off-road recreation until it was acquired in 1972.
Southwestway Park contains some of the most outstanding geological features in central Indiana. Mann Hill and the adjacent river valley are part of a delta complex that were formed during the last glacial period. More specifically, Mann Hill can de described as a kame. A kame is a hill or mound of outwash deposited on or at the edge of a glacier (Camp 1999). As the ice melted, these materials were deposited onto the ground. The materials are stratified, or layered, by the flowing action of the melting ice. The melting or stagnant ice formed kames. Camp (1999) references the kames in this area of Indiana as being “as large and impressive as any kames anywhere.” Some of these other kames have been developed whereas Mann Hill has not been. Mann Hill can clearly be seen as can another kame near Glenn’s Valley Nature Park.
The soil types of Southwestway Park are also the result of past glaciation. The soils are comprised of loess over loamy glacial till with predominately Brookston, Crosby, Genesee, Fox, and Miami soil series. Fox series are found on the wooded slopes of Mann Hill and the majority of the adjacent open land. Miami series are found on the open area grading off to the west and Brookston and Crosby are found in the gently sloping northwest corner. Genesse and Sloan are found on the floodplain along the White River. The Miami and Fox series are generally more prone to erosion than any other types of soil. Therefore, some forested areas consisting of this type of soil are prone to soil erosion.
During pre-European settlement, approximately 99 percent of Marion County was covered with closed canopy forest (Barr 1999). The forested area included flatwoods, mesic forest, upland forest and ephemeral swamps, including bogs and fens (Hedge 1997). Historical surveys can be cited that say by 1876 60% of the forest cover was cleared (Barr 1997). The Center for Earth & Environmental Science reported in 1997, using SPOT imagery technology, that no more than 13 % of Marion County was covered with medium to dense forest canopy. Another analysis completed by Indy Parks using 1999 and 1941 aerial photography estimated that only about 1.3 % (1,214 acres) of Marion County was covered with old-second growth forest. No old growth forest remains in Marion County. Essentially all of Marion County has been clear-cut since settlement began. Maps 11 and 12 display the forested areas mapped in and around Southwestway Park by the techniques listed above.
The city or state owns about 37% of the remaining old-second growth forest in the county. The remaining forest is made up of privately owned river corridor and heavily fragmented “postage stamp” flatwoods. Many of these flatwoods are poorly drained and not well suited for agriculture or development. 1n 1997, Purdue agricultural statistics estimated that 11 percent (29,034) of Marion County was farmed. Almost 10,000 acres were taken out of farm use and developed between 1992 and 1997.
Natural area of Southwestway Park
Indy Parks uses a wide range of resources and tools to identify and categorize natural areas by natural community types. GIS, remote sensing, infrared photography, vegetative surveys, floristic inventories, and historical photographs were all used to help divide Southwestway Park into distinctive sections. Natural community types in Southewestway Park include mesic-dry upland forest, mesic floodplain forest, wet-mesic floodplain forest, wet floodplain forest, medium gradient large river (White River) and several wetland communities including sedge meadow, circumneutral seep, and marsh. This wetland complex can also be referred to as a graminoid fen. Each type of natural area can be further divided into conditional classifications based on age and level of “disturbance.” Disturbance includes human endeavors such as logging, farming, and the releasing of invasive-exotic species that have successfully established populations.
The floodplain forest area is characterized by a frequent and prolonged flooding from the adjacent White River. This area lies on the East Side of a levy, which runs north and south within Southwestway Park. The diversity of trees in this area is lowered due to periodic flooding, causing the overstory to become more open. The understory consists of large dense stands of stinging nettle (Laportea canadensis) and Japanese hops (Humulus japonicus), a highly invasive-exotic species. The understory vegetation close to the levy is not heavily infested with stinging nettle and is mostly covered with Virginia wild Rye (Elymus virginicus), cutleaved coneflower (Rudbeckia lacinata) and common greebriar (Smilax rotundifolia). Dominant tree species in this area are silver maple (Acer saccharinum), cottonwood (Populas deltoides), Sycamore (Platanus occidentalis), red maple (Acer rubrum), box elder (Acer negundo), Hawthorn (Crataegus sp.), and hackberry (Celtis occidentalis).
The wet-mesic floodplain forest is composed of Common Hackberry and Box Elder in the overstory while Virginia Wild Rye and Stinging Nettle are the dominant species in the understory.
The mesic floodplain forest consists of dominant species such as Sugar Maple, Silver Maple and Ash species, respectively. The understory species include Wild Ginger, Grape Fern, Sweet Cicely, Virginia Wild Rye, and Amur Honeysuckle.
Mesic upland forest
This area includes the mesic upland forest dominated by black walnut (Juglans nigra). Mann Hill and a wooded riparian ravine leading to White River make up this area. This area is located on Fox complex soil, which is normally found in 6-15 % slopes and consists of gravelly, sandy soil. Fox complex is generally found on outwash plains and terraces, drainage ways, steep breaks, hummocky kames and eskers. This soil also erodes easily as the vegetation is removed. Historical photos from the 1970s show some of the serious erosion along Mann Hill before it became a park. A large effort was undertaken in the mid 1970’s after this property was received by Indy Parks to repair the heavily damaged slopes.
This area includes an old pasture area, which is now densely covered with woody vegetation. It starts from the parking lot area and ends at the beginning of trail 5, encompassing all the woody vegetation along the West Side of the easement. The existing vegetation consists of hardwood species such as Siberian elm (Ulmus rubra), American elm (Ulmus americana), common hackberry (Celtis occientalis), sugar maple (Acer saccharinum), white ash (Fraxinus americana), hawthorn (Crataegus sp.), honey locust (Gleditsia triacanthos), and black walnut. The woody vegetation consists of an understory of Amur honeysuckle (Lonicera maackii) and rough-leaved dogwood (Cornus rugosa). The dominant groundcover is clustered black-snakeroot (Sanicula odorata), Virginia creeper (Parthenococus quinquifolia), with only a small amount of greenbrier (Smilax rotundifolia), Solomon’s-seal (Polygonatum biflorum) and Japanese honeysuckle (Lonicera japonica).
Along the eastern slope of Mann Hill are a number of circumneutral seeps that flow into the floodplain areas and the White River. Species that been observed in these seeps include scouring rush (equisetum), black ash, marsh marigolds, and common wood reed.
The graminoid fen is a 3-acre natural community highly valued for its function and diversity. This area is characterized by mineral rich, alkaline ground water flowing to the surface and spreading in a diffused manner. Graminoid fens, by definition, consist of the early successional plant community dominated by sedge meadow. This wetland, formed as a result of the glacial origins of the terrain, has a large mounded area covered mostly with Fox Soil. This sloping wetland allows the aquifer formed in the sand and gravel to continually seep cold, mineral rich water to the surface. The seep is located at the interface between the bluff (containing Fox soil) and the drainage way at the base of the slope (containing Sloan soil).
The plant community in this area can be roughly divided into sedge meadow, shaded seep, degraded sedge meadow and phalaris marsh. The sedge meadow is the least degraded part of the fen and occupies the northern third of the seepage slope. It is dominated by tussock sedge (Carex stricta). Other plants in this community include swamp aster (Aster puniceus), pink turtlehead (Chelone obliqua), bonest (Eupatorium perfoliatum), cowband (Oxypolis rigidior), lizard’s tail (Saururus cernuus) and swamp goldenrod (Solidago patula). The shaded seep is less degraded, and consists of a black ash (Fraxinus nigra) and green ash (Fraxinus pensylvanica) overstory with an herbaceous understory of golden ragwort (Senicio arureus), marsh marigold (Caltha palustris) and side flowering aster (Aster lateriflorus). Invasive exotic species such as broad-leaved cattail (Typha latifolia) and reed canary grass (Phalaris arundinacea) dominate the southern two-thirds of the seepage area, forming a degraded sedge meadow. The final division of the seep, the Phalaris Marsh is equally degraded and is dominated by invasive reed canary grass (Phalaris arundinacea).
Before European settlement, these communities were often maintained and kept open by native Americans through burning. Fires prevented the invasion of woody plants such as willow, honeysuckle and dogwoods and maintain the diversity of herbaceous understory. Some part of the seepage area remains open due to its location in the easement for the high-tension wires owned by Indianapolis Power and Light.
Due to the presence of the high-tension overhead wires, this area cannot be managed by prescribed burning. Therefore, continued mechanical and chemical removal of the invasive species is the only way to control them. Restoration of the degraded parts in the seep would require expertise from engineers and groundwater analysts. The populations of cattail and reed canary grass should be managed since they have taken over the entire fen. Graminoid fens offer diversity of various flora and fauna, if they are managed properly. They provide habitat for different kinds of birds, reptiles, and insects. This area could also be a source of education for park visitors who are enthusiastic about high quality natural areas and wildlife.
Succession has traditionally been defined as the slow, regular changes that a natural community undergoes after a disturbance. These disturbances can be natural (such as wind damage or flooding) or induced by human activity (such as deforestation). Changing seed sources, climate fluctuations, population fluctuations of herbivores and their predators, and disease all affect succession (Pickett 1995).
Some of the previous agricultural land became a sucessional area when the City of Indianapolis purchased the land in 1984. The vegetation is composed of floodplain species such as box elder (Acer negundo), sycamore (Platnus occidentalis), cottonwood (Populas deltoides), and silver maple (Acer rubrum). The understory is mostly dominated by tall goldenrod and covered with other woody species such as trumpet creeper, poison ivy, greenbrier, milkweed, raspberry, trefoil and Queen Anne’s-lace. The only management strategy for this area would be to keep observing for invasion from exotic species, especially honeysuckles that could spread.
Service learning at Southwestway Park
The primary focus of the Land Stewardship Office in Southwestway Park will be the removal of invasive exotic plant species with the promotion of natural plant communities and habitats. The Land Stewardship Office has completed an invasive exotic species document, which provides photographs and descriptions of the many plant species found in Marion County that should be considered for control.
This four-acre reforestation area lies in the central part of the park, adjacent to the fen. Indy Parks carried out this project in partnership the US Fish and Wildlife Service Partners for Wildlife program. In 1994, the Land Stewardship Section, with the help of volunteers from Decatur High School planted most of this area with tree seedlings from the Vallonia State Tree Nursery.
A second planting was conducted because the earlier installation was not completely successful partially due to predation and weedy competition. The second planting took place in 1998 as part of an Eagle Scout project. The Center for Earth and Environmental Science provided a lot of the volunteers needed to complete the project. Some of the native species planted in this area were swamp oak (Quercus bicolor), sycamore (Platanus occidentalis), bur oak (Quercus macrocarpa ), green ash (Fraxinus pensylvanica) and pin oak (Quercus palustris). Tree shelters/tubes had been installed in the 1998 planting to help prevent predation. It turned out the shelters caused a lot of damage that led to seedling mortality.
This area represents a young growth successional forest. Tall goldenrod (Solidago canadensis) and saplings from dogwood, sycamore, box elder and silver maple dominate the understory vegetation. Other understory plants include common milkweed (Asclepias syriaca), queen-anne’s-lace (Daucus carota), and Virginia water-leaf.
Excerpts from the Land Stewardship Plan of Indy Parks and Recreation.