Eugene field206 2016_09_22
- 1. Eugene Field Park Aquatic Ecosystem Restoration Program Section 206, WRDA 1998 Restoration of Urban Stream and Floodplain Depressional Wetland 2011 - 2016
- 2. Area History Eugene Field Park is a 10-acre public park facility owned and operated by the Chicago Park District. The North Branch of the Chicago River flows along the southern bank of the park. This was not the natural location for the Chicago River, which was moved, straightened and deepened between 1904 and 1907, allowing the area to be used for farming and residential homes. The bottom of the river here is paved with concrete in major sections to shuttle water downstream faster. This action drained away the land and subsequently the prairie sloughs and marshes disappeared. The park and its surrounding residential neighborhood were likely built between 1905 and 1930. The park site was likely utilized as a spoil area for waste materials produced by river channelization. Subsequently, it was left in old field or may even have been lightly farmed, but for the most part it was spared the massive alteration that the surrounding land experienced. Evidence to this point lies in the natural soil types still in existence beneath the surficial fill, which are undescribed but resemble the Martinton Series. The two habitat types that existed naturally at the park were most likely Wet/Mesic Oak Savanna, Marsh, Prairie Slough and Wet Meadow. Historic Photo of Chicago River North Branch (photo by Earl E. Sherff “Vegetation of the Skokie Marsh” early 1900s). 1938 Aerial of Eugene Field Park Eugene Field Park
- 3. Pre-Project Conditions The Eugene Field Park frequently experienced flooding from the North Branch Chicago River, witch lies within the neighborhood of Albany Park. Once floods would receded within the park, it would leave behind mucky residues from the river and surficial soils would remain wet for long periods of time, making the area unusable to the public for picnics, sports or flying a kite. The site’s vegetation was predominately turf grasses and associated Clovers and Plantains, planted ornamental trees and shrubs, and invasion by Eurasiatic trees and shrubs, such as Buckthorn, Siberian Elm, Honeysuckle and Tree of Heaven. Native trees on site were Silver Maple, Cotton Wood and White Oak. Survey within the river channel produced one (1) species of fish, the Blackstripe Topminnow. This section of stream receives high velocity floodwaters that flush fishes and habitat downstream. Usually fishes would be able to recolonize, but due to the dam at River Park, the entire North Branch Chicago River is fragmented from mainstem and Lake Michigan. Frequent Flooding of Grass Parkland in Footprint of Former Wetland Bare River Bank Understory with Overly Dense Eurasiatic Tree & Shrub Canopy
- 4. Invasive Species Removal & Site Clearing Project activities began with establishing a work zone perimeter off limits to the public for safety reasons. All non-native and native old field weed species were removed. Trees were removed with a large saw and claw grip machine called a Feller- Buncher. Shrubs and herbaceous weeds were removed with a bush-hog or by hand. The root masses of large trees removed along the bank were left in place to remain as stream habitat and bank stabilization. Several large Cottonwoods were girdled and left on site to be snag habitat surrounding the wetland for Woodpeckers, birds of prey and many insects. The remnant White Oaks were protected and retained to be keystone species of the Oak Savanna plant community. Feller-Buncher Removing Cottonwood Remnant White Oaks Protected & Retained
- 5. Boulder & Cobble Check Riffle Urban watersheds typically have a syndrome in which bedload sediment transport does not occur. In an attempt to sequester sediment being transported down stream, two large check riffles were placed into the North Branch Chicago River. If these riffles would be able to impede bedload transport of sand, gravels and cobbles, then substrates and benthic habitat for fishes and macroinvertebrates could be restored. These riffles were constructed from rounded fieldstone and river rock, which would also provide interstitial habitat for macroinvertebrates and fishes. The crests of the riffles were hydraulically designed to induce critical flow, which provides conditions for Caddisflies, Stoneflies and certain fishes. Increased velocities downstream of the riffles would keep substrates silt free for spawning fishes. The check riffles were also designed to focus the energy of the stream into the center of the channel and away from the banks. This provides conditions for healthier urban streambank communities and will ad longevity to the historic WPA wall on the south side of the river. Rounded Field & River Stone Stockpile for Check Riffles Slight Concave Downstream Configuration & Induces Critical Flow
- 6. Hyrdro-Geomorphic Contouring Investigations were completed to determine the extent and nature of fill placed over the former wetland complex at Eugene Field Park. An in-depth look at surficial materials was performed in which soil samples were taken in a 50-foot grid pattern at a depth of 40- inches. Characterization of soil materials indicated a natural, but undescribed soil series was in existence beneath a relatively small amount of mixed earthen fill. Evidence of these natural wetland soils were provided by amphibian waste materials and mussel shells. The fill materials were removed over the extent within the identified for wetland depression restoration. Roughly 20,000 cyd of fill material was removed from the floodplain and reutilized on site for ball field leveling and off site for other Chicago Park needs. A six inch (6”) layer of topsoil material was retained and spread over the exposed native soils according to the specified contours and elevations.
- 7. Hydro-Geomorphic Setting The Chicago River is a typical urban river, in which its response to any type of storm is to quickly rise and fall. Riverine hydrology modelling determined that the most fluctuation happens between the 2 and 5 year flood elevations. In order to damper these effects and more closely mimic a natural hydrology, the river was separated from the wetland up to the 5- year flood elevation to completely remove these effects. To ensure that the wetland depression did not become a pond after a flood event higher than 5-years, a one way outlet pipe, or Clemson-Leveler, was installed to ensure floodwaters would drain away in synch with the river subsiding. The wetland depression side slopes were fanned out as much as the site would allow to minimize abrupt hydrology change/fluctuation and maximize the native wet to mesic transition zone. Wetland Depression River 5-year Flood Elevation Subsurface Outlet Pipe 5-year Flood Elevation River Wetland Depression Shallow Sloped Depression for Gentle Hydrology & Plant Species Transition
- 8. Native Plug Planting: June 2012 Nearly __ species of wetland plants were plugged into the designated hydrogeomorphic zones: Streambank, Floodplain Wetland Depression, Wet/Mesic Oak Savanna. The contract required both genetic specificity and for the plants to exhibit a robust vigor, as you can see in the photo they are extremely healthy.
- 9. Fall Seeding: November 2012 Seed Quality Control Rutting Whitetail Buck New England Aster From 2011 Cover Crop Seeding
- 10. Plants in July 2013 Flashy River Bank Zone Difficult to Establish Plant Cover
- 11. Plants in August 2014
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