Boneyard Creek Restoration: Scott Park and the Second Street Detention Basin

Challenge

As Phase 2 of the Boneyard Creek Improvement Plan, this project was intended to provide 100-year flood protection downstream while also creating valuable public open space for the surrounding neighborhood. In addition, the site was to become a key link in a pedestrian and bicycle corridor connecting downtown Champaign to the University of Illinois Campustown. Within a very restrictive urban boundary, the design would need to balance land requirements for water holding capacity with recreational uses, while creating an environment suitable and pleasurable for pedestrians and cyclists.

Solution

The 2006 revised design incorporated both an aboveground and an underground retention system to manage 100-year flood waters while providing ample open space for use during non-flood conditions. The two large retention basins act as the main focal points for the park. Terraces constructed from natural stone are strategically positioned within the basins, allowing visitors to explore the various aspects and contours of the site. The main promenade and overlook were built four feet below street-level to screen them from the adjacent street and parking area. Full pedestrian and bike access is aided by a comprehensive system of pathways that connect the site to the surrounding neighborhood, including Scott Park.

• Two retention basins with a total storage capacity of 47 acre-feet manage runoff from a 100-year storm while providing over 5 acres of open space for recreational use during non-flood conditions.
• The originial meander of Boneyard Creek was restored, replacing the previously channelized design. As it flows under White Street, the creek enters a double culvert and flows into a large pond. The pond drains through culverts at the southern end, flows under Springfield Ave, and eventually joins the buried section of Boneyard Creek.
• In the northeast corner of the site, a 0.25-acre rain garden creates 0.13 acres of wetland habitat and manages stormwater runoff to the site from University Avenue, a high-traffic arterial.
• In Scott Park, a bioswale and rain garden work together to drain and filter the first flush of water from the adjacent parking lot. Together, they contain several thousand new sedge and forb plantings.
• The creek banks were stabilized with large slabs of natural stone, which also provide an amenity for park visitors by creating a series of terraces and vantage points throughout the basin. The stone was sourced from Lanark, Illinois, just 185 miles away.
• Plantings include 250 medium-large shade trees, 100 deciduous and evergreen shrubs, and over 2,000 individual ornamental perennials.
• Two distinct waterfalls were created as park amenities, taking advantage of the 20-ft drop in elevation from the street level to the basin. The waterfalls help block noise from nearby traffic and improve water quality by aerating water that is pumped up from the pond and allowed to cascade back down.
• An amphitheater with seating capacity for approximately 100 people was constructed with large natural stone slabs and is positioned with advantageous views of the basin area.
• More than 50 light fixtures were located around the basin to allow for continuous use of the site and establish a greater sense of safety after dusk.
• 4,115 feet of paved pathways wind throughout the site. The park is linked to the surrounding neighborhood with 20 sidewalk and bike path connections.
• The 500-ft main promenade was located 4 ft below the grade of the adjacent street and parking areas to create a more pleasant pedestrian experience by limiting visual and audio disturbance from cars.

• The local topsoil was found to have high concentrations of clay, thus making the implementation of on-site rain gardens and bioswales more challenging. The ideal soil mix for rain gardens and bioswales includes mostly sand, some compost, and little topsoil. Because of the high clay content, the soil matrix was modified by adding pea gravel, and more underdrains were installed to ensure plant survival.
• Mowing and spot herbicide treatments have been successful in establishing a native plant species-dominated culture, which is imperative in creating habitats that are supportive of native animal species.
• Rice Cutgrass, a native and favorable species, unexpectedly dominates in wetland areas, even though it was not included in the wetland plants or seed mix used to establish these areas. The seeds most likely entered the site from an upstream source or were unintentionally part of the seed mix. Controlling Rice Cutgrass will need to be factored into the maintenance regime for Boneyard Creek to help establish a species diverse plant matrix.

Soils: One-step till-in soil conditioner and structural soil from Midwest Trading Horticultural Supplies, Inc.
Lighting:  Sternberg
Benches & Bike Racks: DuMor, Inc.
Trash Receptacles: Victor Stanley
Tables with Umbrellas: Landscape Forms
Bollards: Trystan Site Furnishings
Tree Grates: Ironsmith
Walls/Stone Veneer: Fisher Stone
Walls/Precast: Continental Cast Stone
Walls/Graffiti Resistant Coatings: RainGuard
Stone/Outcropping Limestone & Granite Cobbles: Fischer Stone
Drainage/Erosion: North American Green and Colbond
Fences: Iron World Aberdeen Fence
Drinking Fountain: Most Dependable Fountains

Project Team

Client: City of Champaign
Landscape Architect: Hitchcock Design Group
Environmental Consultants: Foth Infrastructure & Environment, LLC
Engineers: Lin Engineering LTD
Consulting Engineers: Waterflow Consultants

Role of the Landscape Architect

The landscape architect provided leadership from the initial design phases through construction. As a consultant for the master plan for the adjacent Burnham Hospital site, the landscape architect understood the City’s overall goals for the project and how Boneyard Creek project would be instrumental in revitalizing the wider area.