Shoreline Rehab

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Washington Park celebrates 100 years with restoration project

The Springfield Park District, Springfield, Ill., is looking forward to expanding its greenspace this year with the addition of a new park with cutting-edge recreational activities. Looking to the past has been a key element over the past several years as the park district has focused on a multiphase project in renovating historical Washington Park while maintaining the concepts of the original design.

Riprapping with white rock was done where needed.

Renovating an eroded shoreline and addressing runoff problems from a large parking area help assure the integrity of the century-old park. Originally located just outside the city boundaries, the park is now surrounded by the city. Washington Park was designed by Landscape Architect Ossian Cole Simonds, who designed a number of Chicago sites. He designed the park in a unique prairie style, utilizing the naturally rolling wooded hills around a large lagoon.  

The lagoon shoreline is eroded from heavy use and muskrat damage.

The park district and Illinois Environmental Protection Agency partnered to restore the deteriorating lagoon shoreline. The lagoon has been the centerpiece attraction of the park since its dedication in 1902. Rowing was a very popular activity in the early 1900s, and rowboat rentals continued until the 1970s. Two lagoons were initially created by impoundments of the Jacksonville Branch of Spring Creek. The second lagoon was filled in decades ago.

The park district marked Washington Park’s 100th birthday by launching the project to restore 1,950 linear feet of eroded shoreline. The Springfield Parks Foundation and other organizations have been active in both the restoration and meeting other park needs.

Elliott McKinley, park district director of parks, cited the popularity of the 150-acre park for family activities, a playground and visits to the Thomas Rees Carillon. A bequest from Thomas Rees, who published the Springfield Journal Register for 50 years, funded the Thomas Rees Carillon.

An annual carillon festival draws a high number of visitors to the park, and destination visitors to Springfield have increased dramatically with the completion of the Abraham Lincoln Presidential Library and Museum.

The heavily forested prairie was cleared unmercifully as pioneers moved onto the rich prairie soil. Restoring native tree stands is gaining importance throughout the prairie state. About 25 acres of the park are wooded, including a very old stand of several varieties of oak trees. Ongoing cooperation among private organizations and governmental units is contributing to maintaining the park’s restored integrity and to helping assure the success of a related effort to restore the native oak stand that dates back to Abraham Lincoln’s time in Springfield.

Erosion problems

McKinley noted that shoreline erosion was unsightly, but that the park district is hard-pressed to fund major projects such as the lagoon shoreline restoration. The partnership with the Illinois Environmental Protection Agency provided funding from Section 319 Clean Water Act combined with local matching funding.

Shoreline in the bridge abutment area was stabilized to prevent erosion threat to bridge.Scott Tomkins talks with volunteers preparing to plant aquatic plants.

Shoreline erosion occurred over the years through a combination of heavy park use, destabilization created by muskrats and frequent flooding from the stream. People and animals had trampled the shoreline to the point that much of it was mostly dirt with no grass or other vegetation. Muskrats had undercut the banks, destabilizing the soil. Additionally, frequent flash flooding contributed to shoreline deterioration.

The bridge abutment was damaged by erosion.

Scott Tomkins, Illinois Environmental Protection Agency, said, “Traditional turf does not have root structure to provide stability in flooding. We addressed erosion of the impoundment of the lower lagoon and the runoff from the upper lagoon area where the parking lot is now located.”

Tomkins noted, “The Jacksonville branch of Spring Creek is one of our most heavily urbanized streams. It was great to have a project where we used the past to develop current restoration. We used the thoughts of Simonds about the prairie-style look of the park. He used natural vegetation and slope of the land to develop the park with such things as native logs in the bridges. We used that rich, historical legacy to direct restoration.”

The second lagoon site that was filled in is now the site of the botanical garden, which includes a conservatory, greenhouse and outdoor gardens that feature a 5,000-plant rose garden. Runoff from a parking lot adjacent to the botanical garden created significant silting in the existing lagoon. In 1977, a 42-inch diameter main city sewer line was installed across the lagoon. A berm was built to hold the sewer line that divided the lagoon into two sections.

The partnership allowed improvement of water flowing into the Jacksonville Branch of Spring Creek, which eventually flows into the Sangamon River. At the same time, it allowed improvement of the eroded shoreline of a historical park important to Springfield’s greenspace.

Boardwalk construction begins.

Restoring eroded shoreline

Limiting foot traffic along the banks was a major concern. An elevated fishing pier and boardwalk was constructed using recycled plastic with a fiber core. With the elevated boardwalk, foot traffic is kept off the banks, reducing trampling.  

Work was also completed on a bridge abutment in a high-traffic area crossing the Jacksonville branch. The park district was concerned that erosion could affect the structural integrity of the bridge. A vinyl sheet piling Geo Guard retaining wall was installed to help ensure stream bank stabilization. The pilings were driven up to 5 feet into the existing soil. The vinyl sheet was then installed, and soil was backfilled behind the structure.  

Pilings are driven 5 feet into soil.Volunteers receive plants to plant along banks.

Dredging and regrading were done when needed to obtain the slope necessary. Most of the soil needed was obtained from silt removed from the lagoon, with additional soil brought in as needed to attain the proper slope. Riprapping with 6-by-9-inch white rock was done in selected areas along the stream bank.

A 6-foot chain-link fence was installed to prevent muskrats from burrowing into the stream bank. About 3 feet of the fence was underwater. Because fencing material already owned by the park district was utilized, the fence had to be spliced and overlapped in a few places. The muskrats soon found their way through, and some adjustments in fence construction had to be made to prevent their access to the bank.

Constructed wetlands

The upper lagoon area of the Jacksonville branch was cleared of silt and other obstacles to allow it to become more free flowing. To address the runoff concern from the parking lot in the upper lagoon area, a constructed wetlands area was created adjacent to the lagoon. A buffer zone of native plants helps filter pollutants as natural wetlands have always done in flood zones, and wildlife habitat has been enhanced. Soil was added as needed to the bank area to ensure an appropriate grade and soil depth for seeding and plating.

Native prairie plant seeds were hand-seeded, and a fiber blanket was placed over all seeds to protect them and help in retaining moisture. A 2-foot shoreline buffer of aquatic plants was established with an additional 8-foot zone of native plants that survive well in flooding conditions. Native plants were planted directly on the shoreline and into fiber logs that had been staked into the lagoon. Plants were purchased from J.F. New Plants, Walkerton, Ind., and the Illinois Native Plant Society assisted in this project.

“We were able to salvage a number of native plants with cooperation from the Illinois Department of Transportation,” Tomkins said. “The native plants were growing on concrete in a drainage area along Illinois Route 4. We were able to pull the plants off in mats for replanting.”

A recycled plastic boardwalk keeps foot traffic off the shoreline.

Ongoing maintenance

Ongoing efforts to help maintain the integrity of the shoreline restoration are essential. In addition to weekly mowing of the park’s cool-season grass mix, the lagoon needs to be cleared of debris and trash.

Chuck Smith, Springfield Parks superintendent of natural resources and arborist, noted, “We have several organizations that work with us. The Washington Park Neighborhood Association cleans trash and debris from the lagoon. Friends of Sangamon Valley remove undergrowth, allowing more light to reach the old oaks. They’re removing invasive honeysuckle and reducing competition. We go in later and chip the undergrowth they remove.”

Smith noted that very few chemicals are used at the park. “We don’t spray for weeds and don’t use fertilizer on the turf. We have very good soil and our turf grows extremely well,” he said.

To help make visitors become more aware of the significance of Washington Park, an educational outreach effort is being made. A sign tracing the history and explaining the restoration has been established at the park.

Nancy Riggs is a freelance writer and frequent contributor to Turf. She resides in Mt. Zion, Ill.