New Berlin, Wisconsin: Environmental Stewardship at a City Owned Golf Course

By Kathryn McNelly, environmental scientist

A reach of the Root River had become a degraded resource of this community-owned park. Sediment laden waters became a commonality due to non-point source sediment loading evident by streambank erosion and slumping banks. Construction took place during winter ?EUR??,,????'??? during low flow conditions and when the ground was frozen to reduce disturbance to the golf course turf and course operations.

Approximately 3,300 linear feet of the Root River corridor flows through a section of the New Berlin Hill Golf Course. The park is public, and owned by the city of New Berlin. The waterway, which should have been seen as an amenity to the park, had over time become an eyesore to golfers and other park users.

Non-point source sediment loading had become an issue within this reach of the river and also downstream. The river banks were badly eroding, head cuts were forming and blockages greatly impaired this waterway. Before restoration efforts were made sediment laden water was often present and the riverbed consisted of a silt clay substrate creating low quality habitat for fisheries. Downstream portions of the Root River are listed as impaired by the Environmental Protection Agency due to sediment and phosphorous pollutants, which were some of the very targets of the project restoration efforts.

Bonestroo provided services that included collecting geomorphology information, engineering, writing a grant submittal and providing construction oversight and management. All in all, the project was a great success. A Wisconsin DNR 50 percent cost share grant was awarded and most recently the project was awarded by the Wisconsin Park and Recreation Association 2004 Park Design Award.

Factors affecting streambank erosion, streambed stability and sediment transport were analyzed along with other technical factors such as shear stress, flow and duration to determine the chosen preliminary design for regulatory review and approval.

The main focus of the restoration effort was to control non-point source pollution loading into the Root River from the golf course. Through cooperative efforts between the City of New Berlin, the Wisconsin Department of Natural Resources (DNR), the United States Army Corps of Engineers (ACOE), Bonestroo Rosene Anderlik & Associates (a multi-disciplinary engineering consulting firm hired by the City in 2002) and the contractor, the outcome of the restoration efforts were immediately noticeable.

Human impacts that may be seen as minor, such as the placement of a culvert or as dramatic as channel straightening or placement of a bridge, can significantly aggravate and further promote streambank and streambed erosion. Streambank and streambed erosion is a natural process. However, human impacts can further disrupt a stream?EUR??,,????'???s sediment transport and in turn cause bank erosion. As a result, undercut banks, gullies, headcuts, flooding, loss of shoreline property and even loss of or damage to structures can occur. To restore the natural process, which is often induced by human impacts, a wide variety of restoration techniques can be implemented.

Dewatering the river in order to grade back the banks was not a major issue as water flow was fairly insignificant. Final design aspects included recreating stable channel cross-sectional geometry with low flow and bank full bench at key locations. In-stream C-boulder (Rosgen) and cross vane structures were installed along with coir fiber logs, rock low-flow channel segments, riffle structures and temporary and permanent erosion matting. This photograph shows the use of a C-boulder (Rosgen) feature at the location of the head cut, as well as staking in coir fiber logs.

Bonestroo?EUR??,,????'???s engineers and scientists put applied fluvial geomorphology experience in harmony with quantitative field assessments consisting of Rosgen streambank erodibility factors to work to prioritize conditions of the Root River reach. This project also included detailed topographic surveys, a wetland delineation and a geomorphology assessment. After the detailed geomorphic study was performed on the subject area, a range of preliminary design solutions were selected for further analysis. The project was designed to minimize disturbance to the course during the golf season so as to not impact the revenue flow while minimizing the impact to the aquatic life in the stream and reduce the risk of a flood event during construction. The final construction design considered the existing fairways and drainage and user circulation patterns. The last step in the design process was the completion of final construction plans, a maintenance plan and specification documents for bidding purposes. Final design aspects included native seed, rootstock, willow cuttings and shrub plantings.

Construction is complete at this segment. A new rock low-flow channel and cross vane structure was installed. A native seed mix was planted under the erosion matting and coir fiber logs were placed to further protect the banks.

This more natural stabilization approach of combining native plant materials, coir fiber logs, erosion mat, with the in-stream C-boulder and Cross vane structures and rock low flow features serves multiple purposes particularly specific to reducing streambank erosion, establishing grade control, re-establishing a stable bankfull channel and enhancing fish and wildlife habitat. The in-stream boulder structures also offer additional benefits to the river corridor including natural maintenance of width/depth ratio, and dissipation of excess energy. Aesthetically these structures are more pleasing than heavy rock armor. Furthermore in-stream boulder structures have proven themselves to be more ecologically suitable than other alternatives such as riprap, gabions and concrete. The natural approach of this project has also generated secondary benefits. Annual mowing or maintenance of the vegetation planted on the banks of the waterway is not necessary. The no-mow zone along the streambank corridor acts as a buffer, further reducing pollutant loading into the River and also provides beneficial wildlife habitat. A wide variety of native plant materials were also used to enhance the restored portions of the site. A combination of grasses, sedges and perennial wildflowers offer a great variety of color and texture, replacing what was once a monotypic area of grass which had been mowed to the river banks.

Bonestroo assisted the City with construction administration and inspection in the final phase of the project. Construction took place in the winter of 2003 and final landscaping took place in the spring of 2004 at a cost of $225,000. The City was able to use Wisconsin DNR funding from the Urban Non-Point Source Program to offset project expenditures, including assessment, design and construction administration and inspection. As of April 15,

2004 the golf course was open and the project was well received by regulatory authorities, golf course staff and golf course users.

An innovative project such as this may serve as a model for other communities.

After one full growing season since the completion of construction, the native plants have taken hold of the banks providing bank support and stabilization while offering a buffer to the waterway. Within time, the coir fiber logs will naturally degrade but in the meantime they will offer bank support allowing planted materials to build additional strength. In-stream boulder features have provided additional streambank support and erosion of the bank is no longer an issue. A reduction of pollutant loading is evident because the natural cobble substrate is now noticeable instead of the silt clay substrate which was present before construction took place.

(For more information, contact: City of New Berlin, Mark Schroeder Park, Recreation, Forestry Director at mschroeder@newberlin.org; Cathy Schwalbach Project Engineer/Project Manager at cschwalbach@newberlin.org; Bonestroo Rosene Anderlik & Associates, Kathryn McNelly, Environmental Scientist at kmcnelly@bonestroo.com).