Silver Lake Buffer Project Underway

Submitted by Barbara J. Huberty, from the City of Rochester, Public Works Department.
Monday, June 11, 2007

In three years, the new look of the native plants will be something like this.
Photograph courtesy of the Kestrel Design Group.

Park users that enjoy the trail around Silver Lake may start noticing some unexpected activities this week. Prairie Restorations, Inc. (PRI) has started the construction of the shoreline buffer of native vegetation that, once growing, will help reduce water pollution entering Silver Lake. The plants, shrubs, and trees will act like a filter to clean storm water that flows overland, into the lake.

PRI’s first step is to apply herbicide to eliminate the existing vegetation in the buffer area. The native plants will not establish successfully without this step. Fences are being installed to protect existing trees and the park benches are being moved out of the buffer area into adjacent non-buffer areas. People will also see PRI installing fencing in the lake to protect the new vegetation from foraging geese and fish.

Geese and pet waste contains microscopic fecal coliform bacteria that, when discovered in water samples, may indicate the presence of disease-causing organisms. The Zumbro River in Rochester is classified as being “impaired” because it contains too much fecal coliform bacteria. The installation of this shoreline buffer project is one way the City is meeting state and federal mandates to reduce these pollutant loads.

The vegetated shoreline buffer will consist of three planting zones: an upland zone with prairie and wetland areas, a transition zone with mixed prairie and wetland plants installed above the waterline on top of the pillow rip-rap; and emergent zone with aquatic plants installed below the waterline at thirty locations around the lake. The native plants will establish slowly, so fences will surround the plants for the next three years.

Park uses can help make this project a success by staying out of the fenced area, not littering, and reporting any fence breaks to 328-2440. Background information about this project is posted on the
City web site.

Frequently Asked Questions About the Silver Lake Buffer Project

What is the point of this project?
Native plants are being installed to reduce the amount of pollution reaching Silver Lake. This pollution comes from eroding sediment, goose waste, litter, and storm water runoff. The plants will take up some of the excess nutrients, anchor the soil to prevent erosion and loss of sediment, and block the movement of litter.
If the geese are such a problem at the Park, why are we feeding them?
The goose feeding stations will be discontinued in April 2007.
Will the installation of the Silver Lake buffer drive geese to neighboring yards?
The native plants may discourage some of the geese from using the shoreline, in which case, they will move to other open areas of the park or elsewhere in the City.
Will this project reduce the goose population in Rochester?
Vegetation alone will not significantly reduce the resident or migratory goose populations in and around the City. It may encourage dispersal of geese away from Silver Lake and, over time, it may make Silver Lake a less attractive migratory stop over location.
What will the shoreline look after this project is completed?
The buffer will average about 30 feet in width. It will consist of native plants that are well-suited to the three planting areas:
1. An upland zone planted with prairie grasses and flowers or wetland plants (depending on the drainage conditions); this is the area upslope from the pillow rip rap. Some upland areas will also receive tree and shrub plantings.
2. A transition zone of wet prairie/wetland species on top of the upper portion of the pillow rip rap,
3. An emergent zone of aquatic plants for the portion of the pillow rip rap below the water’s edge.
The species selected will be those that provide the best combination of pollutant removal and aesthetic enhancement in each zone. The following diagram prepared by The Kestrel Design Group presents a typical shoreline cross-section. The target plant communities for this project are the floating, emergent, wet prairie/sedge meadow and wet/mesic prairie buffer.