Shoreline Erosion Control

Of the Garden's 385 acres, nearly one-quarter (81 acres) is water. A 60-acre system of lakes winds throughout the gardens and research facilities. About 5.7 miles of shoreline encircles the Garden's lakes, so it is not surprising that the Garden is keenly interested in protecting its shoreline soils and enhancing aquatic habitat.

Identifying shoreline Problems
A 1998 study of shoreline conditions revealed that 80 percent of the Garden's lakeshores were experiencing moderate to severe erosion. In 1999, the Garden completed an Illinois Clean Lakes Program Diagnostic/Feasibility Study. This comprehensive study investigated existing lake quality problems and their causes, and identified remedial measures to restore and protect the lakes' water quality and aquatic habitat.

The problems documented in the Clean Lakes Program study were not unusual or unique for lakes in urban settings. Steep shoreline slopes, weakly rooted nearshore plants (often turf grass), and poor soils dominated the lakeshores. Excessive nutrient loading (primarily from nuisance levels of Canada Geese), as well as rough fish activity (primarily carp) and invasive submerged plants (primarily curlyleaf pondweed, and more recently, Eurasian watermilfoil) contributed to degraded water quality.

Finding Environmentally Sensitive Solutions
The Garden embraces the philosophy that "a lake is a reflection of its watershed," and all of our efforts are guided by watershed management principles that strive to prevent water resource problems at their source of origin, together with the use of environmentally sensitive approaches that provide sustainable, long-term solutions. By controlling water pollution at its point of origin (for example, by reducing nutrient and sediment runoff from urban development sites, or preventing soil erosion from occurring along lakeshores), we can improve the quality of our water resources most efficiently and effectively. For an excellent introduction to watersheds and how you can restore and protect them, visit the Conservation Technology Information Center's Know Your Watershed website.

In June 2000, the Garden began restoring its most critically eroding shorelines. Wetland habitats along the lakeshores — previously measured in inches — now expand out from the lake edge by 30 feet or more. Innovative bioengineering approaches for creating stable, shallow-water "shelves" along the shoreline allow water-loving plants to flourish and anchor shoreline soils. These approaches are in contrast to traditional approaches that rely solely on "hard edge" techniques such as sheet piling or impenetrable masses of stone riprap. Creative uses of interplanted stones and boulders, as well as specialized plastic mesh and webbing materials, further help stabilize the shoreline edge and protect our newly installed aquatic plantings. Both private and public funds have been used to support the Garden's ambitious efforts, including significant assistance from the U.S. and Illinois Environmental Protection Agencies' Section 319 Nonpoint Source Pollution Management Program, as well as the U.S. Army Corps of Engineers' Section 206 Ecosystem Restoration Program.

restored shoreline