Chicago Botanic Garden
Shoreline Gardens and Restoration
Introduction
Scenic water vistas and diverse aquatic habitat are defining landscape elements throughout the Chicago Botanic Garden’s 60-acre system of interconnected lakes. Beginning in 1999, the Garden engaged in a systematic rejuvenation of our 5.7 miles of lake shoreline using innovative “bioengineering” techniques. These approaches rely heavily on dense stands of healthy native vegetation to control erosion of fragile lakeshore soils, establish ecologically diverse communities of native shoreline plants, enhance wildlife habitat, and demonstrate the importance of healthy lake ecosystems for our visitors. To date, 3.1 miles (54%) of the Garden’s lakeshore has been rejuvenated.
The Garden is expanding our comprehensive shoreline restoration and habitat enhancement to include the North Lake’s 1.2 miles of shoreline. Representing the most egregious remaining sections of unrestored lakeshore at the Garden, the project area includes the perimeter of the Fruit and Vegetable Garden island as well as areas along the North Lake’s western and northern shorelines.
The Problem
Intensive scientific studies in 1997 and 1998 documented serious threats to the Garden’s lakes, noting in particular the poor stability of soil along the shoreline edge and the near-absence of shoreline vegetation. Over 80 percent of the Garden's lakeshores were experiencing moderate to severe erosion. Steep shoreline slopes, weakly rooted nearshore plants (often turf grass), and poor soil conditions dominated the lakeshores. Excessive nutrient loading, rough fish activity (primarily carp) and invasive submerged plants (especially Eurasian watermilfoil) further contributed to degraded water quality and aquatic habitat. In short, the lakes at “The Garden on the Water” were in serious trouble.
The Solution
Thanks to the vision and generosity of the Woman’s Board of the Chicago Horticultural Society, an endowed Curator of Aquatics position was created and in 1999 the Garden immediately began restoring its most critically eroding shorelines. Aquatic habitat and wetland plantings along our lakeshores – previously measured in inches – now extend out from the waters’ edge by 30 feet or more. Innovative bioengineering approaches for creating stable, shallow-water shelves along the lakeshore allow the ¼-million new native water-loving plants to flourish and anchor shoreline soils. Our planting palette focuses on resilient native "workhorse" species that are carefully chosen for their ability to anchor shoreline soils and withstand environmental stresses inherent to urban waterways. Representing over 150 native taxa, these plants provide form and function throughout the year, and the result has been ecologically functional lakeshore landscapes that offer a widely accepted aesthetic appeal. 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. The Garden has also pioneered the development of environmentally sensitive, partially vegetated solutions for circumstances where site conditions require a hard-armored (e.g., sheet pile) solution.
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, the U.S. Army Corps of Engineers, the Illinois Department of Natural Resources, and the Woman’s Board of the Chicago Horticultural Society. Our shoreline restoration efforts have received widespread recognition and commendation at the regional, state, and national levels.
For this project, the U.S. Army Corps of Engineers Ecosystem Restoration Program is providing $3,737,500 of the total project cost of $5,750,000.
Conclusion
The restored shorelines in the North Lake will demonstrate to public and professional audiences innovative and effective approaches for restoring and protecting urban lake ecosystems – while serving as a living laboratory for Garden scientists and their colleagues studying urban water resource conservation. 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 improvements. Through the Joseph Regenstein, Jr. School of the Chicago Botanic Garden, courses, workshops, and seminars help landscape and conservation professionals learn from the Garden’s experiences. Planting beds in restored habitats include identification labels so that visitors can learn more about the wide diversity of native plants used. Publications, brochures, interpretative signage, tours, and Web site information allow the public to expand their knowledge about urban lake ecosystems even more.
(Please see the downloadable document for photos of the restorations.)