Yesterday, Greg Osborne, PE, Epstein's director of civil engineering, was the featured speaker at the Friends' of the Chicago River Summer Speaker Series, a weekly free event that takes place every Monday at 12:15 p.m. outside the McCormick Bridgehouse & Chicago River Museum. Greg gave a presentation called 'Engineering Nature into the Chicago River' which highlighted many of the environmentally friendly infrastructure elements Epstein has designed along the Chicago River, specifically at the Wolf Point, River Point and 150 N. Riverside developments, as well as the soon to be constructed Riverview Bridge at Addison Street.
Greg began his presentation by pointing out that sadly there's nothing really natural about the Chicago River in its current state. As Greg stated, 'It's (The River) been engineered to be straighter, wider and deeper for shipping. It's been engineered to flow backwards. It's been engineered to provide storage for sewer overflows. It's been engineered to dilute partially treated effluent from treatment plants.' But Greg then spoke about how the River and more importantly the public's opinion about the River is changing and moving towards a healthy and clean waterway, which has necessitated that nature is starting to be engineered back into the River.
At this point in the presentation Greg then covered how there are two very basic principles when engineering nature back into the River – the first is to eliminate or minimize direct discharge of stormwater into the river and the other is to provide vegetation along the river. Greg spoke about how at Wolf Point, River Point, and 150 N. Riverside were, before development, either parking lots or empty lots and were all 100% impervious sites, with stormwater discharging directly into the river. Runoff was carrying silts, metals, oils and petrochemicals directly into the water. Epstein's engineers then developed nature back into the sites like River Point by introducing a landscaped river walk and which is fed by stormwater runoff that flows through a separator which removes debris and cleans the water. These bio-infiltration beds filter the water and irrigate the landscaping and any excess stormwater runoff is directed to an aggregate detention area that stores the water and releases it in a slow rate back into the River.
At Wolf Point, the initial instinct was to construct a sheet pile river wall like River Point, but in order to expedite the permit process, Epstein recommended cantilevering the river walk above the flood plain to avoid any impacts to the river. Working with the US Army Corps of Engineers and Chicago's Metropolitan Water Reclamation District, Epstein set the river walk elevation above the 100-year flood elevation. This created an opportunity restore, stabilize and re-vegetate the immediate shoreline and bring it back to more natural condition. The shoreline has been landscaped with hearty, long-stemmed, water tolerant plant material such as wild rye, switch grass, prairie sedge and low shrubs. Irrigation has been added to ensure its growth and success. The hope is that in a few years this Riverwalk will appear to float above a lush, green river bank.
For 150 N. Riverside, the development enhanced the site from 100% impervious to 37% impervious by building over the existing Amtrak tracks, adding open space and park land. Any stormwater that does runoff gets filtered through a filtration and separator before being discharged to the river.
For the upcoming Riverview Bridge, the existing bank has robust vegetation including trees. Epstein's engineers are preserving the vegetation by completely separating the trail from the bank and constructing it on structure into the river. The vegetation that has not survived and is at risk of falling into the river is being selectively cleared. New deep rooted trees and other vegetation that can withstand periodic inundation will be planted along with permanent turf reinforcement mats. Epstein has also designed a bio-swale to avoid direct discharge into the river from California Park. The water will enters the bio-swale and infiltrates into the ground before entering the river.
Greg then introduced Zachary Damato and Nick Wesley, from Urban Rivers, to speak specifically about how to reintroduce vegetation into the Riverbank. Zach and Nick have a test project located on the east bank of Goose Island consisting of floating gardens and wildlife habitat which will help teach communities about urban rivers and help clean the Chicago River of trash and pollutants. It's Urban Rivers' goal to develop a floating garden rom North Avenue to Division Street. (For more information on Urban Rivers visit - http://urbanriv.org/)
After Zach & Nick finished speaking, the 40+ attendees, who spent their collective lunch hour learning about the engineering nature and enjoying the sun and cool breeze along the river, asked a series of questions to Greg and the guys from Urban Rivers about the projects highlighted in the presentation as well as what's coming up along the River.
For further information regarding the Friends' Summer Speaker Series on the Riverwalk visit http://www.chicagoriver.org/events/friends-summer-speaker-series-on-the-riverwalk and if you have questions regarding some of Epstein's civil engineering efforts in reintroducing nature into the River send Greg a note at email@example.com