In 2006, Lawson-Fisher and Rundell Ernstberger were retained to design a new upscale condo complex as well as the surrounding river walk on a brownfield site in downtown Mishawaka, Indiana. Part of the project included stabilizing and vegetating the banks of the St. Joe River, which included maintaining some of the natural habitat. The native plant community not only stabilizes the bank in front of the river walk wall, but also provides forage and cover to indigenous animals that use the river corridor. This design strategy was cost effective and appealing to the permitting agencies.
Rundell worked with D2 Land & Water Resource on three project site locations for vegetative system solutions. The north slope included two components. The upper section of the slope utilized un-vegetated coir logs for slope contouring. The 7 lbs/ft3 density coir logs were used to break up the length of slope. Channelized flow on banks can start rills in un-vegetated areas which lead to complex erosion issues. Coir logs minimize the potential for this erosion by diverting the water through the coir log and discontinuing channelized flow. The bank was also seeded and protected with an erosion control blanket till germination could take place.
The lower section of the north slope included aesthetic river rock to protect the toe, pre-vegetative 9 lbs/ft3 density coir logs to transition to the soft armor system of a permanent turf mat, North American Green P-550. This permanent turf mat was chosen to increase the shear strength of the vegetation on the slope to match the proposed conditions. The pre-vegetative coir log allows for a successful introduction of a plant community in a vulnerable zone where plugs tend to dislodged, suffocated, or erode prior to establishment. Coir logs help prevent all these failures as noted throughout the Design Guide created by D2. The third location, the south bank, was designed the same as the lower section of the north bank.
As the plant communities “grow up”, the coir logs degrade, becoming part of the cover and are virtually unseen as shown in the August 2009 picture. This successful project is wonderful to look at on walk along on the riverwalk!