Study Area

The Brandon Road control point was identified in the GLMRIS analyses as the only single location that can address upstream transfer of Mississippi River species through all CAWS pathways. Implementation of technologies at the Brandon Road control point was a feature of three out of six structural alternatives presented in the GLMRIS Report.

The Brandon Road site is located south (downstream) of the confluence of the Des Plaines River and the Chicago Sanitary and Ship Canal (CSSC). Previous investigations have indicated that a potential hydrologic bypass can occur during periods of high precipitation from the Des Plaines River to the CSSC. A one-way control point at the Brandon Road site would minimize the likelihood of bypass of Mississippi River ANS into the Great Lakes basin during flood events. 

A project at the Brandon Road site is likely to minimize a number of previously identified adverse impacts to existing waterway uses and users, such as increased potential for flooding or degradation of water quality. These impacts contributed significantly to the lengthy timeframes and significant costs of the structural alternatives presented by the GLMRIS Report. 

The physical configuration of the Brandon Road Dam prevents the upstream transfer of Mississippi River ANS. There is a minimum 25-foot difference in water elevation from the downstream side of the dam to the upstream side, which effectively limits upstream transfer. Operation of the lock at this location currently provides the only known aquatic pathway that allows transfer of Mississippi River ANS to the Great Lakes through the CAWS.