Over the last six years GEI staff have proposed, designed, permitted and helped construct a mile of new channel for a landfill expansion in Montrose, MI. In order to provide the re-routed creek with a new valley, almost 2 MCY were excavated out and used to build the landfill’s new cell walls. In the process, over 26 acres of wetland were also created. This presentation will provide a summary of the entire process. We will also provide the results from our first sets of post-construction hydrology, geomorphology and biological monitoring.
Besides the magnitude, another unique aspect of the project were the permit requirements, including bed load and suspended load sampling and modeling. This sediment transport analysis proved to be a key component of designing “self-maintaining” pool-riffle sequences for the new channel.
One important conclusion our team has reached during this process is that natural channel design based on emulating a set of reference stream dimensions is a coarse-scale design process and engineering tools like hydraulic and sediment transport analysis are fine-scale tools. We contend that when these tools are used together the chances that the design will establish a self-maintaining pool-riffle morphology go up substantially. Results from the Brent Run post-construction geomorphology assessment show that among the large variety of adjustments the pool-riffle sequences are undergoing, several appear to be establishing self-maintaining conditions.