Chicago has just proposed a new 6 acre extension to the shoreline park at Fullerton Avenue complete with new concrete revetment. Having recently combed the sand dunes of Indiana’s Lake Michigan shore, we wonder about softer shore styles they might have considered. Surely concrete barricades aren’t the only strategy for interfacing between land and water at the city’s edge … maybe we should be looking into a new go-to plan for how to deal with Chicago’s shoreline.
CHICAGO’S CHANGING SHORELINE
The majority of Chicago’s shoreline is far from natural. During our city’s development, the shore line has been pushed back (out into the lake) again and again with new edges constructed and interior areas filled in with land more stable and buildable than the marshy area which was here when the area was settled.
To protect that new line between water and land, the city’s design has always defaulted to hard edges – engineered structures with names borrowed from military defense terminology (revetment, bulkhead, bulwark, etc). Are we really mounting a defense, or worse, an attack, on the lake shore? You know what these looks like:
While it may be effective in keeping the city’s shoreline exactly where its put, this doesn’t seem like a solution exactly in line with natural development. It feels like a relic of an earlier time and in fact, its already been undermined (pun intended) by new plans for the re-development at Northerly Island where Studio Gang’s master plan on the Chicago Parks District website (their image below) rejects that concept as old fashioned and proposed an alternative, more habitat-friendly approach to our urban shoreline:
But, but, but … can a soft shoreline actually work to maintain Lake Michigan’s shore? Won’t it just wash away? Well … aside from the fact that Chicago’s “coast” was sandy shore before we started messing with it, there are still intact dune shorelines working just fine all around the southern tip of Lake Michigan. They include beautiful natural areas and ecosystems so valuable that they’ve been protected both as the Indiana Dunes State Park and the Indiana Dunes National Lakeshore (part of the National Park System.
Not only do the dunes effectively define the lakeshore in that area, they provide an amazingly diverse habitat for plants and animals, both local and just passing through. From the NPS website:
“The biological diversity within the national lakeshore is amongst the highest per unit area of all our national parks. Over 1,100 flowering plant species and ferns make their homes here. From predacious bog plants to native prairie grasses and from towering white pines to rare algal species, the plant diversity is rich.”
These miles of protected lakeshore, and thousands of acres of parkland, are easily accessible from Chicago by train (no car travel needed) via the South Shore Line which departs many times a day from Millennium Station downtown … check them out for yourself! (This and all other dune images by Malea Huffman.)
HOW DUNES WORK
Sand dunes might seem like a very unstable way to line a shore but, while they shift during the seasons they actually have an amazing system for self-shoring in one of their principal plant types: dune grass.
These unassuming little sprays of green may not look like much but they are actually amazing tough and surprisingly interconnected by their rhizomes (the underground stems which shoot grass upwards and roots downward to create the network that stabilizes dunes).
“A single plant can produce more than 130 feet of rhizomes in 3 years.”
Read all about the amazing powers of Marram grass at Chicago Wilderness.org. Dune (or Marram) grass can withstand the harsh conditions of their sandy environment using a symbiotic relationship with sub-surface fungi that break down stray organic material and produce nutrients and water for the dune grass.
The image below gives a glimpse of the subsurface life of dune grass. Its deep and interconnected roots keep the sand stabilized throughout the years even when they are exposed (as below) by seasonal wave action.
CHICAGO’S OWN LITTLE SAND DUNE
You probably know Chicago has beaches but did you know we have a dune which is an active (and growing) natural area. We’ve talked about Montrose Beach before, but only touched on the Montrose Beach Dunes which are actually an Illinois Natural Areas Inventory (INAI) site.
The Montrose Beach Dune may be a natural area of note AND the Chicago shoreline was originally “a natural sand edge, with dunes and swales and marshy lowlands,” but our little swath of dune is probably not a remnant of that earlier ecosystem. In fact, experts are puzzled about how it did come about – the dune grass which began its formation wasn’t intentional and “plants that haven’t been seen in Chicago for years are showing up on their own,” according to site-steward, Leslie Borns.
Dunes do require space and the right wind and wave conditions to thrive but the re-emergence of a natural dune at Montrose beach is a promising start. As Chicago continues to care for its coast line, perhaps this is an alternative to all those miles of concrete revetment!