Miller Beach - Natural Environment

Natural Environment

The natural landscape of Miller Beach includes "some of the most pristine habitats that remain in Northwest Indiana". The freshwater panne habitat, found at Miller Woods and West Beach, is considered globally imperiled by the Nature Conservancy. The dune and swale complex is unique to the southern Great Lakes, with only a few isolated pockets remaining. Sand oak savanna, of which Miller Woods provides "one of the finest in the Chicago region", is both globally and state imperiled.

This varied landscape of dunes and wetlands is the legacy of fluctuations in Lake Michigan and the Grand Calumet River since the last Ice Age. The Wisconsinan glaciation ended in the Miller Beach area around 18,000 years ago, forming Glacial Lake Chicago as the glaciers melted. Some boreal species remained in hospitable habitats after the climate had warmed, while more heat-tolerant species such as the six-lined racerunner and prickly pear cactus moved in during the Holocene climatic optimum to inhabit the mesic uplands.

After the glaciers retreated, factors including isostatic rebound of the earth's crust led to a series of different lake levels, each of which left a mark on the landscape. During the Algonquin stage, the dune-and-swale ridges of the Tolleston Beach were formed across much of the Calumet Region, including the southern part of Miller Beach. The later and lower Nipissing stage created the high dunes that mark the northern, lakeward part of Miller Beach. Around 2600 BP, the Grand Calumet River formed; prior to the 19th century, it emptied into Lake Michigan at Marquette Park in Miller Beach, where the Grand Calumet Lagoons are today. The direction of the Grand Calumet was changed in 1862. Because the river is nearly flat, however, the direction of flow through the lagoons sometimes reverses after heavy rains.