Geological Survey Circular 1085 Our Changing Landscape: Indiana Dunes National Lakeshore

(NASA)

Our landscape is constantly changing in response to forces both natural and artificial. The actions of wind, water, and people all change the land surface. Some changes occur over centuries, whereas others occur within weeks. Changes may be global in extent or have only local effect. Regardless of the type of change or length of time over which the change occurs, earth-science information plays a critical role in our adaptation to these changes.

This report highlights some of the landscape changes and some of the processes taking place at one of our parks—Indiana Dunes National Lakeshore. With each earth-science issue addressed, a national or global perspective is presented first, followed by a description of the implication the issue has for the park—in other words, the reality of that issue at the local level. The issues are global change, land use, wetlands, coastal erosion, and contamination. With each of these issues, human involvement has played some role. The concept of living in harmony with nature is challenged daily.

The first section, "Global Change," explains that change is a natural process, not just a process caused by people's insensitivity to the environment. Human activities, however, influence the rate at which these global changes are taking place. The section "Land Use" shows the diverse imprints people have left on the landscape. In the "Wetlands" section, the many functions that wetlands serve and the threats being imposed upon wetlands by human activity are discussed. The section "Coastal Erosion" explains that erosion, too, is a natural process and is one that human activity can accelerate. Millions of dollars are spent each year because we have difficulty coexisting with nature. We continue to build structures near or on coastlines and lakeshores, where they may be destroyed by the natural processes of wind and water. Although there are natural sources of contamination, in the section "Contamination" we show that most of the threats to the quality of our air and water are related to human activities.

How society deals with these issues today will no doubt affect future generations. How the National Park Service (NPS) manages these issues within the boundaries of Indiana Dunes National Lakeshore will affect the park for many years. Information is the key to responsible management of global, national, regional, and local earth-science issues. Indiana Dunes has a unique geologic setting. Its landscape has been shaped by dynamic processes of wind, waves, water, and ice. One of the guiding principles in the study of the Earth is the theory that the present is the key to the past. The ongoing natural processes are similar to those that shaped the Earth hundreds, thousands, even millions of years ago.

SCENES FROM THE DUNES

(upper left, lower left) Bob Daum,
(upper right, lower right) Indiana Dunes National Lakeshore

Earth-science information teaches us that

• Lake Michigan was created as a result of natural global climate change

• The natural progression is for wetlands eventually to fill in with sediment

• The surface water in wetlands is a mixture of rainfall and ground water that has resurfaced

• Shorelines shift in response to the actions of wind and water; water levels and wind speed and direction respond to global climate changes

• Ground water can travel over very long distances and take hundreds of years to do so

• Dune migration is a natural process, and rates of movement can sometimes be predicted

Earth-science information is essential for making responsible land-management decisions.

Our ability to make responsible decisions in managing natural resources depends upon our ability to predict future changes. Without adequate and timely earth-science information, we will not be able to predict changes. This report discusses several earth-science issues of national and local significance and also presents earth-science information that will help us effectively and wisely manage our natural resources for future generations.

Global change (Gary North)

Land use (Linda Jackobsen)

Wetlands (Gary North)

Coastal erosion

Contamination (Gary North)