Why We’re Mapping Historical Wetlands

You have to know where you’ve been to know where you want to go.

We’ve all heard that expression before. It turns out that its true for environmental issues too.  

That’s exactly why our National Wetlands Inventory program is taking a historical look back at the way the country used to look, specifically focusing on wetlands.  By locating and mapping where wetlands used to be on the landscape, we can move forward in knowing where the best places to re-establish wetlands are.

Wetlands at 
Blackwater National Wildlife Refuge (USFWS)

At the time of European settlement in the early 1600’s, the area that would eventually become the United States had approximately 221 million acres of wetlands, but less than 400 years later, only 103 million acres remained.  

Even today, all of the effects of these losses might not be fully realized. Historical events, technological innovations, and human activities have had destructive effects on wetlands. By examining the historical backdrop of why things happened, when they happened, and the consequences of what happened, we can move forward in wetland restoration and conservation.  

Federal, state and local governments, along with non-governmental organizations need historic information to help them in land use planning, guiding habitat restoration projects, tracking land use changes and determining possible wetland re-establishment opportunities.

So how do you know where wetlands used to be? Maps, aerial photographs and various biological databases often provide information about past wetland locations. More recently, surveying soil types and studying hydrology (the study of the movement, distribution and quality of water) can tell us a lot about what the landscape originally looked like and how water shaped it. 

The evidence from historical map information, inventories of past wetland extent or other information collected that relate directly to wetland filling, drainage or other modifications can tell us a lot about how our land uses have changed the hydrology of an area. And looking at that information is really important as we move forward in identifying locations where we can re-establish wetlands on the landscape.

Re-establishing wetlands and restoring wetland habitats is a priority for the our agency. Wetlands provide a multitude of ecological, economic and social benefits. They provide habitat for fish, wildlife and a variety of plants. Wetlands are nurseries for many saltwater and freshwater fishes and shellfish of commercial and recreational importance. Wetlands are also important landscape features because they hold and slowly release flood water and snow melt, recharge groundwater, act as filters to cleanse water of impurities, recycle nutrients, and provide recreation and wildlife viewing opportunities for millions of people.

If you want to see the historic wetlands for the areas completed so far, visit the historic wetlands data layer. Then check back later as we’ll be adding more historic maps from around the country.


  1. uno-chart reblogged this from usagov
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  4. usagov reblogged this from usfws and added:
    From the U.S. Fish and Wildlife
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    Really cool to see they have an active Tumblr, but anyone know if there is an RSS feed for the over all United States...
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