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Overview of Maps & Data

Quickview of Data
These "zoomable" maps allow the user to quickly view the selection of land cover and impervious surface datasets developed to date. These include, two time periods, ~1990 and ~2000, for the state of Minnesota , and four time periods 1986, 1991, 1998, 2002 for the Twin Cities Metropolitan Area (TCMA). Viewing of impervious surface data is enhanced by maps which also display it in the context of the change in the degree of imperviousness between time periods.

More Detail
This "MapServer" application allows the user to view maps and statistics for land cover and impervious surface by county, city, ecoregion, lakeshed and watershed.

Data Download
This link allows the user to download the data for use in their own GIS software. We ask you to fill out a brief survey before downloading simply to track the level of interest in this type of research.

What are Impervious Surfaces?
Any surface that is not penetrable by water. From an urban standpoint, this includes streets, parking lots, sidewalks, and building roof tops. Past studies have proven that transportation elements contribute the most to impervious surface area.

Why do we need to know the spatial extent of impervious surfaces? Impervious surfaces have several adverse environmental impacts. In many cases, the amount, or percentage of a landscape that is impervious can help us determine the extent of environmental impact. Some of the more important environmental impacts are water quality, water quantity, and the urban heat island effects.