ESRI Conservation Support Program: GIS Experiences from Prior Recipients

Iowa Natural Heritage Foundation

Mission Statement: The Iowa Natural Heritage Foundation builds partnerships and educates Iowans to protect, preserve and enhance Iowa's natural resources for future generations. The Foundation's current priorities include permanent land protection, trail, greenway, and habitat complex establishment, and promotion of improved land management.

NATURAL CHALLENGE, TECHNOLOGICAL TOOLS: BY KYLE SWANSON. WHICH RESTORABLE WETLANDS COULD BE MOST EFFECTIVE IN KEEPING THE IOWA GREAT LAKES CLEAN? COMPUTER TECHNOLOGY POINTS THEM OUT. Standing on the banks of Spirit lake on a cool foggy fall morning makes clear the feelings that the residents have for these natural lakes. Without a doubt, the beauty of the water and sky have made the Iowa Great Lakes of northwestern Iowa the vacation hot spot of Iowa. Yet, in the past decades, the residents and landowners have struggled with declining water quality in these lakes at risk. The Iowa Natural Heritage Foundation is using modern computer technology to help solve this age old problem.

The cause of declining lake water quality are clear, as are the solutions. Vast natural wetlands once covered the Prairie Pothole Region. They removed sediment, controlled flooding, and maintained clear lakes. The conversion of more than 80% of the wetlands to croplands, plus the use of commercial inorganic fertilizer on farmland and lawn alike, have accelerated the aging of the lakes (eutrophication). Inadequate sanitary sewers also contributed to the problem until their upgrading over the past two decades.

The best hope for lake quality is to restore some of the wetlands in the watershed. But high land values in the region can make restoration costly. Likewise, restorations haphazardly placed throughout the watershed may benefit water quality very little. It is important to know which restorable wetland areas can best reduce nutrient, sediment, and water transfer to the Iowa Great Lakes.

This ability to prioritize wetland restoration became a major goal of the Clean Water Alliance for the Iowa Great Lakes. Founded in 1987 by the Iowa Natural Heritage Foundation, the Alliance is a network of 22 groups and agencies that coordinate their water quality activities. Alliance members have helped restore more than 2,000 acres of private and public wetlands in the Iowa Great Lakes watershed.

A scientific approach to wetland prioritization would require computer technology capable of handling data for the entire 62,300 acres of the watershed. A Geographic System (GIS) was chosen as the planning tool. GIS can organize and evaluate large amounts of information while retaining the characteristics of even the smallest areas of land. The Iowa Natural Heritage Foundation provided a college intern (funded by the R. J. McElroy Trust) to conduct the computer work. With the Iowa Department of Natural Resources supplying office space and computer equipment, work began in May 1993.

The process is conceptually simple, but mathematically complex. Imagine taking two overhead transparencies of your property. One has the various uses of your property drawn on it: well locations, lawn areas, cropland, wetlands, windbreaks, etc. The other transparency contains a copy of your land's soil survey information. The various types of soil are clearly delineated along with streams and roads. If you were to align one transparency over the other you could see, for example, which areas with wetland soils or highly erodible soils are being used for fields or roads or houses.

The GIS system completed this process for all 62,300 acres in the Iowa Great Lakes watershed. Additional information was added in layers: streams that empty into the lakes, topography of the region, watershed boundary lines, and publicly-owned lands.

Once these layers of data are organized together by location, you can start to answer planning questions about the area. Where are all the restorable wetlands that are nears streams? Where are the most potentially erodible soils and slopes? And finally, which changes in the watershed can most directly affect water quality?

Over the course of 16 months, the data has been analyzed and priority areas for wetland restoration have been formed in both the Iowa and Minnesota portions of the watershed. This should give planning officials a reasonable basis for their work - but it's still just a starting point. With scientific information in hand, they can begin to ask other difficult questions which are equally important: Will key landowners consider some management or land use changes? Can the landowners receive any cost-share money for the changes? How can a wetland restoration be funded?

The Clean Water Alliance partners will contact those who own the most crucial sites. Some landowners will choose to restore their wetlands. The result of their work are likely to be separately small but, as a whole, the benefits will reinforce the economic viability and the future health of the Iowa Great Lakes watershed.

Coming Attractions:

Maquoketa River Watershed Project: (incorporating water testing data > into GIS to assist in settingsub-watershedd priority areas)

Blufflands Alliance: (developing GIS project database for four state partnership of land trusts focusing on the Upper Mississippi River Blufflands)

Text and graphics: Iowa Natural Heritage Foundation
January 2, 1997, (Iowa Natural Heritage Foundation, 505 Fifth Ave., Suite #444, Des Moines, IA 50309, Phone: 515/288-1846 Fax: 515/288-0137 E-mail:

Web layout & design: ESRI Conservation Program, January 2, 1996

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