UNI teams with Kennedy Space Center
to extend the use of remote sensing

Landsat ETM satellite image of Silver Lake	Water Quality information of Silver Lake
SDT = Secchi Disk Transparency; TSI = Carlson Trophic State Index

Assessing Iowa's estimated 130 polluted surface waters by on-the-ground chemical monitoring is a Herculean task by anyone's reckoning. For the past five summers, University of Northern Iowa (UNI) undergraduate students and faculty in the Iowa Summer Lakes Study (ISLS) have been attempting to do just that by collecting and analyzing water samples on two lakes and a wetland.

Now an opportunity has presented itself for the ISLS to work with the Kennedy Space Center (KSC) to develop a model to monitor lakes and predict water quality from airborne hyperspectral images and high-resolution satellite images. The joint endeavor is part of a recently awarded $100,000 grant from NASA to the Iowa Space Grant Consortium (ISGC). The KSC has been exploring the feasibility of using remote sensing to monitor water quality and submerged vegetation in shallow water, an approach that would be useful in Iowa.

"If we can employ remote sensing technology to measure water quality, this would be a promising alternative," said William Stigliani, professor of chemistry and ISLS co-director, along with Maureen Clayton, assistant professor of biology. "Although the approach we have been using has been very beneficial to students, who have gained firsthand experience as part of a multidisciplinary environmental team, the ISLS model is too capital- and labor-intensive to monitor lakes statewide."

Remote sensing has been employed to measure water quality in the open ocean, but little research has been done on the applicability of remote sensing in shallow waters, including small lakes, coastal waters and wetlands. If remote sensing can be successfully applied to shallow waters, it would allow for continuous long-term monitoring.

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Other Midwestern states have applied remote sensing to gauge water quality, but their surveys have been limited to multispectral remote imaging. In the past several years, multispectral remote sensing has been successfully used to analyze and predict water quality, particularly to assess parameters such as temperature, chlorophyll a, turbidity and total suspended solids for lakes and reservoirs. The water quality map above is derived from a multispectral satellite image for Silver Lake in Iowa.

Newly developed hyperspectral imaging, which can simultaneously record up to 200+ spectral channels, is a much more powerful probe. Hyperspectral imaging has greater potential because of its simultaneous collection of images covering many narrow, contiguous wavelength bands that allow various aspects of water quality to be measured and monitored.

Dr. Ramanathan Sugumaran, UNI assistant professor of geography, will direct this aspect of the collaboration with KSC, which will investigate the potential of hyperspectral remote sensing to quantify and assess various water-quality constituents of inland and coastal areas and study the relationships between hyperspectral data classification and laboratory measurements using geostatistical analyses.

The experiments at UNI and KSC will employ an Airborne Imaging Spectrometer, a hyperspectral sensor developed by the Jet Propulsion Laboratory. Ground truthing will be done simultaneously to monitor water quality and calibrate the signals. While KSC will investigate water quality in saline habitats with submerged aquatic vegetation and relatively low chlorophyll a values, UNI will study freshwater habitats dominated by phytoplankton and with very high chlorophyll a concentrations. The complete data set will allow remote sensing to be validated as a technique for the prediction of water quality over a wide range of water-quality conditions.

"This project allows UNI students to conduct remote sensing research at KSC and to share data and data analysis techniques with KSC researchers," said William Byrd, ISGC director. "It's a great opportunity for Iowa students, to be exposed to the environmental research being conducted at KSC." KSC staff will also visit UNI to give seminars and work with faculty in designing a remote sensing protocol.

"We anticipate that the initial collaboration of UNI faculty and KSC staff will continue to develop," Byrd noted, "and this will certainly strengthen the recruitment and retention of UNI undergraduate and graduate students in the sciences."