Anthony Vodacek 
Digital Imaging and Remote Sensing Laboratory
Center for Imaging Science
Rochester Institute of Technology

Funding for this project was provided by Monroe County, NY, the Finger Lakes - Lake Ontario Watershed Protection Alliance, and the Great Lakes Protection Fund.

The purpose of this research was to combine hyperspectral imagery collected from aircraft with field collect data in order to map cladophora algae and bottom substrates along the southern shoreline of Lake Ontario in New York State, including the Rochester Embayment. The Rochester Embayment is a portion of Lake Ontario extending from Bogus Point (Parma, NY) to Nine Mile Point (Webster, NY). Image processing of the hyperspectral imagery was performed with the following goals: 

1. Extraction of bottom features. 
2. Comparison of hyperspectral data to field collect information. 
3. Comparison to similar work done during the International Field Year on the Great Lakes (IFYGL).

[See a related hyperspectral remote sensing of water quality project dealing with the generation of chlorophyll-a, chromophoric dissolved organic matter (CDOM), and total suspended solids (TSS) maps using hyperspectral imagery.]

Cladophora algae is prevalent in the Rochester Embayment. This type of benthic algae attaches itself to rocky bottom such as cobble or bedrock. In the summer months the algae dies and washes ashore where it decays. The rotting algae promotes the growth of coliform bacteria, which not only makes the beaches aesthetically unpleasing but hazardous to health. There have been numerous beach closings because of this nuisance algae. The believed cause of the algae is excessive nutrients such as phosphorus in the water. The following can cause this excess of nutrients:

1. Agricultural runoff
2. Storm water runoff
3. Wastewater treatment facilities
4. Sewage disposal systems
5. Atmospheric deposition

Analysis of airborne hyperspectral images based on a knowledge of aquatic optics can be used to assess near shore water quality. This project used images from AVIRIS and MISI (RIT's Modular Imaging Spectrometer Instrument) to map the bottom type. The images were processed in order to extract bottom features and produce maps of these bottom materials using a noise adjusted principal components analysis based on approaches taken in prior work (Wezernak and Lyzenga, 1975; Philpot, 1988; Green et al. 1988; and Wilson, 2000).

Field collections in the Rochester Embayment include latitude, longitude, depth, temperature, algal biomass and chlorophyll-a measurements. The equipment used in these collections are a bottom grabber, secchi disk, GPS and water collection bottles. 

Bottom types in turbid or deep waters are determined with the bottom grabber which pulls up algae, sand, sediment or whatever is on the lake bottom. The secchi disk measures water depth and estimates lake water quality. Latitude and longitude are measured with the GPS. Water sample collections are analyzed for chlorophyll-a, colored dissolved organic matter and total suspended solid concentrations. Water samples are filtered and concentrations are measured with a Shimadzu spectrophotometer. 

The results of this project are presented in PDF (4 files) and Excel (2 files) format. Download all six files for the complete results. For an overview and brief results, download only the Project Overview.

Project Overview (pdf)

Presentation with images from June 2001 (9 Mb, pdf)

Presentation with images from June 2001 (56 Mb!, ppt with tif images)

Presentation with images from July 2002 (10 Mb, pdf)

Presentation with images from July 2002 (69 Mb!, ppt with tif images)

Presentation with images from October 2002 (8 Mb, pdf)

Presentation with images from October 2002 (55 Mb!, ppt with tif images)

Ground truth part 1 (Excel sheet)

Ground truth part 2 (Excel sheet)

Publications and Presentations:

Vodacek, A. Journal article in preparation. Remote mapping of bottom materials along the southern shoreline of Lake Ontario: A comparison of IFYGL to 2002

Anthony Vodacek and Nina Raqueno, 2002, "Algal bed patterns in the Rochester Embayment and along the western shoreline of Lake Ontario", Lake Ontario Algae Cause and Solution Workshop, May 30, 2002, Greece, NY

Kristen Kelly, "Comparison of 1972 Airborne Imagery of Lake Ontario Cladophora Distributions to Recent Airborne and Satellite Imagery", Great Lakes Research Consortium Student Faculty Conference, 2001, Syracuse, NY

Personnel: 

Prof. Anthony Vodacek, RIT
Kristen Kelly, RIT undergrad
Aleksey Tentler, RIT undergrad
Bob Kremens, RIT staff
Nina Raqueno, RIT staff
Tim Gallagher, RIT Staff

Acknowledgments: 

We thank Charlie Knauf of the Monroe County Department of Environmental Services for his support of this project.

References: 

Green, A.A., M. Berman, P. Switzer, and M.D. Craig. 1988. A transformation for ordering multipspectral data in terms of image quality with implications for noise removal. IEEE Trans. Geosci. Remote Sens. 26:65-74.

Philpot, W.D. 1988. Bathymetric mapping with passive multispectral imagery. Appl. Opt. 28:1569-1578.

Wezernak, C.T., and D.R. Lyzenga. 1975. Analysis of Cladophora distribution in Lake Ontario using remote sensing. Remote Sens. Environ. 4:37-48.

Wilson, N.L. 2000. Hyperspectral imaging for bottom type classification and water depth determination. M.S. Thesis, Rochester Institute of Technology, Rochester, NY.