Dr. Boyd’s Research Lab

These few web pages provide supplementary material for the paper by Philip Chaney, Claude Boyd, and Mike Polioudakis: Number, size, and distribution of small impoundments in Alabama, forthcoming in 2011 in the Journal of Soil and Water Conservation.

Mike Polioudakis did the basic GIS work. Donn Rodekhor provided essential technical assistance to Mike in many ways. Nathan Campbell collected data for evaluating “ground truth”. Mike Polioudakis did the analysis of ground truth.

The work in this paper is not intended to find once-and-for-all every pond in Alabama. Recent survey work (cited in the paper) indicates that Georgia contains more small ponds than is obvious from present GIS analyses, and Alabama is likely quite similar. This work intends to find as many ponds as possible by focusing entirely on water while excluding other kinds of ground cover.

The material in these web pages is provided at the request of some of the reviewers of the paper. In this material, we do not attempt to further defend the paper or to argue with any reviewers. We only present the project as it was carried out, and some of the results, in hopes of clarifying.

The first step in the project was to identify all water in Alabama, and only water in Alabama. Whatever is not water is simply background. This step resulted in files called “unmasked”. The second step was to mask out large water bodies, and to mask out a zone of 90 meters (3 rastars) around all water bodies and streams. This step resulted in files called “masked”. The masked files were the source of most of the data. Third, water bodies of 1 rastar size were eliminated. Fourth, water bodies were counted, and their size noted. Fifth, the data was broken down by categories, such as the number and size of ponds between 5 and 10 acres in size in Lee County. Data was produced for unmasked files but used mostly in cases where we needed to look at large water bodies, as in some ground truth operations.

All the maps in these web pages are in TIF format unless otherwise specified. These files were derived from “image” files for GIS programs. If you seek additional information, please contact Mike Polioudakis as long as he is available, at polioej@auburn.edu or mpolioudakis@hotmail.com .

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