an air-borne thermal imager in Fall of 2001. The section of canal analyzed in this report consists of a 6.6 mile unlined (earth) segment and an 11 mile concrete-lined segment (Figure 1). The thermal imagery was processed and 45 sites were identified as having possible leaks. The DMS Team visited and evaluated 11 these sites using a Site Evaluation Rating Procedure. Photographs were also taken to document the cause of the leaks. Additional information on procedures is included below. The thermal sensor was provided and operated by Dr. Steve Mass, USDA-ARS Scientist in Lubbock. The thermal imagery was recorded on a standard VHS video tape. The air plane was provided by the USDA-ARS Remote Sensing Lab in Weslaco. Image processing was done by the District Management System Team, Agricultural Engineering Department, Texas Cooperative Extension.
The study was conducted as follows:
1. Digitize the VHS video tape containing the thermal imagery;
2. Capture the frames of interest and enhance using image processing techniques;
3. Create a GIS map to locate each frame (or image) based on GPS coordinates;
4. Invert and overlay the processed images with DOQQ images to better identify the locations;
5. Go to the field with using the maps and overlaid DOQQ images as a guide;
6. Conduct field evaluation with pre-designed criteria (below); and
7. Complete the analysis.