The objectives o f this project were to:
1. develop and evaluate several methods for mapping aquatic habitat using remote sensing; and,
2. describe the relationships between river discharge and the amount of meso-habitat types (eg. side channels, sloughs, shoals, backwaters, riffles, pools) at the two study segments chosen.
Four imaging systems were evaluated for mapping aquatic habitat, colour photography, colour infrared photography, multispectral videography and compact airborne spectrographic imaging (.casi).
1. Colour aerial photography was judged to be inappropriate for habitat assessment, based on this trial. The colour photography did not allow for easy discerning of the water’s edge because it does not include the infrared wavelengths of light and it was poor for discerning vegetation.
2. Infrared photography fared very well in this trial. Because water absorbs infrared light, imaging systems that include the infrared wavelength can identify the water’s edge very accurately. The infrared colour photography was judged to be the most cost effective to meet the requirements ofthis study. Aerial photography also allowed inexpensive and accurate georeferencing. Infrared colour photography would not be a good choice for classifying turbidity, depth and substrate.
3. The casi system although the most expensive, but because of its 256 bands for spectral resolution, is the most accurate for determining features that have similar spectral signatures such as substrates in the dry and near shore areas or correlating reflectance with field parameters such as total suspended solids. In this study the casi resulted in some loss of accuracy in determining areas and was the least accurate in georeferencing.
4. Multispectral videography was midway between infrared aerial photography and the casi system in terms of cost and accuracy.
To meet the objectives of this study, infrared aerial photography was judged to be the most appropriate method in terms of meeting the objectives cost effectively.
Developing an available habitat versus flow relationship was not very successful as the range of flows that were available over the course of the study was limited. Additional imaging over a greater range of flows will be necessary to accurately characterize these relationships. Poor conditions for imaging also played a part in these difficulties.