Unfortunately, the lack of a method to rapidly determine and map the water quality of streams has hampered efforts to incorporate water quality concerns and management into land-use decisions and planning documents. The Ontario Ministry of Environment and Energy contracted ThinkSpace Inc. to develop a spatial processing model to address this problem. Water quality map of Stoney Creek near London, Ontario. Stream reach colours explained above.
Streams are allochthonous systems.
They depend on an external supply of energy and nutrients from the surrounding riparian habitat and water quality is highly dependent on the nature of that habitat. Riparian wildlands, which include forests, swamps, and marshes, contribute to water quality by lowering water temperatures through shading, reducing suspended solids loads by controlling soil erosion, removing nutrients from runoff waters, improving summer base flow conditions, and increasing habitat diversity. Empirical data show that the presence of riparian wildlands correlates strongly with unimpaired water quality and can be used as a predictor of stream water quality. Riparian wildlands were identified by determining their reflectance signature from the three spectral bands of SPOT satellite images. Water quality was predicted based on the proportion of wildlands within 100 m of the stream.