water quality monitoring. Traditional water quality sampling is time-consuming,
expensive, and can only be done for small areas. Remote sensing provides a
revolutionary technique to monitor water quality repetitively over a large area. The
major concerns regarding the use of remote sensing for water quality monitoring are:
1) suitable spectral channels for deriving various characteristics of water quality
variables, and 2) appropriate and efficient image processing techniques to convert
image brightness to traditional water quality indices.
The first purpose of this research is to incorporate remote sensing data into a water
quality model as a more accurate initial condition. The second purpose is to adapt a
geographic information system (GIS) to enhance the contribution of water quality
modeling to practical water quality forecasting. The water quality model (QUAL2E)
and an image processing and GIS package (ERDAS IMAGINE) were used in a case
study of the Te-Chi Reservoir in Taiwan. All water quality variables from simulations
are displayed on a geographically registered map and in color to correspond with
varying water quality levels. The visualizing technique is helpful for rapid
understanding of water quality conditions.