Filamentous algae can be found in all seasons in rivers that originate in the central-south region of Taiwan, including unpolluted or mildly polluted shallow rivers. These algae are highly abundant, especially Cladophora and Spirogyra is the second most abundant, but Microspora is less observed and is not found in severely polluted river regions. A preliminary study showed that the upstream river channels of various dams, from south of the Liyutan Dam in central Taiwan, to Mudam Dam in Pintung, experience massive growth of attached large filamentous algae in different seasons. Benthic algae grows well in low nutrient rivers and can be harvested; it is a good wetland plant. Therefore, further study of its nutrient eliminating speed and the living environment of the algae would be worthwhile. In the part1 of the study, we choused river channels from the upstream side of southern dams to do investigation and analysis on species of attached large filamentous algae and their relative abundance, their biomass and its seasonal variation, and the algae’s habitat. The characteristics, living history and morphology of the algae also were studied, to evaluate the feasibility of eliminating plants for nitrogen and phosphorus nutrients. In the part2, algal bed ecological engineering of attached large filamentous algae was investigated, including discussions on the model construction of benthic algal beds, the growth rate of attached algae, the elimination rate of nitrogen and phosphorus sources, the actual variable on the practical design of algal bed ecological engineering, and evaluation of the effectiveness of elimination. In the part3, the harvesting and uses of attached filamentous algae were analyzed. Moreover, the method of harvesting and processing, the algal composition, and their structural characters were analyzed to discuss possible utilization of the algae. A remote satellite sensing-based method of reservoir watershed pollution was undertaken to study the spatial distribution of point and non-point pollution condition in reservoir watershed. This study, the prototype performs the mechanical function to identify appropriate point and non-point pollution, watershed boundaries, prepare the pollutants data, and visualize the results. A remote satellite sensing-based method of reservoir eutrophication was undertake to study the spatial distribution of eutrophication conditions in reservoir environment. A trophic state index include chlorophyll a concentration, non-algal particles (NAP) and colors dissolved organic matter (CDOM). A remote satellite sensing overlay technique was applied to synthesize the information into a final map illustrating the spatial distribution of eutrophication conditions within the study area. The different tools and methods associated with reservoir eutrophicartion assessment using rensing were discussed.

benthic algae, remote sensing, nutrient