The purpose of this study is to find the bi-polar adjectives for rural stream landscape evaluation by the semantic differential scale and to suggest the major determinants of visual preference in rural stream landscapes. For this, the bi-polar adjectives for rural stream landscape evaluation was found by the method of the reliability test, and the spatial image was analyzed by the factor analysis. The level of visual preference was measured by slide simulation test, and these data were analyzed by the multiple regression. The major findings of this study can be summarized as follows : 1) Of the bi-polar adjectives expressing psychological and physical characteristics, the hi-polar adjectives which demonstrated reliability and consistency run as follows : Bi-polar adjectives expressing psychological characteristics : 'calm-bustling', 'unfamiliar-familiar', 'still-active','depressing-brisk', 'discomfortable-comfortable', 'suppressed-free', 'lifeless-living', 'quiet-noisy', 'unpleasant-pleasant'. Bi-polar adjectives expressing physical characteristics : 'artificial-natural', 'narrow-wide', 'rocky-not rocky', 'desolate-fertile', 'dirty-clean', 'enclosed-open', 'flat-steep', 'not gravelly-gravelly', 'thicketed-not thicketed', 'not weedy-weedy'. 2) Two factors, the harmony and the movement, were derived from the factor analysis for the psychological variables. Three factors, the naturalness, the rock, and the vegetation, were derived from the factor analysis for the physical variables. 3) Rural stream landscape types were classified into four types by the multi-dimensional scaling method. Type III, IV obtained higher rank of visual preference and type I, II obtained lower. 4) For all types, the factors determining the level of visual preference were found to be the harmony, the naturalness, and the vegetation. The visual preference determinants of rural stream landscape need to be considered in improving or restoring the rural stream landscapes.

The increase of population and industrial activities had brought into eutrophication in the Nakdong river. A remarkable acceleration of eutrophication brought about serious problems for water supply. Therefore, for the purpose of conservation of water quality in the Nakdong river it is necessary to control nutrients. MBOD method was used to evaluate algal growth limiting factor and algal growth potential in the Nakdong river from June to August 1994. The modified biochemical oxygen demand(MBOD) depends on the amount of available inorganic nutrient and organic substrate during 5 day incubation in the dark at 20℃. The MBOD assay depends on inorganic nutrients such as P and N as well as reduced carbon and called the MBOD, the MBOD-P, and the MBOD-N, respectively. The results of bioassay by MBOD(Modified BOD) method showed that the MBOD, MBOD-P and MBOD-N value were found to be in the ranges of 3.8∼96.0 ㎎O_2/ℓ, 5.6∼94.0 ㎎O_2/ℓand 42.0∼220 ㎎O_2/ℓ, respectively. And the the bioassay value was found to be the highest in Koryong area and the lowest in Waekwan area throughout the Nakdong river. The variations of MBOD-P and MBOD-N value showed similar tendencies to the variations of phosphorus and nitrogen value, respectively. By MBOD method, the relationships of MBOD, MBOD-P and MBOD-N value were MBOD ≒ MBOD-P ≪ MBOD-N. The MBOD value was nearly equal to the MBOD-P value, and the MBOD-N value was 3 to 20 times more than the MBOD-P value, approximately. Therefore, in the Nakdong river, phosphorus was the limiting factor for algal growth during summer season. The algal growth potential as the concentration of chlorophyll-a in the summer was maximum 5 times more than standing crop as it.