- Volume 13 Issue 11
The rapid industrialization and urbanization in Osaka Bay have produced many serious water pollution problems since the 1960s. A symbolic phenomenon is algae bloom (red tide), which occurred 53 times in 1976. The special law was enacted in 1973 and a number of administrative steps were taken, such as cutting COD loading, reductions in phosphorus (P) and restriction of land reclamation. As a result, the pollution of Osaka Bay has gradually been reduced, and the environment has been improved to some extent. In this study, to analyze the relations between water qualities as well as a social, economic activity by the coastal zone, the water quality data in Osaka Bay of 70 years past since 1921 were collected. Data such as population, livestock, fertilizer, industrial product etc. were also collected for estimating nutrients flowing into bay from land. It was found that the water quality was changed of a similar trend of estimated nutrients load, with delay of about four or five years.
Water quality;Nutrients load;Field data analysis
- Yamane, N., K. Nakatsuji, H. Kurita and K. Muraoka, 1997, Field data collection and modeling for verification of an ecosystem model in Osaka Bay, Japan, Estuarine and Coastal modeling, Proceeding of 4th Conference, ASCE, 196-210pp
- Nakatsuji, K. and T. Fujiwara, 1997, Residual baroclinic circulation in semi-enclosed coastal sea, J. Hydraulic Engineering, 123(4), 362-373 https://doi.org/10.1061/(ASCE)0733-9429(1997)123:4(362)
- Osaka Prefecture Fisheries Experimental Station, 1986, Field Survey Reports (1972-1992)
- Joh, H., 1986, Studies on the mechanism of eutrophication and effect of it on fisheries production in Osaka Bay, Bulletin of Osaka Prefecture fisheries Experimental Station(Japanese), 7, 174