I3 EUTROPHICATION << Nuisance caused by eutrophication >> Unusual algal bloom, disturbed filtration in cleaning beds, foul smell of tap water << Supplementary notes >> To suppress the bloom of Microcystis, a device for intermittent aeration and vertical water mixing is being tested. << Records of Microcystis bloom in Lake Sagami >> Year Blooming period Max. cel no. [ml-1] Note --------------------------------------------------------------------------------------------------------------- 1967 Aug-Sep 2,200 First observation 1968 Aug 380,000 1969 Aug-Sep 1,500 1970 Aug 380 1971 May-Aug 13,000 1972 Jun-Aug 3,100 1973 Jul-Oct 590,000 Water supply rate was reduced due to clogging of sand filters. 1974 Jul-Oct 1,000,000 1975 Jun-Oct 180,000 A floating fence was built to prevent algal dispersion 1976 Jun-Jul 1,200,000 1977 Jul-Aug 2,000,000 1978 Jul-Sep 130,000 1979 Jul-Oct 2,500,000 ---------------------------------------------------------------------------------------------------------------- * Surface water.(Compiled from the data of Kawasaki Municipal Waterworks Bureau)