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
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  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
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* Surface water.(Compiled from the data of Kawasaki Municipal Waterworks Bureau)