Liyang reservior is located in the Liyang town

Ningbo City

Zhejiang province. Reservoir water is the sources of tap water to Liyang town residents

however

blue-green algae blooms happened twice at the spring and autumn during the year of 2002. The algae blooms produced toxic organic matters which influencing the quality of tap water. We surveyed the topography

the level of eutrophication and the course of algae blooms happening at November

2002 and February

2003. This paper presented a series of measures of controlling the processes of eutrophication and purifying reservoir water of (i) the concentrating treatment of living and livestock sewages

(ii) the buffering strips of mountainous region and woodlands

(iii) the engineering of constructed wetlands acting as the biological barrier at the relatively low area of reservoir

(iv) the buffering strips of reservior bank to prevent soil erosion from naked mud road around the reservior

(v) the engineering of cultivating the Immobilized Nitrogen Cycle Bacteria (INCB) and floating plants to ecology-floating-island in the reservior

and (vi) the physico-ecological engineering (PEEN) that is two filter enclosures and cultivated plant

fish and mollusk etc between the enclousure water at the outlet

in order to filter and reduce the algae output

guaranteeing the quality of tap water.