Macro-invertebrates Composition Study for Water Quality Bio-monitoring in the Brantas River, Brantas River Basin, Indonesia

摘要

The Brantas River basin with itscatchment area of 11,800 km2 is one of the largest river systems in Indonesia.The basin is located in eastern part of Java Island,functiom as the most important source of water supply in East Java Province.In the Brantas River basin,water quality problem has caused a significant impact to the river ecosystem.In the lower reach of Brantas River located a Metropolitan City of Surabaya.The mw water supply for Surabaya City is provided mainly from Brantas River which the Dissolved Oxygen(DO) has dropped to very low level.This causes the standard of water quality for drinking water that produced by local municipal drinking water company often deteriorated.Macro-invertebrates are small animals that exist in streams,rivers,wetlands and lakes.The term macro-invertebrate describes those animals that have no backbone and can be seen with the naked eye.These animals live in the water for all or part of their lives,so their survival is related to the water quality.If there is a change in the water quality,perhaps cause by a pollutant entering the water,people activities along the river(for example sand mining) or a change in the flow downstream of a dam,then the macroinvertebrate community may also change.Therefore,the richness of macro-invertebrate community composition in a water body can be used to provide the information of water body health.The sampling was taken on December,19 to 22,2008,in five locations in the upper stream of Brantas River i.e.,Brantas Origin,Coban Talun,Punten Bridge,Gedhang Klutuk and Pendem Bridge.The activities followed in June,8 to 11,2009,in four locations in the upper of the Brantas River watershed i.e.,Coban Rondo (Konto River),Mount Kawi (Lekso River),Mount Kelud (Badak River) and Mount Arjuna——Welirang(Krecek River).According to the water quality classifications for the Hilsenhoff' s Biotic Index/BI(Hilsenhoff 1987),the Coban Rondo (Konto River) and Mount Kawi (Lekso River)was categorized as slight organic pollution; the Mount Kelud (Bladak River) and Mount Arjuna-Welirang (Krecek River) was categorized as slight organic pollution and some organic pollution; the Brantas Origin was categorized as some organic pollution and fairly substansial pollution.Coban Talun and Punten Bridge were categorized as fairly substansial pollution,and Gedang Klutuk was categorized as fairly substansial pollution and substansial pollution.Pendem Bridge was categorized as fairly substansial pollution and substansial pollution.