assessment of stream water quality in tropical grassland using water quality index

water quality is a serious issue in tropical grasslands that must be addressed to ensure the continuity and sustainability of water resources. this study aimed to assess the stream water quality of tropical grassland under long-term moderate (2.7 animal unit ha-1 y-1 for 34 years) and short-term heavy (5 animal unit ha-1 y-1 for 2 years) grazing systems at catchment and farm scales in kuala lumpur, malaysia. water samples were collected in the streams of both grazed and ungrazed grasslands monthly throughout the year. samples were analyzed forph, ec, do, nh3-n, cod, tss, bod5, fecal coliform (fc) and e. coli. harkins’ index was used to classify stream water quality status. mean values of nh3 and fc were similar amongst the streams in both catchment and farm (p>0.05). mean values of tss, cod, bod and ph of streams in grazed grassland were higher than those in streams of ungrazed grassland in both catchment and farm (p0.05). water quality of the streams in grazed grassland wasclassified as class ii, however, the streams in ungrazed grassland had water quality of class i in the catchment. water quality was not affected by short-term heavy grazing in farm scale. the negative impact of grazing on water quality was prominent in long-term moderately grazed grasslands than short-term heavily grazed grassland.