Abstract:
The Maharagama urban area is a heavily populated area in Colombo district. Groundwater in this area is
having a great vulnerability for pollution by anthropogenic activities. The present study was carried out to
monitor some important water quality parameters, to evaluate the quality of groundwater in the study area
using a Water Quality Index (WQI) and to compare the water quality between Grama Niladari (GN) divisions
in the study area. Five GN divisions (Jambugasmulla, Gangodawila south B, Wijerama, Navinna and
Wattegedara) were selected for the study. 55 wells were sampled during the study. The resulted WQI values in
groundwater ranged from 17.08 to 280.91. The results revealed that the water quality of the wells deviate
from excellent to very poor quality. The nitrate concentration was high (>45mg/l) in some wells. Considering
all the water quality parameters, the poorest water quality was recorded in Navinna GN division. It was
observed that unregulated garbage dumping, uncontrolled application of organic and inorganic fertilizers,
constructing toilet pits very close to wells and unregulated human settlements have been increasing in the
study area.
