Abstract:
This study primarily aimed to identify suitable locations for well establishment
in the Kolugala Pahalgama Grama Niladhari Division (GND) with the utilization
of Geographic Information Systems (GIS) and Satti’s Analysis Hierarchy. The
main problem addressed was the decline in well water yield. This research
involved the collection of primary data on sample well locations, garbage pits,
and quarter water levels, and integrated various thematic layers including
geology, elevation, slope, drainage density, soil type, and land use to pinpoint
groundwater potential zones. Additionally, weights were assigned to these factors
using Satti's Analytic Hierarchy Process. The findings of the study revealed that
the GND had 9.64% very good, 42.17% good, 39.76% moderate, and 7.23% poor
groundwater potential zones. Among the examined wells, 6% were categorized
as very good, 56% as good, and 38% as moderate in terms of groundwater
potential. The average annual water levels in these zones varied, with very good
zones having an average depth of 12 feet 6 inches, good zones at 8 feet 5 inches,
and moderate zones at 7 feet 4 inches. It is noteworthy that 34% of the wells were
situated in suitable regions, while 66% were in unsuitable areas. Eighteen wells
had notably lower water levels than others due to their proximity to certain
limiting factors. Furthermore, the study identified 29 hectares as unsuitable zones
and 54 hectares as suitable zones for the establishment of wells. The ultimate
conclusion of the research emphasized that slope angle played a significant role
in defining groundwater potential zones geographically.
