Abstract:
Many regions of Sri Lanka experience frequent droughts due to climate
change. The increasing demands for groundwater resources along with decreasing
availability in the dry zone of Sri Lanka emphasize the need for implementation of
sustainable groundwater management practices. This study is an approach to better
assess groundwater recharge potential zones using geospatial techniques and Multi
Influencing Factors (MIF). Since cascade systems can moderate the effects of extreme
weather events by capturing runoff and storing rainwater in numerous tanks, it is bet-
ter to assess the potential zones for groundwater recharge in these cascade systems.
Cascade systems in Malwathu Oya, Yan Oya and Ma Oya river basins within the
Anuradhapura district area were selected for the study. The geo-environmental varia-
tions such as geomorphology, geology, soil type, slope, lineament density, drainage
density, and land use layers were created as thematic layers and converted into raster
data. Based on the MIF and literature, weights were assigned to the relevant thematic
layers and overlay analysis was performed to create groundwater potential (GWP)
zones. These potential zones were categorized as ‘high’, ‘moderate’, and ‘low’ GWP
zones concerning the assigned weights. From the total area of selected cascades within
the Anuradhapura district, cascades in the Malwathu Oya basin showed a higher per-
centage of high (9.33%) and moderate (34.19%) potential zones. Further, when ana-
lysing the GWP zones separately for the selected three river basins within the Anura-
dhapura district area, Ma Oya basin showed a higher percentage of high (37.84%) and
moderate (55.95%) GWP zones. Yan Oya showed 30.11% of high and 47.51% mod-
erate GWP area and Malwathu Oya showed 16.21% of high and 59.37% of moderate
GWP zones area. Based on the study Ma Oya has the highest groundwater potential
zones compare to Yan Oya and Malwathu Oya within Anuradhapura District. These
results suggest that the high-potential zones will have a key role in future groundwater
management projects for sustainable management.
