Abstract:
Gradual increase of areal extent of saline water with sea level rise in coastal region
may cause a serious alarming situation for agriculture. Salinity affects crops
depending on degree of salinity at the critical stages of growth, which reduces yield
and in severe cases the total yield is lost. In this study, historic high tidal water level
data in the study area shows a rising trend which indicates the increase of areal extent
of tidal inundation in future. In addition, concentration of salinity shows an
increasing trend over the years in the area. So there is a possibility of having
consequence of increasing saline water concentration as well as areal extent of saline
water with different levels in future. In this connection, the present study shows, the
agricultural land use risk from salinity perspective due to sea level rise from 2015 to
2030 in Dhalua Union under Barguna Sadar Upazila. The study findings also show
that, all water level stations are observing a rising trend which also influences on
high tidal inundation extents in different years. Inundation extent will become more
than doubled estimated to 9.64 sq. km to 20.58 sq.km from the year 2015 to 2030. In
2015, about 38% of total agricultural land will be inundated by peak high tidal
inundation which will be also more than doubled in 2030. There is an inverse
relationship exist between high tidal water level and salinity (Ec) level. Peak high
tidal inundation with sea level rise induced salinity concentration will be decreased in
future. The Dhalua union occupies a total 25.16 sq. km of agricultural land of which,
in 2015, 17.52 %, 12.67 %, and 8.50 % agricultural land will be under moderate,
high and very high risk categories respectively. In 2020, about 0.299 sq.km of
agricultural land will be under low risk of salinity (441 – 680) which is absent for
2015 and on the other hand, no agricultural land will be found under very risk of
salinity. Moderate risk of salinity area will be significantly increased amounted to
47.45 % of total agricultural land in 2020. In 2025, 75.31 % of total agricultural land
will be under low risk of salinity. Almost 95 % of the inundated crop area will be
exposed by very low risk of salinity and remaining will be under low risk of salinity
in 2030.
