TITLE:
The Influence of Weather and Climate Variability on Groundwater Quality in Zanzibar
AUTHORS:
Leluu Ramadhan Mohammed, Kombo Hamad Kai, Agnes Laurence Kijazi, Said Suleiman Bakar, Sara Abdalla Khamis
KEYWORDS:
Quality of Groundwater Parameters, Climate Variability, Mean Changes of Climate and Water Quality Parameters
JOURNAL NAME:
Atmospheric and Climate Sciences,
Vol.12 No.4,
August
26,
2022
ABSTRACT: Climate change and variability have been inducing a
broad spectrum of impacts on the environment and natural resources including groundwater resources.
The study aimed at assessing the influence of weather, climate variability, and changes on the quality
of groundwater resources in Zanzibar. The study used the climate datasets
including rainfall (RF), Maximum and Minimum Temperature (Tmax and Tmin), the records acquired from
Tanzania Meteorological Authority (TMA)
Zanzibar office for 30 (1989-2019) and 10 (2010-2019) years periods. Also, the Zanzibar Water Authority
(ZAWA) monthly records of Total Dissolved Solids (TDS), Electrical Conductivity
(EC), and Ground Water Temperature (GWT) were used. Interpolation techniques
were used for controlling outliers and missing datasets. Indeed, correlation,
trend, and time
series analyses were
used to show the relationship between climate and water quality parameters.
However, simple statistical analyses including mean, percentage changes, and contributions to the annual and
seasonal mean were calculated. Moreover, t and paired t-tests were used to show
the significant changes in the mean of the variables for two defined periods of
2011-2015 and 2016-2020 at p ≤ 0.05. Results revealed that seasonal variability
of groundwater quality from March to May (MAM) has shown a
significant change in trends ranging from 0.1 to 2.8 mm/L/yr, 0.1 to 2.8
μS/cm/yr, and 0.1 to 2.0℃/yr for TDS, EC, and GWT, respectively. The changes in climate
parameters were 0.1 to 2.4 mm/yr, 0.2 to 1.3℃/yr and 0.1 to 2.5℃/yr in RF, Tmax,
and Tmin, respectively. From October to December (OND) changes in groundwater parameters ranged from
0.2 to 2.5 mm/L/yr 0.1 to 2.9 μS/cm/yr, and 0.1 to 2.1℃/yr for TDS, EC, and GWT, whereas RF, Tmax, and Tmin changed
from 0.3 to 1.8 mm/yr, 0.2 to 1.9℃/yr and 0.2 to 2.0℃/yr, respectively. Moreover,
the study has shown strong correlations between climate and water quality parameters
in MAM and OND. Besides, the paired correlation has shown significant changes in all parameters except
the rainfall. Conclusively, the
study has shown a strong influence of climate variability on the quality of groundwater in Zanzibar, and calls
for more studies to extrapolate these results throughout Tanzania.