Abstract:
The Kivu Lake level is subjected to high fluctuations during the recent years.
The aim of this research was to identify the causes for the fluctuations in Lake
Level. SWAT model was used to generate water balance components of Lake
catchment.
The results, using the reference period 1976 to 1990, indicate that the mean
annual rainfall over the lake is 1266 mm and the mean annual evaporation from
the lake is 583 mm. When compared with lake level changes, there is imbalance
of 21 %. Adding this amount to the calculated evaporation, it was possible to
reconstruct the inflow variation into the Lake from 1976 to 1990 and the water
balance of the lake. Sensitivity analysis shows that the discrepancy in the
balance is most likely due to water abstraction from the lake as some of water is
used for domestic supply around the lake and minor abstracts In this research, the water balance of Lake Kivu is carried out using the SWAT
rainfall runoff model. The inflow from the catchment into the lake has been
generated using SWAT model. Evaporation is estimated using Penman formula.
Rainfall over the lake is estimated from the catchment rainfall employing the two
classes 'A' gauging stations around the lake as weather generating stations to fill
the gaps in the other rain stations.
Finally the main cause for high Lake level fluctuation is found to be the rainfall
variability analyzed with hydrological components in their variability trends
especially in the second rainy season in October, November and December ,
