Measurements of water circulation in mangrove swamps in Zanzibar

Field investigations of water circulation and flushing in Chwaka Bay, Zanzibar were carried out as part of a UNESCO/COMARAF training workshop on mangrove ecosystems and estuarine processes, held June 5-16 1989. Three sites M1 (tide pole site in the centre of Chwaka Bay), M2 (at the entrance to the mangrove creek) and X1 (in the mangrove creek)An echo-sounder measured depth along east-west transects in the bay and in the mangrove creek on the south-western side. Measurements were taken (using a mud probe) of longitudinal distribution of temperature, salinity and turbidity. A current meter which sampled at 5 min intervals was deployed for a day at sites M1 and M2. Tidal height was recorded 15 min intervals at M1 while surface temperature, salinity, dissolved oxygen concentration and nutrient concentrations were simultaneously recorded at M2.For use in the two-dimensional model, the Bay was divided into 32 cells adapted to the local bathymentry (depth measurements).
To train workshop participants in aspects of field techniques to investigate water circulation and flushing, and in data analysis.
For training purposes, the model was also applied to Tudor Creek, Mombasa, Kenya (but no field data are available for this).