This made it possible to see how sediment velocity varied with depth, determine the direction of tidal currents and magnitude, and measure the salinity at different points of the estuary.Īnswering the third question required the ability to analyze the dispersion of the suspended particulate matter as detected by satellites. To gather data for the model he deployed a current meter which allowed him to create an acoustic Doppler current profile. Each trap was set out in such a way that it could pick up suspended particulate matter in a pattern covering the southern, central, and northern areas of the estuary.Īnswering the second question required both fieldwork and the development of a hydrodynamic model, using a brand of software called MIKE 21. Each month he faced the difficulty of locating these traps, retrieving their samples, and taking the samples to the lab to quantify the amounts of sediment.
These activities are important to Tanzania because they inevitably expose the soil to erosion, and this erosion in turn affects the downstream fisheries, navigation, and other uses of the large estuary.Īnswering the first question, said Pamba, has been a matter of “pure field work.” Major tasks were to design sediment traps and deploy them around the Pangani estuary. All of these questions are relevant in setting policy to control runoff from agriculture, industry, forestry, and other activities. In this ambitious project, he faced at the outset difficult unknowns: (1) where in the Pangani estuary did suspended particulate matter “prefer” to be deposited, and at what rate (2) how much did tidal current, salinity, river discharge, and monsoon winds affect the deposition of matter and (3) to what extent can satellites be used to map the dispersion of suspended matter. His particular focus has been the Pangani River and its estuary. His specialty, as he describes it, is “non-living things” - the transport and dispersal of suspended particulate matter in Tanzanian estuaries.
Siajali Pamba has been a lecturer and researcher at the University of Dar es Salaam since he earned his PhD there in 2015 through WIO-RISE. A Specialty of ‘Non-Living Things’ (WIO-RISE)