On Friday 2 December 2011, at 14:30, Frans Buschman will publically defend his PhD thesis, entitled "Flow and sediment transport in an Indonesian tidal network". The defence will take place in the Academiegebouw, Domplein 29, Utrecht
Research abstract
The Berau river, situated in east Kalimantan (Indonesia), discharges substantial amounts of water and sediment into the coastal zone. The nearby coral reef (see Figure below) hosts an extremely diverse, but sensitive ecosystem. Due to deforestation, the sediment loads in the Berau river are likely to increase, posing a possible threat for the coral reefs. The impact of an increased sediment load on the health of the coral reef system depends on the pathway of the sediment through the network of river channels (see Figure below). In his thesis, Frans Buschman focusses on the distribution of water and sediment through the Berau channel network.
A topographic map of the Berau region in Kalimantan, Indonesia. At Tanjung Redeb two rivers join to form the Berau river that splits close to Batu-Batu in an estuarine channel network.
The figure above shows how the Berau river splits into several interconnected channels as it approaches the sea. Since the largest areal of the coral reefs is situated close to the northern branch, the threat of increased sediment loads is largest when sediment is expelled at this channel mouth. Using both field measurements and numerical modelling, Buschman shows that the division of the flow through the channels depends on the tidal range. The pathway of sediment in particular is also affected by the flow circulation across the channels. Additionally, density differences between the channels have an effect on the distribution of both water and sediment.
With these insights into the physical processes governing the distribution of sediment through a tidal network, improved predictions of the impact of increased sediment loads on the coral reefs can be made.
Links
Order a printed copy or download the pdf of Frans Buschman's thesis "Flow and sediment transport in an Indonesian tidal network" here.
More info on Frans Buschman's research.
Item on Frans Buschman's defence on the website of the Faculty of Geosciences (in Dutch).