Here you can find the latest updates from the Delta Alliance network, Delta Alliance newsletters, and news items on deltas and climate change. Items older than two months are stored in the Archive section:
JCP Bangladesh-The Netherlands, newsletter April 2020 This newsletter of the Joint Cooperation Programme Bangladesh–The Netherlands is about the Corona virus, the annual meeting & field visit, the Plenary session in ICSD4, progress in 2019, the Bangladesh Meta Model, DWKD2019, the successful H@CKATHON and makes a closure with relevant upcoming events.
Joint Cooperation Programme Bangladesh–The Netherlands, Thursday 9 April 2020
Collective learning by Delta Alliance Wings The Delta Alliance advocates peer learning, referred to as Delta2Delta learning. In the period 18-20 November 2019, a Delta2Delta learning process has been organized between Bangladesh and Egypt. What are the lessons learned? What are conditions for effective Delta2Delta learning?
Delta Alliance Secretary, Monday 30 March 2020
Geophysical Research Letters publication: 'Scale‐Dependent Evanescence of River Dunes During Discharge Extremes' Abstract: During high river discharge extremes, the growth of dunes can reach a maximum beyond which a transition to upper stage plane bed may occur, enhancing the river's conveyance capacity and reducing flood risk. Our predictive ability of this bedform regime shift in rivers is exclusively built upon high Froude number flows dominated by asymmetric dunes with steep downstream‐facing slipfaces that are rare in natural rivers. By using light‐weight polystyrene particles as a substrate in an experimental flume setting, we present striking dune morphodynamic similarity between shallow laboratory flow conditions and deep rivers, preconditioned that both flow and sediment transport parameters are accurately scaled. Our experimental results reveal the first observation of upper stage plane bed in a shallow laboratory flume that is reached for a Froude number well below unity. This work highlights the need to rethink widely used dune scaling relationships, bedform stability diagrams, predictions of flow resistance, and flood risk.
S. Naqshband & A.J.F. Hoitink, in Geophysical Research Letters, Friday 6 March 2020