Urban Flood Modelling in Dhaka

In the latest module at UNESCO-IHE, we have been given a selection between Urban Flood Modelling and River Basin Modelling. The splitting of our course has given us the opportunity to delve deeper into the aspects of flooding that most interest us and I believe all on the course can agree that the opportunity to select a course preference has been greatly rewarding.

Flood Hazard Map
by Siobhan Gleeson

Those on the FRM course who chose the Urban Flooding route have spent a considerable time creating (surprisingly) sophisticated models of Bangladeshi floods in the city of Dhaka. The main project that we have worked on in the course's three week duration, has been the creation of a 1D-2D coupled model. This has involved taking a 1D model of an urban drainage network (created on DHI's MOUSE software) and coupling (or, in less technical terms, 'linking') it to a 2D model, representing the surface topology (using MIKE 21). The surface model was created on a highly fine resolution (2.5m) and, accordingly, is able to accurately include road recesses, and micro-topology features, such as alleyways, in addition to accurately recording buildings. With such high resolution data, the models are very accurate in their representation of reality.

After the models were ran, complex flood risk maps were created on ARC GIS and analysed (as picured). This is a process that is a key component of the EU Flood Directive's recommendations, with all EU nations agreeing to have created extensive flood risk maps by September 2013. Accordingly, the work we are doing is extremely pertinent to the flooding sector upon our graduation and is likely to be relevenent to the working world upon our graduation.

As part of these models we were also able to plot the flood event in 3D through the streets of Dhaka. The below video displays the maximum water depth for the model with both buildings and on a bare-earth model. The building model is useful to demonstrate the height of water that will impact buildings, and the maximum wave heights can be seen by the blue 'splashes' on the sides of some buildings. The bare-earth model is of use to determine which buildings will be affected by the flood event, without the disruptances of flow that buildings provide - accordingly, this is the model that we use to create our flood risk maps.


Hope you enjoyed the video. And hope you equally enjoyed its Daft Punk soundtrack.

by Richard Vause

An international fieldtrip to Florida

As part of the Erasmus Mundus Flood Risk Management course, each student is fortunate enough to be provided with a monthly scholarship, from which a proportion is automatically taken each month to contribute towards the enticingly mysterious "international fieldtrip". In Dresden, as the course commenced, the vague information fuelled much speculation about the destination for the trip - 'Asia' was mentioned, many had their hearts set on Bangladesh, whilst other were hoping for somewhere Latin American. Ultimately, I think we were all agreed on hoping that the trip wasn't to the local river at the bottom of out street in our home country!

In early 2012, the mystery was answered and our location was announced: 17 days in Florida with the rest of the Hydroinformatics group from UNESCO-IHE. A collective sigh of relief was sighed with no American students in the group and much excitement quickly ensued.

The fieldtrip is part of an existing exchange and partnership between UNESCO-IHE and a number of organisations in Florida; namely the US Geological Survey and the Florida Earth Foundation, with contributions from the University of South Florida, South Florida Water Management District and the Department of the Interior.

The fieldtrip will take place from the 23rd May until the 7th June and is now rapidly approaching. With our visas applied for from the US consulate in Amsterdam, hotel rooms booked and base-tans being sought in anything that resembles sunlight, the group are raring to go now!

An initial draft for our schedule when we are in Florida can be seen here, containing a vast number of activities and lectures at an equally vast variety of locations. We will be closing our trip by attending the 9th Intecol International Wetlands Conference in Orlando, where the group have been bestowed the responsibilities of water ambassadors. We are greatly honoured by this privilege and look forward to making the most of the opportunity presented to us. As students, we are available for sponsorship, as water ambassadors, by firms from here - organisations have been welcomed to provide sponsorship to help continue the exchange program long into the future and all interested are advised to view the previous link.

But, for now, there are 18 excited students in Delft, researching sunglasses, sandals and swimsuits.

by Richard Vause