intro story Coast / Estuary

Coast / Estuary

Coastal systems are among the most dynamic physical systems on earth and are subject to a large variety of forces. The morphodynamic changes occurring to coastlines worldwide are of great interest and importance. These changes occur as a result of the erosion of sediments, its subsequent transport as bed load or suspended load, and eventual deposition. 
 
Estuaries are partly enclosed water bodies that have an open connection to the coast. Estuaries generally have one or more branching channels, intertidal mudflats and/or salt marshes. Intertidal areas are of high ecological importance and trap sediments (sands, silts, clays and organic matter).
Within the Delft3D modelling package a large variation of coastal and estuarine physical and chemical processes can be simulated. These include waves, tidal propagation, wind- or wave-induced water level setup, flow induced by salinity or temperature gradients, sand and mud transport, water quality and changing bathymetry (morphology). Delft3D can also be used operationally e.g. storm, surge and algal bloom forecasting. 
 
On this discussion page you can post questions, research discussions or just share your experience about modelling coastal and/or estuarine systems with Delft3D FM. 
 

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Sub groups
D-Flow Flexible Mesh
DELWAQ
Cohesive sediments & muddy systems

 

 

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RE: Newbie here

Chandan Das, modified 8 Years ago.

Newbie here

Youngling Posts: 2 Join Date: 9/28/11 Recent Posts
I am an student starting a thesis work in river morphology using RS imagery. Could you advice me of the procedure and references :I would be very grateful to any advice.
The ToR of the work is outlined below:

Recently important progress has been made in the prediction of the erosion during the next monsoon in braided rivers (EGIS, 2002)[1] based on the exploring studies carried out by Klaassen& Masselink (1992) and Klaassen et al (1993). Bank erosion along the main rivers of Bangladesh is nowadays routinely predicted on a yearly basis and these predictions are used for taking appropriate measures, either the construction of bank protection works or measures to reduce the damage (retiring levees, shifting important infrastructure like roads and irrigation canals, and to relocate the threatened population).. The methodology developed is presently also tested in Assam to predict year-to-year planform changes of the braided Brahmaputra River. For the Koshi River the methodology should concentrate on the prediction of the attack by channels on the banks and of planform changes.

For the development of such a methodology, first sufficient insight should be obtained in detailed morphological processes which cause or influence the bank erosion processes. Although probably these processes are active in every braided river and hence are generic, they need to be assessed for every river separately because rivers are different in terms of discharges, sediment loads, sediment calibre of bed and bank, and adjacent vegetation. These detailed morphological processes can be studied by analysing year-to-year changes of channel pattern and bank lines on the basis of satellite imagery. Low flow images are used to better identify changes and because low flow often coincides with cloud free conditions. The methodology is best suited for larger braided river because of the resolution of the satellite images to be used, which presently for low-prized imagery like Landsat is in the order of 20 m.

The study to be is to the production of mainly maps showing the yearly erosion and accretion of banks and bars for the period 1973 to 2011 and the analysis of detailed morphological processes like bank erosion rates, channel abandonment and bifurcation dynamics. The development of the methodology has to be done in a later stage. Hence the study consists of the selection and purchase of suitable satellite images in principle for every low flow season since 1972-1973 including 2010-2011 and as far as images are available, the processing of these images to identify the main channels, the production of yearly change maps, the identification and analysis of detailed morphological processes and the preparation and reproduction of a report.
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[1] Sarker, M.H. and Khayer, Yasmin, (2002), Developing and updating empirical methods for predicting morphological changes of the Jamuna River, EGIS (Environment and GIS Support Project for Water Sector Planning), EGIS Technical Note Series 29
Bert Jagers, modified 8 Years ago.

RE: Newbie here

Jedi Knight Posts: 201 Join Date: 12/22/10 Recent Posts
Hi Chandan,

I have to say, that is a very interesting topic; I worked on it myself for my PhD. My thesis on Modelling Planform Changes of Braided Rivers contains some more background information and references up to 2002. You may want to think carefully what you want to do within the time you have available. The description of work refers mostly to processing of satellite imagery; see section B.3 of my thesis for an algorithm that you could use, however, I started with images that had already been classified into channel, exposed sand, vegetated, and undefined. Since you ask this question on the Delft3D forum, you may want to do some Delft3D modeling for such a river as well. In that case you should get in touch with the group of Maarten Kleinhans at Utrecht University, who did some really nice simulations of braided rivers.

Bert
GW
Grant Wilson, modified 7 Days ago.

RE: Newbie here

Youngling Posts: 2 Join Date: 11/7/19 Recent Posts
Bert Jagers:

Hi Chandan,

I have to say, that is a very interesting topic; I worked on it myself for my PhD. My thesis on Modelling Planform Changes of Braided Rivers https://research.utwente.nl/en/publications/modelling-planform-changes-of-braided-rivers http://buyessays.cheap/ contains some more background information and references up to 2002. You may want to think carefully what you want to do within the time you have available. The description of work refers mostly to processing of satellite imagery; see section B.3 of my thesis for an algorithm that you could use, however, I started with images that had already been classified into channel, exposed sand, vegetated, and undefined. Since you ask this question on the Delft3D forum, you may want to do some Delft3D modeling for such a river as well. In that case you should get in touch with the group of Maarten Kleinhans at Utrecht University, who did some really nice simulations of braided rivers.
 
Bert

Hi Bert,

My topic is closely connected with the Numerical Modelling of Braided River Morphodynamics. So I was hoping to find the pdf materials for my thesis: to rely on the cited materials and official projects for using Sobek and Delft3D.
Sanjay Giri, modified 8 Years ago.

RE: Newbie here

Youngling Posts: 1 Join Date: 10/6/11 Recent Posts
Hi Chandan,

I had received your message through a connection at IHE as well. Hopefully this info would be of interest to you. In effect, the two master fellows from IHE together with us at Deltares have been engaged in the research activities on modeling braided rivers, namely looking at fundamental aspects of the effect of graded sediment and downstream fining as well as the effect of barrage and embankments on channel plan form and braided index in general. Whereas, in particular, these studies aim at the application of the Delft3D model for a number of case studies on the Koshi river, namely the effect of the barrage and embankments alignment on morphological processes, replicating the sediment transport through the breaches etc (2008 event). Besides, one master student from TU Delft (also working with us at Deltares) is going to finish his study on modeling Koshi river (from Chatara to barrage) later this month.
Meanwhile they are also involved in the literature review as well as data collection activities. So, it would be nice if we find some way to cooperate. Please get in touch if you find yourself willing to cooperate in sharing the knowledge and the information with us.

Best regards,
Sanjay