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. 
 

** PLEASE TAG YOUR POST! **

 

 

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

 

 

Message Boards

Validating WAVE model outputs to buoy

CL
Charlotte Lyddon, modified 1 Year ago.

Validating WAVE model outputs to buoy

Youngling Posts: 7 Join Date: 10/19/15 Recent Posts

Hello,

I am currently running online FLOW-WAVE simulations for a hypertidal estuary in 2D-horiztonal depth averaged mode. The model is forced from each end using tidal and river time series, space varying wave conditions along open sea boundary (using a .bcw file) and a space varying wind and pressure field. The model grid has been refined along the coastline for improved accuracy of wave height prediction. I am running simulations for 36 hours which covers a spring tide and a passing storm event. As an additional note, the model becomes unstable when triads and diffraction turned on in WAVE and exits, so my wave simulations do not include this. 

The tidal time series from FLOW validates well to 4 tide gauges along coastline. However I am currently having issues validating modelled significant wave height to 4 wave buoys in the estuary (the locations of which are shown in the attached image in the grid). As shown in the attached image, there is significant tidal modulation not present in the wave buoys. The magnitude of Hs at times seems correct, but the overall time series is not well matched.

Is it possible to limit tidal modulation in model, or are there any settings I might be missing which could help? I have tried changing Manning friction, JONSWAP friction, running WAVE without extending wind and water level from FLOW, but none of these make that much of a difference. I understand that bathymetry is hugely important, and the fact this is an estuary with a tidal range exceeding 10 m makes things complicated.

I'm just looking for some advice as what I could do next to improve the accuracy of my wave simulations in the estuary, or if I need any additional forcing data to help! Maybe someone here has had a similar issue and is able to offer some advice!

Best wishes
Charlotte