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Lake

Lakes and reservoirs are important resources for communities around the globe. They provide food, drinking and irrigation water and can also offer spots for recreation. Under certain conditions lakes can also represent a threat for local communities, such as flooding or limnic eruptions. The ecological state of shallow lakes may be hampered by suspended sediments due to wind driven currents and waves. In deep lakes, stratification can cause undesirable anoxic conditions in the deeper areas. Understanding these systems is crucial to enable a sound management of these water bodies.

 
Delft3D is the state-of-the-art modelling framework for hydrodynamics, water quality, ecology, waves and morphology.
 
Here, in this space, we share knowledge & experiences, and discuss issues related to modelling of lakes.

 

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Bathymetry for inland lakes above MSL

AK
Abusoma Kemal, modified 8 Years ago.

Bathymetry for inland lakes above MSL

Youngling Posts: 1 Join Date: 3/10/13 Recent Posts
The lake forum is empty so I want to ask this question here. I have downloaded two types of Lake Bathymetry data,

1) The first one is elevation above mean sea level, downloaded from http://maps.ngdc.noaa.gov/viewers/wcs-client/, all elevations are 200 m above MSL including the lake bottom.
2) I also have bathymetry in the form of depth, the lake bathymetries are negative depths referenced to local datum , the land topography near the lake are positive depth above the local datum.

My question is which data to use in Delft. In coastal modeling all bathymetry elevations below MSL have to be positive and the land topography above MSL have to be negative. 1) In my case all elevations are above MSL, so I can change all the elevations in # 1 above to negative and use in Delft? Is correct OR 2) Can I use the second data (# 2 above) as it is by changing the lake bathymetry to positive and by changing the land topography elevations to negative similar to coastal modeling?

I am asking this because these things are not explained the Delft3D Flow manual.

Abusoma

Thanks for your help
Richard Measures, modified 8 Years ago.

RE: Bathymetry for inland lakes above MSL (Answer)

Jedi Knight Posts: 178 Join Date: 3/23/11 Recent Posts
Hi Abusoma,

Either of the two approaches you outline should work i.e.

1) Specify all depths as negative (e.g. lake bed -190m, lake shore -200m, surrounding topography -210m)
2) Specify lake bathymetry as positive and surrounding topo as negative (e.g. lake bed = 10m, lake shore = 0m, surrounding = -10m)

Cheers,

Richard